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Three Dimensional Kinematics of Local Luminous Compact Blue Galaxies

Permanent Link: http://ufdc.ufl.edu/UFE0024381/00001

Material Information

Title: Three Dimensional Kinematics of Local Luminous Compact Blue Galaxies
Physical Description: 1 online resource (161 p.)
Language: english
Creator: Perez-Gallego, Jorge
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: blue, compact, evolution, formation, galaxies, luminous, mass, quenching, starburst, triggering
Astronomy -- Dissertations, Academic -- UF
Genre: Astronomy thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: In the local universe, galaxies fall into one of two populations: a star-forming 'blue cloud' and a 'red sequence' lacking star formation. At z~1.5, however, the red sequence has yet to develop. Over the past 9 Gyr some process has quenched the enhanced star formation in blue galaxies, and caused them to evolve onto the 'red sequence' by fading and/or merging of their stellar populations. While such a transformation may be occurring across the full range of masses, the highest rate of evolution occurs in massive starbursts at the luminous end of the blue cloud. These galaxies are the Luminous Compact Blue Galaxies (LCBGs). We use three dimensional (3D) optical spectroscopy observations of a representative sample of 22 local LCBGs to address the following three fundamental questions through the study of their kinematics: (i) what processes are triggering the current starbust in LCBGs? We use velocity maps to search for signatures of recent minor/major mergers/interactions that may be the trigger for the current enhanced star formation found in our sample. In addition, we look for nearby companions that could be interacting with these LCBGs. We find 5% of objects show evidence of a major merger and 10% of objects to show evidence of a minor merger. On the other hand, 45% of objects have a companion. This argues in favor of a companion as responsible for the enhanced star formation in these galaxies. (ii) what processes are quenching the current starbust in LCBGs? Velocity and velocity width maps, together with emission-line ratio maps, may reveal signatures of Active Galactic Nuclei (AGN) activity or supernova (SN) driven galactic winds that could halt the current burst. We find 95% of objects with no evidence of AGN activity, and 5% of objects with clear evidence of AGN activity. On the other hand we find 27% of objects with spectrally resolved kinematic components in agreement with SN-driven galactic winds. This argues in favor of of these mechanisms not being typical in LCBGs. (iii) What can the study of local LCBGs tell us about the distant population of LCBGs? We provide velocity and velocity width maps of a representative sample of LCBGs that allow us to classify the kinematics of these galaxies between three different classes: Rotating Disks (RDs), Perturbed Rotation (PRs), and Complex Kinematics (CK). We find 48% of RDs, 28% of PRs, and 24% of CKs. We find for RDs rotational velocities that range between ~50 and ~200 km/s and dynamical masses that range between ~1x10^9 and ~3x10^10 solar masses. We find velocity widths of RDs, rather than accounting exclusively for the rotation nature of these objects, may account as well for other kinematic components, and may not be good tracers of their dynamical masses. We, therefore, need to be careful with dynamical mass estimates from integrated properties of distant LCBGs. Finally, we use 3D spectroscopy data of local LCBGs to simulate observations of distant LCBGs. These simulations may help in the correct interpretation and discussion of results linked to current and future observations of distant LCBGs, and compensate for any possible biases introduced by the intrinsic limitations of distant surveys.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Jorge Perez-Gallego.
Thesis: Thesis (Ph.D.)--University of Florida, 2009.
Local: Adviser: Guzman, Rafael L.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-05-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0024381:00001

Permanent Link: http://ufdc.ufl.edu/UFE0024381/00001

Material Information

Title: Three Dimensional Kinematics of Local Luminous Compact Blue Galaxies
Physical Description: 1 online resource (161 p.)
Language: english
Creator: Perez-Gallego, Jorge
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: blue, compact, evolution, formation, galaxies, luminous, mass, quenching, starburst, triggering
Astronomy -- Dissertations, Academic -- UF
Genre: Astronomy thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: In the local universe, galaxies fall into one of two populations: a star-forming 'blue cloud' and a 'red sequence' lacking star formation. At z~1.5, however, the red sequence has yet to develop. Over the past 9 Gyr some process has quenched the enhanced star formation in blue galaxies, and caused them to evolve onto the 'red sequence' by fading and/or merging of their stellar populations. While such a transformation may be occurring across the full range of masses, the highest rate of evolution occurs in massive starbursts at the luminous end of the blue cloud. These galaxies are the Luminous Compact Blue Galaxies (LCBGs). We use three dimensional (3D) optical spectroscopy observations of a representative sample of 22 local LCBGs to address the following three fundamental questions through the study of their kinematics: (i) what processes are triggering the current starbust in LCBGs? We use velocity maps to search for signatures of recent minor/major mergers/interactions that may be the trigger for the current enhanced star formation found in our sample. In addition, we look for nearby companions that could be interacting with these LCBGs. We find 5% of objects show evidence of a major merger and 10% of objects to show evidence of a minor merger. On the other hand, 45% of objects have a companion. This argues in favor of a companion as responsible for the enhanced star formation in these galaxies. (ii) what processes are quenching the current starbust in LCBGs? Velocity and velocity width maps, together with emission-line ratio maps, may reveal signatures of Active Galactic Nuclei (AGN) activity or supernova (SN) driven galactic winds that could halt the current burst. We find 95% of objects with no evidence of AGN activity, and 5% of objects with clear evidence of AGN activity. On the other hand we find 27% of objects with spectrally resolved kinematic components in agreement with SN-driven galactic winds. This argues in favor of of these mechanisms not being typical in LCBGs. (iii) What can the study of local LCBGs tell us about the distant population of LCBGs? We provide velocity and velocity width maps of a representative sample of LCBGs that allow us to classify the kinematics of these galaxies between three different classes: Rotating Disks (RDs), Perturbed Rotation (PRs), and Complex Kinematics (CK). We find 48% of RDs, 28% of PRs, and 24% of CKs. We find for RDs rotational velocities that range between ~50 and ~200 km/s and dynamical masses that range between ~1x10^9 and ~3x10^10 solar masses. We find velocity widths of RDs, rather than accounting exclusively for the rotation nature of these objects, may account as well for other kinematic components, and may not be good tracers of their dynamical masses. We, therefore, need to be careful with dynamical mass estimates from integrated properties of distant LCBGs. Finally, we use 3D spectroscopy data of local LCBGs to simulate observations of distant LCBGs. These simulations may help in the correct interpretation and discussion of results linked to current and future observations of distant LCBGs, and compensate for any possible biases introduced by the intrinsic limitations of distant surveys.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Jorge Perez-Gallego.
Thesis: Thesis (Ph.D.)--University of Florida, 2009.
Local: Adviser: Guzman, Rafael L.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-05-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0024381:00001


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Andthen,onemorning,afteraquietnight'ssleep,yourealizetherearejusttwokindsoftravelers.Therearethosewhodepart,andtherearethosewhoreturn.Theformerwanderaroundmaps,thelatterlookforthemselvesinthemirror.Andthen,onemorning,afteraquietnight'ssleep,yourealizelifeisajourney.Andyouneedtogureout,whatisthatyouhaveinfrontofyoureyes.Mirrorsormaps?Andthen,onemorning,afteraquietnight'ssleep,youletgoonetear,anddrawabittersweetsmile.Andthen,onemorning,afteraquietnight'ssleep,youwakeup.Istheresomeonethere?You~were,andIthankyouforthat. 4

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page ACKNOWLEDGMENTS ................................. 4 LISTOFTABLES ..................................... 9 LISTOFFIGURES .................................... 10 ABSTRACT ........................................ 13 CHAPTER 1INTRODUCTION .................................. 15 1.1LuminousCompactBlueGalaxiesintheDistantUniverse ......... 15 1.2LuminousCompactBlueGalaxiesintheLocalUniverse .......... 21 1.2.1WhatIstheMechanismResponsibleforTriggeringtheBurstofStarFormation? ................................ 22 1.2.2WhatIstheMechanismResponsibleforQuenchingtheStarFormationandLimitingtheStellarMass? ..................... 24 1.2.3WhatCantheStudyoftheLocalPopulationofLCBGsTellUsAbouttheDistantPopulationofLCBGs? ............... 25 2SAMPLESELECTION,OBSERVATIONS,ANDDATAREDUCTION ..... 28 2.1SampleSelection ................................ 28 2.2Observations .................................. 35 2.3DataReduction ................................. 37 2.4BasicMeasurements .............................. 44 3ATLASOFLOCALLUMINOUSCOMPACTBLUEGALAXIES ........ 49 3.1StatisticalProperties .............................. 49 3.2Atlas ....................................... 64 4PROTOTYPICALLUMINOUSCOMPACTBLUEGALAXIES ......... 87 4.1SampleSelection ................................ 87 4.2NGC7673 .................................... 87 4.2.1VelocityMap .............................. 88 4.2.2NeutralHydrogenGas ......................... 91 4.2.3VelocityWidthMap .......................... 94 4.2.4Discussion ................................ 96 4.2.4.1MinorMergerScenario .................... 96 4.2.4.2Mass .............................. 100 4.3NGC7714 .................................... 102 4.3.1VelocityMap .............................. 104 4.3.2VelocityWidthMap .......................... 107 7

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................................ 108 4.4NGC6052 .................................... 109 4.4.1VelocityMap .............................. 112 4.4.2VelocityWidthMap .......................... 114 4.4.3Discussion ................................ 114 4.5NGC469 .................................... 118 4.5.1VelocityMap .............................. 119 4.5.2VelocityWidthMap .......................... 120 4.5.3Discussion ................................ 120 5LUMINOUSCOMPACTBLUEGALAXIESATHIGHREDSHIFT ....... 124 5.1DistantLCBGs ................................. 124 5.2Simulations ................................... 126 5.3DistanceIndicators ............................... 133 5.3.1SelectionoftheDataSample ...................... 135 5.3.2Results .................................. 139 5.3.3Discussion ................................ 141 6CONCLUSIONS ................................... 145 REFERENCES ....................................... 150 BIOGRAPHICALSKETCH ................................ 160 8

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Table page 2-1SampleProperties .................................. 34 2-2ObservingLog .................................... 38 2-3ObservationalStrategy ................................ 40 3-1KinematicsandMorphology ............................. 52 3-2KinematicComponents ................................ 58 4-1NGC7673ObservationalProperties ......................... 88 4-2NGC7673ObservingLog .............................. 89 4-3NGC7714ObservationalProperties ......................... 104 4-4NGC7714ObservingLog .............................. 104 4-5NGC6052ObservationalProperties ......................... 111 4-6NGC6052ObservingLog .............................. 111 4-7NGC469ObservationalProperties ......................... 119 4-8NGC469ObservingLog ............................... 119 5-1SelectedStarburstGalaxieswiththeirPropertiesandDistanceModuli ..... 137 9

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Figure page 2-1LocalDistributionofLCBGs ............................ 30 2-2SloanDigitalSkySurvey(SDSS)Imagesof12LCBGs .............. 31 2-3SDSSSpectraof12LCBGs ............................. 32 2-4MBvs.SBe(B)andMBvs.BV 35 2-5PPAKInstrumentLayout .............................. 36 2-6ExampleofPPAKRawSpectra ........................... 39 2-7ExampleofPPAKReducedSpectra ......................... 41 2-8ExamplesofPPAKExtractedSpectra ....................... 45 2-9ExamplesofSingleandDoubleGaussianProleFits ............... 47 3-1Tully-FisherRelation ................................. 54 3-2RotationCurvesofSixLCBGs ........................... 55 3-3RotationCurvesofFourLCBGs ........................... 56 3-4ThreeSpectralComponentsonUCM0000 ..................... 61 3-5ActiveGalacticNucleiDiagnosticDiagram ..................... 62 3-6NGC7673 ....................................... 66 3-7NGC7714 ....................................... 67 3-8NGC6052 ....................................... 68 3-9NGC469 ....................................... 69 3-10UCM0000 ....................................... 70 3-11UCM0156 ....................................... 71 3-12UCM1428 ....................................... 72 3-13UCM1431 ....................................... 73 3-14UCM1648 ....................................... 74 3-15UCM2250 ....................................... 75 3-16UCM2258 ....................................... 76 10

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....................................... 77 3-18UCM2327 ....................................... 78 3-19SDSS1134 ....................................... 79 3-20SDSS1507 ....................................... 80 3-21SDSS1605 ....................................... 81 3-22SDSS1652 ....................................... 82 3-23SDSS1703a ...................................... 83 3-24SDSS1703b ...................................... 84 3-25SDSS1710 ....................................... 85 3-26SDSS2327 ....................................... 86 4-1WFPC2ImageofNGC7673 ............................. 89 4-2PPAKVelocityMapofNGC7673andPPAKVelocityMapContoursOverlaidontheWFPC2ImageofNGC7673 ......................... 92 4-3RotationCurveofNGC7673 ............................ 93 4-4PPAKVelocityMapContoursOverlaidontheDENSEPAKVelocityMapofNGC7673 ....................................... 94 4-5PPAKVelocityMapContoursOverlaidontheVLAVelocityMapofNGC7673 95 4-6PPAKVelocityWidthMapofNGC7673andPPAKVelocityWidthMapContoursOverlaidontheF555WWFPC2ImageofNGC7673 ............... 96 4-7PPAKVelocityMapContoursOverlaidonthethePPAKVelocityWidthMapofNGC7673 ..................................... 97 4-812+log(O/H)vs.MB 100 4-9LHvs. 101 4-10F814WWFPC2ImageofNGC7714 ........................ 103 4-11PPAKVelocityMapofNGC7714andPPAKVelocityMapContoursOverlaidontheDSSImageofNGC7714 ........................... 105 4-12RotationCurveofNGC7714 ............................ 106 4-13PPAKVelocityWidthMapofNGC7714andPPAKVelocityWidthMapContoursOverlaidontheDSSImageofNGC7714 ...................... 107 11

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..................................... 108 4-15WFPC2ImageofNGC6052 ............................. 110 4-16PPAKVelocityMapofNGC6052andPPAKVelocityMapContoursOverlaidontheWFPC2ImageofNGC6052 ......................... 112 4-17RotationCurveofNGC6052 ............................ 113 4-18PPAKVelocityWidthMapofNGC6052andPPAKVelocityWidthMapContoursOverlaidontheF555WWFPC2ImageofNGC6052 ............... 114 4-19PPAKVelocityMapContoursOverlaidonthethePPAKVelocityWidthMapofNGC6052 ..................................... 115 4-20NGC6052KinematicComponents ......................... 116 4-21SDSScontoursoverlaidonHIintensityofNGC6052 ............... 117 4-22SDSSImageofNGC469 ............................... 118 4-23PPAKVelocityMapofNGC469andPPAKVelocityMapContoursOverlaidontheSDSSImageofNGC469 ........................... 120 4-24PPAKVelocityWidthMapofNGC469andPPAKVelocityWidthMapContoursOverlaidontheSDSSImageofNGC469 ...................... 121 4-25PPAKVelocityMapContoursOverlaidonthethePPAKVelocityWidthMapofNGC469 ...................................... 122 5-1SimulationsofStarFormationRate,andVelocityMaps .............. 128 5-2SimulatedObservationsofaPrototypicalLyman-breakGalaxy .......... 130 5-3SimulationsofSFR,Velocity,Extinction,andMetallicityMaps ......... 131 5-4SimulationsofanIntegratedSpectrum ....................... 133 5-5DMvs.zforVariousCosmologicalModels .................... 138 5-61-Constraintsinmvs.ParameterSpace .................. 140 5-7logMzvs.logLHforLCBGsatDierentEpochs ................. 142 12

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Inthelocaluniverse,galaxiesfallintooneoftwopopulations:astar-forming\bluecloud"anda\redsequence"lackingstarformation.Atz1:5,however,theredsequencehasyettodevelop.Overthepast9Gyrsomeprocesshasquenchedtheenhancedstarformationinbluegalaxies,andcausedthemtoevolveontothe\redsequence"byfadingand/ormergingoftheirstellarpopulations.Whilesuchatransformationmaybeoccurringacrossthefullrangeofmasses,thehighestrateofevolutionoccursinmassivestarburstsattheluminousendofthebluecloud.ThesegalaxiesaretheLuminousCompactBlueGalaxies(LCBGs).Weusethreedimensional(3D)opticalspectroscopyobservationsofarepresentativesampleof22localLCBGstoaddressthefollowingthreefundamentalquestionsthroughthestudyoftheirkinematics:(i)whatprocessesaretriggeringthecurrentstarbustinLCBGs?Weusevelocitymapstosearchforsignaturesofrecentminor/majormergers/interactionsthatmaybethetriggerforthecurrentenhancedstarformationfoundinoursample.Inaddition,welookfornearbycompanionsthatcouldbeinteractingwiththeseLCBGs.Wend5%ofobjectsshowevidenceofamajormergerand10%ofobjectstoshowevidenceofaminormerger.Ontheotherhand,45%ofobjectshaveacompanion.Thisarguesinfavorofacompanionasresponsiblefortheenhancedstarformationinthesegalaxies.(ii)whatprocessesarequenchingthecurrentstarbustinLCBGs?Velocityandvelocitywidthmaps,togetherwithemission-lineratiomaps,mayrevealsignaturesofActiveGalacticNuclei(AGN)activityorsupernova(SN) 13

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Nearbygalaxies,accordingtotheircolorsandabsolutemagnitudes,andtheirpositionincolor-magnitudediagrams(CMDs; Blantonetal. 2003 )fallintotwocategories:(i)thosebelongingtothe\redsequence,"typicallybrighterandredder;and(ii)thosebelongingtothe\bluecloud,"bluer.Whilethe\bluecloud"extendsalongawiderangeofluminositiesandcolors,the\redsequence"extendsalongawiderangeofluminosities,andanarrowrangeofreddercolors.Aninterestingrecentndingisthatinthenearbyuniversethisbi-modalityisnotonlyseeninCMDs,butalsoinotherdiagramssuchasthefollowing:(i)thegalaxyluminosityfunctions(LFs; Baldryetal. 2004 ; Belletal. 2003 );(ii)thegalaxystellarmassfunctions( Baldryetal. 2004 ; Baloghetal. 2004 ; Hoggetal. 2004 );(iii)thestarformationrates(SFRs; Kaumannetal. 2003 );(iv)thestellarpopulationages( Kaumannetal. 2003 );(v)thegas-to-stellarmassratio( Kannappan 2004 );and(vi)thegalaxyenvironment( Blantonetal. 2006 ). Furthermore,thesamecolorbi-modalityhasbeenobserveduptoz1( Belletal. 2004 ).CMDmorphologiesareratherconstantoverthelast9Gyr,whichsuggeststhat 15

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Thefractionofgalaxiesinthe\redsequence"decreaseswithredshift,uptothepointofbeingnegligiblebyz1:5( Driveretal. 1998 ; Belletal. 2004 ; Faberetal. 2007 ).Thisbehaviorcanbeseenintheevolutionoftheopticalandtheinfrared(IR)LFsofthe\redsequence"galaxieswithtime.ThenumberdensityofredL?galaxieshasgrownbyafactorof10inthelast9Gyr.ThisgrowthimpliesthatthosegalaxiesthatmergedandevolvedintoredL?galaxiesmustpopulatethe\bluecloud"whentheUniversewasjust4Gyrold. Ontheotherhand,wecantakeasimilarlookattheevolutionoftheultraviolet(UV)andtheopticalLFsofthe\bluecloud"galaxieswithtime.Insteadofanincrease,therehasbeenadecreasewithtimeinthenumberdensityofblueL?galaxiesforthepast9Gyr.Inparticular,thosegalaxiesthatarebrightestintheUVaretheoneswhichhaveexperiencedthehighestdecrease(30%; Schiminovichetal. 2005 ). SincetheUniversewas6Gyrold,theaverageSFRperunitcomovingvolume{theso-calledcosmicSFR{hasdecreasedbyanorderofmagnitude( Madauetal. 1998 ; Hoggetal. 1998 ; Hopkins 2004 ; Lillyetal. 2007 ).ItiswellknownthatthemaincontributorstothecosmicSFRuptoz1arespiralgalaxies( Madauetal. 1998 ; Hoggetal. 1998 ; Hopkins 2004 ; Lillyetal. 2007 ).Nevertheless,athigherredshiftsthestarformationtakingplaceinbulge-,irregular-,andinteracting-likebluegalaxies,becomesequallyimportant. Fromamorphologicalpointofview,galaxiesfromthe\bluecloud"are,uptoz1,mostlyspiralgalaxies.LaterHubbletypegalaxies,orgalaxiesshowingeitherbulge-,peculiar-,orinteracting-likemorphologiesrepresentonlyupto30%( Wolfetal. 2005 ; Belletal. 2005 ; Ilbertetal. 2006 ).However,thisgalaxypopulationisresponsibleformostof 16

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Arnoutsetal. 2005 ; Zuccaetal. 2006 ; Ilbertetal. 2006 ; Zamojskietal. 2007 ). Furthermore,closerthanz1,mostofthestarformationactivitytakesplaceinmorphologicallyundisturbedgalaxies.Thissuggeststhatwhilegas-richmergersmayberesponsiblefortheenhancedstarformationactivityandpeculiarmorphologiesoftherapidevolvingpopulationseeninthe\bluecloud"beyondz1( Zuccaetal. 2006 ),theyarenotforthelowstarformationactivityseencloser( Wolfetal. 2005 ; Belletal. 2005 ; Zamojskietal. 2007 ).Gassupplyandconsumptioninaquiescentmodeaccountsforthestarformationactivitycloserthanz1. Ifallthisistakenintoaccountweareleftwithtwodierentepochs,onecloserandonefurtherawaythanz1.Furtheraway,weareleftwithauniversedominatedbyyoung,blue,active,late-typegalaxies;whilecloser,weareleftwithauniversedominatedbyolder,redder,quiescent,moremassive,early-typegalaxies.Thisimpliesthatgalaxiesfromthe\bluecloud"mustevolveintothe\redsequence."Inorderforthistohappen,galaxymergingandstarformationquenchingmustplayarole.Mostmassive,spheroidal-likeearly-typegalaxiescanbeexplainedbymeansofmergersbetweenlessmassive,disk-likegalaxies.Furthermore,forthestellarpopulationsofyoung,blue,active,late-typegalaxiestoageintothe\redsequence"boththestarformationandthegassupplyneedtofadeaway.Withnogasleft,starscannotbeformedanymore,andgalaxiesfromthe\bluecloud"enterthe\redsequence"via\wet"{gas-rich{mergers,andthenevolvealongthe\redsequence"via\dry"{stellar{mergers.Nevertheless,thephysicalprocessesthatrulethemigrationofgalaxiesbetweenthesetwopopulationsstartingatz1:5arenotyetunderstood. Thisimpliesthatalargefractionoftoday'sredL?galaxiesancestorsmustbevisibleamongthegalaxiesinthe\bluecloud"atz1:5andlater.Thecruxofthematteristoaccuratelyestablishwhichgalaxypopulationorpopulationshavethesegalaxiesevolvedinto.Sofar,severalscenarioshavebeenproposed.Iftheyareintrinsicallylow-mass 17

