• TABLE OF CONTENTS
HIDE
 Title Page
 Acknowledgement
 Table of Contents
 List of Figures
 Abstract
 Introduction
 Observational techniques and...
 Results and the QSO monitoring...
 Polarimetric observations of BL...
 Summary and conclusions
 Bibliography
 Biographical sketch














Title: Optical brightness and polarization of quasars and related objects
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
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STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00097553/00001
 Material Information
Title: Optical brightness and polarization of quasars and related objects
Physical Description: x, 128 leaves. : illus. ; 28 cm.
Language: English
Creator: McGimsey, Ben Quiller, 1946-
Donor: unknown ( endowment )
Publication Date: 1974
Copyright Date: 1974
 Subjects
Subject: Quasars   ( lcsh )
Physics thesis Ph. D
Dissertations, Academic -- Physics -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Thesis: Thesis -- University of Florida.
Bibliography: Bibliography: leaves 123-127.
Additional Physical Form: Also available on World Wide Web
Statement of Responsibility: by Ben Q. McGimsey.
General Note: Typescript.
General Note: Vita.
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Bibliographic ID: UF00097553
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000580845
oclc - 14089461
notis - ADA8950

Table of Contents
    Title Page
        Page i
    Acknowledgement
        Page ii
        Page iii
    Table of Contents
        Page iv
        Page v
    List of Figures
        Page vi
        Page vii
    Abstract
        Page viii
        Page ix
        Page x
    Introduction
        Page 1
        Page 2
        Page 3
        Page 4
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        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
    Observational techniques and equipment
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
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        Page 35
        Page 36
        Page 37
        Page 38
    Results and the QSO monitoring program
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
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        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
    Polarimetric observations of BL Lacertae 3C 120, and 3C 273
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 104a
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    Summary and conclusions
        Page 115
        Page 116
        Page 117
        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
    Bibliography
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
    Biographical sketch
        Page 128
        Page 129
        Page 130
        Page 131
Full Text












OPTICAL BRIGHTNESS AND POLARIZATION
OF QUASARS AND RELATED OBJECTS




By



BEN Q. McGIMSEY, Jr.


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE-REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA


1974










ACKNOWLEDGMENTS


The author wishes to express his appreciation and

thanks to Dr. A. G. Smith, the chairman of the author's

Graduate Committee, for his guidance and support during the

course of the research reported in this dissertation. The

author also wishes to acknowledge the contributions made by

Drs. A. E. S. Green, R. C. Isler, F. B. Wood, and S. T.

Gottesman-as members of his Graduate Committee.

Thanks are extended to A. G. Smith, R. J. Leacock, G. H.

Folsom, R. L. Hackney, K. R. Hackney, R. L. Scott, and P. L.

Edwards for their help in obtaining and reducing much of the

data presented in this study. Special appreciation is

expressed to R. L. Scott and P. L. Edwards for their assis-

tance in the preparation of the photographs. The assistance

of W. W. Richardson, H. W. Schrader, and E. E. Graves in the

construction and maintenance of equipment used in the QSO

program is gratefully acknowledged. Without their help it

would have been difficult to conduct the research reported

here. The efforts of Mrs. Elizabeth Godey in preparing the

typed manuscript are appreciated. The data presented here

were reduced with computer time donated by the Northeast

Regional Data Center of the State University System of Florida.





The author has been partially supported by an NDEA Title

IV fellowship and by Graduate School and Arts and Sciences

fellowships from the University of Florida. This support is

gratefully acknowledged.

The support of the author's family never failed during

the years of his graduate career and is deeply appreciated.

The author's greatest debt of gratitude is owed to his wife,

Karen, for her understanding and encouragement and it is to

her that this dissertation is dedicated.


iii











TABLE OF CONTENTS


Page

ACKNOWLEDGMENTS . . . . . . . . . . ii

LIST OF TABLES . . . . . . . . .

LIST OF FIGURES . . . . . . . . . . vi

ABSTRACT . . . . . . . . ... . viii

CHAPTER

I INTRODUCTION . . . . . .... ... 1

Quasars . . . . . . . . .
Optical Properties . . ..... 3
Models . .. . ..... ..... .. 10
Polarized Component ....... . 20

II OBSERVATIONAL TECHNIQUES AND EQUIPMENT . . 24

The General Photographic Program . . .24
The Polarimetry Program . . . . 30

III RESULTS OF THE QSO MONITORING PROGRAM . . 39

Discussion of Individual Objects . . 48

IV POLARIMETRIC OBSERVATIONS OF BL LACERTAE,
3C 120, AND 3C 273 ............ . 99

Error . . . . . . . . . . 99
ELaror .................... 99
BL Lacertae . . . . . . ... 102
3C 120 ....... ........... .108
3C 273 . . . . . . . . . 112

V SUMMARY AND CONCLUSIONS . . . . . 115

BIBLIOGRAPHY ................ . 123

BIOGRAPHICAL SKETCH . . . . . . . . .. 128









LIST OF TABLES


Table Page

1 Calibrated Sources . ....... . . 42

2 Sources with Tertiary Calibrations . . . 46

3 Sources with No Calibrations . .. . . 50

4 Sources with Known Polarization . . . . 103

5 Polarimetric Observations . . . . .. 106











LIST OF FIGURES


Figure Page

1 A spinar model of a QSO . . . . ... .14

2 RHO 30-inch reflector showing the Cassegrain
camera and Polacoat 105 UV filter ...... 34

3 Light curves of OB 338, 01 318, and OK 290 . 56

4 Comparison sequence of OQ 208 . . . . 60

5 Light curves of OQ 208, OX 074, and
PKS 0202-17 . . . . . . . . . 62

6 Comparison sequence of PKS 0202-17 . . . 66

7 Light curves of PKS 0222-23, PKS 0336-01,
and PKS 0458-02 . . . . . . . 68

8 Comparison sequence of PKS 0222-23 . . . 70

9 Comparison sequence of PKS 0458-02 . . . 74

10 Light curves of PKS 0518+16, PKS 1252+11,
and PKS 1347+21 . . . . . . . . 77

11 Comparison sequence of PKS 1252+11 . . . 79

12 Comparison sequence of PKS 1347+21 . . . 82

13 Light curves of PKS 1607+26, PKS 2209+08,
and PKS 2345-16 . . . . . . ... 85

14 Comparison sequence of NRAO 140 . . ... .89

15 Light curves of NRAO 140 and NRAO 512 . .. 91

16 Light curves of 3C 371 and 3C 446 . . .. 95

17 Comparison sequence of 3C 446 . . . ... 98

18 Percent transmission versus wavelength
for Kodak GG-13, Polaroid HN-32, and
Polacoat 105 UV filters . . .. . .. 101





LIST OF FIGURES Continued


Figure Page

19 The B magnitude, percent linear polariza-
tion P, and position angle of polarization
e for BL Lacertae . . . . . .. 105

20 The B magnitude, percent linear polariza-
tion P, and position angle of polarization
6 for 3C 120 . . . . . . . . . 111

21 The B magnitude, percent linear polariza-
tion P, and position angle of polarization
8 for 3C 273 . . .. . . . . . 114


vii





Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy


OPTICAL BRIGHTNESS AND POLARIZATION
OF QUASARS AND RELATED OBJECTS


By

Ben Q. McGimsey, Jr.

December, 1974


Chairman: Dr. Alex G. Smith
Major Department: Physics


Photographic monitoring of over 130 quasars and related

objects has shown definite optical variability to be present

in nineteen of these objects and suspected variability in

forty-four others. Regular observations of the optically

violent variables OB 338, OX 074, PKS 0518+16, PKS 2345-16,

NRAO 512, and 3C 371 have revealed that these objects continue

to undergo violent optical outbursts of a magnitude or more

with the flare and subsequent return to minimum sometimes

occurring within a few weeks. The earlier observations of

PKS 2345-16 and NRAO 512 have been reported in a paper by

G. H. Folsom, A. G. Smith, and R. L. Hackney, "Optical Flares

in the Quasi-Stellar Radio Sources PKS 2345-16 and NRAO 512,"

in Astrophysical Letters, 7, 15 (1970); and the observations

of OB 338 and OX 074 in a paper by G. H. Folsom, A. G. Smith,

R. L. Hackney, K. R. Hackney, and R. J. Leacock, "Optical

Changes in Eleven Ohio Radio Sources with Unusual Spectra,"

in The Astrophysical Journal (Letters), 169, L131 (1971).


viii





In addition, optical variability was observed for the first

time in the objects PKS 0202-17, PKS 0222-23, PKS 1252+11,

and NRAO 140. Both OQ 208 and PKS 0222-23 showed a total

range of variability of a magnitude or more. The optically

violent quasar 3C 446 underwent a 275 flare in 1974 with an

extremely rapid decay time.

Two types of characteristic variability were observed.