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Kooetal. 1994 ; Guzmanetal. 1996 1997 1998 ; Phillipsetal. 1997 ; Noeskeetal. 2006 ; Bartonetal. 2006 ).Ontheotherhand,iftheyaremoremassivesystemstheycouldfadelittleandremainluminous,becomingthecentersofmoremassivediskgalaxies( Phillipsetal. 1997 ; Guzmanetal. 1998 ; Hammeretal. 2001 ; Barton&vanZee 2001 ; Bartonetal. 2006 ; Puechetal. 2006 ).Finally,iftheyremainluminousandblue,theycouldevolveintopresent-dayMagellanicirregularorsmallspiralgalaxies( Phillipsetal. 1997 ; Guzmanetal. 1998 ; Bartonetal. 2006 ). Oneofthemostintriguingobservationalcluestotheoriginofthisgalaxybi-modalityisthefactthatwhilethe\redsequence"extendsalongawiderangeofmasses,the\bluecloud"seemstobetruncatedatM?31010M( Kaumannetal. 2003 ).Therefore,starsneednottobeformedanymoreforsuchanupperlimittoexist.Starformationquenchingmayplaythenanimportantroleingalaxyevolution. Aninterestingscenarioistheoneproposedby Cattaneoetal. ( 2006 ).Accordingto Cattaneoetal. ( 2006 ),amassivehaloquenchingmodelisabletoexplainthistruncation.Galaxieswouldgrowalongthebluesequencethroughcoldlamentaryowsuntilthehosthalogrowsaboveacriticalshock-heatingmass(MHalo1012M)and,inconsequence,thegasaccretionishalted.Afterreachingthiscriticalmass,galaxiesfromthe\bluecloud"wouldreddenandfade,movingupalongtheCMDtowardsthe\redsequence".Oncethere,thebrightendwouldbereachedthrough\dry"mergers.Atthispoint,mergersmightcombinewithseveralothergasremovalmechanismssuchasstarburstheating( Mihos&Hernquist 1994 ; Sanders&Mirabel 1996 ),supernova(SN)drivengalacticwinds( Murrayetal. 2005 ),mergerorbitalenergyinjection( Coxetal. 2006 ),andactivegalacticnucleus(AGN)feedback( Granatoetal. 2004 ; Springeletal. 2005 ).Thesephenomenahavebeenalreadyintegratedinauniedmodeltoexplaintheformationofspheroids,quasars,andblackholes( Hopkinsetal. 2006 ).Nevertheless, 18

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Withallwehavediscussedsofarinmind,ifwewishtoimprovethecurrentviewontheoriginofthegalaxycolorbi-modalityandtheevolutionfromthe\bluecloud"intothe\redsequence,"theubiquitouspopulationofyoung,blue,active,late-typegalaxiesthatdominatetheuniversebeyondthetransitionepochinthestarformationhistoryoftheuniversebeyondz1,isoneofourbestcandidates.Mostofthesegalaxiesareluminous,small,andblue( Fergusonetal. 2004 ).ThetypicalL?galaxyatz>1,asseenindeepopticalsurveys,isneitheragrand-designspiral,noramassiveelliptical,butabright,small,blue,starburstgalaxy.Thesearetheso-calledLuminousCompactBlueGalaxies(LCBGs) Galaxiesinwhichstarformationandassociatedphenomenadominatethetotalenergeticsareknownasstarburstgalaxies( Weedman 1983 ).TheseobjectshavealargeSFRperunitareacomparedtonormalgalaxies,andthetimeitwouldtaketoproducethecurrentstellarmassatthecurrentstarformationrateismuchlessthantheageoftheUniverse.Theseequivalentdenitions( Kennicutt 1998 )covergalaxieswithawidevarietyofpropertiesatdierentredshifts.DistantLyman-breakgalaxies( Steideletal. 1996 ; Lowenthaletal. 1997 ),andLCBGs( Werketal. 2004 )fallunderthiscategory.ThisdenotestheircosmologicalrelevanceandturnslocalstarburstgalaxiesintouniquelaboratoriestostudythecomplexecosystemofthestarformationprocessthroughouttimewhentheycanbeproperlyandequallyselectedatdierentepochsoftheUniverse. ThelaunchoftheHubbleSpaceTelescope(HST),andtheadventofthe10-mclasstelescopesresultedinthetippingpointfordistantLCBGdetailedinformationregardingtheirmorphologies,kinematics,SFRs,andmasses.MostofwhatweknowtodayspecicallyaboutLCBGsatz1wehavelearnedinthelastdecade.KeckObservatoryobservationsshowedthattheirintegratedemissionlinevelocitywidthare 19

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Kooetal. 1995 ; Guzmanetal. 1996 ; Phillipsetal. 1997 ).Ontheotherhand,HSTobservationsshowedtheircomplexandknottedstructure,andthattheirtypicalhalf-lightradiiarer1=2<5kpc( Phillipsetal. 1997 ; Guzmanetal. 1998 ; Noeskeetal. 2006 ).LCBGs,althoughintrinsicallyluminous(L0:2{5.0L?),havelowmass-to-lightratios(M=L0:1{1.0ML1),smallerthanatypicalnearbyL?galaxy( Guzmanetal. 1997 ).LCBGsareundergoingvigorousepisodesofstarformationthatinvolveupto10%oftheirtotalmass( Kooetal. 1994 ; Guzmanetal. 1996 1997 1998 ; Phillipsetal. 1997 ; Hammeretal. 2001 ; Noeskeetal. 2006 ; Puechetal. 2006 ; Rawatetal. 2007 ).Furthermore,whilemorphologicallyandspectroscopicallyheterogeneous, Phillipsetal. ( 1997 )and Guzmanetal. ( 1998 )wereabletodividethemintotwocategories:(i)\SBN-like,"featuringanuclearstarburstandaspiraldiskmorphology;and\HII-like,"featuringahighresemblancetogiantHIIregionsandanirregularmorphology.Andlast,butnotleast,thetypicalstellarmassofLCBGsrangesfrom5109Mto1011M( Guzmanetal. 2003 ),whichplacesthisgalaxypopulationapproximatelyrightatthelocationofthecriticalmassvalueobservedinthe\bluecloud,"ultimatelyturningthemintothekeypopulationtostudyinordertounderstandthenatureofthecolorbi-modalityofgalaxies. RecentprogresssuggestthatLCBGsmayarguablyholdthekeytostudythetwomainphysicalmechanismsthatrulegalaxyformationandevolutionsincez1:5(i.e.,mergingandquenching).Inparticular,LCBGsmayprovidetheanswertothreefundamentalquestions: i Whatisthemechanismresponsiblefortriggeringtheburstofstarformation? ii Whatisthemechanismresponsibleforquenchingtheburstofstarformationandlimitingthestellarmass? iii WhatcanthestudyofthelocalpopulationofLCBGstellusaboutthedistantpopulationofLCBGs? 20

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Yangetal. 2008 ; Epinatetal. 2009 ; ForsterSchreiberetal. 2009 ).Nevertheless,weneedtobeverycarefulwiththeintrinsiclimitationsofthesesurveyswhendiscussingtheirresults,asshowninChapters 3 and 4 .Alternatively,wefocusonacomprehensivemulti-wavelengthstudyofasampleofnearby,young,blue,active,late-typegalaxiesthatbestresemblethepropertiesofthedistantpopulationofLCBGs.OursamplecanbeusedasthenecessaryreferenceforinterpretingandunderstandingthenatureofthedistantpopulationofLCBGs.Thisdissertationisoneofthecornerstonesofthismulti-wavelengthstudy. Theopticalrangeisthebestunderstoodinnearbygalaxies,andwillbesystematicallystudiedindistantgalaxieswiththeforthcomingnewgenerationofinstrumentson10-mclasstelescopes.Ontopofthat,threedimensional(3D)opticalspectroscopydataprovideacompletedescriptionofthephysicalpropertiesofgalaxiesasafunctionofspatialpositionwithinthegalaxy,whichallowsforaproperanalysisofthephysicalprocessesresponsiblefortheformationandevolutionofLCBGs.Furthermore,kinematicpropertiesthemselvesareabletoshedsomelightintothequestionsstatedaboveandaddressednext.The3Dopticalkinematicstudyofasampleof22localLCBGs{ourrepresentative 21

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Kooetal. 1994 ; Guzmanetal. 1996 1997 1998 ; Phillipsetal. 1997 ; GildePazetal. 2000 ; Hammeretal. 2001 ; Noeskeetal. 2006 ; Puechetal. 2006 ; Rawatetal. 2007 ),andcontributethemosttothecosmicSFRincreaseinthelast9Gyr.Suchepisodesmaybecausedbybothmajorandminormergers,andtheecienttransformationofaccretedcoolgasintostars.Foransweringthisquestionneutralatomic,ionized,andmoleculargascontentandkinematicestimatesarenecessary.MorphologicalinformationandaccurateSFRestimatesmayhelpaswelltofullyisolatethetriggeringmechanisminLCBGs. UV-continuumimages,and[OII]3727andHopticalemissionlineuxmapscantracestarformationinLCBGsasafunctionofspatialpositionwithinthegalaxy.Inparticular,theHopticalemissionlineuxmapsoftheLCBGsinourrepresentativesampleshowthatstarformationtakesplaceinmultiplegiantHIIregionsthroughoutthegalaxy.TheSFRoftheseregionsrangebetween0.1{10Myr1( Castillo-Morales,Gallego,Perez-Gallego,etal. 2009a b ).Ontheotherhand,near-andfar-UVcolorimagesshowredhalos,whichshowthatstarformationtakesplaceouttothelowsurfacebrightnessoutskirtsofthegalaxy.AccurateestimatesoftheSFRsinLCBGsareessentialtoinvestigatethetriggeringmechanismsinthisgalaxypopulation. Whilemajormergersareknowntotriggerintensestarformationandevolveintospheroidal-likeremnants( Mihos&Hernquist 1994 1996 ),mostLCBGsshowdisk-likemorphologiesrangingfrom\SBN-"spiral-likegalaxiesto\HII-"irregular-likegalaxies 22

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Guzmanetal. 1997 1998 ).Therefore,fromamorphologicalpointofview,majormergers,responsibleforspheroidal-likemorphologies,arenotfavoredasthemaintriggeringmechanisminthesegalaxies.Ontheotherhand,minormergersareaplausibletriggeringmechanismforthecurrentburstsofstarformationinLCBGs.MinormergermodelsaccountforenhancedSFRs,andpeculiarphotometricfeatures( Smithetal. 1996 ).Thestudyofopticalemissionlinevelocitymapshasthepotentialtodiscriminatebetweenthenatureofthesemergers,asshowninChapters 3 and 4 .Furthermore,mergersignaturescanalsobeseeninHImaps( Garlandetal. 2007 ). Results,previousandcurrent,showthatwhileabout50%oflocalLCBGsarenotisolatedandhavecloseopticalorradiocompanions(somegas-richcompanionsareonlyrevealedbymeansofHIobservations; Garlandetal. 2004 ; Pisano,Garland,Perez-Gallego,etal. 2009a ),only30%ofeldgalaxieshavethem( Jamesetal. 2008 ; Pisanoetal. 2002 ).Nevertheless,LCBGsfromtheSloanDigitalSkySurvey(SDSS),withandwithoutcompanions,shownodierenceinluminosity,color,size,emissionlinewidth,HImass,totalmass,orSFR.ThepossibilityofacorrelationbetweenthekinematicsignaturesofrecentinteractionsinLCBGsandtheirenvironmentisdiscussedinChapter 3 .SuchacorrelationwouldimplythattheseinteractionsareresponsiblefortriggeringtheenhancedstarformationinLCBGs. KinematicsignaturesofrecentinteractionsshouldbeeasytoidentifyinopticalandHIvelocityandvelocitywidthmaps,asshowninChapters 3 and 4 .Inparticular,bothmajorandminormergersshowdeviationsfromsmoothrotations,andthequalityofourdataallowustolookforthose.Asanexample, Homeier&Gallagher ( 1999 )discussedwhetheraminororamajormergerinNGC7673,oneofthegalaxiesstudiedindepthinChapter 4 ,wasresponsiblefortriggeringtheenhancedstarformationinthisparticulargalaxy.Ingeneral,fromakinematicpointofview,minormergersareeasiertoidentifywhentheyaectanoverallrotatingsystem.Analternativeoptionisthatthepresenceofbarsdrivinggastothecenterofthegalaxy(e.g., Jogeeetal. 2005 )isresponsiblefor 23

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Triggeringmechanismsincludemassivehalos,AGNs,andSN-drivengalacticwinds.Halomassmeasurementsareneededtostudytheeectsofmassivehalos,whilebothuxandkinematicsignatures,asshowninChapter 3 ,areneededtostudythepresenceofAGNsandSN-drivengalacticwindsinthesegalaxies. Wehavealreadymentionedbeforethattheexistenceofamaximalhalomass(i.e.,Mhalo1012M)mightberesponsibleforthestarformationquenching( Cattaneoetal. 2006 ).Thismaximalhalomassarisesfromshockheatingofaccretinggasabovethismass.Sincethisgasisneededtokeepthestarformationactivitygoing,whenitstemperatureincreasesandtheaccretionceases,sodoesthestarformation.Inordertostudythisscenario,accuratehalomassestimatesareneeded. HalomassestimatescanbeinferredfromHIdynamicalmasses.Insteadofionizedgas,neutralatomicgasisusedbecauseittracesthegravitationalpotentialtolargerradii.TypicalHIdynamicalmassestimatesofLCBGsarebelow1012Masshownby( Pisano,Garland,Perez-Gallego,etal. 2009a ),whoalsondafewoutlierswithHIdynamicalmassestimatesupto1013M.Inaddition,bycomparingresolvedHIdynamical 24

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OtherquenchingmechanismsincludeAGNsandSN-drivengalacticwinds( Mihos&Hernquist 1994 1996 ; Sanders&Mirabel 1996 ; Murrayetal. 2005 ; Granatoetal. 2004 ; Springeletal. 2005 ; Hopkinsetal. 2006 ).Whilethepresenceofquasarscanberuledout,wecannotdiscardthepresenceofAGNsinLCBGs,afterinvestigatingtheSDSSspectraofthesegalaxies.Inparticular,3Dopticalspectroscopyhasthepotentialofrevealingthepresenceoflow-levelAGNbymeansofunusuallyhighlineratios[OIII]/Hand[NII]/H( Brinchmannetal. 2004 ),andspectrallyresolvedkinematiccomponents,asshowninChapter 3 .Theextentandstrengthofthesekinematicalsubcomponentsallowsustoquantifytheoutow/inowofgasfrom/ontogalaxies( Marloweetal. 1995 ).Itisimportanttonoticethatwecanderivethesepropertiesasafunctionofpositionwithinthegalaxy,andthatourobservationaltechnique,explainedindepthinChapter 2 ,allowsustofullyresolveeachoftheobjectsinourrepresentativesampledowntoaspatialresolutionof1arcsec.Attheaverageredshiftofoursample1arcsectranslatesintolessthan400pcacross. Amulti-wavelengthstudyofarepresentativesampleofnearbyLCBGscanbeusedasareferenceforstudiesofdistantyoung,blue,active,late-typegalaxies,including 25

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Melnicketal. ( 1987 )involvingtheirHluminositiesandtheirintegratedvelocitywidths,whichcanbeusedasadistanceindicatorandisdiscussedindepthinChapter 5 .Suchareferenceisnecessaryinordertocorrectlyinterpretresultscomingfromtheanalysisofdatafromdistantsurveysandcompensateforanypossiblebiasassociatedtothelimitationsofdistantobservations.Butalso,dierentpropertiescanbeinferredbyunderstandinghowdierentobservationalandphysicalpropertiesofthenearbypopulationrelatetoeachother.Anobviousexample,wehavealreadymentioned,isthepossiblerelationbetweendynamicalmassesderivedfromtheionizedgasinLCBGsandtheHIwhichcannotbemeasuredfordistantLCBGs. Current3Dspectroscopysurveysinclude Yangetal. ( 2008 ), Epinatetal. ( 2009 ),and ForsterSchreiberetal. ( 2009 ).Thesestudiesuse3DspectrographsGIRAFFE(intermediate-redshift)andSINFONI(high-redshiftwithadaptiveoptics)attheVeryLargeTelescopeoftheEuropeanSouthernObservatory.Alltogethertheycoverabroadredshiftrange(0:4
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5 ,wecanuse3DspectroscopydataofourrepresentativesampleoflocalLCBGstosimulateobservationsofdistantanalogs.Bydoingso,wecanshedlightintothelimitationsofthedistantsurveys,andcompensateforanypossiblebiasesintroducedbycosmologicalfactors,lowsignal-to-noiseratios,andinstrumentalconstraints,associatedtoobservationsofhigh-redshiftgalaxies. Thebulkofthisdissertationistobepublishedin Perez-Gallegoetal. ( 2009a ), Perez-Gallegoetal. ( 2009b ),and Perez-Gallegoetal. ( 2009c ). Perez-Gallegoetal. ( 2009a ),alreadysubmitted,includesthediscussioncarriedoutinSection 4.2 ,whilecitetperez09b,abouttobesubmitted,inlcudesSections 4.3 to 4.5 .Finally, Perez-Gallegoetal. ( 2009c ),includesthediscussioncarriedoutinChapter 4 .Thisdissertationusesalsomaterialfrom Siegel,Guzman,Perez-Gallego,etal. ( 2005 ), Gruel,Guzman,&Perez-Gallego ( 2009 ), Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2009a ), Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2009b ),and Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2010 ),allstudiesIhaveactivelybeeninvolvedin. Throughoutthisdissertationweadopttheconcordancecosmology,i.e.,aatuniversewith=0:7,=0:3,andh=0:7,unlessotherwiseexplicitlystated.Thisdissertationisstructuredasfollows.InChapter 2 wedescribeoursampleselection,observationsanddatareduction.InChapter 3 weshowthestatisticalpropertiesofourrepresentativesampleof22localLCBGs.AnindepthanalysisoffourlocalLCBGsisdiscussedinChapter 4 .InChapter 5 westatetheconnexionbetweenlocalLCBGsandmoredistantpopulations.ConclusionsarehighlightedinChapter 6 27

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Scovilleetal. 2007 ).Atz1theselimitscorrespondtorest-frameMVegaB18:5mag,andSBe(B)Vega21magarcsec2,respectively.Furthermore,LCBGsatz1arecharacterizedbyhavingcolorsbluerthanatypicalspiralgalaxyasseennearby( Phillipsetal. 1997 ). TheSloanDigitalSkySurvey(SDSS)isamajormulti-lterimagingandspectroscopicredshiftsurveyusingadedicated2.5-mwide-angleopticaltelescopeatApachePointObservatoryinNewMexico.TheDataRelease4,releasedin2005,isthefourthmajorSDSSdatareleaseandprovidesimages,imagingcatalogs,spectra,andredshiftsfor180millionobjectswithinanareaequalto6,670squaredegrees.Wehaveexaminedmorethan560,000galaxieswithspectroscopicdataoveralmost5,000squaredegreesontheskyintheDR4oftheSDSS( Adelman-McCarthyetal. 2006 )andfound1,632local(D<200Mpc)LCBGswhichsatisfyourcriteria.LCBGsareasmallsubsetofthetotalgalaxypopulationinthelocaluniverse,asexpectedforthefastestevolvingpopulationsincez1.Figure 2-1 illustrateshowextremeandrarelocalLCBGsareascomparedtothedistributionofarepresentativesampleofthegalaxypopulationinthe 28

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2-2 and 2-3 ),andcanbegroupedintothesametwobroadcategories:\SBN-like"and\HII-like"galaxies(Guzmanetal.1997;GildePazetal.2000). LCBGsnearandfaroverlapineveryparameterinwhichwecancomparethem.Theyhavesimilarvaluesofeectiveradii(Re1{4kpc),StarFormationRates(SFR5-{20Myr1),metallicities(Z0:3{0.7Z),emissionlinevelocitywidths(30-{100kms1),dynamicalandstellarmasses(109{1011M),andSFRperunitmass( Phillipsetal. 1997 ; Guzmanetal. 1997 ; GildePazetal. 2000 ).PreliminaryresultsalsoshownearbyLCBGsarepreferentiallyfoundinover-denseregionsinthesky,asareLCBGsatz1( Capaketal. 2007 ; Castander,Guzman,Perez-Gallego,etal. 2009 ).Assuch,webelievethatoursampleofz0LCBGsarethebestanalogsforinferringthepropertiesofthedistantpopulationofLCBGs.NotethatwewillbeapplyingtheresultsofourstudyoflocalLCBGstoLCBGsatz1,nottohighermassgalaxiessuchasgrand-designspirals. TheSDSSLCBGsampleatD<200MpcwillbeusedtostudythestatisticalpropertiesoflocalLCBGsascomparedtothegeneralgalaxypopulationinthenearbyuniverse.Inparticular,theanalysisoftheopticalphotometricandspectroscopicdataintheSDSS,alreadyinhand,willallowustoderivethenumberdensityoflocalLCBGs,theircontributiontobothluminosityfunctionandthestellarmassfunctionoflocalbluegalaxies,andtheirclusteringproperties( Castander,Guzman,Perez-Gallego,etal. 2009 ).Far-andnear-ultraviolet(UV)GalaxyEvolutionExplorer(GALEX)dataalreadyexistfor200localLCBGsallowingustoderiveUV-basedSFRs( GildePazetal. 2007 ),andstudytheircontributiontothecosmicSFRoflocalUVgalaxies.Inaddition,wealreadyhavesingle-dishHIdataonatotalof142localLCBGsincludingoriginalobservationsof57LCBGsusingAreciboandtheGreenBankTelescope.TheintegrateduxoftheHI

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B A)BVcolorversusaveragesurfacebrightness(B-magarcsec2)withinRe.Opencirclesshowthepropertiesof4,000galaxiesinthelocalUniversefrom Prugniel&Maubon ( 2000 );lledtrianglesshowarepresentativesampleofLCBGsatintermediateredshiftsfrom Phillipsetal. ( 1997 );trianglesrepresentasubsetofSDSS-selectedLCBGsinthelocalUniverse.ThedashedlinesdemarkthecolorandsurfacebrightnesscriteriausedtoselectLCBGs.B)WedgediagramofSDSSDR5galaxieswithr16:5andavailablespectrauptoredshiftz=0:06(blackdots).Galaxiesareplottedinadeclinationrangefrom0to5.ThelargerreddotsrepresentlocalLCBGsinthisrange. lineallowsustoderivethemassofatomichydrogenineachgalaxy,givingusanestimateofthetotalsupplyoffuelforfuturestarformation.WhencombinedwiththeSFR,thisyieldslimitsonthepotentiallengthofthecurrentburstineachLCBG( Garlandetal. 2004 2005 ; Pisano,Garland,Perez-Gallego,etal. 2009a ). ThestatisticalanalysisisneededtocharacterizetheglobalpropertiesofLCBGscomparedtothegeneralgalaxypopulationinthelocaluniverse,andwithsimilarstatisticalstudiescurrentlybeingcarriedoutforLCBGsathigherredshifts.However,anunderstandingofthenatureandevolutionoflocalLCBGsultimatelyrequiresdetailedmappingofthephysicalpropertiesatvariouswavelengths,includingkinematics,metallicity,age,andSFRasafunctionofspatialpositionwithineachgalaxy.Ourgoalistobuildacompletedata-setfortheselocalLCBGsincludingfar-andnear-UVimagesusingGALEX,optical3DspectroscopyusingPPAKatCalarAlto(CAHA),andHImappingusingtheVeryLargeArrayandtheGiantMetrewaveRadioTelescope.This 30

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SDSSimagesofthe12SDSSLCBGs. uniquedata-setwillprovideacompletepictureofthestarformationhistoryandmassassemblyoflocalLCBGs. WeemphasizethatwhilethecolorandsurfacebrightnesscriteriaimplythatoursamplebelongstothewidelystudiedcategoryofBlueCompactDwarfgalaxies(BCDs)(e.g., Kunth&Ostlin 2000 ,andreferencestherein),LCBGsareadistinctclass.BCDsarefaint,withabsolutemagnitudes18magMB11mag,whileLCBGshave 31

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SDSSspectraofthe12SDSSLCBGs. luminositiesMB18mag.ThelowerluminositiesofBCDsimplytheycannotbeseenatintermediateredshiftsinmostwide-eld,deepHSTsurveys,andthusarenotcounterpartstotheobservedpopulationofdistantLCBGs.AlthoughasmallnumberofMB18magblue,compactgalaxieshavebeenstudiedinthelastfewyears(e.g., Homeier&Gallagher 1999 ; Ostlinetal. 2001 2004 ; Werketal. 2004 ),ourinvestigation 32

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Thespecicaimofthisdissertationistheanalysisofthe3DkinematicpropertiesofalocalrepresentativesampleofLCBGs.Outofthe1,632LCBGscloserthan200Mpcweselected12LCBGsfromtheDR4oftheSDSS.WealsoselectedSDSS1703b,whichisthecompanionofLCBGSDSS1703a,andwhoseobservationalpropertiesarecloseenoughtothoseofanLCBGtobeconsideredasone(i.e.,itsatisesthecolorcriterion,andiftheuncertaintiesofitsobservationalpropertiesareconsidered,itiswithin1-ofsatisfyingtheothertwoselectioncriteria).Wenoteherethatastudyoftheaccuracyofourselectioncriteriawhichdeals,amongotherthings,withthesharpbordersusedtoclassifyLCBGs,isinprogress( Castander,Guzman,Perez-Gallego,etal. 2009 ).Furthermore,weselectedsevenLCBGsfromtheUniversidadComplutensedeMadrid(UCM)surveycatalog( Zamoranoetal. 1994 ).WecompletedoursamplewithLCBGNGC7714.WeselectedobjectswitharangeofpropertiesthatbestresembletherangeofMB,SBe(B),andBVshownbyLCBGsinourvicinity.LCBGswitheectiveradiilargerthan4arcsecandcloserthan100Mpcweregivenprioritytotakefulladvantageoftheeldofview(FOV)andspatialresolutionoftheinstrumentused.Figure 2-4 showshowtheobservationalpropertiesoftheobjectsinourrepresentativesamplecomparetothoseofasampleof320LCBGscloserthan100Mpcfoundthesamewayasour1,632LCBGscloserthan200Mpcsample(noticethat18outofthe22LCBGsinoursamplearecloserthan100Mpc).Furthermore,amongthe12LCBGsfromtheSDSSinourrepresentativesample25%are\SBN-like"(i.e.,UCM1431,SDSS1134,andSDSS1652)and75%are\HII-like." Guzmanetal. ( 1997 )foundasimilarpercentageofbothcategoriesatz0:4(54%\HII-like"and46%\SBN-like"),andoverafactoroftwomore\HII-like"galaxiesatz>0:7(68%\HII-like"and32%\SBN-like").Thesepercentagesdonotallowustoconcludeanythingabouttheevolutionofeachcategory.Athoroughlookatthestatisticalpropertiesofoursample,whosepropertiesarelistedinTable 2-1 ,isthepurposeofChapter3. 33

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SamplePropertiesa NGC7673e0.01136848.0-20.3613.2819.950.418.92.1NGC77140.00933339.7-20.1013.0020.000.4014.32.7NGC6052d0.01580867.6-20.6913.3719.710.417.62.4NGC469d0.01367358.4-19.1314.7420.050.424.71.3UCM00000.02196091.6-20.5014.6120.870.307.53.7UCM01560.01303054.9-18.8415.3320.770.495.31.6UCM1428d0.01489062.6-19.0814.7820.360.245.21.7UCM1431d0.031000127.9-19.9915.7620.700.524.42.7UCM1648d0.032969134.6-20.3215.6920.320.263.92.4UCM22500.042149171.6-21.5915.4020.230.403.83.1UCM22580.02159290.1-19.3615.7920.840.214.42.0UCM23170.031962131.7-21.9114.1620.900.5310.26.4UCM2327n0.02060086.0-19.2315.7919.630.242.31.0UCM2327s0.01913080.0-19.0615.8020.300.433.21.3SDSS11340.01733571.7-19.9114.4720.710.507.32.5SDSS15070.01123146.8-19.2314.1920.380.457.11.6SDSS16050.00664027.8-18.6513.6319.000.304.80.7SDSS16520.01037643.3-18.4814.7820.110.476.21.3SDSS1703a0.01969081.2-19.6214.7419.680.364.01.6SDSS1703b0.01976081.5-18.4016.2021.130.404.01.5SDSS17100.01475761.2-18.8015.2120.690.535.11.5SDSS23270.01604466.5-20.2014.0120.250.587.32.4 Meanf0.018978-19.7014.7620.300.406.02.16Standarddeviationf0:001980:200:200:110:020:60:25 Garlandetal. ( 2005 )dAlsointheSDSScatalog;eAlsointheUCMcatalog;fMeanandstandarddeviationofthesample

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Kelzetal. 2006 )atthe3.5-mtelescopeintheCentroAstronomicoHispanoAleman1(CAHA).PPAKisanintegraleldunit(IFU)consistingof331scienceberswithadiameterof2.7arcseceach,coveringanhexagonalFOVof7465arcsec2.Furthermore,thereare15calibrationbers,whicharealwaysilluminatedbyaThArlampandusedtoalignimagesontheChargeCoupledDevice(CCD)camera;and36skyberslocated80arcsecawayfromthecenterofthehexagonalFOV(Figure 2-5 ).ThePPAKbundlehasgapsbetweeneachberanditsnextneighbors.However,itispossibletollthesegapsbyrepeatedobservationsofthesamesourcewithsmallpointingosets.Thisisknownasdithering. PPAKobservationsofthe22targetsinoursampleweremadeduringthreeobservingrunsbetween2005and2006(Table 2-2 ).Therstobservingrun(Run47)tookplace 35

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GeometricallayoutandsizeofthecentralhexagonalIFU(331bers)andsixsurroundingskyberbundles(eachconsistingof6bers).Onlyopenplotsymbolsareopticallyactivebers,lledcirclesareindicatingauxiliaryberswhichwereemployedinthemanufacturingprocessformechanicalreasons.NotethatthePPAKber-bundlehasgapsbetweeneachberanditsnextneighbors. duringthenightsofAugust8to14,2005.Thesecondobservingrun(Run56)tookplaceduringthenightsofApril17to23,2006.Finally,thethirdobservingrun(Run64)tookplaceduringthenightsofJuly28toAugust3,2006. Twodierentcongurationswereused(Table 2-3 ).First,a300linesmm1grating(V300)centeredat5316Awasused.Thislowresolutioncongurationprovidedaspectralresolutionof10.7AFWHM(255kms1at5316A)coveringthespectralrangefrom 36

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Second,a1200linesmm1grating(V1200)centeredat5040Awasused.Thishighresolutioncongurationprovidedanominalspectralresolutionof2.78AFWHM(70kms1at5040A),coveringthespectralrangefrom4669to5400A,includingHand[OIII]5007.Threedierentditheringpositionswereobservedduringthersttworuns.Duringthelastrunosetswerenotappliedbetweenditheringpositions.Threeexposures,eachone900slong,weretakenforatotalexposuretimeof2700sperditheringpositionduringtherstrun.Duringthelasttworunseachexposurewas1200slongforatotalexposuretimeof3600sperditheringposition.Thesechangeswereimplementedinordertoimprovethesignaltonoiseratio(S/N)inthecontinuumoftheLCBGsinoursampleinordertostudytheirunderlyingolderstellarpopulations.Nevertheless,suchastudyisoutofthescopeofthisdissertation. 2-6 showsanexampleofintegraleldspectroscopy(IFS)correspondingtoPPAK,illustratingthisdistribution.Eachofthe382spectraisdispersedalongthex-axis.Foreachwavelength,eachofthe382spectra(i.e.,science,sky,andcalibrationspectra)isalsospreadalongthey-axisfollowingacharacteristicproleofnitewidth(Figure 2-6 ). 37

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ObservingLog NameRADECV300aV1200aNotes NGC767323h27m41.0s+23d35m20s08.10.0508.11.05...NGC771423h36m14.1s+02d09m19s08.10&14.0508.11&12.05V1200:d1indierentnightsNGC605216h05m12.9s+20d32m32s08.09&14.0508.11&12.05V1200:d12twoexposuresNGC46901h19m32.9s+14d52m19s08.14.0508.12&13.05V1200:d3indierentnightsUCM000000h03m09.6s+21d57m37s07.28.0607.30.06&08.02.06V1200:noosets,nod3UCM015601h59m15.7s+24d25m00s08.14.0508.13.05V300:onlyd1;V1200:onlyd1UCM142814h31m08.9s+27d14m12s...04.18.06...UCM143114h33m20.7s+28d41m36s08.14.0508.12&13.05V1200:nod3UCM164816h50m47.9s+28d50m45s07.28.0604.20.06V1200:nod3UCM225022h52m34.7s+24d43m50s07.28.0608.01.06&08.02.06V1200:nod3UCM225823h01m07.1s+19d36m33s07.29.06......UCM231723h20m05.7s+24d13m16s08.10.0508.13.05...UCM2327n23h30m09.9s+25d31m58s08.14.0507.31.06...UCM2327s23h30m09.9s+25d31m58s08.14.0507.31.06...SDSS113411h34m21.2s+15d39m37s...04.20.06...SDSS150715h07m48.4s+55d11m08s...04.19.06V1200:nod3SDSS160516h05m45.9s+41d20m41s08.14.0508.03.06V1200:noosetsSDSS165216h52m03.6s+63d06m57s...08.02.06V1200:noosetsSDSS1703a17h03m14.9s+61d27m04s07.28.0607.30.06V1200:noosetsSDSS1703b17h03m12.2s+61d27m21s07.29.0607.31.06V1200:noosetsSDSS171017h10m11.1s+21d38m58s07.29.0608.12&13.05...SDSS232723h27m14.8s-09d23m13s07.29.0608.03.06V1200:noosets;d123twoexposures

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NGC7673IFSrawdatacoveringthespectralrangefrom3600to7000A.Thisimageincludes331sciencespectra,36skyspectra,and15calibrationspectra.Thex-axiscorrespondstothedispersionaxis,whilethey-axiscorrespondstothespatialaxis. 39

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ObservationalStrategy CongurationRunTimeperDitheringOsetsa(s)(arcsec) V300Run473330d2:(+1.56,+0.78);d3:(+1.56,-0.78)V300Run563330d2:(+1.56,+0.78);d3:(+1.56,-0.78)V300Run643330d2:(+1.56,+0.78);d3:(+1.56,-0.78)V1200Run473900d2:(+1.56,+0.78);d3:(+1.56,-0.78)V1200Run5631200d2:(+1.56,+0.78);d3:(+1.56,-0.78)V1200Run6431200d2:(0.00,0.00);d3:(0.00,0.00) ThedatawerereducedusingR3DandE3D( Sanchez 2006 ),IRAF2,andourowncustomsoftware.Alltheimageswerebias-subtracted,at-elded,andcosmic-raycleaned.The331sciencespectraperditheringpositionwerethenproperlyextracted,distortion-corrected,wavelength-calibrated,sky-subtracted,andux-calibrated(Figure 2-7 ). 40

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NGC7673IFS331reducedsciencespectracoveringthespectralrangefrom3600to7000A.Fromlefttoright(i.e.,dispersionaxis),itiseasytoidentifythebrightestlinesas[OII]3727;Hand[OIII]4959,5007;[HeI]5876;Hand[NII]6548,6584;and[SII]6717,6731.Thisisforoneparticularditheringposition.

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Sanchez 2006 ). TheV300wavelengthcalibrationwasperformedusingaHelampwithupto17lineswithintheconsideredspectralrange.Thermsofthebesttpolynomial(n=3)was0.12A.Adierentarcwasobtainedeverysinglenight,nevertheless,thesevalueswereconsistentuptothesecondsignicantgure.Afurtheranalysistoevaluatetheaccuracyofourcalibrationincludingskylinesrevealsanaluncertaintyinourcalibrationof0.2A(10kms1at6000A).Forthisanalysis,vehighsignal-to-noise(S/N)skylinesfromthewavelength-calibratedspectracoveringtheentireV300spectralrangeweretbysingleGaussianprolesforeachber.ThecentroidsoftheselineswerethencomparedtothoseoftheCAHAskyatlas( Sanchezetal. 2007 ).Theuncertaintyofourmeasurementswasgivenbythestandarddeviationoftheresultingresiduals,whichwasconsistentwithintheentireV300spectralrange(i.e.,foreachskylineindependently). Ontheotherhand,theV1200wavelengthcalibrationwasperformedusingbothHeandCslampsbecausetheHelamplackedemissionlinesbluerthan5015A.Duringtherstrun,theCslampwasobservedseparatelyandbothlampswereaddedtoincreasethespectralcoverage.Furthermore,weakcontaminationlinesfromtheThArlampused 42

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Nevertheless,aproperwavelengthcalibrationwaspossibleduringthelasttworuns.ItwasperformedusingbothHeandCslampssimultaneouslywithupto12lineswithintheconsideredspectralrange.Althoughobservingbothlinessimultaneouslyimprovedourwavelengthcalibration,thiswasstillfarfromwhatwewouldhaveexpectedduetotheinappropriatesetofarcsavailable.Thermsofthebesttpolynomial(n=3)was0.06A(4kms1at5000A).Adierentarcwasobtainedeverysinglenight,neverthelessthesevalueswereconsistentuptothesecondsignicantgure.Again,afurtheranalysiswasnotpossibleduetothelackofskylinesintheV1200spectralrange.TakingallthisintoaccountwedecidedtousetheV1200justforvelocitywidthsmeasurements,eventhoughvelocitymeasurementswerealsomadetochecktheirconsistencywiththeV300ones. 43

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Castillo-Morales,Gallego,Perez-Gallego,etal. 2009a ). Thedatareductionprocessprovided331fullyreducedsciencespectraperditheringpositionandpergalaxy.Thisis2,979spectrapergalaxy,and65,583spectraintotal.Anexampleofthese,withdierentvaluesoftheS/NisshowninFigure 2-8 AsfortheV1200conguration,thepresenceofdoubleemissionlinecomponentswasaddressedbymeansofthecalculationofthe2ofsingleanddoubleGaussianproletsasgivenby (NM)NXi=1(OiEi)2 whereOiistheuxobservedforaparticularwavelength;Eiistheuxexpectedforaparticularwavelengthaccordingtoourt;Nisthenumberofdatapointsusedforthet;andMisthenumberofvariableswet.ThesewerefourforsingleGaussianprolets(i.e.,center,amplitude,width,andcontinuum),andsixfordoubleGaussianproletssincethewidthandthecontinuumofeachlinewereforcedtobethesame.Nevertheless,thiswasnotthecaseforUCM0000,wherethepresenceofabroadercomponent,whichisdiscussedinChapter 3 ,wasobvious.Aftercarefullyinvestigatingourdatawedecided 44

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45

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2-9 ).Inordertoguaranteethereliabilityofthereduced2asanindicatorofnon-gaussianityandtoavoidcontamination,wedemandedaminimumS/Nof30fordoubleGaussianproletstobeconsidered. Intheouterareasofthegalaxy,wespatiallybinnedthedatabyco-addingberstoachieveaminimumS/Nof13.Thisway,wewereabletoobtainnewmeasurementsperditheringposition.Furthermore,bersfromdierentditheringpositionswerealsoco-addedtoobtainnewmeasurements.Eachofthesemeasurementswerelinkedtotheaveragepositionofthebersco-added.Thesemeasurementsmadethenalmapsextendtowardsthelowersurfacebrightnessoutskirtsofthegalaxysamplings.Werecoveranareaabout10%largerpergalaxythanbeforeco-addingthesebers. ThevelocitymapsofthegalaxieswerederivedfromtheHemissionlinesforeachditheringpositionwiththelowresolutionspectra.Thedatawereinterpolateddowntoaspatialresolutionof1arcsecpixel1yieldinga6060pixel2squaregrid.Eachoftheoriginalbers(i.e.,originalspatialresolutionelement)wasthereforesampledbyapproximately33pixel2(i.e.,2:72:7arcsec2).Thiskeptusfromoversamplingthedata,whichmayresultintheappearanceofartifacts( Sanchez 2006 ).Thethreemapswerethenregisteredandaveragedpixelbypixel.Thus,boththespatialresolutionandtheerrorassociatedwitheachmeasurementimprovedbyafactorofp Thevelocitywidthmapsofthegalaxieswerederivedfromthe[OIII]5007emissionlinesforeachditheringpositionwiththehighresolutionspectra.ThislinewasselectedastheonewithhighestS/NwithintheV1200spectralrange.Theinstrumentalbroadening(instrument),asmeasuredinskylinesforeachber,wasproperlysubtractedfromthemeasuredbroadening(measured)tondtheintrinsicbroadeningofeachmeasurement(intrinsic)bymeansofintrinsic=p 46

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47

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3 48

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Kooetal. 1994 ; Guzmanetal. 1996 1997 1998 ; Phillipsetal. 1997 ; GildePazetal. 2000 ; Hammeretal. 2001 ; Noeskeetal. 2006 ; Puechetal. 2006 ; Rawatetal. 2007 ).SinceLCBGsareamajorcontributortothecosmicSFRatz1andscarcenearby,theymayholdthekeytounderstandingwhatcausedtheincreaseinthestarformationactivityoftheuniverseobserved9Gyrsago. Whileitisclearthatmajormergersbetweenequalmassgalaxiescantriggerintensestarformationintheremnants,suchmergersalsotendtoproducespheroidalremnants( Mihos&Hernquist 1994 1996 ).AlthoughsomeLCBGshavespheroidal-like,compactmorphologies( Imetal. 2001 ; Ilbertetal. 2006 ; Zamojskietal. 2007 ),mostexhibitdiskmorphologiesrangingfromsmallspiralgalaxies(\SBN-like")toirregulargalaxies(\HII-like"; Guzmanetal. 1997 1998 ).Thisarguesinfavourofminormergersovermajormergersasaplausiblecausefortriggeringthestarbust.SuchmergerswouldbeevidentinLCBGsthroughtheresolvedmapsoftheirinternalkinematicsandfrommorphologicalfeaturessuchastidaltails. ExamplesofwhymeasuringthekinematicsofdistantgalaxiespreciselyandrobustlyismandatoryforstudyinggalaxyevolutionaretherapidtimedecreaseofcosmicSFR,theroleofmergingintheearlyevolutionofgalaxies,andthepossibleevolutionofrelationssuchastheTully-Fisherrelation(TFR).Toidentifythedynamicalstateofagalaxyrequiresthedetailedknowledgeofitskinematicsonkiloparsecscales.IntegralFieldSpectroscopy(IFS)allowsustocomputeaccuratetotaldynamicalmassesfrombothrotationcurvesandintegratedvelocitywidths,andtotracethespatialdistributionofstarsandgas,aswellastheirkinematiccontributions.Suchspatiallyresolvedkinematics 49