The first was a violent optical outburst with rapid rise and

decay times, observed in the objects described above. The

second type of characteristic variability was a slowly varying

component which appeared as a gradual rise and fall in optical

brightness. Both types of variability were observed in

several sources, while other sources exhibited only one type.

There is observational indication that major flares in

optically violent objects tend to be followed by a succession

of minor flares of decreasing amplitude superimposed upon the

decline in brightness following the major flare. This effect

was observed in NRAO 512, OX 074, PKS 2345-16, PKS 2209+08,

and possibly OQ 208 and PKS 0222-23.

Optical linear polarimetric observations were conducted

photographically on BL Lacertae, 3C 120, and 3C 273. These

observations indicate that the peculiar object BL Lac has a

very large, rapidly varying linearly polarized component.

The polarized component of the Seyfert galaxy 3C 120 is

smaller and more slowly varying than that of BL Lac. The

quasar 3C 273 seems to lack a linearly polarized component.

There seems to be a positive correlation between the optical






activity of an object and the magnitude and variability of

its linearly polarized component. These results were par-

tially communicated in a paper by B. Q. McGimsey, A. G.

Smith, R. L. Scott, R. J. Leacock, and P. L. Edwards,

"Optical Linear Polarization in the Extragalactic Sources

BL Lacertae and 3C 120," presented at the 38th Annual Meeting

of the Florida Academy of Sciences, 21-23 March 1974 in

Orlando, Florida.









CHAPTER I

INTRODUCTION


Quasars


The attempt to determine the true nature of quasars and

related objects has been one of the most important efforts of

the past decade in astronomy. In 1960 Sandage and Matthews

photographed the radio source 3C 48 with the 200-inch Palomar

telescope. The optical counterpart to this small angular

diameter radio source was found to be a 16th magnitude

"stellar" object with a wisp of nebulosity. Spectra taken by

a number of astronomers indicated an abnormally blue object

with broad emission lines which could not be identified. This

problem was solved by Schmidt (1963) when emission lines in

3C 273, a similar object, were identified as the Balmer lines

of hydrogen and a line of Mg II shifted toward longer wave-

lengths of the spectrum with a redshift z = AX/X = 0.158.

This led to the determination by Greenstein and Matthews

(1963) that the emission lines of 3C 48 exhibited a redshift

z = 0.367. Later discoveries have shown that these values of

z are low for quasars. The quasi-stellar object with the

largest redshift known at present is OQ 172 with z = 3.53

reported by Wampler et al. (1973a).







Quasi-stellar sources can be briefly described as being

star-like, often variable in both radio and optical emission,

with large ultraviolet and infrared fluxes, and exhibiting

broad emission lines with large red shifts. In addition,

several objects have a large linearly polarized component.

The field has grown to include "quasi-stellar objects," which

have the same optical properties but are very weak radio

emitters; and Lacertids, which have radio and optical spectra

similar to quasi-stellar sources, are very bright and highly

variable, but lack emission lines, thus not allowing a red-

shift to be determined.

The assumption of a cosmological interpretation of the

observed redshifts, i.e., that the redshifts are due to the

relativistic expansion of the universe, leads to difficulties

in explaining the physical mechanism of radiation. These

objects appear to be at least as luminous as galaxies but

the time scale of the optical variability of at least some

objects indicates optical sources of light day to light

months in size. Explanations of quasars assuming the red-

shift to be due to a non-cosmological mechanism are not satis-

factory at the time of this writing.

Assuming the cosmological interpretation, quasi-stellar

objects appear to be the most distant objects in the known

universe, and thus the youngest observed. The study of these

objects will hopefully lead to information about their origin

and radiation mechanisms and perhaps to knowledge of the uni-

verse at earlier epochs, and its evolution. To contribute to







this study is the purpose of the University of Florida pro-

gram.

The present program was established in 1968 by A. G.

Smith and G. H. Folsom, with the Rosemary Hill 30-inch reflec-

tor and has grown into a photographic monitoring program of

about 150 quasars and related objects. This program has been

continued by Smith and others and has been expanded to in-

clude multicolor photometry. Recently linear polarization

observations of several objects have been initiated by the

author.

The terminology used in describing quasars has remained

somewhat unsettled. In general both radio-strong and radio-

weak quasars will be referred to as quasi-stellar objects or

QSO's by the author. Similar objects, such as Lacertids,

Seyfert galaxies and N galaxies, will be referred to individ-

ually by their proper names, and collectively as "related

objects."



Optical Properties


Stellar Image

Quasi-stellar objects, as the name implies, are star-like

optical objects identified with compact radio sources. Some

have associated wisps or jets of nebulosity, as does the QSO

3C 273B, which is associated with an optical jet 3C 273A.

However, this is not the general case.







Quasi-stellar objects are usually identified by checking

a radio source error box for optical objects. If no other

obvious source, such as a galaxy, appears within the error

rectangle, the identification of the radio source is tenta-

tively made with a blue stellar object within the error box,

pending further confirmation. This confirmation is usually a

spectrogram showing a QSO-like appearance. A highly red-

shifted line spectrum is considered definite proof.


Variability

Many quasi-stellar objects show optical variability.

About thirty-four of two hundred and two objects in a catalog

by De Veny et al. (1971) are classified as optical variables.

Several types of variability have been recorded. Some show

small-amplitude (less than 0.5 magnitude) irregular variations

over a period of weeks or months (type V variations). One

such source is the QSO 4C 05.34, which has been reported by

Hackney (1973) to show a statistically significant one-tenth

magnitude variation on the time scale of a year. Others,

classified as optically violent variables (OW), show varia-

tions of a magnitude or more in days or weeks. One example

of such an object is PKS 2345-16 (Folsom et al. 1970;1971).

This source has shown a total change of about lT5 in a period

of three months in late 1969 and early 1970. More recently,

the Rosemary Hill program shows that it has undergone type V

variations in the 1972 observing season, suggesting that a

QSO can show more than one type of variability.







As this is written, there has been only one QSO that

shows possible periodicity in its optical radiation. Kinman

et al. (1968) have seen an eighty-day periodicity in optical

bursts from 3C 345 with one chance in several thousand that

this periodicity is fortuitous. They also see a pattern in

the phases of the eighty-day outbursts indicating a 321.5-day

period. There is a chance of one in eighty that this second

period is fortuitous. Four out of five expected outbursts in

the 321.5 day period have been seen from 1965 to 1969 (Morri-

son 1969). However, data taken from 1970 to 1972 at Rosemary

Hill tend to disprove this periodicity (Hackney 1973).

It is interesting to note that there is a correlation

between violent optical variability and the radio spectral

index (Folsom et al. 1971; Folsom 1970; Andrew et al. 1972).

The violent optical sources usually exhibit radio spectra

with a small spectral index (flat) or spectra which show an

increase in emitted flux toward short (centimeter or milli-

meter) wavelengths.

The diameter of a variable optical source at cosmologi-

cal distances is given by Terrell (1967) for non-relativis-

tically expanding sources. The observable change in luminosity

of a sinusoidally varying source is approximately

4cT
AL T (1.1)


where To is the intrinsic period, D the diameter, L the

observed luminosity and c the speed of light. This merely







gives the familiar result that a change is observable only

if the travel time of light across the object, D/c, is less

than or on the order of the period of variation. The observed

period T is equal to To times l+z where z is the redshift.

Solving for D and expressing AL/L as a change in magnitude

implies

4c T
D 4c T (1.2)

Using observed quantities from some typical QSO's leads to

diameters in the order of a light year for slowly varying

objects, light weeks for PKS 2345-16, and a light day for the

optically violent variable 3C 446 (Burbidge 1967). For a

relativistically expanding source, the right side of equation

(1.1) must be multiplied by the factor y = (1 v2/c2) 1/2 in

order to give correct results.


Ultraviolet Excess

A striking property of most quasi-stellar objects is a

large excess in the ultraviolet component of the electro-

magnetic radiation as compared to galactic stars. The U-B

color index ranges from -1.2 to -0.4. In a plot of U-B versus

B-V color indices, QSO's are above the region of main sequence

stars, in the region of white dwarfs. This ultraviolet excess

is so striking that it is considered a strong factor in favor

of the identification of a stellar-like source as the optical

counterpart of a compact radio source.

This ultraviolet excess has let to discovery of another

subclass of QSO's. During an optical search for QSO's,







objects were found with ultraviolet excess but with no radio

counterpart (Burbidge 1967). When spectra were taken, some

of these objects proved to be galactic stars, while many were

proved to be QSO's that are either radio quiet or weak radio

emitters.