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Recentsurveysaimtocharacterizethespatiallyresolvedkinematicsofdistant(i.e.,fromz0:4toz2)LCBGsbymeansofIFSusinginstrumentssuchasGIRAFFEandSINFONIattheVeryLargeTelescopeoftheEuropeanSouthernObservatory(e.g., Epinatetal. 2009 ; Puechetal. 2006 ; ForsterSchreiberetal. 2006 ).Thesesurveysmayholdthekeytounderstandingtheprocessesthatruletheformationandevolutionofthesegalaxies. InordertoclassifythekinematicsofdistantLCBGs Yangetal. ( 2008 )distinguishedbetweenthreedierentclasses. Yangetal. ( 2008 )foundforasampleof63galaxies32%RDs,25%PRs,and43%CKs,whicharelimitedbyanerrorof12%,conrmingthatat0:4
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3.2 .ThemainstatisticalpropertiesofthissamplearediscussedbelowandlistedinTables 3-1 and 3-2 ForthesakeofthisanalysisthegalaxiesUCM2327nandUCM2327swereconsideredasonegalaxy(i.e.,UCM2327ns).Thispairisabout0.2Mpcawayfromeachotherandseparatedbylessthanabout10arcsec,asseenintheeldofview(FOV)ofPPAK.VelocitywidthmeasurementsforUCM2258werenotpossiblesincehighspectralresolutiondataforthisgalaxywasnotavailable.AsstatedinChapter 2 weconsiderSDSS1703basanLCBG. Table 3-1 listsanestimationofvrotforgalaxiesinwhichthisestimationwaspossible,andameasurementoftheintegratedvelocitywidthasaresultofaddingupalltheavailablespectraforeachgalaxy.Weestimatedforthelatteranaverageuncertaintyof2%asstatedinChapter2forhighS/NGaussianprolets.Furthermore,thegalaxymorphologicaltype,andwhetherornotaknowncompanionispresent,arealsolisted.Whenthemorphologicaltypewasnotavailableintheliteratureaclassicationwasperformedbyeyeusingtherestasareference.Weonlyconsidercompanionshipwhenpreviouslypublishedintheliteratureorwhenfoundinour7465arcsec2FOV(i.e.,2825kpc2attheaverageredshiftofoursample)witharedshiftwithinthemaximumandminimumvelocitiesofthemaintarget.Thus,dierentmethodsbymeansofwhichacompanioncanbefoundareconsidered. Anestimationofvrotwasperformedonlyforthosegalaxieswithagradientinthevelocitymap,andacentralpeakinthevelocitywidthmapthatcouldbeinterpretedasakinematiccenter.Thisaccountsforatotaloftengalaxies.Forthose,galaxyrotationcurvesweredrawnalongtheirmajoraxisasderivedfromthepositionoftheirkinematiccenters,thegeometryoftheirvelocitycontours,andtheirpositionangles(PAs).Nomodelingwasattempted,andvrotwasestimatedashalfthedistancebetweentheredandbluevelocityplateaus(Figures 3-2 and 3-3 ),whichweretbyconstantvalues.The 51

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KinematicsandMorphology Namevrot=siniaMdynbcTypedCompanioneClass(kms1)109M(kms1) NGC7673430:900:2644SaYesRDNGC7714986:030:7575SbYesRDNGC605221225:12:398ScYesRDNGC469...42S0...PRUCM000013615:91:4192Sa...RDUCM0156...57Sb...PRUCM1428...64Irr...CKUCM143113210:91:295Sb...RDUCM1648...47Sa...PRUCM2250...88Sa...CKUCM2258......ScYesRD/PRUCM231714430:92:386Sa...RDUCM2327ns...47Sb&S0YesCKSDSS113422429:22:6193SaYesRDSDSS15071175:090:7738Sd...RDSDSS1605...30IrrYesCKSDSS1652...50Sc...PRSDSS1703a...67IrrYesCKSDSS1703b...31SdYesPRSDSS1710520:940:2258Sd...RDSDSS2327793:480:5346Sc...RD Averagesf1246013117246...... 52

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2-1 .Themassesoftheseobjectsvarybetween1109and31010M,whichcoincideswiththeupperlimitonthestellarmassofgalaxiesfromthe\bluecloud." Furthermore,vrotcanbealsoestimatedfromthemeasurementofthevelocitywidthbymeansofW20(W20=3:58;vrot=0:5W20=sini),or,better,bymeansofWR( Tully&Fouque 1985 ),whichaccountsforrandommotions.ThiscorrectionforrandommotionsdecreasesthelinewidthofthelocalLCBGby26{38kms1,dependingontherotationalvelocity( Garlandetal. 2007 ).ForspiralgalaxiesWRisequaltotwicevrot(i.e., (vrot0:5WR)=vrot0with=0:09; Tully&Fouque 1985 ).Foroursub-sampleofrotatingLCBGswendthatwhilealsoinagreement,thisisbecausethedispersionofthecorrelationisratherlarge(i.e.=0:55).Suchadispersionmayaccountforafactorupto2whenestimatingvrotfromvelocitywidths(withrespecttotheactualmeasurement),whichtranslatesintoafactorupto4whenestimatingdynamicalmasses.ThisimpliesthatthevelocitywidthsofLCBGs,ratherthanaccountingfortheoverallrotationofthesegalaxies,maysignicantlyaccountaswellforotherkinematiccomponentsand,therefore,maynotbeasgoodofadynamicalmassestimator. Figure 3-1 showstheTFRforthesegalaxiescomparedtoarecentcallibrationby Tully&Pierce ( 2000 ).OursampleoflocalLCBGstendtoshowlargerMBthanthesampleofspiralgalaxiesusedfortheircalibrationforaparticularWR.Thissuggeststhat,overall,foraparticularrotationvelocity,theyarebrighter.Therefore,theirmass-to-lightratiosarenotinagreementwiththosefoundforspiralgalaxies,theytendtobelower.Actually,bycombiningthedynamicalmassesshowninTable 3-1 andtheabsolutemagnitudesshowninTable 2-1 ,wendanaveragevalueforM=LBequalto0.6.Suchalowervalueisinagreementwiththosefoundforlate-typegalaxies( Dickel&Rood 1978 ). Ourobservationalstrategyallowedustosamplethelowsurfacebrightnessoutskirtsofthesegalaxies,andacarefullookattheoppositeextremesofourrotationcurvesshows 53

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Tully-FisherRelationforasubsampleof10rotatorsamongoursampleofLCBGs(lledsquares).NGC469,whichisnotanRD,isalsoshown(opensquare)foralatterdiscussion(Chapter 4 ) this.Weinvestigatedfurthertheeectofthisinourdeterminationofvrotbyconsidering1datapointsforthetsoftheplateausandfounditisonlyimportantfortheredplateauofUCM0000asitcanbeseeninFigure 3-2 .Theaveragevarianceofthesetsis1kms1.Theuncertaintyassociatedtoasinglevelocitydatapointis6kms1.Byconsideringa10variationintheestimatedPAswedidnotndimportant(lessthan1%)eectsinourdeterminationofvrot.Fromoursimpleanalysisandplateautsweestimatedanaverageuncertaintyof7kms1inourestimationofvrotforeachgalaxythatdoesnottakeintoconsiderationtheeectsoftheuncertaintiesassociatedtotheinclinationofthesegalaxies. Tocorrectvrotfortheeectsofinclination(i),weapproximatedeachSDSSgalaxy'sinclinationby a;(3{1) 54

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RotationcurvesofUCM0000,UCM1431,UCM2317,SDSS1134,SDSS1507,andSDSS2327.ForeachLCBG,thedashedlinesindicatetheplateaus,whilethedottedlineindicatesthevelocityofthecentralvelocitywidthpeak,whichistakenasareference.Thex-axisindicatesthedistanceinarcsecfromoneextremetotheotherofthemajoraxisofthegalaxy.Thepositionofthecentralvelocitywidthpeakcorrespondstotheintersectionoftherotationcurvewiththedottedline.ThespatiallyresolvedkinematiccomponentsofUCM2317wereremovedforthisanalysis. 55

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RotationcurvesofSDSS1710,NGC7673,NGC7714,andNGC6052.ForeachLCBG,thedashedlinesindicatetheplateaus,whilethedottedlineindicatesthevelocityofthecentralvelocitywidthpeak,whichistakenasareference.Thex-axisindicatesthedistanceinarcsecfromoneextremetotheotherofthemajoraxisofthegalaxy.Thepositionofthecentralvelocitywidthpeakcorrespondstotheintersectionoftherotationcurvewiththedottedline.ThespatiallyresolvedkinematiccomponentsofNGC7673(clumponthenegativevelocityside)andNGC7714(arconthenegativevelocityside)canbeeasilyseenalthoughtheywerenottakenintoaccountintheanalysis. whereaandbarethemajorandminoraxisrespectively.TheSDSSisophotalmajorandminoraxesintherband(6230A)wereused.Inclinationsfrom Garlandetal. ( 2004 )wereusedforNGC7714andNGC6052.TheinclinationsforNGC7673andNGC469weretakenfrom Pisanoetal. ( 2001 )andHyperLeda1respectively.InclinationsfortheUCM 56

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whereaandbarethemajorandminoraxisrespectively( Tully&Fisher 1988 ),assuggestedbytheUCMcollaboration.Ifanuncertaintyof10%intheinclinationisassumed,vrotwouldrange,onaverage,from10%invrot. Ontheotherhand,Table 3-2 liststhepresenceandpropertiesofbothspectralandspatiallyresolvedcomponents.Spatiallyresolvedcomponentswereidentiedbystudyingthevelocitymapofeachgalaxy,whilespectralindependentcomponentswereidentiedbystudyingthenon-gaussianityofthespectraofeachgalaxyasexplainedinChapter2.Thenumber(N),extension(A;areaincomparisonwiththeareaofthegalaxy),andaveragevelocitywithrespecttotheirsurroundings( v)arelistedforthelatter.Theextension(A;areaincomparisonwiththeareaofthegalaxy),theaverageintensitybetweencomponents( Imax),andtheaveragedistancebetweencomponents( c)arelistedfortheformer. Threeofthegalaxiesinoursampleshowspatiallyresolvedkinematiccomponentsdecoupledfromtherestofthegalaxy.Thedetectionofsuchcomponentswerepossibleinrotatingsystemssincetheywereidentiedasakinematicallydecoupledregionwithinarotatingbackground.Thesekindofdetectionswouldhavebeenalsopossible,forexample,withinanhomogeneousvelocitymapinaface-ongalaxy.NGC7673showstwospatialkinematiccomponentsmovingatanaveragespeedof354kms1,whilethearcofNGC7714ismovingatanaveragespeedof635kms1.FurthermoreUCM2327showstwoextracomponentslocatedatitscoremovingatanaveragespeedof19334kms1.Allvecomponentsinthethreegalaxiesaremovingawayfromtheobserverandfallingtowardsthegalaxy,ifweassumethegalaxyisopaque.Thisopacitymayalsoexplainwhywedonotseecomponentsmovingtowardstheobserverandfallingtowardsthegalaxy,sincetheywouldbebehindthegalaxy.Thedetectionofthesecomponentsislimited 57

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KinematicComponents NameSpectralComponentsSpatialComponentsA NGC7673.........23573:00:7NGC77146:80:74592:30:41363163145:80:6NGC60522014363:00:21772.........NGC469..................UCM000022441125:31:331110.........UCM015613648353:30:61955.........UCM14283371101:90:11121.........UCM1431.....................UCM1648.....................UCM2250.....................UCM2258.....................UCM2317............2193904:00:6UCM2327ns.....................SDSS1134.....................SDSS1507.....................SDSS1605.....................SDSS1652.....................SDSS1703a.....................SDSS1703b.....................SDSS17109473241:80:51064.........SDSS2327..................... Averagesa12754152:91:3170761:70:597844:31:4

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Sixofthegalaxiesinoursamplearefoundtoshowspectrallyresolvedkinematiccomponentsinaboutatenthoftheirareaafterinvestigatingtheirspectra.Thetypicaldistancebetweentheseis2.9A,whichattheaverageredshiftofthegalaxiesinoursampleimpliesanosetofabout170kms1.Furthermore,onaverage,oneofthecomponentsistwiceasintenseastheother.ThedetectionofthesecomponentsislimitedbythespectralresolutionandtheS/Nofourdata.Thespectralresolutionofourdatais,asdiscussedinChapter2,2.3AFWHM(60kms1at5040A)andweshouldbeabletomeasurebroadeningeectsdownto40kms1.However,afterinvestigatingouranalysisoftheresidualsofourGaussianproletprocedurewefoundwewereabletoidentifybroadeningeectsdownto60kms1,andosetsbetweencomponentsof1A(60kms1at5040A).Nevertheless,theosetswemeasureforthedierentcomponentsidentiedinseveralgalaxiesofoursamplearetwiceaslargeasthislowerlimit.Again,theareaofthesecomponentswascalculatedbycomparingthenumberofbersperditheringinwhichtheyweredetectedwiththenumberofbersperditheringinwhichthegalaxywasdetected. 59

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Marloweetal. ( 1995 )inalocalsampleofstar-formingdwarfgalaxiesusingEchellespectraandFabry-Perotimages.Whilethecomparisonisobviousforthethreeofourgalaxiesthatdonotrotate,whereweassume,as Marloweetal. ( 1995 ),abubbleisresponsibleforthedoubleprole,itisnotforthosethatdorotate.Forthelatter,weconsiderthatoneofthecomponentsaccountsfortheoverallrotatingbehaviorwhiletheotheroneaccountsforadecoupledcomponent.Theselamentsand/or\superbubbles"havethepotentialofbeingresponsibleforstarburst-drivenmasslossandtheirinabilitytoretainnewlysynthesizedmetals,andthereforelowmetallicities.ForacorrelationbetweentheseIreferthereaderto Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2010 ). OnlyNGC7714showsbothspectralandspatialkinematiccomponents.Furthermore,NGC7714andUCM2317aretheonlygalaxiesforwhichanestimationforvrotwaspossiblewhilealsohavingeitheraspectralorspatiallyresolvedkinematiccomponent.TherotatingnatureofUCM2317wasactuallyfoundafterremovingthesecomponents(Figure 3-17 ). UCM0000shows,notdouble,buttriplespectralkinematiccomponentsin4%ofitsarea,andabroadcomponent(8.0AFWHM,whichtranslatesinto200kms1attheredshiftofthegalaxy)in12%ofitsarea(Figure 3-4 ).Thisistheonlygalaxyinoursampleshowinganobviousbroademissionlinecomponent.Anattempttoinvestigatethenatureofthiscomponentwasmadebycalculatingthe[OIII]5007/H,[NII]6584/H,and[SII]6717,6731/Hratiosfortheparticularregionofthegalaxy(i.e.,0:95,0:18,and0:55dex,respectively),tostudythepossiblepresenceofAGNactivity.Figure 3-5 showstheBPTdiagram( Baldwinetal. 1981 )foremission-linegalaxiesintheSDSSasinFigure2of Obricetal. ( 2006 ).Emission-linegalaxiescanbeseparatedintotwogroupsaccordingtotheirpositionintheBPTdiagram:AGNs,andstar-forming,usingtheseparationboundariesoutlinedbythedashedline.TheseratiosforUCM0000areingoodagreementwiththoseofanAGN( Osterbrock 1989 ).Furthermore,thepressure 60

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Rickesetal. 2008 ).Therefore,UCM0000,istheonlygalaxyamongoursampleof22LCBGstoshowclearevidenceforAGNactivity.NoticethatwhilethebroadcomponentwasdetectedintheV1200conguration,theV300conguration,whereallcomponentsareblended,wasusedtoestimatetheseratios.Therefore,theseratiosmaybelowerlimits. Figure3-4. SingleandtripleGaussianproletsareshown(dashedline)forthisparticularspectrumofUCM0000. Tenofthegalaxiesinoursampleareknowntohaveacompanion.TwoofthosearefoundwithintheFOVoftwoofourgalaxies(SDSS1134andSDSS1605).OneofthosewasfoundaftercomparingitspropertiesaslistedintheSDSScatalog(SDSS1703aandSDSS1703b).TherestwerefoundintheliteraturethroughtheNASAExtragalacticDatabase. Wendthatalmosthalfofoursamplerotates,beingtheaverageratiovrot=2,whichindicatestherotation-dominatednatureoftheseparticularobjects.LocalLCBGsshowvelocitywidthstypicallyrangingfrom30{100kms1,whichareinagreementwiththerangefoundatintermediateredshift(e.g., Guzmanetal. 1997 ).Nevertheless, 61

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BPTdiagramforSDSSemission-linegalaxies(notethatthelineuxratiosareexpressedonalogarithmicscale).UCM0000AGNcandidateisshownasabigblackdot.Emission-linegalaxiescanbeseparatedintotwogroupsaccordingtotheirpositionintheBPTdiagram:AGNs,andstar-forming,usingtheseparationboundariesoutlinedbythedashedline. twoobjects,UCM0000andSDSS1134,showvelocitywidthsashighas200kms1.WhileUCM0000owesitshighvelocitywidthtothepresenceofanunderlayingbroadcomponentthatislikelycausedbyanAGN,SDSS1134'shighvelocitywidthisduetoitsrotatingnature,whichtranslatesintotheonlydouble-hornedvelocityproleweidentifyamongtheintegratedspectraofoursample.ItisimportanttonoticeherethatinorderfortherotatingnatureofobjectssuchasNGC7673,NGC7714,andUCM2327tobefound,itisnecessaryrsttoidentifytheirspatiallyresolvedkinematiccomponents,subtractthem,andonlythen,measurevrot. Almosthalfofourtypicallymid-tolate-spiralsampleareknowntohaveacompanion.Halfofthesegalaxieswithacompanionshowarotatingnatureandvrotwasderivedforthem.ItisimportanttorealizethatobjectssuchasNGC6052,whichisamergeroftwogalaxies,mayowetheirrotatingnaturetoaprojectioneectaccordingtotheanalysisof Garlandetal. ( 2007 ).WestudythisscenarioinChapter 4 62

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Twooutofthethreegalaxieswithspatiallyresolvedkinematiccomponentsarefoundtohaveacompanion,whiletwooutofthesixgalaxieswithspectrallyresolvedkinematiccomponentsarefoundtohaveacompanion.Furthermore,onlyoneofthegalaxiesfoundtohaveacompanion,SDSS1134,showsanunambiguousrotatingnature(i.e.,smoothvelocitygradient,centralvelocitywidthpeak,andnospatiallyresolvedkinematiccomponents).IfweexcludealsoNGC7714,whosespatiallyresolvedkinematiccomponentisaspiralarm,andignoreUCM2258,whichV1200congurationwasnotavailable,weareleftwithveoutofvegalaxieswithbothadistortedkinematicbehaviorandacompanion.Outofthe12galaxieswithoutacompanion,sixshowalsoadistortedkinematicbehavior.Infact,allthegalaxieswithacompanionareeitherclassiedasPRsorCKs,orshowspatiallyresolvedkinematiccomponents,whichdenotestheeectscompanionshaveonthekinematicsoftheirpairs. Thedicultiesfoundwhentryingtoclassifytheobjectsinoursampleintothedierentclassesdenedby Yangetal. ( 2008 ),leadsustobecautiousaboutanyinterpretationthatmayfollowtheclassicationofsuchobjectsatintermediateredshift.AsforoursampleoflocalLCBGswend48%RDs,28%PRs,and24%CKs.NotethatwewereunabletoproperlyclassifyUCM2258,forwhichwedonothavevelocitywidthmeasurements.Thesenumbersseemindisagreementwiththoseof Yangetal. ( 2008 ).Nevertheless,ifwedonotconsiderNGC7376,NGC7714,andUCM2317,forwhich 63

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Yangetal. ( 2008 )found(i.e.,32%RDs,25%PRs,and43%CKs). Thisshowshowthetechnicallimitationofdistantobservationsmayplayaroleinthekinematicclassicationofthisgalaxies.Thus,forexample,thedetectionofaspiralarc,suchastheoneshownbyNGC7714(Chapter 4 ),inthevelocitymapofadistantRD,forwhichthephotometricdeterminationofthespiralarcmightnotbepossible,wouldturnitintoaCK.Furthermore,minormergers,suchastheoneshownbyNGC7673(Chapter 4 ),wouldnotbeseenbecauseoftheactualsizeofthespatialresolutionelementonthesky.Also,projectioneectsinmergersystems,suchasNGC6052(Chapter 4 ),wherethegeometryofthegalaxypairmakesitseemasifitwasjustoneRD,aectthedistinctionbetweenclasses.AllthisistellingusthatwehavetobeverycarefulwiththepercentagesofRDs,PRs,andCKsderivedfordistantLCBGs. ThisambiguitymaybeparticularlyimportantwhentryingtoestimatedynamicalmassesofdistantLCBGs.Mass,notluminosity,isthefundamentalquantitythatremainsconstantthroughouttheevolutionoftheseobjects.ItisunlikelyforLCBGstohaveexperiencedinthelast9Gyralargenumberofmajormergersthatwouldconsiderablyhaveincreasedtheirmasses;theyaremorelikely,instead,tohaveevolvedpassively( Wolfetal. 2005 ; Belletal. 2005 ).Thepresenceofdierentasymmetriesinthevelocitymapsmightbeimportantcontributorstothevelocitywidths,togetherwiththeoverallrotationofthesystem.ThisisanimportantthingtotakeintoaccountwhentryingtoestimatedynamicalmassesofdistantLCBGsfromtheirvelocitywidths.Ifwedonotconsiderthis,wrongdynamicalmassestimatesmightleadtothewrongevolutionaryscenario. 3-6 to 3-26 ).Whenpossible,anopticalimagefrom 64

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3.1 ,andasecondonewithoutthose. 65

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B C NGC7673.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 66

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B C NGC7714.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 67

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B C NGC6052.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 68

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B C NGC469.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 69

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B C UCM0000.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 70

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B C UCM0156.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 71

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B C UCM1428.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 72

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B C UCM1431.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 73

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B C UCM1648.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 74

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B C UCM2250.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 75

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B UCM2258.A)DSSimage.B)Velocitymap. 76

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B C D UCM2317.A)DSSimage.B)Velocitymap.C)Velocitymapaftersubtractingspatiallyresolvedkinematiccomponents.D)Velocitywidthmap. 77

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B C UCM2327.A)DSSimage.B)Velocitymap.C)Velocitywidthmap. 78

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B C SDSS1134.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 79

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B C SDSS1507.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 80

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B C SDSS1605.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 81

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B C SDSS1652.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 82

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B C SDSS1703a.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 83

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B C SDSS1703b.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 84

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B C SDSS1710.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 85

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B C SDSS2327.A)SDSSimage.B)Velocitymap.C)Velocitywidthmap. 86

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Garlandetal. 2007 ; Pisano,Garland,Perez-Gallego,etal. 2009b ).Inparticular,NGC469isacompacteldLCBG,NGC6052isamajormerger(e.g., Alloin&Duot 1979 ),andNGC7714isthememberofagalaxypair(e.g., Smithetal. 1997 ).AsforNGC7673,itisaminormergercandidateassuggestedinthepast(e.g., Homeier&Gallagher 1999 )andinvestigatedhere. Duot-Augarde&Alloin 1982 ; Homeieretal. 2002 ; Pasquali&Castangia 2008 ; Homeier&Gallagher 1999 ,hereafterHG99).Thisirregularstarburstgalaxy(Figure 4-1 )showsaclumpystructurewithbrightknotsofstarformationembeddedinadiusehalothatcanbeseenintheopticalspectralrange(HG99, Perez-Gonzalezetal. 2003 ). Duot-Augarde&Alloin ( 1982 )found6dierentstar-formingclumps(Figure 4-1 ),someofwhicharereferredtointhispaper.FromPPAKHuxes Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2009a ,hereafterCM09a)derivedastarformationrateofatleast6.4Myr1.Furthermore,itssmallsize,highsurfacebrightness,strongemissionlinesandbluecolorsmakeNGC7673aprototypicalLCBG(Table 4-1 ).NGC7673belongstotheUCMcatalog. HI21cmlinemappingofNGC7673anditsenvironment( Nordgrenetal. 1997 ),whichincludesneighboringgalaxyNGC7677,roughly7arcmintothesoutheast(3554 87

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NGC7673ObservationalProperties NamezaM(B)aSBeaBVaRea(mag)(magarcsec2)(mag)(kpc) NGC76730.011368b20:3619.950.412.1LCBGsc0:01890:001919:700:2020:300:200:400:022:160:25 vs.3405kms1;HG99)showsasmallouterirregularitythatpointstothelatter.Nevertheless,apresentmajormergerscenariohasbeenrejectedbecauseofaremarkablyconstantvelocityacrossthegalaxy( Duot-Augarde&Alloin 1982 ).HG99useddatatakenwithDENSEPAKtostudythekinematicsofaportionofthegalaxy.Theywerelimitedbythepointingofthetelescopeandboththeeldofview(FOV;3045arcsec2)andthespatialresolutionoftheinstrument.Theirspatialresolutionsamplingoftwothirdsofthegalaxy,asseeninopticalimages,ishighlyimprovedbyoursampling.Nevertheless,theirspectralresolution(FWHM=32kms1)allowedthemtondthatatwocomponentmodel,onenarrow(FWHM55kms1)andonebroad(FWHM150kms1)ttheobservedspectra.Accordingtotheiranalysisthreearethepossibleexplanationsforthepresenceofsuchabroadcomponent:(i)aconsequenceofintegratingovermanyionizedstructuresatdierentvelocities;(ii)hot,turbulentgasconnedtolargecavitiescarvedoutbymassivestars;and(iii)astarburst-poweredgalacticwindorsimilarbreak-outphenomenon.Furthermore,theyexcludeapresent,butnotpast,interactionbetweenNGC7673andNGC7677,indicatingaminormergerasthetriggermechanismforthemajorstarburst. PPAKobservationsofNGC7673weremadeduringthenightsof2005August10and11usingtwodierentsetupsasdiscussedinChapter2(Table 4-2 ). 4-2 .MeasurementsofthevelocitydowntoourS/Nlimitwerepossibleforaregionextending40arcsecindiameter. 88

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NGC7673ObservingLog CongurationDitheringNightExposureTimeOset(s)(arcsec) V300b110August20053330(0.00,0.00)aV300210August20053330(+1.56,+0.78)V300310August20053330(+1.56,0.78)V1200c111August20053900(0.00,0.00)aV1200211August20053900(+1.56,+0.78)V1200311August20053900(+1.56,0.78) Figure4-1. F555WWFPC2imageofNGC7673labeledwiththestar-formingclumpsidentiedby Duot-Augarde&Alloin ( 1982 ).NorthistothetopandEastistotheleft. Thiscompareswellwiththeeectiveradiusofthegalaxy,whichis8.9arcsec(re=2:1kpc,attheredshiftofthegalaxy).Furtheraway,theS/Nwasnothighenoughtoproceedtothemeasurementofthevelocity.Borderandpixelizationeectsduetotheinterpolationprocesswerenotconsideredintheanalysis.Theseeectsmanifestaseitherasteepincreaseorsteepdecreaseofthevelocitytowardstheedgesoftheavailabledata. 89

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4.2.3 ).Noabsolutecalibrationoftherecessionvelocitywasattempted.Thisredshiftis0.011293,smaller,butwithintwosigmaoftheoneavailableintheNASAExtragalacticDatabase1. Theexistenceofanalmoststraightvelocitycontourthatcrossesthegalaxyfromeasttowestthroughthecentralvelocitywidthpeaksuggeststhatitactuallytracesthepositionoftheminoraxisofthegalaxy,yieldingamajoraxispositionangle(PA)equalto168.APAof122derivedfromopticalimagestakenfromHyperLeda2wasusedinpaststudiesofthisgalaxy.ArotationcurvecanbederivedforbothPAsbyreadingthemeasuredvelocitiesalongthecorrespondingmajoraxis(Figure 4-3 ).APAequalto168providesasmootherrotationcurvefromwhichanuncorrectedbyinclinationrotationvelocityofabout30kms1canbeinferred. Whilethesouthernhalfofthegalaxy(darker)isconsistentlymovingawayfromtheobserver,thenorthernhalf(lighter)isnotuniformlymovingtowards.Twodiscreteregionslocatedinthenorthernhalfofthegalaxyaremovingawayfromtheobserverinoppositedirectiontotheirsurroundings. First,wemeasureasmallercircularregion,about1kpcwide,about10arcsecnorthofthecenteroftheFOV.Thisregionismovingawayfromtheobserveratabout35kms1withrespecttoitssurroundings.Furthermore,thisregion,althoughconnedtoonlytheareaofoneber,wasdetectedonthethreeindependentditheringexposures.Second,weidentifyabiggerelongatedregion,about3.5kpclong,whichislocatedtowardsthenorthwest,about2kpcawayfromclumpF.Thisistoofarfromtheedgeoftheavailabledataforustoconsideritasabordereect.Thisregion,considerably 90

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4.2.4.1 ,whetherthesekinematicallydecoupledcomponentsshowphysicalpropertiesthatdierfromtherestofthegalaxy. WhencomparedtotheF555WWFPC2imageofNGC7673(Figure 4-2 )twocharacteristicsstandout:(i)thevelocityeldisconsiderablymoreextendedthantheregionwherethemoreluminousstarformingregionsareconned;and(ii)whilethesmallerdecoupledregionappearstobelinkedtoclumpB,noopticalcounterpartcanbelinkedtothebiggerone. WecompareourresultstothoseofHG99(Figure 4-4 ).UsingthePPAKHimageofthegalaxyandFigure3fromHG99,ourandtheirFOVwereregisteredbyndingthepositionoftwobersmappingthesameregionofthegalaxy.TheDENSEPAKberarraywasdrawnwithintherectangularFOVontheirgureforthatpurpose.ThiswasneededbecauseHG99didnotstatethepointingpositionfortheirobservations.Avelocitymapusingtheirmeasurementswasthenproduceddowntoaresolutionof1arcsecusingourinterpolationmethodandreferencesystem.Thisallowedustodirectlycomparebothmaps.Theresidualimagerevealsanosetof20kms1andastandarddeviationof12kms1.Whiletheirbetterspectralresolution,asstatedabove,allowedthemtolookformultiplekinematiccomponents,bothourFOVandspatialsamplingarebetter,whichallowsustoextendthestudyofthegalaxy.TheonlynotabledierencebetweenbothmapsisthepresenceofthesmallcircularregioninourdataatthepositionofclumpB.Thiscouldbeexplainedbyboththesamplingandtheditheringtechniqueweused,sincethisregionisnotlargeenoughforthemtodetectwiththeirsetup. 4.2.1 ,thevelocityeldofthegalaxyderivedfromthecentroidsoftheHemissionlineprolesshowsasymmetries.Theneutralhydrogenvelocityeldresemblestheionizedone(Figure 4-5 )inextentdowntothedetectionlimits, 91

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B A)PPAKHvelocitymapofNGC7673usingthelowresolutionV300conguration.Thevelocitymapshowsanasymmetricvelocityeldwithatleasttwoindependentkinematiccomponentsinthenorthernsideofthegalaxy.B)PPAKHvelocitymapcontoursoverlaidontheF555WWFPC2imageofNGC7673.ClumpBfrom Duot-Augarde&Alloin ( 1982 )canbeidentiedwithoneoftheindependentkinematiccomponent.Thereisnoopticalcounterpartofthesecondone. overallappearance,andvelocityrange(90kms1; Pisano,Garland,Perez-Gallego,etal. 2009b ). Bothmapswereregisteredusingtheheadercoordinates.Fortheregistrationprocessseveralimageswereused:F555HST,HPPAK,6cmVLA,20cmVLA,andDSS.Theuncertaintyintheregistrationwasestablishedtobenohigherthanhalfanarcsecond.WhenthedistributionsofHIandHIIarecomparedthereisanobviousslightosetbetweenthem.TheHIIdistributionextendsslightlymoretowardsthenortheastwhiletheHIoneextendsconsiderablymoretowardsthewest.Thisdierencemightbeexplainedbytwoplane-paralleldisks.TheHIIdiskmightbethickerthantheHIandonlythenearestsidemightbevisibletous.Ifaninclinationof45isassumedforbothdisks,aseparationofabout1.7kpccanbederivedbetweenthenearestsideofthethickerHIIdiskandtheHIdisk.Thisisinagreementwiththetypicalscaleheightofathickdisk( Howk&Savage 2000 ).Nevertheless,theuncertaintiesassociatedwiththeseestimationsarequitelarge. 92

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RotationcurvesalongthemajoraxisofNGC7673fortwodierentPAs.FromourdatawederiveaPAequalto168,versus122fromtheHyperledacatalog.Theblueside(dashedline),redside(dottedline),andanaverageofbothsides(solidline)ofthegalaxyareplotted. Ontopofthat,aresidualimagewasgeneratedbysubtractingtheopticalvelocitymapfromtheradiooneforthesharedarea.Theresultingmeanandstandarddeviationare0and15kms1,whichmakethemconsistentwitheachother.Whenonlytherecedingpartofthegalaxywasconsideredthesenumberswere8and9kms1respectivelyindicatingthatthereisnotacancellationeectbetweentherecedingandtheapproachingsidesofthegalaxy. Ontheotherhand,whilethedistributionoftheHIresemblesthatoftheionizedgas,theH2distribution,astracedbyCOobservations,isconcentratedalongclumpA( Garlandetal. 2005 );noCOwasdetectedinclumpB.ItistobenotedthatthehighercolumndensitiesofHItracethelocationofCO.ThislackofCOdetectioninclumpBcouldbeexplainediftheburstwasquenching,opaquetoCOradiation,orbeinginjected 93

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PPAKHvelocitymapcontoursofNGC7673overlaidontheDENSEPAKHvelocitymapofNGC7673fromHG99.Bothvelocitymapsareconsistentwithintheirrespectiveuncertainties. withHIthroughgalacticwinds.AtthecurrentSFR(CM09a)theHIstillpresentinNGC7673(MHI=4:09109M; Pisanoetal. 2001 )wouldbeexhaustedinabout1Gyr. 4-6 and 4-7 )canbeusedincombinationwiththevelocitymaptobetterunderstandthekinematicpropertiesofthegalaxy.Invirializedsystemsthevelocitywidthpeaktendstocoincidewiththecentroidofthevelocitymap,assumingitisorganizedrotationwhichdominatesthegalaxymotions. ThevelocitywidthmapofNGC7673peaks(=545kms1)aroundthecenteroftheFOV,betweenclumpsAandC(Figure 4-6 ).Thispositionroughlycoincideswiththeluminosity-weightedcenter(photometric)andthecenteroftheouter-isophotes(geometric)ofthegalaxy.Thesearelocatedrespectivelyabout3and4arcsec(920and690pc 94

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PPAKHvelocitymapcontoursoverlaidonVLAneutralatomichydrogenvelocitymapofNGC7673.ThecombinedB+C+DarrayswereusedfortheVLAmap.Thesizeofthebeamis6".Bothvelocitymapsareconsistentwithintheirrespectiveuncertainties.Theosetbetweenbothmightbeexplainedbythetwoplane-paralleldisksasdiscussedinthetext. respectively)towardsthewestofthecenteroftheFOV;theseosetsarecomparabletothesizeofoneber.Thegeometriccenterwasfoundastheaverageofthepositionofeachberwithsignalfromthegalaxy;whilethephotometriccenterwasfoundastheaveragepositionofeachberwithsignalfromthegalaxyweightedbyitsintegratedux.Twoadditionalelongatedpeaksinvelocitywidthaslargeasthecentralonecanbefoundtothenortheastandnorthwestofthegalaxy.Thevelocitywidthofthegalaxyrangesfromabout15to60kms1withinaFOVcoveredbybersforwhichtheS/Nisatleast30. AsfortheintegratedvelocitywidthHG99foundW20=126kms1(vrot=0:5W20=sini).Thisisslightlylargerthanthevaluefoundby Pisanoetal. ( 2001 ),W20=119kms1fromKeckechellespectroscopy.Furthermore, Pisanoetal. ( 2001 ) 95

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Pisanoetal. ( 2001 ).DierenceswithHG99mightbeattributedtoourlargerFOV,which,ontheotherhand,islargeenoughtoresemblethatoftheHIobservationsof Pisanoetal. ( 2001 ). B A)PPAK[OIII]5007velocitywidthmapofNGC7673usingtheV1200conguration.Thecentralpeakroughlycoincideswiththeluminosity-weightedcenter(photometric)andthecenteroftheouter-isophotes(geometric)ofthegalaxy,andisassumedtobethedynamicalcenterofthegalaxy.Furthermore,theminoraxisofthegalaxyasderivedfromthevelocitycontoursgoesthroughthispeak.B)PPAKHvelocitywidthmapcontoursoverlaidontheF555WWFPC2imageofNGC7673.NorthistothetopandEastistotheleft. 4.2.4.1MinorMergerScenario ArstattempttoinvestigatethenatureofclumpBwasmadebycalculatingthe[OIII]5007/Hand[NII]/Hratiosfortheentiregalaxy,andthiscomponentin 96

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PPAKHvelocitymapcontoursoverlaidonPPAKVelocityWidthMapofNGC7673. particular,tostudythepossiblepresenceofAGNactivity.Nevertheless,theseratios,around0.3and0:7dex,respectively,areinagreementwiththoseofanHIIregion( Osterbrock 1989 ).Furthermore,thepressurederivedforclumpBfromthe[SII]/H(0.4)and[NII]/H(0.2)ratiosisalsoinagreementwiththatofastarburst( Rickesetal. 2008 ).ForclumpBandtheentiregalaxythoseratiosareconsiderablysmallerthanthosefoundinLINERs,inagreementwiththosefoundinstarburstgalaxies,andonlyclosetothosefoundinSeyfertgalaxiesasshowninFigure12from Rickesetal. ( 2008 ). Asmentionedabove,HG99wereabletottheHemissionlinesoftheirintegraleldspectroscopydatawithtwoGaussianprolesthroughoutmostofthegalaxy.Inparticular,beforeHG99, Taniguchi&Tamura ( 1987 )foundtwo(onenarrow,onebroad)kinematiccomponentsatthelocationofclumpB.Nevertheless,aftersimulatingthosebyusingtheirmeasurementsincombinationwithour[OIII]5007emissionlines,spectralresolution,and 97

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AnotherpossibilityisthatclumpBpeculiarkinematicsareduetogalacticwindsandeventhough,asmentionedabove,thequalityofourdatakeepsusfromestablishinganynalwordaboutthenatureofthisregion,afurtherqualitativeanalysisispossiblebasedontheHluminosity(LH)measuredbyCM09ausing Osterbrock 1989 ),whereQisthenumberofphotonsharderthanLyemittedbyastarformingregion,histhePlanckconstant,HisthefrequencyofH,effHisthecaseBHIrecombinationcoecientforH,andBistherecombinationcoecientforH-likeions.Assumingthenthatallthestarsinthestar-formingregionareO7withamassof60MandaSalpeterInitialMassFunction( Salpeter 1955 )wendthat18,500starsareresponsiblefortheionizationofthegas.WhilethisisanapproximationthepresenceofWolf-Rayetfeaturesinourspectra(CM09a)isconsistentwithmassivestars.Ifallthosestarsweretoexplodeassupernovaewithanenergyof1051erg,thetotalthermalenergyreleased(E=1:851055erg),wouldbeunequivocallysmallerthanthebindingenergy(G=5:231057erg)asdenedby( Yoshii&Arimoto 1987 ).GalacticwindscannotbethenresponsibleforthekinematicpropertiesofthecomponentassociatedwithclumpB.Ifweassumethetotalthermalenergyreleasedistransformedintokinematicenergy,velocitiesupto20kms1areaccountedfor.Suchalowvalueisindisagreementwiththebroadcomponentof Taniguchi&Tamura ( 1987 )andcouldnotbedetectedwithourspectralresolution. Ontheotherhand,asstatedbyHG99,bothphotometricandspectroscopicsimilaritiesbetweenNGC7673andNGC3310(awellknownsystemlargelyclassiedasaminormerger)inbothHIIandHIdataleadstoconsiderNGC7673asacandidateforamajorstarbursttriggeredbyaminormerger.Thisminormergerwithadwarf 98

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Metallicityandcontinuum(5600{5800A)measurementsofCM09ashowmarginallyhighermetallicityvalues,andasecondarypeak(secondinintensityafterthecentralone)atthelocationofclumpBrespectively.ThemetallicityvaluesfoundbyCM09aforclumpBanditssurroundingsfrom[OIII]4363arerespectively8:070:06dexand7:760:06dex.ThesecouldbeexplainedbythepresenceofanextremelygiantHIIregionatthelocationofclumpBwithinalowermetallicityenvironment.WhenwecomparethemetallicityandMBofclumpBwithasampleofintermediate-redshiftLCBGsfrom Hoyosetal. ( 2005 ,Figure 4-8 )clumpB,lessluminousandslightlylessmetallic,fallsclosertodwarfirregularswhileNGC7673fallswithintheregionoccupiedbyintermediate-redshiftLCBGs, TheHluminosityandthevelocitywidthofclumpBfollowthecorrelationfoundby Melnicketal. ( 1987 )fornearbygiantHIIregions(Figure 4-9 ).Nevertheless,clumpBisbrighterandconsiderablymoremassivethananyofthenearbygiantHIIregionswithintheirsample.KnowingthatthiscorrelationholdsfromnearbyHIIregionsandgalaxiestotheHII-likegalaxiesfoundatintermediate-,andhigh-redshift( Siegel,Guzman,Perez-Gallego,etal. 2005 ),suggeststhataninfallingdwarfgalaxy,insteadofagiantHIIregionatthelocationofclumpBmightberesponsibleforitspeculiarbehavior.Iftheminormergerscenarioweretobeconrmed,theelongatedindependentkinematiccomponentcannotbedisregardedasapossiblesideeectwithintheminormergerscenario. Furthermore,CM09ameasurementsoftheequivalentwidthsoftheunderlyingpopulationabsorptionspectralfeatures(e.g.,H,H)showapeculiarityatthelocationofclumpB.Whilethestrengthofthesefeaturesisnoticeablethroughoutthegalaxy,itisalmostnonexistentatthelocationofclumpB.Thestrengthoftheequivalentwidthofthesefeaturesaccountfortheageoftheunderlyingpopulation.Stronglinesaremainly 99

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Figure4-8. 12+log(O/H)vs.MBforasampleofintermediate-redshiftLCBGs.Dotsarefrom Hoyosetal. ( 2005 ).ThepositionofNGC7673andclumpBarealsoshownasmeasuredbyCM09a.Thedashedlinerepresentstheluminosity-metallicityrelationforlocaldIrr( Richer&McCall 1995 ).Thesolidlinerepresentsthisrelationforextremelymetal-poorBCGs( Kunth&Ostlin 2000 ).Theuncertaintiesofourmetallicityandluminositymeasurementsaresmallerthanoursymbols. IfweassumeforNGC7673apeaktopeakvelocityrangeassuggestedbytherotationcurvederivedabove(60kms1),theinferredrotationalvelocityvrot=q RetranslatesintoadynamicalmasswithintheRemeasuredby Pisanoetal. ( 2001 )of 100

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Melnicketal. ( 1987 ).ThepositionofNGC7673andclumpBarealsoshownasmeasuredbythiswork()andCM09a(LH).Thesolidlinerepresentsthecorrelationbetweentheseparameters.ThiscorrelationholdsfromgiantHIIregionstosimilarstarburstgalaxiesobservedathighredshift( Siegel,Guzman,Perez-Gallego,etal. 2005 ).Theuncertaintiesofourluminositymeasurementsaresmallerthanoursymbols. Pisanoetal. ( 2001 )inferredadynamicalmassof2:51010MwithinRHI(RHI=8:3kpc4:5Re)fromtheirW20measurements.Inbothcasesaninclinationof45isassumed. Ontheotherhand,consideringtheKmagnitudeofNGC7673andthemassluminosityrelationM=LK=0:51forBCDsfrom Perez-Gonzalezetal. ( 2003 )wederiveastellarmassof1:51010M.Atotalmassof1:91010Misthencalculatedbyaddingthemassoftheneutralhydrogenestimatedby Pisanoetal. ( 2001 ).Ifthesystemistobevirializedtheresultingrotationalvelocitywouldbevrot=133kms1.InorderfortherotationcurvederivedforaPAequalto168toagreewiththisvrottheinclinationofthegalaxymustbecloseto15,whichontheotherhandisnotunreasonablewhenonetakesalookattheopticalimageofthegalaxy. FromourintegratedPPAKdatawendW20=1594kms1.Ifaninclinationequalto15isalsotobeconsideredtherotationalvelocitywouldrisetovrot=290kms1. Asitis,neitherthepeaktopeakvelocityrangeshownbytheopticaldatanortheoneshownbytheradiodata,accountsforsuchalargevroteventhoughtheentireFOV 101

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deVaucouleursetal. 1991 )labeledasaprototypicalstarburstgalaxyby Weedmanetal. ( 1981 ).Itshowsabulgeandadistorteddisk,abarandspiralarmsand,atleast,threemajorclumpsofstarformation(Figure 4-10 ).Fluxesatdierentwavelengths,fromX-raytoradio,areexplainedasaconsequenceofanintensestarformationactivitycenteredonitsnucleus.Inparticular, Weedmanetal. ( 1981 )explainedtheX-rayandradioluminositieswith104supernovaremnants.Asforitsopticalcontinuumandfar-IRcolors, Bernloehr ( 1993 )foundthatthestarformationinNCG7714isconsistentwithacontinuousSFRduringthepast20Myr,whichhadprobablybeentriggeredbytheinteractionwiththecompaniongalaxyNGC7715( Smithetal. 1997 ),found2arcmin(i.e.,22kpc,attheredshiftofthegalaxies)awayfromthenucleusofNGC7714.FromPPAKHuxes Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2009b ,hereafterCM09b)derivedastarformationrateof10:60:8Myr1. Verydetailedstudieshavebeencarriedoutintheopticalandnear-IRpartofthespectrumtocharacterizethegaspropertiesinthenuclearandcircumnuclearregionsofNGC7714( Gonzalez-Delgadoetal. 1995 ; GonzalezDelgadoetal. 1999 ).Thesestudiesconcludedthatthenuclearburstofstarformationshouldhaveanagearound4{5Myr,takingintoaccountthedetectionofaWolf-Rayetbump,andnoticedthepresenceofapreviousburstofstarformationinviewofthedetectionofthecalciumabsorptiontripletat8600A.Modelsby Garcia-Vargasetal. ( 1997 )indicatethatayoungburst3{5MyroldwouldbeabletoexplaintheemissionlinespectrumandWolf-RayetbumpdetectioninthreecircumnuclearHIIregionsofNGC7714. Lanconetal. ( 2001 )found,using 102