Line Spectra and Redshifts

Possibly the most striking feature of quasi-stellar

objects is the presence of large redshifts in their line spec-

tra. The spectra may consist of both emission and absorption

lines. The emission lines are broad ('l00A), of the type

which may be expected to arise in hot gaseous nebulae, in

radio galaxies, and in the nuclei of Seyfert galaxies. The

stronger lines seen are the Balmer lines for objects with

small redshifts, Lyman -, C IV X 1549, C III A 1909 and Mg II

X 2798. Absorption lines are seen in many, but not all,

QSO's. They are narrow and are usually resonance lines. The

only line feature observed in the radio region has been the

21 cm hydrogen line in absorption recently found by Brown

and Roberts (1973) in 3C 286, believed to be due to a fore-

ground object. The redshifts for 3C 286 are zem = 0.849 and

Zabs = 0.692.
The size of the emission line redshifts z = AX/X range

from 0.06 for B 234 to the recently established 3.53 for OQ

172. Some objects, e.g., PKS 0237-23, exhibit several differ-

ent values of zabs, all of which may be different from zem.

Usually the absorption redshifts are smaller than the







emission redshift. There is some evidence that absorption

lines may be more prevalent in high redshift objects (Bur-

bidge 1967).


Continuous Energy Distribution

Knowledge of the shape of the continuous energy distri-

bution of quasi-stellar objects is important to construction

of models and mechanisms for radiation emission. Stein (1967)

has plotted a spectrum for 3C 273 covering a large part of the

spectrum. This is the only object for which there are enough

data to make such a plot. The steep rise into the infrared

suggests a non-thermal process, either the synchrotron or

inverse Compton mechanism.

There is no "average" QSO spectrum, because of individual

differences among the sources (Oke 1966). Even so, one can

fit a simple equation to the form of the optical spectrum:


F(v) C v-n (1.3)

F(v) e-VVo (1.4)


where F(v) is the observed energy distribution and v is fre-

quency. Since there is no typical QSO spectrum, there is

some disagreement about the form of the distribution. Schmidt

(1968) found a value of n = 0.7 using equation (1.3) after

correcting UBV colors of several sources for interstellar

reddening. Lari and Setti (1967) prefer equation (1.4) with
= 1.2x15 Hz.
vo = 1.2x10 Hz.







X-rays have been observed from the direction of 3C 273

(Friedman and Byram 1967). If 3C 273 is the source, the

authors claim that the intensity in the X-ray region is about

the same as the optical intensity.

In the radio region QSO's have spectra of the form of

equation (1.3) with a median value of n near 0.7. Some QSO's

have spectra that show curvature, getting flatter towards

longer wavelengths. In some cases a maximum appears and the

flux decreases toward longer wavelengths (Burbidge 1967).

Williams (1963) proposed that the shape of this part of the

spectrum indicates a synchrotron origin (Slish 1963).


Related Objects

There are several classes of objects showing many simi-

larities to QSO's. These objects may help to determine the

true nature of QSO's. The three main types of these related

objects are Seyfert galaxies, N galaxies, and Lacertids.

Seyfert galaxies are spiral galaxies with bright,

stellar-appearing nuclei. They exhibit strong emission lines

which are greatly broadened. Seyferts are strong emitters in

the infrared but show enough ultraviolet excess to appear

bluish. The observed redshifts in the emission lines are

assumed to be due to cosmological expansion of the universe.

The nuclei of N galaxies are even bluer and more star-

like than those of Seyferts. The envelope is smaller and

more amorphous. N galaxies also exhibit both the strong

emission lines and large infrared flux seen in Seyfert galax-

ies and strong low frequency radio emission.







"Lacertid" is the name given to a class of bright objects

of which BL Lacertae is the prototype. The spectrum of these

objects is non-thermal with a peak in the infrared, an ultra-

violet excess, and no emission or absorption features. Lacer-

tids also exhibit rapid, large amplitude variations in the

optical, infrared, and radio flux. There is some indication

that there may be appreciable optical variability on a time

scale of less than one hour (Scott et al. 1973a).

Recently reported observations by Oke and Gunn (1974)

indicate that Lacertids may be at cosmological distances.

The authors, using the 200-inch telescope at Mt. Palomar,

observed a redshift of z = 0.07 in the nebulosity surrounding

BL Lac when the center was occulted by using an annular aper-

ture. The spectrum shows lines seen in ordinary giant ellip-

tical galaxies. This leads to the assumption that the very

strong spectral continuum masks redshifted emission features

in Lacertids.


Models


There is considerable disagreement among astronomers

concerning the nature of quasi-stellar objects. Many, for

example Morrison (1969), believe these objects to be extra-

galactic at the cosmological distance "D" indicated by the

observed redshift z.

D v (1.5)
Ho







where v is determined by (l+v/c)/(1-v2/c2)1/2 = l+z, where

Ho is Hubble's constant, v is the velocity of recession and

c the speed of light. Others, such as Kellerman (1972),

suggest that QSO's are extragalactic but closer than distance

D. Thus the redshift would be of Doppler or gravitational

origin. Receiving more attention recently has been the idea

that the redshifts are partly of cosmological origin and

partly of some other origin. All of these hypotheses and /

several models to account for the observed phenomena will be

discussed below.


Cosmological Hypothesis

The cosmological hypothesis assumes that the redshifts

of QSO's are due to the expansion of the universe. The main

objection to this assumption is that the observed variations

in optical flux indicate a small diameter (see equation 1.1)

for QSO's while the assumption of cosmological distances

indicates large amounts of radiation being emitted, 1047

erg/sec in 3C 273, for example (Burbidge 1967). On the

other hand, QSO's are similar to Seyfert and N galaxy nuclei,

which are assumed to be at cosmological distances. The

results of Oke and Gunn (1974) showing the similarity of the

spectrum of the nebulosity surrounding BL Lac to spectra of

giant elliptical galaxies support this hypothesis. In addi-

tion, Bahcall and Hills (1973) have found that for the optic-

ally most luminous quasars with redshifts from 0.2 to more

than 2, the slope of the magnitude-redshift relation is






consistent with the value of five expected from the expansion

of the universe. The fact that there are no observed blue-

shifted QSO's adds credence to this theory.


Spinar Model

Morrison (1969; 1973) has proposed that QSO's are super-

ficially similar to pulsars, though on a much larger scale.

Quasi-stellar objects are assumed to be compact, spinning

masses with a corotating magnetic field surrounded by a pool

of relativistic material (see Figure 1). The ultimate energy

source is gravitational. As the object contracts gravita-

tional energy is converted to rotational energy and, through

the magnetic stirring and accelerating processes in the pool,

into particle and electromagnetic energy. Mass is emitted

from the surface in a relativistic beam which corotates with

the spinar. Optically, one observes the varying emissions

from the pool except for the QSO 3C 345. In this case,

Morrison theorizes, the observer is in the plane of the

emitted beam and directly observes the 321.5-day rotation

period. The primary emission is infrared, by the synchrotron

process. Optical and x-radiation arise from the inverse

Compton process involving the infrared photons and the rela-

tivistic particles. The radio bursts are due to expanding

lumped mass ejections beyond the critical surface. Optical

emission and absorption lines arise in hot and cool gas

regions beyond the critical surface.


























Figure 1.


A spinar model of a QSO (Morrison 1973).
Reproduced by permission of Physics Today.
The numbered regions are (0) spin axis,
(1) surface of spinar, (2) synchrotron
emission of infrared, (3) Compton-recoil
emission of optical and x-ray continue,
(4) critical surface, (5) radio burst
clouds, (6) emission-line optical source,
(7) absorption line optical source, and
(8) radio emission from weak-field synchro-
tron plasma.





14

























t t-i. *. eo**


~o Component A









itral spi ar 5 6 7
W>V....* ', ," -. ,, -, *,,' '" *... ,; : -
n.t. .. .. '. *- ,*, D,, -.. U.





T. I ...... ...

*' . S *. _______. -e
t _a l .pina...~ i.;. U ... e d, ,;. .:.,



*1 I I I I I I I I
0 10'.s <1016 >1016 lO10Ms 103-101I 1020 1023 Radius R (cm) 104

10os 104 > U0 1-10-. Magnetic field B (gauss) 10-s







Magnetic Rotator

Piddington (1970) assumes that a weak intergalactic

magnetic field perpendicular to the rotation axis of a proto-

galaxy is wound several times around the protogalaxy. The B

field is strengthened and finally erupts in tongues along the

rotation axis due to the Rayleigh-Taylor instability. The

final stage is a star-depleted gas cloud of mass 10 Me,

radius 1016 cm and surface speed of 10 cm/sec with a frozen-

in field of 105 gauss. Particles are accelerated by pulsar

mechanisms and account for the optical and infrared continuum

by the synchrotron process. The shrinking gas cloud heats up

to provide emission lines. The connection between the tongues

and the internal field system provides for escape of rela-

tivistic electrons into the tongues, where they are trapped.

These electrons radiate by the synchrotron mechanism, leading

to the familiar double-lobed radio source. Radio-quiet QSO's

never developed the external field system. The energy source

is again electrodynamic conversion of gravitational energy.


Supernova Theory

Colgate (1969) has proposed that the energy source of

quasi-stellar objects is a chain reaction of supernovae.

Stars in a dense cluster collide and coalesce when the rela-

tive kinetic energy is insufficient for disruption. A few

stars will rapidly grow to sizes of about 50 Mo, evolve to

the supernova stage in about 106 years and erupt at a rate of

about five supernovae per year to account for the observed







energy radiated. Permeating the cluster is a gas of density

6x106 particles/cm3 the result of the stellar collisions and

material from previous supernovae. The optical continuum

arises from the collisional heating of the expanding supernova

envelope by the ambient gas to give a peak output of 1046

ergs/sec. The optical emission lines arise from the excita-

tion of the entire gas cloud. Thus, the continuum will fluc-

tuate depending on the time of the supernova eruptions while

the line emission will be fairly constant. The emission lines

are broadened by self-absorption in the centers of the lines,

causing them to be five to ten times as wide as the absorption

lines, as is observed. The infrared and millimeter radiation

is due to the scattering of photons within a plasma (the

ionized gas cloud) excited into oscillation by the two-stream

instability.


Local Hypotheses

Another suggested model of QSO's is that they are expelled

from galaxies and that the redshift is due to the velocity of

recession. For local objects moving at relativistic veloci-

ties, the number of blueshifted objects should be at least

4 times the number of redshifted objects for z = 1.5 (Burbidge

1967; Chiu et al. 1973). Since no blueshifted QSO's have been

identified, the expectation is that QSO's must have been

ejected from some nearby center. Terrell (1967) derived a

mass of 103 Me for the average QSO from the upper limit of

the proper motion of 3C 273. Assuming that the approximately







106 QSO's (Schmidt 1969) were expelled from the center of the

Milky Way and radiate with 10% efficiency of conversion of

mass to energy, all the mass within 100 parsecs of the center

of the galaxy would be consumed, an improbably high number.

The same energy problem holds for any nearby source.

A second local model assumes that the spectral lines of

QSO's are formed next to a compact massive object, thus caus-

ing a redshift due to the gravitational potential of the

object. The gradient of the potential over the emitting

region must be small since the line widths are much smaller

than the wavelength shift. The main objection to this model

is that, according to theory (Burbidge 1967), z must be less

than or equal to two, which conflicts with observed redshifts.

A model consisting of a cluster of collapsed objects can show

a redshift greater than two (Hoyle and Fowler 1967), but it

shows much too short a lifetime to be acceptable (Zapolsky

1968).


Other Hypotheses

There have been several observational indications that

redshifts cannot be entirely cosmological. Although no com-

plete model has been advanced, these objections to the cosmo-

logical hypothesis should be noted since they probably will

have a direct effect on future theories of QSO's.

Burbidge and Burbidge (1967) have pointed out that there

is a frequent occurrence of the redshift z = 1.95 in both

emission and absorption lines of QSO's. This suggests that







a mechanism other than cosmological expansion is causing at

least portions of the redshifts. While not to be dismissed,

this evidence for non-cosmological z has not been completely

convincing (Schmidt 1969).

Stein et al. (1971) assumed that the spectrum of the

Lacertid BL Lac can be attributed to synchrotron radiation

and that synchrotron self-absorption occurs. From these

assumptions they have derived an upper limit to the distance

of BL Lac as 300 kpc. This conflicts with the distance of

350 Mpc. measured by Oke and Gunn (1974).

Arp (1971) has claimed to see a luminous bridge between

a peculiar galaxy and a QSO but this has been disputed by

others (Lynds and Millikan 1972; Ford and Epps 1972). Further

evidence for galaxy-QSO association has been advanced by

other observers (Burbidge et al. 1971; 1972). Using the 3C

and 3CR catalogs of radio sources, the Burbidges and their

coworkers found that five of forty-seven QSO's lay within a

few minutes of arc of bright galaxies of markedly different

redshift. They calculated the probability of this effect

being a chance occurrence as 10-5. Further, the galaxy-QSO

separations are inversely proportional to the galaxy red-

shifts. No statistically significant close association

between galaxies and QSO's in the Parkes 2.7 GHz survey in

the 40 declination zone was found by the authors. However,

they claim this may be due to selection effects. The authors

conclude that galaxies give rise to QSO's.






Hazard et al. (1973) have found four QSO's within one

arc minute of one or more galaxies. The search involved look-

ing for blue stellar objects near galaxies two or three mag-

nitudes fainter. The four objects noted were later identi-

fied as QSO's. The authors note that the chances are one in

one hundred of finding one such QSO-galaxy grouping, assuming

cosmological distances.

There have been two discoveries of close pairs of QSO's

with very different redshifts. Stockton (1972) found that

Ton 155 and Ton 156 are approximately 35 arc seconds apart.

Wampler et al. (1973b) have discovered that two QSO's, PKS

1548+115a and 1548+115b, are separated by five arc seconds

with redshifts of 0.44 and 1.90, respectively. (PKS

1548+115b had not previously been identified as a QSO.) The

authors also note the wavelength ratio (l+z)a/(1+z)b = 2.02,

a curious coincidence. The probability that this is a chance

occurrence of two QSO's at cosmological distances is esti-

mated as 4 x 10- by the authors. However, Bahcall and

Woltjer (1974) found a much greater probability (0.50) for

random associations and concluded that these two pairs could

be merely apparent associations of widely separated objects.

Chiu et al. (1973) have pointed out in defense of the
cosmological theory that astronomers may be observing two

types of objects: (1) the majority of QSO's at cosmological

distances and (2) a "dwarf" branch originating from explosions

in nearby galaxies. The authors propose that the Lacertids

are blueshifted members of the dwarf branch, with the shifted






infrared continuum swamping the lines. In conclusion, there

is still much disagreement on the meaning of the redshift.



Polarized Component

Recently, there has been great interest in the polarized

component of the radiation of QSO's and related objects. As

this is written, there have been no observations of signifi-

cant optical circular polarization (Landstreet and Angel 1972;

Schmidt 1969). However, Conway et al. (1971) have observed

small (less than 0.1%) circular polarization at 21 cm and 49

cm in several QSO's and BL Lac (Biraud 1969).

Significant variable linear polarization has been

observed in the continuum emission in many QSO's and related

objects (Burbidge 1967; Schmidt 1969; Visvanathan 1973a).

There has been no linear polarization observed in emission

lines of QSO's. The polarized component amounts to 10% or

more of the optical continuum flux in some objects (Visvana-

than 1969; 1973a). There is some evidence that optical vari-

ability in QSO's is accompanied by a higher percentage of

linear polarization than in non-variable sources (Kinman

et al. 1969). Lacertids, which tend to be violently vari-

able, show large amounts of polarization, thus supporting

this evidence (Visvanathan 1973a; 1973b; Kinman et al. 1967).

In general, increases in the total flux from an object tend

to be accompanied by an increase in polarized flux (Visvana-

than 1973a; Williams et al. 1972). Kinman et al. (1974)







report interesting behavior of linear polarization in both

the radio and optical wavelengths of 3C 345 and OJ 287. The

position angle of polarization in both objects tends to show

sudden departures from a smooth trend, followed by a return

to the original trend.


Possible Mechanisms

The two mechanisms discussed as possible sources for the

observed polarization from QSO's and related objects are the

synchrotron mechanism and the inverse Compton effect. In a

simplified view of the synchrotron mechanism, relativistic

charged particles move with a component of velocity perpendicu-

lar to a magnetic field. The particles describe a circle or

helix about the magnetic lines of force. Radiation is emitted

in a narrow cone in the direction of the particle velocity.

This radiation is almost completely polarized with the elec-

tric vector parallel to the plane of the instantaneous circu-

lar motion. The assumed reason that only a small percentage

of linear polarization is measured is that the observed radi-

ation is the resultant emission from particles moving in an

inhomogeneous field, or emissions from several discrete

sources with different alignments of magnetic field.

The inverse Compton process involves the collision of a

high energy particle, usually an electron, and a low energy

photon, which results in a high energy recoil photon and a

decrease in electron energy. If the low energy photons are

polarized, the inverse Compton effect would result in high







energy photons with the polarization preserved. However,

this preservation of polarization during inverse Compton

scattering has been disputed by Bonometto and Saggion (1973).

The inverse Compton process becomes more important as the

electromagnetic energy density increases and it will dominate

the synchrotron mechanism as the mechanism for particle

energy losses if the electromagnetic energy density is greater

than twice the magnetic field energy density (B2/8T).

There are as yet no suggestions for any other possible

mechanisms.

The facts that a power law representation of the optical

continuum is valid, and that percentage polarization is inde-

pendent of wavelength, are taken as indications that the

optical continue of OJ 287 and BL Lac are of synchrotron

origin (Visvanathan 1973a; 1973b). The shape of the continuum

in the infrared has been taken to indicate that this portion

of the spectrum is also due to synchrotron emission (Ozernoy

and Sazonov 1971).