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F814WWFPC2imageofNGC7714labeledwiththenucleusandthreestar-formingclumpsusedby Gonzalez-Delgadoetal. ( 1995 ).NorthistothetopandEastistotheleft.NorthistothetopandEastistotheleft.WehadtocombinetwoF814WWFPC2imagesofNGC7714inordertocoverthefullFOVofPPAK,sinceeachofthosecoveredonlyhalfofthegalaxy. populationsynthesismodels,thatthestarburstisresponsibleforonlyasmallportionofanextendedstarformationepisode,triggeredapproximately108yrago. HI21cmlinemappingby Smithetal. ( 1997 )showedanextendedHIemissionaroundNGC7714,formingabridgethatspreadsouttowardsitseasterncompanion.Deviationsfromcircularmotionarefoundintheouterregionsofthegalaxydisk,whiletheinnerregionsshowasmoothgradientforarotatingdisk.Inthesamestudy,NGC7715wasalsofoundtoexhibitsignsofrotation.Thispairofgalaxies,knownasArp284( Arp 1966 ),isoneoftheprototypicalcollisionalstarburstsystemsknown.Numericalmodelsandtheobservedstellarandgasmorphologiessuggestarecentcollision,between100{200Myrago( Struck&Smith 2003 ).Multiwavelengthdata,summarizedin Smithetal. ( 1997 ),revealyoung,intermediate-age,andoldstellarpopulationsinNGC7714.Itshighsurfacebrightness,strongemissionlinesandbluecolorsmakeofNGC7714aprototypicalLCBG(Table 4-1 ).Furthermore,itsapparentsizemakesitasuitablecandidateforouranalysis. 103

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4-4 ). Table4-3. NGC7714ObservationalProperties NamezaM(B)bSBebBVbReb(mag)(magarcsec2)(mag)(kpc) NGC77140.009333c20:1020.000.402.70LCBGsc0:01890:001919:700:2020:300:200:400:022:160:25 ( 1999 );b( Garlandetal. 2005 )cThisgivesascaleof0.189kpcarcsec1dMeanandstandarddeviationofoursample Table4-4. NGC7714ObservingLog CongurationDitheringNightExposureTimeOset(s)(arcsec) V300b110August20053330(0.00,0.00)aV300214August20053330(+1.56,+0.78)V300314August20053330(+1.56,0.78)V1200c111August20053900(0.00,0.00)aV1200211August20053900(+1.56,+0.78)V1200312August20053900(+1.56,0.78) 4-11 .Beingthegalaxyinoursamplewiththelargestapparentsize,re=14:3arcsec(i.e.,re=2:7kpc,attheredshiftofthegalaxy),measurementsofthevelocitydowntoourS/Nlimitwerepossibleforaregionextendingover40arcsecindiameter.Furtheraway,theS/Nwasnothighenoughtoproceedtothemeasurementofthevelocity.Neitherbordernorpixelizationeectsduetotheinterpolationprocesswereconsideredintheanalysis.Thesemanifestaseitherasteepincreaseorsteepdecreaseofthevelocitytowardstheedgesoftheavailabledata. 104

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B A)PPAKHvelocitymapofNGC7714usingthelowresolutionV300conguration.B)PPAKHvelocitymapcontoursoverlaidontheF814WWFPC2imageofNGC7714. Thevelocitymapshowsamostlysymmetricvelocitygradientthatrangesfromapproximately80to80kms1.Thevelocitiesshowninthemaparereferencedtotheredshiftofthecentralpeakvelocitywidthofthegalaxy(Section 4.3.2 ),whichroughly(withinonesigma)coincideswiththeoneavailableintheNASAExtragalacticDatabase(z=0:009333). Theexistenceofaratherstraightvelocitycontourthatcrossesthenucleusofthegalaxyfromthenortheasttothesouthwestthroughacentralvelocitywidthpeaksuggeststhatitactuallytracesthepositionoftheminoraxisofthegalaxy,yieldingamajoraxisPAequalto135.ArotationcurvecanbederivedforthisPAbyreadingthemeasuredvelocitiesalongthecorrespondingmajoraxis(Figure 4-12 ).APAequalto135providesasmoothrotationcurvefromwhicharotationvelocityofabout75kms1uncorrectedbyinclinationcanbeinferred.Thedatacorrespondingtomeasurementsofthevelocitiesofthespiralarcofthegalaxywereleftoutofthisanalysis. Gonzalez-Delgadoetal. ( 1995 )foundasimilargradientforaPAof110. 105

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RotationcurvealongthemajoraxisofNGC7714foraPAequalto135.Thedashedlinesindicatetheplateaus,whilethedottedlineindicatethevelocityofthecentralvelocitywidthpeak,whichistakenasareference. Thenorthwesternhalfofthegalaxy(darker)isconsistentlymovingawayfromtheobserver,whilethesouthesternhalf(lighter)ismovingtowardswiththeexceptionofanelongatedregion,about4kpclong,about20arcsecsoutheastofthecenteroftheFOV.Thisregionismovingawayfromtheobserveruptoatabout60kms1withrespecttoitssurroundings,ingoodagreementwiththeoverallvelocitybehaviorofthenortheasternhalfofthegalaxy.Wediscussbelowwhetherthiskinematicallydecoupledcomponentshowphysicalpropertiesthatdierfromtherestofthegalaxy. WhencomparedtotheF814WWFPC2imageofNGC7714(Figure 4-11 )twocharacteristicsstandout:(i)thevelocityeldfollowsratherwellthedistorteddiskofthegalaxy;and(ii)thedecoupledregionappearstobelinkedtothespiralarmofthegalaxy. 106

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4-13 and 4-14 andcanbeusedincombinationwiththevelocitymaptobetterunderstandthekinematicpropertiesofNGC7714. B A)PPAK[OIII]5007velocitywidthmapofNGC7714usingtheV1200conguration.B)PPAKHvelocitywidthmapcontoursoverlaidontheDSSimageofNGC7714.NorthistothetopandEastistotheleft. ThevelocitywidthmapofNGC7714showsapeak(=812kms1)about6arcsec(1.1kpc)westothecenteroftheFOV,whichislocatedabout7arcsec(1.3kpc)southeastfromthenucleusofthegalaxy(Figure 4-13 ).Thispeakisinagreementwiththemeasuredvelocitygradientalongthediskofthegalaxy(Figure 4-14 ).Theluminosity-weightedcenter(photometric)andthecenteroftheouter-isophotes(geometric)ofthegalaxyarelocatedrespectivelyabout4arcsec(760pc)northwest,and3arcsec(570pc)westfromthecenteroftheFOV.SeveralotherpeaksarefoundwithintheFOV.Thesecanbeexplainedbythepresenceofspectrallyresolvedcomponentsinupto6%ofthetotalareaofthegalaxy.Thevelocitywidthofthegalaxyrangesfromabout15to90kms1withinaFOVcoveredbybersforwhichS/Nisatleast30. 107

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PPAKHvelocitymapcontoursoverlaidonPPAKVelocityWidthMapofNGC7714. SpiralArm.Asstatedabove,anindependentkinematiccomponentisfoundinNGC7714movingatanaveragevelocityofabout60kms1.Thiselongatedcomponentislocatedatthepositionofthewesternspiralarmofthegalaxyandmovingatapositivevelocitywhichisingoodagreementwiththeoverallvelocityoftheoppositesideofthegalaxy.Ontheotherhand,theaveragemetallicityalongthespiralarm,12+log(O=H)=8:550:25isinbetteragreementwiththeoverallmetallicityofthebluehalfofthegalaxyinstead,higherthantheonefoundontheredhalfmovingatthevelocityofthespiralarm( Castillo-Morales,Gallego,Perez-Gallego,etal. 2009b ). Re=98kms1translatesintoadynamicalmasswithinRe=2:7kpcofaround 108

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Garlandetal. 2004 ).Forthisgalaxy Garlandetal. ( 2004 )found,fromtheirHIstudy,MHI=7:6109M,andMdyn(Re)=1:11010M. Garlandetal. ( 2004 )estimatetherandomerrorsassociatedwiththedynamicalmasstobeapproximately50%. FromourintegratedPPAKdatawendW20=2726kms1.Ifaninclinationequalto50isalsotobeconsideredarotationalvelocityvrot=177kms1canbederived,whichwouldtranslateintoamassaboutfourtimeslargerthantheonederivedfromthepeaktopeakanalysis. 4-15 ;e.g., Heidmann 1987 )includedintheAtlasofPeculiarGalaxies( Arp 1966 ).ColormapsofNGC6052indicatestarformationisoccurringinnumerousregionsspreadovernearlytheentiresystem,andthepresenceofalarge-scale,inhomogeneousabsorptionpattern( Papaderosetal. 1998 ).Meanwhile,theHemissionisclumpyandsuggestiveofoutows,withloops,tendrils,andnumerouslaments( Cairosetal. 2001 ; Martnez-Delgadoetal. 2009 ). Martnez-Delgadoetal. ( 2009 )catalogedatotalof30starformationknots.FromPPAKHuxesCM09bderivedastarformationrateashighast25:21:9Myr1.Ontheotherhand,infraredstudies(e.g., Metcalfeetal. 2005 ; Whelanetal. 2007 )havelabeledNGC6052asaLuminousInfraredGalaxy(LIRG)withatotalIRluminosityof1:01011L.NGC6052belongstotheSDSScatalog. OneremarkablefeatureofNGC6052isthedoubletailintheeastsideofthegalaxy,extendingoutinthenorth-southdirection.Thisgalaxyhasbeeninterpretedastheresultofacollisionbetweentwolate-typespiralgalaxiesforwhich Alloin&Duot ( 1979 )identiedtwopeaksinthecontinuumframesastwocompactcoresembeddedinacommonenvelope.Ithasalsobeeninterpretedastheresultofacollisionbetweenaspiralandanirregular( Burenkov 1988 ),whichinducedstarformationthroughoutthe 109

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F555WWFPC2imageofNGC6052.NorthistothetopandEastistotheleft. galaxy. Taniguchi&Noguchi ( 1991 )found,usingnumericalN-bodysimulations,thattheopticalmorphologicalpropertiesofNGC6052canbeexplainedastheresultofacoplanarradialpenetrationcollisionbetweentwodiskgalaxies.Theysuggestthatinthiscollision,thetargetgalaxywasdeformedintothenorth-south\wing"bytheface-onintrudergalaxy.TheHImapof Garlandetal. ( 2007 )showsatidaltailthatismuchmoreextendedandlopsidedthantheopticalwingtowhich Taniguchi&Noguchi ( 1991 )matchedtheirsimulation.TheHIobservationsof Garlandetal. ( 2007 )donotappeartosupportthecoplanarradialpenetrationmodel.NGC6052maybeinalaterstageofmergingthansuggestedbythismodel. HI21cmlinemappingby Garlandetal. ( 2007 )showadisturbed,asymmetricdistributionofHIinNGC6052,withanorth-southelongation.Aslightextensionisalsovisibleintheopticalimage.TheHIvelocityeldofNGC6052derivedby Garlandetal. ( 2007 )showsavelocitygradientacrossthemainpartofthegalaxy,butthenorth-southextensionisatanearlyconstanthighervelocity.ThemeasuredHImass,6:3109M,is90%ofthatmeasuredwiththeGBT Garlandetal. ( 2007 ).Theydidnotexpectanycontamination,asNGC6052hasnoknowncompanions. 110

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4-5 ),plusithasoneofthehighestinfraredluminosity,dynamicalmass,moleculargasmass,andratioofmoleculartoatomicgasmass( Garlandetal. 2004 2005 2007 ).Itssuggestedmergerstatemayexplaintheseobservations.Closeinteractionsliketheone Garlandetal. ( 2007 )inferredcouldtriggerquickconversionofatomictomoleculargas,resultinginabrightstarburst,centrallyconcentratedCO,andadisturbedHIcomponent,asinultra-luminousinfraredgalaxies( Solomon&Sage 1988 ). PPAKobservationsofNGC6052weremadeduringthenightsof2005August9,11,12,and14usingtwodierentsetupsasdiscussedinChapter2(Table 4-4 ). Table4-5. NGC6052ObservationalProperties NamezaM(B)aSBeaBVaRea(mag)(magarcsec2)(mag)(kpc) NGC60520.015808b20:6919.710.412.42LCBGsc0:01890:001919:700:2020:300:200:400:022:160:25 Table4-6. NGC6052ObservingLog CongurationDitheringNightExposureTimeOset(s)(arcsec) V300b19August20053330(0.00,0.00)aV30029August20053330(+1.56,+0.78)V300314August20053330(+1.56,0.78)V1200c111August20053900(0.00,0.00)aV1200211August20053900(+1.56,+0.78)V1200312August20053900(+1.56,0.78) 111

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4-16 .MeasurementsofthevelocitydowntoourS/Nlimitwerepossibleforaregionextendingover40arcsecindiameter.TheapparenteectiveradiusofNGC6052isre=7:6arcsec(i.e.,re=2:4kpc,attheredshiftofthegalaxy).Furtheraway,theS/Nwasnothighenoughtoproceedtothemeasurementofthevelocity. B A)PPAKHvelocitymapofNGC6052usingthelowresolutionV300conguration.B)PPAKHvelocitymapcontoursoverlaidontheF555WWFPC2imageofNGC6052. Thevelocitymapshowstwodierentiatedbehaviors.First,asymmetricvelocitygradientthatrangesover200kms1invelocityfromeasttowestcanbeseentowardsthesouthernhalfofthegalaxy.Second,aratherconstanteldcanbeseentowardsthenorthernhalfofthegalaxy.Thevelocitiesshowninthemaparereferencedtotheredshiftofthepeakvelocitywidthofthegalaxy(Section 4.4.2 )whichroughlycoincideswiththeoneavailableintheNASAExtragalacticDatabase(z=0:015808). Theexistenceofaratherstraightvelocitycontourthatcrossesthenucleusofthegalaxyfromnorthtosouththroughahighcentralvelocitywidthpeaksuggeststhatitactuallytracesthepositionoftheminoraxisofthegalaxy,yieldingamajoraxisPAequalto120.ArotationcurvecanbederivedforthePAwederivebyreadingthemeasured 112

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4-17 ).APAequalto120providesasmoothrotationcurvefromwhichanuncorrectedbyinclinationrotationvelocityofabout75kms1canbeinferred.Thevelocitygradientandoverallaspectofthevelocitymapisinagreementwhichthatof Garca-Lorenzoetal. ( 2008 ),whocoveredasmallerregionofthegalaxyusingthebersystemINTEGRALattachedtotheWilliamHerschelTelescope. Figure4-17. RotationcurvesalongthemajoraxisofNGC6052forPAequalto120.Thedashedlinesindicatetheplateaus,whilethedottedlineindicatethevelocityofthecentralvelocitywidthpeak,whichistakenasareference. Thenorthhalfofthegalaxyisconsistentwitharatherface-ongalaxy,whilethesouthhalfofthegalaxyisconsistentwitharotatingdiskwithaninclinationofatleast45. WhencomparedtotheF555WWFPC2imageofNGC6052(Figure 4-16 )onecharacteristicstandsout:thevelocitygradientislocatedunderneathandtotherightofamorphologicalstructurethatbendstogetherformingarightangle. 113

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4-18 and 4-19 showthevelocitywidthmapofthegalaxyNGC6052asderivedfromourhighresolutionPPAKobservations. B A)PPAK[OIII]5007velocitywidthmapofNGC6052usingtheV1200conguration.B)PPAKHvelocitywidthmapcontoursoverlaidontheF555WWFPC2imageofNGC6052.NorthistothetopandEastistotheleft. ThevelocitywidthmapofNGC6052showsahighvelocitywidthelongatedregion(150kms1)southfromthecenteroftheFOV(Figure 4-18 ).Thisregionisinagreementwiththemeasuredvelocitygradientalongthediskofthegalaxy(Figure 4-19 ).Thesewidthsaretheresultoftwowelldenedspectrallyresolvedcomponentsthroughouttheentireregion.Thevelocitywidthofthegalaxyrangesfromabout25to200kms1withinaFOVcoveredbybersforwhichS/Nisatleast30. MergerScenario.Asstatedaboveasharpvelocitygradientfromeasttowestisvisibleinthesouthernhalfofthevelocitymap.Furthermoreahighvelocitywidthelongatedregion,whosewidthistheresultoftwowelldenedspectrallyresolvedcomponents,crossesperpendicularlythisgradient.Theaveragedistancebetweenthese 114

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PPAKHvelocitymapcontoursoverlaidonPPAKVelocityWidthMapofNGC6052. componentsisabout3A(i.e.,175kms1,attheredshiftofthegalaxy).Theaverageintensityratiobetweenthiscomponentsisabout2:1. InFigure 4-20 weshowthevelocitymapofNGC6052accordingtothefollowingcriteria.First,weshowavelocitymapbyusing,foreverysinglespatialresolutionelement,thecomponentwhosevelocityissimilartothosemeasuredforitssurroundings.Second,weshowavelocitymapbyusingthosecomponentsoppositetotheonesbefore.Therstmapshowsasteepervelocitygradientalongthenorth-southdirection,inagreementwiththeHIelongation(Figure 4-21 ).Ontheotherhand,thesecondmapshowsaverydistortedvelocitygradientwherespatiallyresolvedkinematiccomponentscanbefound.Noticethatthesecomponentsarenotfoundineverysingleresolutionelementthatsamplesthehighvelocitywidthregion.Becauseofthis,themapshowsaclumpystructure.Nevertheless,thebluer(lighter)velocitiesmeasuredinthered(darker)regionareinagreementwiththevelocitiesmeasuredthroughoutthewesternhalfofthegalaxy. 115

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B A)PPAKHvelocitymapofNGC6052.Whenpossible,twospectrallyresolvedkinematiccomponentsweremeasured.Inthatcasetheonewithameasuredvelocityinbetteragreementwithitssurroundingswasused.B)PPAKHvelocitymapofNGC6052.Whenpossible,twospectrallyresolvedkinematiccomponentsweremeasured.Inthatcasetheonewithameasuredvelocityinworstagreementwithitssurroundingswasused. Withallthisinmind,thevelocityeldmaybetheresultofthesuperpositionoftwocollidingsystems,oneinthebackground,andasecondoneclosetoedge-onintheforeground;andtheobservedeast-westvelocitygradientmightjustbeduetoaprojectioneect.TheoverlapisobviousinFigure 4-20 B,wherebluecomponentscanbeseenwheretheedge-onforegroundgalaxywouldbeaccordingtotheHIobservationsfrom Garlandetal. ( 2007 ).Therefore,ourkinematicresultscorroboratetheinteractionscenarioproposedinpreviousworks( Alloin&Duot 1979 ; Taniguchi&Noguchi 1991 ; Garlandetal. 2007 ).Inparticular,Figure1of Garlandetal. ( 2007 ),enforcesthisscenariobecauseofthenorth-southelongation,theoverallnorth-southvelocitygradient,andtheratherconstantvelocitythroughoutthewesternhalfofthegalaxy(Figure 4-21 ).Insummary,thedoublenucleus,thetail,therecentstarformation,thelargevelocitygradientsinthe 116

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B A)SDSSopticalimage(contours)overlaidonagray-scalemapoftheHIintensity.Thebarindicatesthegray-scalerangeinunitsofJybeam1ms1;onlyHIintensitiesabovethe3-level,45Jybeam1ms1,areplotted.ThebeamfortheHImapisshowninthebottomrightcorner.Theopticalcontoursarearbitrary.B)HIvelocityeld.Thebarindicatesthegray-scalerange,44315069kms1.Thecontoursareat50kms1intervals.Thebeamisshowninthebottomrightcorner. extranuclearregions,andtheperturbedgasinthewholeFOVareallsignsofamergerevent. Alternatively, Castillo-Morales,Gallego,Perez-Gallego,etal. ( 2009b )ndsforthedierentcomponentsinthehighvelocitywidthregion,[OIII]5007/Hand[NII]6584/Hratiosthatdiernoticeablefromonecomponenttotheother.Thebluercomponentratiostendtobe40%higher.However,whencombinedtoestimatetheirmetallicitybymeansoftheO3N2indicator( Pettini&Pagel 2004 ),bothcomponentsareinagreementwithintheerrorsofthe Pettini&Pagel ( 2004 )calibration(0.25dexat 117

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4-22 ; Garlandetal. 2004 2005 ).Thisparticulargalaxyisagoodexampleofthemostcompactgalaxiesinoursample(Table 4-7 ).Lenticulargalaxiesarediscgalaxieswhichhaveuseduporlostmostoftheirinterstellarmatterandthereforehaveverylittleongoingstarformation.FromPPAKHuxesCM09bderivedastarformationrateofjust1:30:1Myr1.NGC469belongstotheSDSScatalog. Figure4-22. SDSSimageofNGC469.NorthistothetopandEastistotheleft. 118

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4-8 ). Table4-7. NGC469ObservationalProperties NamezaM(B)aSBeaBVaRea(mag)(magarcsec2)(mag)(kpc) NGC4690.013673b19:1320.050.421.30LCBGsc0:01890:001919:700:2020:300:200:400:022:160:25 Table4-8. NGC469ObservingLog CongurationDitheringNightExposureTimeOset(s)(arcsec) V300b114August20053330(0.00,0.00)aV300214August20053330(+1.56,+0.78)V300314August20053330(+1.56,0.78)V1200c112August20053900(0.00,0.00)aV1200212August20053900(+1.56,+0.78)V1200312&13August20053900(+1.56,0.78) 4-23 .MeasurementsofthevelocitydowntoourS/Nlimitwerepossibleforaregionextendingover40arcsecindiameter.TheapparenteectiveradiusofNGC469isre=4:6arcsec(i.e.,re=1:3kpc,attheredshiftofthegalaxy),whichmakesitoneofthemostcompactgalaxiesinoursample.Furtheraway,theS/Nwasnothighenoughtoproceedtothemeasurementofthevelocity. Thevelocitymapshowsadistortedasymmetricgradualvelocityeldthatexpands60kms1invelocity.Thevelocitiesshowninthemaparereferencedtotheredshiftof 119