It is difficult to compare the observed polarization

properties mentioned in the previous section with QSO models,

as the models do not give a detailed picture of emission

mechanisms. The polarization observations are probably con-

sistent with the spinar or the magnetic rotator models,

although the spinar model does predict that the optical com-

ponent is of inverse Compton origin in contradiction to

Visvanathan's results. It is difficult for the writer to




23


believe that the linear polarization reported could originate

in the supernova model. Kinman et al. (1974) have reported

that their observations of OJ 287 are inconsistent with an

expanding source model.











CHAPTER II

OBSERVATIONAL TECHNIQUES AND EQUIPMENT



The General Photographic Program


The Rosemary Hill observing program consists of regular

observations of QSO's and related objects to search for opti-

cal variability and to monitor known variables. In addition,

possible changes in spectral slope are monitored by observa-

tions in the Johnson UBV magnitude system (Hackney 1973).

The method of photographic photometry was chosen for the

Rosemary Hill monitoring program for several reasons. The

first and most obvious is that with a 30-inch reflector photo-

electric observations of many faint (on the order of 15th

magnitude or fainter) QSO's would be difficult. Objects

fainter than this magnitude make up a large percentage of the

present observing program. While observation of the few 14th

magnitude or brighter QSO's and related objects would be

possible photoelectrically with this telescope, these obser-

vations would require integration times of several minutes

each for the object, comparison star, and sky background.

For an object of about 14th magnitude, a typical unfiltered

photographic exposure time for object and comparison sequence

is about four minutes. Thus, time resolution is improved by

the photographic method, enabling the observer either to







measure a larger number of sources or, by making many expo-

sures, to check for short term variability in a single source,

both important segments of the Rosemary Hill program.

Photographic photometry is also advantageous in that

changes in transparency affect both the object and comparison

sequence (typically a one-half degree or smaller diameter

field) simultaneously and thus do not seriously affect results.

For photoelectric observations, however, good weather with

constant, excellent sky transparency is required. Weather

studies have been conducted at Rosemary Hill with results

that indicate 66 percent of the nights available are usable

photographically while only 35 percent are useful photoelec-

trically (Hackney 1973).

The photographic program also lends itself to observa-

tions of faint objects or nebulosity through the use of fine-

grain emulsions. Finally, many known radio sources which are

unidentified or of doubtful optical identification are moni-

tored infrequently to search for possible variations and

identification of new QSO's. These plates are of similar

scale and easily comparable to the Palomar Sky Survey to aid

in identification of objects and to check for variability

over a twenty-year time span.

Telescope time at Rosemary Hill is awarded on the basis

of half nights. The QSO monitoring program is typically

given observing time equivalent to eight whole nights per

month divided between twelve observing sessions.







Telescope and Equipment

Most observations of the optical brightness of objects

were made at the f/4 Newtonian focus of the 30-inch Tinsley

reflector. A few observations of the optical brightness of

BL Lac (shown in Figure 19) were made with the 18-inch

Ritchey-Chretien telescope. The Newtonian focus of the 30-

inch was chosen for several reasons. The first is that the

field is one degree in diameter; while only one-half is

usable due to comatic aberration, this is a large enough

field to include a good comparison sequence for almost all

objects. In comparison, the Cassegrain field is only one-

fourth degree in diameter. The exposures at the Newtonian

focus are also much shorter than would be required for the

f/16 Cassegrain focus since atmospheric turbulence causes

each star to exhibit a finite disc, thus increasing exposure

times for the larger focal length Cassegrain system. A final

reason is that the physical process of removing the photo-

electric photometer usually mounted at the Cassegrain focus

is difficult and time-consuming; this process is avoided by

using the Newtonian focus. The Newtonian program does have a

disadvantage in that the moonlit sky is too bright for success-

ful exposures. Consequently, a Cassegrain camera was developed

by R. L. Scott to monitor bright objects during moon time.

As this program has been in operation for several years,

focus, guiding, exposure, and development procedures have

already been described thoroughly elsewhere (Folsom 1970;

Hackney 1973). These procedures are not repeated here. One







recent change in the program is that most exposures are now

made on Kodak 103a-0 plates hypersensitized by baking (Scott

and Smith 1974), whereas untreated 103a-0 plates were used

in the past.

Iris Photometry

The QSO photographic plates are reduced on a Cuffey Iris

Astrophotometer. Since Folsom (1970) has given a complete

description of the instrument and its use, a simplified dis-

cussion will be given here to give the reader a working knowl-

edge of its operation. The density and diameter of an image

of a point source on a photographic plate are related to the

magnitude of the source. The iris photometer transmits a

light beam through a variable iris diaphragm, the photographic

plate and the QSO or star image. This beam and a reference

beam adjusted for each plate alternately enter a photocell.

By changing the diaphragm opening, which is encoded to a

digital reading, the currents produced by the two beams can

be equalized, thus nulling a galvanometer. The iris reading

at the galvanometer null is the recorded reading.

The magnitude of an object is related to the iris read-

ing in the form:


m = al + bl + c (2.1)

where m is the magnitude, I the iris reading and a, b, and c

are constants (Hackney 1972). For each plate the iris read-

ings of the source and several stars of known magnitude are







determined. A least squares parabolic fit is made to the

magnitudes versus iris readings of the known stars. The

magnitude of the unknown is then determined from this curve

by substituting the iris reading. The distances on the mag-

nitude axis of the plotted known stars from the fitted curve

are known as the "residuals." The error for a magnitude

determination is taken to be the rms of the residuals.

A complete listing of the factors causing error in these

measurements is given by Hackney (1972). The most important

is fluctuation in the background density of the emulsion.

The best error obtainable in the University of Florida pro-

gram is about 0.05 magnitude for bright objects on nights of

excellent transparency. An average value is 0.10 magnitude.

A possible effect that should be noted is the apparent

change in the magnitude of an object due to increasing air-

mass. Much of the optical energy of QSO's is radiated in the

blue and ultraviolet regions of the spectrum, the regions in

which optical radiation suffers the greatest scattering by

the atmosphere. Hackney (1972) found that for the Seyfert

galaxy 3C 120 this effect is 0.05 magnitude per airmass, thus

showing that this effect is not of great importance.

An important part of the program is detecting variability

in objects not previously reported as variable. In order to

detect variability, a comparison sequence of nearby stars of

known magnitude is needed. The method used in the Rosemary

Hill program to calibrate a comparison sequence is to expose

an unknown QSO and its surrounding field on the same plate







with a field containing stars of known magnitude. These two

exposures are of identical length and are made only during

excellent sky conditions. When read on the iris photometer,

the reference beam is the same for both fields. Each poten-

tial member of the new comparison sequence is treated as an

unknown and has its magnitude determined from a calibration

curve of known stars on the second half of the plate. While

this process is not as accurate as a photoelectric determina-

tion of the amplitude of each comparison star would be, it is

much superior to attempts to determine variations in QSO's

by "eyeball" methods.


Data Reduction

Two programs have been developed by Hackney (1972) for

the reduction of iris photometer data. The first is for the

University of Florida IBM 370/165. This program is most suit-

able for large amounts of data gathered over one or more

observing seasons. The comparison star magnitudes and the

iris readings are entered on punched cards. The program fits

a linear and a parabolic curve to the data and prints the

solution which minimizes the error. A linear fit is given to

those objects with high scatter in the comparison sequence or

with too few stars for a parabolic fit. The output gives the

magnitude of the QSO with the residuals for each comparison

star for every plate, the error for each plate (rms of the

residuals), and the airmass for each observation, plots a

light curve, and smooths the comparison sequence by printing







a new magnitude for each star. The new magnitude is derived

by averaging the residuals from all plates and adding this

increment to the original magnitude. The use of this feature,

combined with accuracy in recentering each field, reduces the

error caused by field effects in the observing system. In

addition, the program tests the data for significance of vari-

ation by use of a chi-squared test of the hypothesis of con-

stant mean devised by Penston and Cannon (1970) and modified

by Hackney (1972).

The second program is for the Hewlett-Packard 9810A cal-

culator. This machine provides high accuracy with a fast

turn-around time, but it can process only one plate at a time,

thus providing no test for variability. This machine is best

used when accurate magnitudes are needed quickly, for example

when an object is suspected of undergoing an outburst. The

program makes a linear or parabolic fit to the data at the

discretion of the programmer. The calculator print-out gives

the magnitude of the object, the residual for each comparison

star and the error. The program and comparison sequence mag-

nitudes are entered from magnetic cards. The iris readings

may be entered manually or electronically through a photometer-

calculator interface built at the University (Hackney 1972).


The Polarimetry Program


As noted in the previous chapter, there is presently

great interest in polarized emission from QSO's and related







objects. The nature and distance of these objects are the

cause of much controversy. Further observational knowledge

can help reduce the controversy and lead to an understanding

of the physical nature of these objects. One of the most

valuable of the observational tools is linear polarization.

From a knowledge of the spectral shape and variability of the

linearly polarized continuum one can construct source models

and even estimate an upper limit to the distance of the object

(Visvanathan 1973b).

In order to substantiate and extend the work of others

in this field, linear polarization observations of three

selected sources were initiated by the author at Rosemary Hill.

As was mentioned in the remarks concerning the regular moni-

toring program, most of these QSO's and related objects are

too faint to observe photoelectrically with the 30-inch

reflector. Unpolarized light incident upon a polarizing ele-

ment is reduced in intensity by at least 50 percent, and some-

times as much as 65 percent, upon transmission. This in

effect reduces the brightness of a source by about one magni-

tude. For this reason, photoelectric polarimetric observa-

tions of even the brightest QSO's are not possible with the

present equipment. As an alternative, a photographic deter-

mination of linear polarization was decided upon by the author.

This method has the advantage of being able to measure fainter

sources. In addition, the equipment for exposing, developing,

and reducing photographic plates was at hand. The method does

have the disadvantages of long exposure times and increased







error compared to photoelectric methods. However, it was

felt that the importance of adding to the data on such objects

was enough to outweigh these disadvantages.


Method of Exposure

The f/16 Cassegrain focus of the 30-inch reflector was

used for the linear polarization measurements to avoid spuri-

ous polarization induced by the flat Newtonian secondary

mirror. The Cassegrain camera designed by R. L. Scott and

shown in Figure 2 was employed in the measurements. Most

exposures were made in the Johnson B magnitude system through

a sheet Polaroid HN-32 filter and a Schott GG-13 filter on

Kodak 103a-0 emulsions hypersensitized by baking. After June

1, 1974, a Polacoat 105UVWRMR polarizing coating on a quartz

substrate was used as the polarizing element. The spectral

response of the HN-32 has been determined by use of a Beckman

spectrophotometer. This curve and the GG-13 spectral response

from the Kodak "Schott Color Filter Catalog #365e" are shown

in Figure 18. As can be seen, the polaroid does cause some

change in the spectral response of the system in the region

of interest (about 390-480 nm). It also causes a 60 percent

reduction in the amount of light reaching the plate, result-

ing in longer exposure times to reach the plate limit. The

Polacoat 105UVWRMR response from Polacoat Bulletin P-113-

3/1/71 is also shown. It is nearly flat in the region of

interest and also transmits only about 40 percent of the

incident light.




















Figure 2. RHO 30-inch reflector showing the Cassegrain camera and
Polacoat 105 UV filter.











U7


4


K ,







Five exposures are made for one measurement. The first

is a standard magnitude determination taken without the polar-

izing filter. The subsequent exposures are made with the

filter in place. The axis of polarization of the filter is

known precisely and is initially aligned north-south. The

dark slides are opened and the first polarization exposure

is made. The camera, together with the plate and filter,

which are locked in place, is then rotated counterclockwise

so that the polarization axis is east-west. The second expo-

sure is made. The camera is rotated clockwise 450 into a

northeast-southwest position for the third exposure and then

counterclockwise 900 to a northwest-southeast position for the

fourth exposure. These four exposures are made whenever pos-

sible in one-inch diameter fields on one plate to avoid pos-

sible errors arising from variations in background conditions

in the emulsion from plate to plate. However, for some objects

there are not enough stars to form a comparison sequence in a

field of this size. In this case, exposures are made in two-

inch diameter fields on two plates. Possible errors are

minimized by choosing two plates from the same emulsion batch

and hypersensitizing and developing them together.

Focusing is accomplished by the knife-edge method. The

Cassegrain secondary mirror is motorized, and is moved in and

out to achieve the best focus. Guiding is accomplished with

the Cassegrain guide box, which contains a large diagonal

mirror to deflect a portion of the beam at a right angle to

the optical axis into a microscope. The procedure is







thoroughly described by Hackney (1972). The development of

plates follows exactly the same procedure as that described

by Folsom (1970) for the plates taken at the Newtonian focus.

Data Reduction

The magnitude of an object is determined for each of the

four polarization exposures by exactly the same method as

that described above for normal photographic exposures, using

the iris astrophotometer and the HP 9810A calculator. This

procedure gives four magnitude values, one for each exposure.

The values are reduced in pairs according to the procedure

given by Hall and Serkowski (1963). A brief description of

this procedure follows.

The reduction is accomplished with the use of Stokes

parameters expressed in stellar magnitudes. The Stokes param-

eters for linearly polarized light are:

I I max+ min (2.2)

Q = (Imax min ) cos28 = PI cos26/100 (2.3)

U = (Imax- I mi ) sin26 = PI sin28/100 (2.4)

V = 0 (2.5)

where Imax is the maximum intensity observed using a perfect

polarizer and Imin is the intensity observed with the polar-

izer rotated by ninety degrees. The position angle of Imax

in equatorial coordinates is e. The parameter V is a measure

of elliptical polarization and is zero for light showing only







linear polarization. Observational results indicate that the

presence of optical elliptical polarization in QSO's is doubt-

ful (Landstreet and Angel 1972).

The ratio of Imax to Imin can be expressed in terms of

stellar magnitudes:

I
p = 2.5 log imax (2.6)
min

The linearly polarized percentage of the total flux is


max min


If one expands Imax /Imin = 10p/25 in a Taylor series and

assumes that p<<2.5 then it can be shown

P = 20(ln 10)p = 46.05 p (2.8)


Equation (2.8) becomes invalid for P of about 40 percent or

more.

The Stokes parameters in magnitudes are given by


Px p cos20 = 0.4605 (2.9)

U
Py -p sin28 = 0.4605 I (2.10)

and are derived by dividing equations (2.3) and (2.4) by

equation (2.2) and substituting from equation (2.8). These

parameters are given in terms of the measured magnitudes by


Px = m(90) m(0) (2.11)


py = m(135) m(45)


(2.12)






where the arguments give the alignment of the polaroid axis
relative to the celestial sphere during the exposure. After
obtaining px and py, p and 6 are determined by solving equa-
tions (2.9) and (2.10) simultaneously. The degree of polariza-
tion P is then determined using equation (2.8).

Error is determined by using the rms of the residuals as
explained above. These are taken to be an estimate of the

error e in px and p The error is independent of the true

values of px and py, as explained by Hall and Serkowski (1963).

The true value of the amount of polarization p is re-
lated to the most probable observed value p by
2.1 21 /2
(po2 + E21e )for p 0
p = (2.13)
Po + 2 for po>>C

The rms deviation 6 of the observed polarization from the

true value po is

EC/ for p = 0
6 = o (2.14)
P e for p >>e
f o

The mean error p of the amount of polarization, which is the
rms deviation of p from p is

1 1/2
c(2 1 T 2 for p ~ 0
eP (2.15)
for p >>E

while the mean error Ec of the position angle 0 is

t rad for p 0 0
Ce = (2.16)
0 p rad for p >>E












CHAPTER III

RESULTS OF THE QSO MONITORING PROGRAM


The present program of photographic observations of

extragalactic radio sources at Rosemary Hill includes over

one hundred fifty sources. In such a large program many

objects are of necessity observed infrequently, with perhaps

as few as one or two plates per year. The more interesting

and active objects may be observed weekly or more often during

periods of activity. The results of observations of sixteen

of these objects have been reported recently (Scott et al.

1973b), while the results of observations of several more

objects will be reported elsewhere. All of the remaining

objects currently being monitored are reported in this chapter.

It should be noted that the QSO monitoring group consists

presently of four members under the direction of Dr. A. G.

Smith. Exposure, development, and reduction of photographic.

plates is a cooperative effort of all members of the group.

Therefore, many of the data presented in the present chapter

were taken by present and former members of the group and

their work is referenced whenever appropriate. However, in

addition to participation in the joint group efforts, many

calibrations, the refinement of comparison sequence magnitudes,

the compilation and plotting of data, the research into the







literature, and the conclusions drawn in this chapter and

Chapter V are solely the work of the author.

In the following tables all radio sources identified by

Parkes catalog numbers have had the prefix PKS dropped and

are identified by the right ascension and declination suffix.

All sources from other catalogs are identified by their full

designations.

In Table 1 are listed all objects which have had a photo-

electric comparison sequence published, or which have had a

comparison sequence established by photographic transfer from

selected areas as described in Chapter II. All objects for

which the X2 statistic indicates eighty percent or greater

confidence level for variability are discussed separately

with light curves given. These constitute 50 percent of the

calibrated sample. This large number is probably caused by

the practice by the author and coworkers of giving priority

to establishing comparison sequences for those objects which

appear to exhibit interesting activity. There is some evi-

dence that all QSO's may be variable on a very long time

scale (years) (Lu 1972; Penston and Cannon 1970).