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B A)PPAKHvelocitymapofNGC469usingthelowresolutionV300conguration.B)PPAKHvelocitymapcontoursoverlaidontheSDSSimageofNGC469. thecentralpeakvelocitywidthofthegalaxy(Section 4.5.2 ).Noabsolutecalibrationoftherecessionvelocitywasattempted.ThisredshiftroughlycoincideswithintwosigmawiththeoneavailableintheNASAExtragalacticDatabase(z=0:013673). 4-24 and 4-25 ),incombinationwiththevelocitymapdiscussedinSection 4.5.1 ,discardsNGC469asarotatingdiskeventhoughthevelocitymapshowsadistortedbutoverallrotation. ThevelocitywidthmapofNGC469showsaratherconstantwidththroughouttheentiregalaxy(40kms1;Figure 4-18 )eventhoughthepresenceofadistortedasymmetricgradualvelocityeld.AnellipticalbackgroundgalaxywasneededtoberemovedfromtheFOVinordertoproceedtothisanalysis.Thevelocitywidthofthegalaxyrangesfromabout30to70kms1withinaFOVcoveredbybersforwhichS/Nisatleast30. Mass.IfweassumeforNGC469apeaktopeakvelocityrangeassuggestedbythevelocitymapderivedabove(60kms1),theinferredrotationalvelocityvrot=q Re

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B A)PPAK[OIII]5007velocitywidthmapofNGC469usingtheV1200conguration.B)PPAKHvelocitywidthmapcontoursoverlaidontheSDSSimageofNGC469.NorthistothetopandEastistotheleft. translatesintoadynamicalmasswithinRe=1:3kpcofaround3:0108M.Aninclinationof84wasassumedasderivedfromthemajorandminoraxisavailableintheSDSScatalogbymeansofEquation 3{1 .Forthisgalaxy Garlandetal. ( 2004 )found,fromtheirHIstudy,MHI=2:0109M,andMdyn(Re)=3:9109M.Thedierencebetweenbothdynamicalmassescanbeaggravatedbythefactthat Garlandetal. ( 2004 )usedW20toestimatevrotandwehaveshowninChapter 3 howbydoingthis,thevalueofvrot(and,therefore,Mdyn)tendstobehigherthantheoneestimatedfromtherotationcurveforLCBGs.Nevertheless,thedierencebetweenthedynamicalmasswederiveandtheHImassfrom Garlandetal. ( 2004 )mightbeduetothefactthatthevelocitygradientwendisnottracingthedynamicalmassofthisgalaxy.Rememberthatitisnotclassiedasarotatingsystembecauseofitsratherhomogeneousvelocitywidthmap. FromourintegratedPPAKdatawendW20=1524kms1.Ifaninclinationequalto84isalsotobeconsideredarotationalvelocityvrot=76kms1canbederived,whichwouldtranslateintoamassaboutfourtimeslargerthantheonederivedfromthepeaktopeakanalysis. 121

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PPAKHvelocitymapcontoursoverlaidonPPAKVelocityWidthMapofNGC469. Kooetal. 1994 ; Guzmanetal. 1996 1997 1998 ; Phillipsetal. 1997 ; Noeskeetal. 2006 ; Bartonetal. 2006 ).AtthecurrentSFR(CM09a)theHIstillpresentinNGC469wouldbeexhaustedinabout1Gyr.Oncethegasisexhausted,NGC469maybeinapositiontoevolveintoadwarfellipticalgalaxy. Thespectraandbroadbandcolorsofdwarfellipticalgalaxiescanbestbeexplainedbythepresenceofanoldstellarpopulationandarecentburstofstarformationthathasnowalmostorcompletelyceased.CM09bfoundforNGC469alowSFR,asstatedabove,andZ=(0:60:2)Z.Themorphology,thedynamicalmass,andthemetallicityof 122

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Young&Lo 1997 ; Richer&McCall 1995 ).Furthermore,avelocitygradientaccompaniedbyaratherhomogeneousvelocitywidthdistributionthroughoutthegalaxy,asitisthecaseforNGC469,isalsotypicalofdwarfellipticalgalaxies( vanZeeetal. 2004 ).Therefore,despiteaslightlylargereectiveradius,itssimilaritieswiththedwarfellipticalpopulationseemtoindicatethatNGC469mayevolveintooneofthem.Ifweconsiderthemass-to-lightratio(M=L=0:5)andcolorBV(BV=0:42)ofNGC469wecanqualitativelypredicthowthisgalaxywillevolveoncetheburstisover.FollowingthemodelpredictionsfortheevolutionofagalaxysuchasNGC469afterasingleinitialburstofstarformation,andafterasecondburstinvolving1%ofthetotalgalaxymass(Figure3from Guzmanetal. 1998 ),wewouldexpectNGC469tofadeabout3magnitudesafter1Gyr,whichwouldplaceNGC469marginallyattheTFRfordwarfellipticalgalaxies(Figure 3-1 ; vanZeeetal. 2004 ).Therefore,wecanconcludethatNGC469mightbeaprogenitorofadwarfellipticalgalaxy. 123

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Madau&Shull 1996 ; Pei&Fall 1995 ; Peietal. 1999 ).Wehavealreadydiscussedtheexistenceofatransitionepochatz1inChapter 1 .Therange11.Atz2,actually,iswhentheoverallstarformationrate(SFR)intheUniversepeaks. BymeansoftheHubbleSpaceTelescopeand10-mclasstelescopesdatafromlargesamplesofgalaxiesat11,theepochofmaximumstarformationactivityintheuniverse.Thefoundationoftheprojectisanear-IRspectroscopicsurveyof2500galaxiesatz>1usingguaranteedtimewithEMIR,acryogenicnear-IRmulti-slitspectrographatthe10.4-mGranTelescopioCanarias(GTC).EMIRwillprovidesimultaneousintegratedspectraofupto50objectsinaeld 124

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However,theempiricalunderstandingofgalaxyformationultimatelyrequiresdetailedmappingofthephysicalproperties,includingkinematics,metallicity,age,starformationrate,andextinction,asafunctionofspatialpositionwithineachgalaxy.CurrentsurveysfocusonLCBG-likegalaxieswithredshiftsrangingfromz=0:4toz=0:6(e.g., Puechetal. 2006 ; Yangetal. 2008 ),fromz=1:2toz=1:6(aroundthepeakofstarformation;e.g., Epinatetal. 2009 ),andatz2(e.g., ForsterSchreiberetal. 2006 2009 ),usinginstrumentslikeGIRAFFEorSINFONIattheVeryLargeTelescopeoftheEuropeanSouthernObservatory.Theresultsofthesesurveysseemtoimplythatgalaxykinematicsareamongthemostrapidlyevolvingproperties,becausewhilelocallyonlyafewpercentofthegalaxiesinthismassrangehavecomplexkinematics,thisappearstobeatrendathigherredshifts( LeFevreetal. 2000 ).Galaxiesundergoingamergerhavecomplexlarge-scalemotions,thereforemergersarelikelytoberesponsibleforthestrongevolutionofgalaxykinematics. Thesesurveyshavethepotentialtosetthebasistounderstandtheessentialsbehindgalaxyformationandevolution.Nevertheless,itwillbethecombinationofthecollectingareaofthenewgenerationof30-mclasstelescopes,theuniquecapabilitiesofAdaptiveOptics(AO),andtheexibilityprovidedbymultipleIRIntegralFieldUnits(IFUs),whichmayrevolutionizethestudyofgalaxiesattheseandyoungerepochs,enablingdetailedmappingofthesephysicalpropertiesforthousandsofgalaxiesatz=2{6.Suchasurveywillbeamajormilestonetowardsanempiricaldeterminationofthephysicsandtimelineofgalaxyassemblyinthismostinterestingeraofpeakstarformationactivity. InadditiontousinglocalLCBGsasaproxyforlearningaboutthenatureandevolutionofz1LCBGs,threedimensional(3D)spectroscopydataoflocalLCBGs 125

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Puechetal. 2008 ; Gruel,Guzman,&Perez-Gallego 2009 ).Thesesimulationsareessentialinordertohelpinthecorrectinterpretationoftheresultsassociatedtocurrentandfutureobservationsofdistantgalaxies,andcompensateforanypossiblebiasesintroducedbycosmologicalfactors,lowsignal-to-noise,andinstrumentlimitations,associatedtotheseobservations.InSection 5.2 wesummarizetheworkIhavebeendoingincollaborationwithNicolasGruelandRafaelGuzmanonthissubject.Inparticular,Iwasinchargeofimplementingthesimulationmethodandproducingtherstsimulationsoftheseobjects.Later,NicolasGruel,wasinchargeofmakingthesesimulationsuser-friendly,processinwhichiwasalsoinvolvedbyprovidingeverythingilearnedfrommywork. Additionally,ifLCBGsareobtainedatavarietyofredshiftsbetween2z4,andreliablemeasurementsoftheirvelocitywidthsareprovided,togetherwithredshifts,Hluminosities,andmetallicities,dierentcosmologicalmodelscanbetestedbymeansofawell-stablishedstandardcandle( Melnick,Terlevich,&Moles 1988 ; Melnick,Terlevich,&Terlevich 2000 ; Siegel,Guzman,Perez-Gallego,etal. 2005 ).Thisparticularmethodhasthepotentialofprovidingverytightconstraintsinthespecicmeasurementofthemassdensity(m),independentofanyconstraintsarisingfromothersources,includingcosmicmicrowavebackground(CMB)andtypeIasupernova(SNIa)data.InSection 5.3 wesummarizetheworkIhavebeendoingincollaborationwithEthanSiegelandRafaelGuzmanonthissubject.Asidefromactivelycontributingonalltheaspectsoftheproject,Iwasinchargeofcompilingthenecessarydataforthestudyoftheuniversalityofthestandardcandlediscussed,anddiscussingthisuniversality. 126

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5-1 ).FRIDAisaninfraredimagerandIFS,andtherstinstrumentthatwillbebuiltfortheadaptiveopticssystemofthe10.4-mtelescopeGTC.TheinputdataforthesesimulationsareactualPPAK3DspectraofanearbyL?starburstgalaxy(NGC7714;NorthistotheleftandEastistothebottom;Chapter 4 ),scaledtothecharacteristicvaluesofthehigh-redshiftLyman-breakgalaxypopulation(i.e.,L=4L?Re=4:5Kpc,LH=1043ergs1).WeconsideredaFRIDAinstrumentalcongurationwith30slitswithaspatialscaleof0:020:04arcsec2,aFOVof1:21:2arcsec2,andR=4000.Thesesimulationsconsistessentiallyof(i)redshiftingthegalaxy3Dspectratothedesiredredshift,whichtranslatesintoadropintheincominguxbecauseofthedierentdistancemoduli;(ii)addingtheappropriatesky3Dspectratoourobject3Dspectra(e.g.,atz=2:5therest-frameopticalcorrespondstotheKband);(iii)makingthespectragothroughtheinstrumentalset-up(i.e.,thetelescopeandthespectrograph);(iv)subtractingtheskyfromournal3Dspectracomposedoftheobject's,thesky's,andnoiseduetotheobservationprocess,whichisgenerallydominatedbybackgroundnoise.WeusedierentbutequivalentskyspectrageneratedbyMonteCarlosimulations,sowedonotaddandsubtracttheexactsameone.Forthesimulationatz=1:5,weassumedt=1hourintegrationtimeonsource,whileforthesimulationatz=2:5weassumedt=4hours.InFigure 5-1 therighttwopanelsshowtheactualmapsforSFRandvelocityasderivedfromtheactualPPAKrest-frameopticalspectraofourreferencegalaxyatz0.ThetoppanelshowstheSFRmap.ThereareclearlythreegiantregionsofstarformationwithtypicalscalesofafewhundredparsecsandSFRrangingfrom12M/yrto1M/yrsuperimposedonanextended,underlyingpopulationwithaverageSFR0.01M/yr.ThebottompanelshowsthevelocitymapderivedfromtheHemissionlinecentroids.Thederivedrotationalvelocityisv=sini=98kms1.Themiddletwopanelsshowthesamemapsderivedfromthe 127

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Figure5-1. 128

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5-2 and 5-3 showtheresultsderivedfromrealisticsimulatedobservationsofaprototypicalLCBG-likeLyman-breakgalaxyatz=2:5andatz=5:5. Figure 5-2 simulatesobservationsofatypicalLCBG-likeLyman-breakgalaxyatredshiftsz=2:5andz=5:5usingFRIDA2with20IFUsata30-mtelescope.TheinputdataforthesesimulationsareactualPPAK3DspectraofanearbyL?starburstgalaxy(NGC7714;NorthistotheleftandEastistothebottom;Chapter 4 ),scaledtothecharacteristicvaluesofthehigh-redshiftLyman-breakgalaxypopulation(i.e.,L=4L?Re=4:5Kpc,LH=1043ergs1).WeconsideredaFRIDA2instrumentalcongurationwith50masslitletswidthandR=4800.Forthesimulationatz=2:5,weassumedt=1hourintegrationtimeonsource,whileforthesimulationatz=5:5weassumedt=4hours.ThetoprightpanelshowsanimageoftheHubbleUltraDeepField.Lyman-breakgalaxycandidatesatz=2{6areidentiedwithgreensquares(e.g., Elmegreenetal. 2005 ; Malhotraetal. 2005 ).AnactualFRIDA2probescongurationisshowninyellowlines.Thetopleftpanelshowsthesimulateddeepnear-IRimageofourprototypicalLyman-breakgalaxyatz=2:5asseeninasingleFRIDA2IFU.TheIFUFOVis1:12:2arcsec2.Thetwomiddlerightpanelsshowthesky-subtractedspectraatz=2:5forvariousslitletsinthewavelengthrangearoundHand[OIII]4959,5007asobservedinH-band,andaroundHasobservedinK-band.Spatiallyresolvedemission-linesubstructureisclearlyseeninthese2Dspectra.Thebottomrightpanelshowsthesky-subtractedspectraatz=5:5forvariousslitletsinthewavelengthrangearound[OII]3727asobservedintheK-band.TheleftmiddleandbottompanelsillustratethecharacteristicS/Nintheobservedemissionlinesatvarious 129

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A)Simulateddeepnear-IRimageofourprototypicalLyman-breakgalaxyatz=2:5asseeninasingleFRIDA2IFU.B{C)2Dsky-subtractedspectraatz=2:5forvariousslitletsinthewavelengthrangearoundHasobservedinH-band,andaroundHasobservedinK-band;andatz=5:5around[OII]3727asobservedintheK-band.D)CharacteristicS/Nintheobservedemissionlinesatvariousuxlevels. uxlevels:1.6x1017ergs1cm2inHatz=2:5,3.2x1018ergs1cm2inHatz=2:5,and3.2x1019ergs1cm2in[OII]3727atz=5:5. 130

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A{D)ActualmapsforSFR,velocity,extinction,andmetallicityasderivedfromtheactualPPAKrest-frameopticalspectraofourreferencegalaxyatz0.TherstpanelshowstheSFRmap.E{H)ThesamemapsderivedfromthesimulatedFRIDA2observationsofthesamegalaxyatz=2:5.I{L)TheSFRandvelocitymapsderivedfromthesimulatedFRIDA2observationsof[OII]3727forthesamegalaxyatz=5:5. 131

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5-3 thetopfourpanelsshowtheactualmapsforSFR,velocity,extinction,andmetallicityasderivedfromtheactualPPAKrest-frameopticalspectraofourreferencegalaxyatz0.TherstpanelshowstheSFRmap,thesecondpanelshowsthevelocitymapderivedfromtheHemissionlinecentroid,andthethirdpanelshowstheextinctionmapasderivedfromtheH/Hratio.Finally,thefourthpanelshowsthemetallicitymapasderivedfromtheNII/Haratio.Theincreaseinextinctionandmetallicityinthecentralstarburstregioncomparedtotherestofthegalaxyisclearlynoticeable.ThemiddlefourpanelsshowthesamemapsderivedfromthesimulatedFRIDA2observationsofthesamegalaxyatz=2:5.TheFRIDA2detectionthresholdallowsregionswithSFRaslowas0.01M/yrperresolutionelementtobedetectedatz=2:5.Finally,thebottompanelsshowtheSFRandvelocitymapsderivedfromthesimulatedFRIDA2observationsof[OII]3727forthesamegalaxyatz=5:5.AlthoughonlyregionswithSFR>0:05M/yraredetectedineachresolutionelement,byaveragingtheinformationfromthelowersurfacebrightnessareas,correctvaluesfortheSFRs,rotationalvelocity,extinctionandmetallicitymaystillbederived(seebottomrightpanels).Insummary,thespatialresolutionandsensitivityofFRIDA2ata30-mtelescopewillallowstudyof30Dor-likestarformingregionsinstarburstgalaxiesuptoz6.Inaddition,intermediatespectralresolutions(R5000{10000)wouldprovidedetailedkinematicmeasurementsdownto10{30kms1.Thisresolutionisidealtostudyvelocitywidthsofindividualstar-formingregions,whichtypicallyrangebetween10and30kms1( Melnick,Terlevich,&Moles 1988 ),kinematiccomponentsrevealingthepresenceofSN-drivengalacticwindsoverkiloparsec-scalestructuresexpandingattypicalvelocitiesof20{100kms1( Marloweetal. 1995 ),orgalaxyrotationcurves.Inparticular,thedirectmeasureoftheamountofthermalenergytransferredtotheinterstellarmediumfromthesekinematicfeatureswillallowquanticationoftheimportantroleSN(orAGN)drivenwindsmayplayasthemainfeedbackmechanismingalaxy/starformationmodelsataveryearlyepoch. 132

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5-4 ).ThesesimulationscanbecomparedwithactualobservationsusingEMIRatGTC,whichwillbeprovidingintegratedspectraforastatisticallyrepresentativesampleofLCBGsatz2inthenearfuture,whichwillfacilitate,amongother,reliablemeasurementsoftheuxesandvelocitydispersionsoftheseobjects. Figure5-4. SimulatedintegratedspectrumofanearbyLCBGredshiftedtoz=2:5asifithadbeenobtainedusingEMIRattheGTC.Inthepanelwecanseeanactualobservationofastarburstgalaxyatz>2by Erbetal. ( 2003 ).NoticethatoursimulatedisspectrumisperAandnotperresolutionelement. Bennettetal. 2003 ),SNIa( Riessetal. 2000 ),andgalaxysurveys( Hawkinsetal. 2003 ; Bahcalletal. 2003 )have 133

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misthecosmologicalparameterwiththegreatestnumberofindependentmeasurementapproaches:theSunyaev-Zel'dovicheect( Gregoetal. 2001 ),weakgravitationallensing( Hoekstraetal. 2001 ),X-rayluminosities( Borganietal. 2001 ),largescaleclustering( Schueckeretal. 2003 ),peculiarvelocitiesofgalaxypairs( Feldmanetal. 2003 ),andSNedata( Knopetal. 2003 ).Theseapproacheshaveyielded2-consistentresultsrangingfromm=0:13{0.35.Theseapproaches,however,arenotsensitiveenoughto,k,andwtodierentiatebetweendierentcosmologicalmodels.Inordertoovercomethis,areliablestandardcandleisneededathighredshift,wherethedistancemoduliofextragalacticobjectsbecomesensitivetothesecosmologicalparameters. Melnick,Terlevich,&Moles ( 1988 ,hereafterMTM)rstfoundacorrelationbetweentheluminosityintheHline(LH),thevelocitydispersion(),andmetallicity(O/H)ofnearbyLCBG-likeHIIgalaxies.Thiscorrelation,whenappliedtodistantLCBGs,allowsfordiscriminationbetweendierentvaluesofm(asrstsuggestedby Melnick,Terlevich,&Terlevich 2000 ,hereafterMTT),andhasthepotentialofbeingthatstandardcandleneededfordieretiatingbetweendierentcosmologicalmodels,asdiscussedinmoredetailin Siegel,Guzman,Perez-Gallego,etal. ( 2005 ),andsummarizedhere. LCBG-likeHIIgalaxies(andHIIregions)arecharacterizedbethepresenceofalargestar-formingregion,whereO-andB-typestarsarebeingformandionizingthesurroundinghydrogengas.Thetypicalspectrumofthesegalaxiesshows,therefore,strongHandHemissionlines.TheLHofgiantHIIregionsisstronglycorrelatedwiththeir( Terlevich&Melnick 1981 ). Melnicketal. ( 1987 )andMTMextendedthiscorrelationtoLCBG-likeHIIgalaxiesandshowedthepotentialofthiscorrelationasadistance 134

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logLH=logMz+29:60;Mz5 wheretheconstant29.60isduetoazero-pointcalibrationofnearbygiantHIIregions(MTT),andourchoiceoftheHubbleconstant(H0=71kms1Mpc1).LCBGsobservedatdierentepochsshowthesamestrongBalmeremissionlinesandintensestarformationactivity( Pettinietal. 2001 ; Erbetal. 2003 )asnearbyLCBG-likeHIIgalaxies. wheretheconstant26.18isduetoH0,andEquation 5{1 .Interestingly,Equation 5{2 expressesDMintermsofonlyobservationalparameters.Asdiscussedabove,whileDMisinsensitivetom,,k,andwatlowredshifts(z0:1),athighredshifts(z>2),itcandierupto3magnitudesdependingonthechoiceofparameters.Amongthefourcosmologicalparameters,asalreadystatedbyMTT,DMismostsensitivetochangesinm.However,forvaluesofm0:3,DMissensitivetovariationsintheotherparametersby0:2{0:5mag.Sinceothermeasurementsindicatethatm0:3,wealsoconsidervariationsinandk. WeselectedLCBG-likegalaxiesfrom Pettinietal. ( 2001 )and Erbetal. ( 2003 ).Measurementsformanyofthedesiredobservationalparametersandrelatedquantitiesforthe36galaxiesintheirsampleswerealreadyavailable. AsLCBG-likeHIIgalaxiesevolveintimeandthegasavailableforstarformationisconsumed,thedeathrateofshort-livedO-andB-starsexceedstheirbirthrate,causingagalaxytobeunder-luminousinHandHforitsmass.ThecorrelationbetweenLH,,andO/HholdstrueforgalaxieswhosedynamicsaredominatedbyO-andB-typestars, 135