In Table 2 are listed those objects for which "tertiary"

comparison sequences have been established by photographic

transfer from other QSO fields, rather than by direct cali-

bration. These are easily accomplished since two QSO fields

are exposed on one plate as standard practice. Many such

tertiary calibrations have proven to lead to inaccurate

results when compared to results from later direct







Key to Table 1


(1) Source name. Prefix PKS deleted where applicable.

(2) 1950 Right ascension to the nearest minute.

(3) 1950 Declination to the nearest minute of arc.

(4) Number of plates taken at Rosemary Hill.

(5) Mean Mpg.

(6) Total range of variation (in magnitudes) observed at Rosemary Hill.

(7) Average RMS error of a single determination (in magnitudes).

(8) Confidence level for variability.

(9) Classification (from literature) N = N-galaxy;
Sey = Seyfert galaxy;
BSO = blue stellar object.

(10) Redshift (from literature).

(11) References to previous publications.






Table 1


Calibrated Sources


Source
(1)

0013-00
OB 338
0119-04
0139-09
0159-11
0202-17
0222-23
0229+13
0251+18
NRAO 140
0336-01
0340+04
0350-07
0451-28
0458-02
0518+16
OH 471
01 318


R.A.
(2)

00h 14
00h 24
01h 20
01h 39
01h 59
02h 03
02h 23
02h 29
12h 51
03h 34
03h 37
03h 41
03h 50
04h 51
04h 59
05h 18
06h 43
07h 11


Mean
Dec. Plates Mpg
(3) (4) (5)


m
m
m
m
m
m
m
m
m
m

m
m
m
m
m
m
m
m


-00031'
+34052'
-04037'
-09042'
-11047'
-17016'
-23026'
+13010'
+18053'
+32008'
-01056'
+04048'
-07020'
-28012'
-02004'
+16035'
+44055'
+35040'


18.53
19.55
16.56
17.02
16.77b
17.00
16.37
17.09
17.07
17.33
17.47
17.96
16.76b
18.16
19.25
18.96
17.83
18.15


Range
(6)


(6) (7) (8) (9 *) (10~ (11 ~


.78
1.09
.62
.63
.63
.64
1.32
.52
.21
.48
.72
.35
.10
.55
.56
1.24
.22
.82


RMS
(71)


.16
.20
.13
.10
.10
.11
.15
.12
.11
.11
.12
.07
.13
.09
.14
.15
.10
.15


Confidence
Level
(8)


25
>99.5
41
68
64
92
>99.5
61
1.5
>99.5
>99.5
58
10
65
>99.5
>99.5
41
80


Type
(9)


QSO?


QSO
QSO?
QSO
QSO
QSO?
QSO
QSO?
QSO
QSO
QSO
QSO
QSO?
QSO
QSO
QSO
QSO


z
(10)


1.955


?
1.74


2.07


1.263
0.852


References
1( 1)


c,d,j
g


b,h,i
c,i,k


c
0.962 c,j


0.760
3.40
1.620


i
c,i


b ,h





Table 1 Continued


Source
(1)
OK 290
0957+00
OL 333
ON 343
1252+11
OP 114
1347+21
1354+19
1402-012
OQ 208
1607+26
1618+17
NRAO 512
3C 371
2128-12
OX 074
2209+08
3C 446


R.A.
(2)

09h 54m
09h 58m
10h 20m
12h 26m
12h 52m
13h 09m
13h 47m
13h 55m
14h 02m
14h 05m
16h 07m
16h 18m
16h 39m
18h 07m
21h 29m
21h 45m
22h 10m
22h 23m


Mean


Mean
Dec. Plates Mpg
(3) (4) (5)


+25030'
+00020'
+30056'
+36052'
+11057'
+14033'
+21025'
+19033'
-01016'
+28041'
+26049'
+17044'
+39053'
+69049'
-12020'
+09016'
08004'
-05012'


24
7
14
8
17
13
13
5
8
26
28
8
190
64
3
60
33
16


16.97
16.72
16.74
17.78
16.17
18.24
15.11
16.09b
18.84
15.58
17.82
16.49b
18.16
15.11
15.12
17.41
17.83
16.73b


Range
(6)


.70
.48
.37
.57
.55
.44
.53
.18
.57
1.00
.60
.29
2.26
1.43
.12
1.29
.67
2.83


RMS
(7)


.09
.14
.16
.19
.09
.17
.12
.05
.18
.08
.10
.11
.12
.13
.04
.13
.13
.11


Confidence
Level
(8)


>99.5
47
54
15
98
2
89
11
53
>99.5
95
13
>99.5
>99.5
69
>99.5
>99.5
>99.5


Type
(91


QSO
QSO
BSO


QSO


QSO?
QSO
QSO
Sey
QSO?
QSO
QSO
N
QSO
BSO
QSO


z
(10)


(10) (4)1(5


0.712
0.907


References a
f1ll


b,g,h,i


b
b
e
b


0.720 d,f,i,j


0.077 a,b,i,j


0.555
1.6
0.050
0.501


0.486


e,f,j
g,i
i
J
b,g


QSO 1.404 e,i,k


m






Table 1 Continued


Mean
Dec. Plates Mpg


Range RMS


Confidence
Level


Type


z Referencesa


(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
2300-18 23h 00m -18058' 16 17.88 .73 .14 59 N 0.129
2345-16 23h 45m -16048' 89 17.04 1.97 .11 >99.5 QSO 0.6 i


aKey to references:


(a) Craine and Warner (1973); (b) Kraus et al. (1968);
(c) Peach (1969); (d) Hunter and Lu (196DT; e) Penston and
Cannon (1970); (f) Tritton and Selmes (1971); (g) Stull (1972);
(h) Burbidge and Strittmatter (1972); (i) Medd et al. (1972);
(j) Lu (1972); (k) Dent and Kojoian (1972).


bMB.


Source


R.A.







Key to Table 2


(1) Source name. Prefix PKS deleted when applicable.
(2) 1950 Right ascension to the nearest minute.

(3) 1950 Declination to the nearest minute of arc.

(4) Number of plates taken at Rosemary Hill.
(5) Mean M .
pg"
(6) Total observed range of variation (in magnitudes).

(7) Average RMS error of a single determination (in magnitudes).

(8) Classification (from literature) N = N-galaxy.
(9) Redshift (from literature).

(10) References to previous observations.






Table 2


Sources with Tertiary Calibrations


Source
(1)


OA 33
0056-00
0333+12
0408+07
01 363
0802+10
0812+02
0829+18
0920-07
OL 318
1049+21
1055+01
1123+20B
1148-00
1217+02
OQ 172
4C 26.51
IZw 1727+50
1801+01


R.A.
(2)

00h 35m
00h 57
03h 34m
04h 09m
07h 38m
08h 02m
08h 13m
08h 29m
09h 20m
10h 11m
10h 49m
10h 56m
11h 23m
11h 48m
12h 18m
14h 43m
16h 57m
17h 27m
18h 02m


Dec.
(3)


Plates
(4)


+41020'
-00009'
+12053'
+07000'
+31019'
+10024'
+02004'
+18043'
-07002'
+35001'
+21036'
+01050'
+20022'
-00007'
+02020'
+10011'
+26034'
+50015'
+01001'


Mean Mpg
(5)


20.23
16.99
17.70
18.20
17.13
18.10
16.05
17.93
18.83
19.63
18.24
17.42
17.85
17.61
15.23
19.41
18.16
16.24
16.72


Range
(6)

.55
.44
.21
.66
.31
.37
.63
.23
.31
.81
.19
.52
.38
.43
.36
.42
.25
1.05
.83


RMS
(7)
.22
.09
.10
.12
.09
.12
.18
.12
.10
.13
.18
.08
.09
.11
.15
.20
.09
.14
.12


Type
(8)


QSO
QSO?
QSO?
QSO
QSO
QSO


QSO?


QSO?
QSO
N
QSO
QSO
QSO
QSO?
N?
QSO


References


0.717





1.947
0.402


c



b,h,i
c


i,k


1.982
0.240
3.53



1.522


c,d,e,j





Table 2 Continued


Source
(1)


OV 080
OW -006
2059+034
2111-25
2203-18
2216-03
CTA 102
2251+24
2254+024
2335-18
2354+14
2354-11


R.A.