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Asecondcut-oisnecessarytoaccountforthefactthatalargefractionoflocalLCBG-likeHIIgalaxiescontainmultipleburstsofstarformation( Melnicketal. 1987 ).Whenmultipleunresolvedburstofstarformationarepresent,relativemotionsofthosewillbroadentheobserved( Melnicketal. 1987 ).ThecorrelationbetweenLH,,andO/Hholdstrueforgalaxiesdominatedbyonemajorburstofstarformation.SincewedonothaveneitherthesucientS/N,norresolutiontoremovethiseect,weapplyacuton.MonteCarlosimulationsindicatethatwhen>130kms1,itislikelyduetothepresenceofmultipleburstsofstarformation,therefore,allgalaxieswith>130kms1arediscarded.WhenimposingthecutsonandEWwewereleftwith15outofthe36originalgalaxies,creatingthesampleusedforouranalysis(Table 5-1 ; Siegel,Guzman,Perez-Gallego,etal. 2005 ). Unfortunately,notallofthenecessarydatatocalculateDMusingEquation 5{2 wereavailableintheliteratureforthesegalaxies,soassumptionswerenecessarytoaccountforthemissinginformation.zwasmeasuredforallgalaxiesbythevacuumheliocentricredshiftsofthenebularemissionlines.wasobtainedforallgalaxiesfromthebroadeningoftheBalmeremissionlines,Hforthegalaxiesfrom Erbetal. ( 2003 ),andHforthegalaxiesfrom Pettinietal. ( 2001 ).FHwasmeasureddirectlyforthegalaxiesin Pettinietal. ( 2001 ),but Erbetal. ( 2003 )measuredFHinstead,thusFHwasconvertedtoFH.Theconversionfortheemitteduxisgivenby Osterbrock ( 1989 )asFH=2:75FH,whereobserveduxesmustbecorrectedforextinction.Therefore,thecompleteconversionisgivenby 2:75FH10(AHAH whereAHandAHaretheextinctionsinHandH,respectively.ObtainingO/Hwasmoredicult,asmeasurementsofmetallicityonlyexistedfor5ofthe36originalgalaxies. 136

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SelectedstarburstgalaxieswiththeirpropertiesandDM. NamezFH12+log(O=H)EWDMa(kms1)(1017ergs1cm2)(mag)(A)(mag) Q0201-B132.1762290:90:28.550.0132347:49+2:103:43Q1623-BX4322.1851221:90:58.550.1577245:45+1:973:07Q1623-MD1072.54421:30:38.550.1412144:82+0:311:58Q1700-BX7172.44601:30:38.550.2852546:64+0:311:58Q1700-MD1032.3275212:40:68.550.7354746:72+1:381:80SSA22a-MD412.17107152:60:78.550.2143148:96+0:780:85CDFaC13.11633:41:08.550.5052845:77+0:311:58Q0347-383C53.236941:78.550.2372747:12+0:440:32B20902+343C123.3987122:70:38:700:080.7733746:96+0:710:81Q1422+231D813.1011684:10:48:620:070.2374348:81+0:380:40SSA22a-MD463.096762:38.550.1103146:76+0:560:51SSA22a-D33.0711371:30:38:390:161.012549:71+0:430:41DSF2237+116aC23.3210043:50:48.550.8522547:73+0:250:25B20902+343C63.0955153:01:08.550.2844045:22+1:381:76MS1512-CB582.73811:350:28:490:101.142647:49+1:221:57

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AnaveragevalueofO/HwasusedforthosegalaxiesforwhichO/Hmeasurementswerenotavailable. ValuesofO/Hforvegalaxiesin Pettinietal. ( 2001 )wereobtainedbymeansofmeasurementsofthe[OII]3727,and[OIII]4959,5007emissionlines.TheR23( Pateletal. 1979 )indexwasassumedtohaveitstemperature-metallicitydegeneracybrokentowardsthehighervalueofO/H,asitseemstobethecaseforLCBGsatintermediateredshifts( Kobulnicky&Koo 2000 ).ThemeanofthevaluesofO/Hforthesevegalaxieswasthentakentobetheaveragemetallicityforeachoftheothergalaxieswheresuchlinemeasurementswerenotavailable.Alternatively, Shapleyetal. ( 2004 ),usingthe[NII]6548,6584/Hratioastheirmetallicityindicator,obtainedanaverageO/Hof8.33forthegalaxiesfoundin Erbetal. ( 2003 ). Gordonetal. 2003 ),theyhavenotbeenestablishedforstarburstgalaxiesingeneral.IfweassumedustinLCBGstobecomparabletothatingiantHIIregions,AH

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Gordonetal. ( 2003 )fortheHIIregionsoftheLMCandSMC.Abesttappliedtothedatain Gordonetal. ( 2003 )yieldedAH=(3:280:24)E(BV)andAH=(2:140:17)E(BV)forstarburstgalaxies.TheseresultswerealsoapplicabletotheuxconversioninEquation 5{3 .Forthegalaxiesfrom Pettinietal. ( 2001 ),forwhichE(BV)wasnotavailable,E(BV)wasderivedfromthecorrelationbetweenE(BV)and(GR)correctedcolorsforstarburstgalaxiesin Erbetal. ( 2003 )(i.e.,E(BV)0:481(GR)). Finally,EWwasmeasuredforallgalaxiesin Pettinietal. ( 2001 ),butnotforthosein Erbetal. ( 2003 ).ForthelatteronlythespectrafortheHline.EWwasestimatedforthe Erbetal. ( 2003 )galaxiesbyestimatingthecontinuumheightfromeachspectraandtheareaundereachHpeak,calculatingtheequivalentwidthinH,andconvertingtoHusingtheBalmerdecrementsof Osterbrock ( 1989 ).ThecompletedatasetislistedinTable 5-1 ( Siegel,Guzman,Perez-Gallego,etal. 2005 ). 139

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1-constraintsinmvs.parameterspacefromstarburstgalaxies,alongwitholderconstraintsfromCMBandSNIadata,foundin deBernardisetal. ( 2000 ). individualpointsandfromthedistributionofpoints.TheaveragevalueobtainedisDM=47:03+0:460:56ataredshiftz=2:800:11.Thedierentcosmologicalmodels,alongwiththemostlikelypointandtherawdatapoints,aredisplayedinFigure 5-5 (Figure1of Siegel,Guzman,Perez-Gallego,etal. 2005 ),withH0=71kms1Mpc1. Theconstraintsplacedonmfromtheanalysisdescribedherearem=0:21+0:300:12ina-dominateduniverse(m+=1;k=0)andm=0:11+0:370:19inanopenuniverse(m+k=1;=0)( Siegel,Guzman,Perez-Gallego,etal. 2005 ).Figure 5-6 (Figure2of Siegel,Guzman,Perez-Gallego,etal. 2005 )showsthecomparisoninmvs.parameterspacebetweenthepreliminaryconstraintsofthisworkandearlyconstraintsarisingfromCMBdataandSNIadata(from deBernardisetal. 2000 ). CMBandSNIaconstraintsledtotherstreliableestimatesofmand.ThepreliminaryconstraintspresentedherearecomparabletoearlyconstraintsfromCMBandSNIadata,asshowninFigure 5-6 (Figure2of Siegel,Guzman,Perez-Gallego,etal. 2005 ).Theaccuracyinmand,asdeterminedfromrecentCMBandSNIadata( Bennettetal. 2003 )isnow0:04ineachparameter.Asimilar,andperhapseven 140

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5{1 ,asshowninFigure 5-7 (Figure3of Siegel,Guzman,Perez-Gallego,etal. 2005 ).ThevalidityofthecorrelationbetweenLHandMzcanbetesteddirectlytodetermineitsrangeofapplicability.Byassumingacosmology,logLHcanbewrittenpurelyintermsofluminositydistance(dL),FH,andAH,whichareeithermeasurableorcomputablefromobservablesforeachgalaxy.logMzcanbedeterminedthroughmeasuredvaluesforandO/H.ComparingthequantitieslogLHandlogMzthenallowsatestofthecorrelationinEquation 5{1 forallgalaxiesofinterest.AllavailableLCBG-likeHIIgalaxiesandLCBGswithappropriatelymeasuredquantitiesareincludedtotestthecorrelation.LocalgalaxiesaretakenfromMTMandfromtheUCMcatalog( Gallegoetal. 1996 ; Vitoresetal. 1996 ),intermediateLCBGsaretakenfrom Guzmanetal. ( 1997 ),andhighredshiftLCBG-likeLyman-breakgalaxiesarefrom Pettinietal. ( 2001 )and Erbetal. ( 2003 ).Thecosmologyassumedtotestuniversalityism=0:3,=0:7,andcutsareappliedtoallsamplessothatEW>20Aand<130kms1. ThemajorreasonstoconcludethattheassumptionofuniversalityisvalidlieinFigure 5-7 (Figure3of Siegel,Guzman,Perez-Gallego,etal. 2005 ),wheretheseresultsareshown.ThereisanoverlapbetweenallfoursamplesinbothLHandMz,fromthesamplewherethecorrelationiswellestablished(nearbysamples,MTMandUCM),tointermediateredshiftLCBGs( Guzmanetal. 1997 ),tothehighredshiftsampleusedinthispaper,from Erbetal. ( 2003 )and Pettinietal. ( 2001 ).ThesefoursamplesallfollowthesamecorrelationbetweenLHandMzwithinthesameintrinsicscatter(although 141

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logMzvs.logLHforlocalHIIgalaxiesandstarburstgalaxiesatintermediateandhighredshifts.Thesolidlineisthebesttofthecorrelationtothelocaldataset,ankedbythedashedlines,whichgivethe2-rmsscatter.Thelargediamondsrepresenttheselectedhighredshiftdatasample;thesmalldiamondsarethedatanotselectedonthebasisofeitherEWor.Theverticaldottedlineisthederivedcutonof130kms1.Thecrosshairsrepresentsthetypicaluncertaintyineachselecteddatapoint. theobservedscatterbroadensathighredshiftsduetomeasurementuncertainties).Allsamplesareconsistentwiththesamechoiceofslopeandthesamechoiceofzero-point.Forthesereasons,thecorrelationofEquation 5{1 appearstobejustasvalidforLCBGsasfornearbyLCBG-likeHIIgalaxies. TheotherassumptionswhichareinherenttothismethodarethechoicesofwheretocutonEWandon,andtheassumptionthatAHisthesameforstarburstgalaxiesasitisforlocalHIIregions.MovingtheEWcutfromEW>20AuptoEW25A,assuggestedinMTT,wouldsystematicallyraisetheDMby0:14magforthissample.Ontheotherhand,acutonat130kms1retains95%ofthevalid,singleLCBG-likeHIIgalaxies,whileeliminating75%ofthecontaminatingobjects.Additionally,itcanbeshownthatthecontaminatingobjectswhicharenoteliminateddepartonlyslightlyfromtheempiricalcorrelationofEquation 5{1 .Finally,thederivedAHitselfhasanuncertaintyof38%,duetothefactthattherearecompetingextinctionlawsthat 142

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Gordonetal. 2003 ; Calzettietal. 1994 2000 ).Bothlawsarecomparablygrey,buthavedierentnormalizations.ThedierencebetweenthetwolawsleadstoasystematicuncertaintyintheDMof0:17mag. Therehavealsobeenassumptionsmadespecicallytocompensateforincompletedatainthe Pettinietal. ( 2001 )and Erbetal. ( 2003 )datasets.Thesystematicuncertaintiesthattheseassumptionsinducecanbeeliminatedinfuturesurveysthroughmeasurementsofallrequiredquantities.Futuresurveys,forexample,willallowmultiple,independenttechniquestobeusedtomeasureabundancesofhighredshiftstarburstgalaxies,signicantlyreducingerrorsandovercomingassumptionsregardingtheO/Hoftheseobjects.UncertaintiesincludedinouranalysisbymeansofthemeasurementsoftheEWofthegalaxiesinthe Erbetal. ( 2003 )samplewillberemovedbymeasuringequivalentwidthsinHwithahigherS/Nspectraforallgalaxiesinfuturesurveys.Ontheotherhand,uncertaintiesincludedinouranalysisbyusinganapproximatecorrelationbetweenE(BV)andthecorrected(GR)colorstoderivetheextinctionforthegalaxiesin Erbetal. ( 2003 )willbeeliminatedwhenAHmeasurementsareexplicitytakenforallgalaxies. Randomerrors,duetobothuncertaintiesinmeasurementandtothelargescatterinthedistributionofpoints,areperhapsthebestunderstoodofthesourcesoferror.MeasurementsofAHareuncertainby0:04to0:11dex,dependingonthegalaxy'sbrightness.Improvedmeasurements,whichrelyontheH=HratioinsteadofsolelyonE(BV)colors,mayreducetheuncertaintysignicantly.MeasurementsofFHareuncertainbyroughly20to25%onaverage,andrandomuncertaintiesinO/Hareoforder0:10dex.Thelargestmeasurementuncertaintycomesfrommeasurementsof,whichisobtainedbythebroadeningoftheBalmeremissionlines.Evenrelativelysmalluncertaintiesinoforder15%caninduceuncertaintiesinDMof0:8magpergalaxy.Theinduceduncertaintyissolargebecause,asseeninEquation 5{2 ,DMisdependenton5,whereasitdependsonlylinearlyontheotherquantities.Futureworkwillbeable 143

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UsingLCBGsathighredshiftasastandardcandleisapromisingandwell-motivatedavenuetoexploreforprecisioncosmology.Afuturesurveyofhighredshiftstarburstgalaxieswithmeasurementsofz,,AH,FH,O/H,andEW,suchasGOYAattheGTC,willreducebothrandomandsystematicerrorsdramatically.Sincetheinherentscatterofthemethodislarge,alargesamplesizeisrequiredtoobtainmeaningfulconstraints.Thispapercontainsasamplesizeofonly15galaxies,butfuturesurveysshouldbeabletoobtainhundredsofstarburstgalaxiesthatsurvivetheselectioncuts.Forasampleof500galaxies,thiswillimproveconstraintsonmtoarestrictionof0:03duetorandomerrors.Additionally,allofthesystematicsspecictothissampleduetoincompletedatawilldisappear. 144

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LuminousCompactBlueGalaxies(LCBGs)arehighsurfacebrightnessstarburstgalaxiesbluerthanatypicalSBcspiralgalaxyandbrighterthan0.25L?whichareundergoingamajorburstofstarformation.LCBGsareselectedtobetheclosestcounterpartsofthenumerouspopulationofdistantstarburstgalaxies,includingLyman-breakgalaxiesatz2.Therefore,LCBGsinthenearbyuniversemayholdthekeytounderstandingthenatureofthedistantpopulationandtheirevolutionintotoday'sgalaxypopulation.Wehaveselectedarepresentativesampleof22LCBGsinthelocaluniversefromtheSloanDigitalSkySurvey,andtheUniversidadComplutensedeMadridcatalogs,tobeobservedwithanIntegralFieldUnit(IFU).Threedimensional(3D)opticalspectroscopydataprovideacompletedescriptionofthephysicalpropertiesofgalaxiesasafunctionofspatialpositionwithinthegalaxy.Althoughsmall,thisrepresentativesampleprovidesanexcellentreferenceforstudyingthekinematicpropertiesofLCBGsasaclass,andcomparingwithcurrentandfutureobservationsofthedistantLCBGpopulationwithopticalandinfraredintegraleldunitsin10-and30-mclasstelescopes.Inparticular,weareabletoshedlightintothefollowingthreefundamentalquestionsaboutthenatureofLCBGs,aswellastheirformationandevolution. Inparticular,velocityandvelocitywidthmapsallowustoclassifythekinematicsofLCBGsbetweenthreedierentclasses:rotatingdisks(RD),perturbedrotation(PR),andcomplexkinematics(CK).Wend48%RDs,28%PRs,and24%CKs.Traditionally,PRsandCKshavebeenlinkedtothepresenceofbothminorandmajormergers,orgalaxypairinteractions.Accordingtothis,halfofthegalaxiesinourrepresentativesample(PRs 145

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Spatiallyresolvedkinematiccomponentsarefoundin14%ofthegalaxiesinourrepresentativesample.WhilethekinematiccomponentfoundinNGC7714islinkedtoaspiralarm,thosefoundinNGC7673andUCM2327maybeproofofarecentminormerger.Inparticular,thespatiallyresolvedkinematiccomponentfoundatthelocationofclumpBinNGC7673,showsnoevidenceforneitherActiveGalacticNuclei(AGN)activity,norsupernova(SN)galacticwinds,andisinagreementwithbeingeitheranextremelygiantHIIregion,oraninfallingdwarfgalaxy.Whilewendspatiallyresolvedkinematiccomponentsthatmightduetoaminormergerin10%ofthegalaxiesinourrepresentativesample,proofofanongoingmajormergerisfoundonlyinoneofourgalaxies(5%ofthesample). Outofthe22LCBGsinourrepresentativesample,21(95%ofthesample)shownoevidenceAGNactivity.ThissuggestthatsuchaphenomenaisnotcommoninLCBGs.Ontheotherhand,onegalaxy(5%ofthesample)showclearevidenceforAGNactivity. 146

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Ontheotherhand,27%ofthegalaxiesinourrepresentativesampleshowspectrallyresolvedkinematiccomponents.Eventhoughwecannotunambiguouslystatethenatureofthesecomponents,boththeirintensitiesandosetsareinagreementwithSN-drivengalacticwindspreviouslydiscussedby Marloweetal. ( 1995 )inasampleofdwarfgalaxieswithstarformationactivity.Nevertheless,SN-drivengalacticwindsdonotseemtobetypicalamongourrepresentativesampleoflocalLCBGseither. Yangetal. 2008 ).Nevertheless,ourclassicationisonlycarriedoutafterathoroughanalysisofeachobjectisperformed.ThisanalysisallowustondtherotatingnatureofLCBGsafterremovingasymmetriesintroducedbyspatiallyandspectrallyresolvedkinematiccomponents.Beforethisanalysisiscarriedout,thepercentagesforboththenearbyanddistantpopulationsareinagreement.ItisimportanttonoticethatsuchananalysisisnotpossibleforthedistantpopulationofLCBGsbecauseoftheintrinsiclimitationsofobservationsofdistantgalaxies. Inparticular,onlyafterinvestigatingthevelocityandvelocitywidthmapsofNGC6052wewereabletodiscardtheapparentlyrotatingnatureofthisgalaxy.Wendthatouranalysis,togetherwiththedoublenucleus,thetail,therecentstarformation,thelargevelocitygradientsintheextranuclearregions,andtheperturbedgasinthewholeFOVareallsignsofamergerevent. FromourdetailedanalysisofvelocityandvelocitywidthmapsweconcludethateventhoughmostLCBGsshowhighlyasymmetricmaps,48%ofthesegalaxiesrotateandbothadynamicalcenterandapositionanglecanaccuratelybederived.Usingthisinformationwecanderiverotationalvelocitiesbyconsideringrotationcurvesalongthemajoraxisof 147

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Thoseobjectsinourrepresentativesampleof22LCBGswhichshowrotatingnaturescanbecomparedwiththespiralgalaxiesusedtocalibratetheTully-FisherRelation(TFR; Tully&Pierce 2000 ).WendthatLCBGs,likespiralgalaxies,showacorrelationbetweendirectmeasurementsoftheirrotationalvelocitiesandestimatesfromtheirintegratedvelocitywidths.Nevertheless,adispersionvetimesbiggerthantheonefoundforspiralgalaxiesimpliesthatthevelocitywidthsofthoseLCBGsthatrotate,ratherthanaccountingexclusivelyforthisrotation,mayaccountaswellforotherkinematiccomponents. Therefore,anaccurateestimationofthedynamicalmassoftheseobjectsisneeded.Whencompared,dynamicalmassesderivedfromrotationcurvesandintegratedvelocitywidthsdierinourrepresentativesampleofLCBGsuptoafactorof4.SuchadierencemayhaveanimportantimpactonthestudyofdistantLCBGswhenobservedthroughmulti-objectlong-slitspectrographs.Thesekindofsurveysrelyonintegratedspectralmeasurementstoderivedierentphysicalproperties,suchasdynamicalmasses. Furthermore,LCBGsshowlargerMBforaparticualrrotationalvelocitythanspiralgalaxies.Therefore,theirmass-to-lightratiosarelowerthatthosefoundforthelatter.BycombiningthedynamicalmassesandtheabsoluteB-magnitudesofLCBGs,wendM=LB0:6.Suchalowervalueisinagreementwiththosefoundforlate-typegalaxies( Dickel&Rood 1978 ). 148

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Siegel,Guzman,Perez-Gallego,etal. ( 2005 )onapowerfulstandardcandlethatreliesonaccuratemeasurementsoftheuxesandvelocitywidthsofthesegalaxiesatdierentredshifts. 149

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JorgePerezGallegowasbornin1980,inthecityofTerrassa,intheprovinceofBarcelona,Spain.Hewasbornintoahumble,buthappy,familyhome.HeissonofConstantinoandTrinidad,andbrotherofNuria.Apartfrombeinghisfamilyandhousemates,togetherwithhismaternalgrandmother,whoalsolivedatthehouse,theyarealsohisbestfriends.HegrewupinCanParellada,alittleneighborhoodwhereeveryoneknewhimbecauseeveryonekneweitherhisfatherorhismother.HeplayedeverlastingsoccermatchesandhadepicadventuresinthestreetsofCanParellada.Withhim,therewasalwayshisinseparableneighbor.Theyhavebeenfriendssincetheywerebornandtheywillalwaysbe.Hedoesnotremembercryingthersttimehewenttoschool,whenhewasfouryearsold.FortenyearshestudiedattheColegioPublicoFrancescAldea,knowninTerrassaforbeingshapedafteraship.Stilltoday,heretainsgoodmemoriesfromthoseyears,mostofthem,relatedtohisclassmates.Threeofthem,hewillneverforget,twowhoarenolongeramongus,andathirdonethathasalwaystimeforhimwhenlifebringshimbackhome.Becauseofhisearlyacademicsuccess,hechangedfromapublicelementaryschoolfromtheoutskirtsofTerrassatoadowntownrenownedhighschool.Eventhoughhefeltoutofplaceatthebeginninginanewenvironment,earlyenoughhefoundhimselfenjoyingthisnewopportunity.Itwasthen,whenhelaidthefoundationsofwhoheistoday.Hestillremembershisclassmatesandprofessors.Amongthose,fourhavebeenwalkingwithhimeversince:theThreeMusketeersandJohntheFearlessItwasthenwhenhestartedworkingatanautoelectricshopunderthesupervisionof,literally,thegreatestmanonEarth,anenlightenedbeing.Duringthosedayshelearnedhowtomakegoodcontactsbothwithcorporationbusinessmenandpettythieves.Furthermore,healsoworkedasawarehousekeeperandatacinema,wherehewatchedasmanymoviesashecould. 160

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