(2)

19h 4
20h 0
20h 5
21h 1
22h 0
22h 1
22h 3
22h 5
22h 5
23h 3
23h 5
23h 5


Dec. Plates Mean Mpg
(3) (4) (5)


8m
4m
9m
2m
3m
6m
0m
2m
5m
5m
5m
5m
5m


+07059'
-02033'
+0330'
-25054'
-18050'
-03051'
+11028'
+24029'
+02027'
-18009'
+14029'
-11043'


18.16
18.62
16.84
17.90
17.77
15.84
18.44
17.16
17.01
16.28
17.34
18.01


Range RMS Type
(6) (7) (8)


.68
.13
.63
.74
.03
.24
.53
.39
.19
.59
.30
.36


.14
.11
.14
.14
.05
.08
.19
.13
.09
.12
.09
.11


QSO
QSO
QSO?
QSO?
QSO
QSO
QSO?
QSO
QSO?
QSO
QSO


z Referencesa


(9)


0.901
1.037


2.09


1.810


(10)


b,i


aKey to references:


(a) Craine and Warner (1973); (b) Kraus et al. (1968);
(c) Peach (1969); (d) Hunter and Lu (196T;-Te) Penston and
Cannon (1970); (f) Tritton and Selmes (1971); (g) Stull
(1972); (h) Burbidge and Strittmatter (1972); (i) Medd et al.
(1972); (j) Lu (1972); (k) Dent and Kojoian (1972).







calibrations. Direct calibrations from selected areas have

not been made for these objects because of the large number

of program objects and the infrequency of nights with the

excellent transparency conditions required. However, it is

the opinion of the author that the use of these tertiary

calibrations gives a better indication of the behavior of an

object than a visual inspection gives. About 39 percent of

these objects appear to be variable as determined by comparing

their rms error to the range of observed magnitudes.

In Table 3 are listed those objects with no calibrations

and usually with very few plates taken. Some may be deleted

from the program due to lack of optical identification or

lack of interesting activity. Others will probably be cali-

brated and observed more regularly in the future. A few

objects in this table, such as PKS 2135-14, are well-known

objects which are recent additions to the Rosemary Hill pro-

gram.



Discussion of Individual Objects

OB 338

Kraus et al. (1968) found that OB 338 has a slightly

peaked radio spectrum with a maximum at 500 MHz. Thompson

et al. (1968) found two stellar objects near the radio posi-

tion. Folsom (1970) proposed the bluer of the objects as the

optical counterpart and reported the Rosemary Hill observa-

tions. Hackney (1973) reported a calibration of the







Key to Table 3


(1) Source name. Prefix PKS deleted when applicable.

(2) 1950 Right ascension to the nearest minute.

(3) 1950 Declination to the nearest minute of arc.

(4) Number of Plates taken at Rosemary Hill.

(5) Type of variation observed (visual inspection):
O none
PSS change since Palomar Sky Survey plate
V significant variation on RHO plates

(6) Classification (from literature):

N = N-galaxy
L = Lacertid
G = Galaxy
BSO = Blue Stellar Object

(7) Redshift (from literature).

(8) References to previous observations.






Table 3


Sources with No Calibration


Type Variation
(5)


Type
(6)


z
(7)


Referencesa
(8)


OB 343
OC 328
3C 43
OC 457
DA 58
PHL 1226
0347+13
0408+17
NRAO 190
0454+06
0605-08
OI -039
01 -072
01 -187
0758+14
OJ -100
0850+14
0854-03
0855+14


oo0h


O1h
01h
Olh


03h


04h
04h
04h
06h
07h
07h
07h
07h
08h
08h
08h
08h


27m
17m
27m
35m
41m
51m
47m
09m
40 m
54m
06m
23m
43m
52m
59m
00OO
50o"
55m
56m


+34040'
+31055'
+23023'
+47055'
+33055'
+04034'
+13011'
+17005'
-00023'
+06040'
-08035'
-00047'
-00036'
-11039'
+14023'
-17044'
+14004'
-03029'
+14021'


0
0
V
0
0
0
V?
0
V
0
0
0
0
PSS
0
0
PSS
0
0


b
0.059 b


QSO
QSO?
QSO


1.455
0.404


QSO


QSO
QSO?


QSO?


BSO


QSO
QSO?
N


b,i,k


1.109


Source
(1 )


R.A.
2( )


Dec.
(3-1


Plates
(4)


r2) (3)r


A





Table 3 Continued


Type Variation
(5)


Type
(6)


z
(7)


References
(8)


0903+16
0922+14
0945+07
0949+00
1021-00
1040+12
1049-09
B21101+38
1107+10
OM 133
1127-14
OM -272
OM -076
1229-02
1237-10
1330+02
1340+05
1341+14
1342-00
3C 295


09h
09h
09h


10h
10h

10h
11h
11h
11h
11h
11h
11h
12h
12h

13h
13h
13h
13h

14h


04m
22m
45m
49m
22m
40m
49m
02m
07m
20m
28m
44m
45m
29mn
37m
30m
40m
42m
43m
10m


+16058'
+14058'
+07039'
+00012'
-00037'
+12019'
-09002'
+38029'
+11000'
+18022'
-14033'
-24031'
-07008'
-02008'
-10007'
+02016'
+05019'
+14024'
-00042'
+52026'


V
0
V
0
V
0
V
V
PSS
0
0
0
0
V
V
PSS
PSS
0
0
0


QSO
QSO
N
N
QSO?
QSO
QSO
L
QSO?


QSO



QSO
QSO
N
N
QSO?
QSO?
QSO


0.411
0.896
0.086



1.028
0.344



b
i



0.388 c


0.216


Source
(1)


R.A.
(2)


Dec.
(3)


Plates
(4)


--






Table 3 Continued


Source
(1)


1437+22
1455+24
1502+036
1505+01
1546+027
4C 05.64
1606+10
1615+029
OS 094
NRAO 530
OT -068
OT -174
OU -033
OV -236
OW -015
OX 131
2131-021
2135-14
2154-18
OY 602


R.A.


(2

14h
14h
15h
15h
15h
15h
16h
16h
16h
17h

17h

17h
18h
19h
20h
21h
21h
21h
21h

22h


Dec.
(3)


38m
56m
03m
06m
47m
48m
06m
15m
56m
30m
41m
44m
20m
22m
09m
19m
32m
35m
54m
02m


+22004'
+24048'
+03038'
+01014'
+02046'
+05036'
+10037'
+02054'
+05020'
-13002'
-04001'
-19020'
-09040'
-29021'
-06053'
+18048'
-02007'
-14046'
-18028'
+62025'


Plates
(4)


Type Variation
(5)


PSS
PSS
V
0
0
V
V
V
PSS
V
0
0
0
0
0
0
V


V
PSS


Type
(6)


z
(7)


Referencesa
(8)


N


QSO


0.412 g,h


QSO
QSO?
QSO


i,k


QSO
QSO
QSO?


0.20


d,j


_ __ __ __


1




Table 3 Continued


Plates Type Variation


Type


z Referencesa


(1) (2) (3) (4) (5) (6) (7) (8)
OY -172.6 22h 44m -12023' 1 0
3C 455 22h 53m +12058' 2 0 QSO 0.543
OZ -252 23h 31m -2400' 2 PSS QSO?


aKey to references:


(a) Craine and Warner (1973); (b) Kraus et al. (1968);
(c) Peach (1969); (d) Hunter and Lu (196-T;-Te) Penston and
Cannon (1970); (f) Tritton and Selmes (1971); (g) Stull
(1972); (h) Burbidge and Strittmatter (1972); (i) Medd et al.
(1972); (j) Lu (1972); (k) Dent and Kojoian (1972).


Source


R.A.


Dec.







surrounding field by photographic transfer from SA 20 (Brun

1957) and updated the observations.

The object is variable with greater than 99.5 percent

confidence with an rms error of 0.2. The light curve in

Figure 3 shows a well-defined peak in 1970 with no further

flares of that size since. However, due to the few plates

taken since 1970, this type of burst may have been repeated

since that time. There seems to be no indication of a slowly

varying component, the minimum brightness being nearly con-

stant at about 19m5. A sequence finder is given by Hackney

(1973).


01 318

Kraus et al. (1968) found 01 318 to have a radio spectrum

peaked at 1600 MHz. Thompson et al. (1968) reported a pair of

red and blue objects within the radio error box. Blake (1970)

proposed the blue object as the optical counterpart and this

was confirmed by Folsom (1970). Burbidge and Strittmatter

(1972) found a redshift of z = 1.620, confirming the object

as a QSO. Hackney (1973) reported a comparison sequence

established by photographic transfer from SA 50 (Brun 1957)

and indicated that the object was variable with 99.2 percent

confidence. The magnitudes of the comparison sequence were

recalculated more accurately by the author, using an elec-

tronic calculator.

The data indicate that OI 318 is variable at the 80 per-

cent confidence level with an rms error of 0.15. The light




















Figure 3. Light curves of OB 338, OI 318, and OK 290.






Mpg


I 8.g.

1 9. O
19.0

19.5

20.0

20.5


17.5

18.0

18.5

19.0

16.5

17.0

17.5







curve is shown in Figure 3. An 08 burst was observed in

late 1970. More recently the object shows a 0.25 decline in

1973-1974 with a 0.5 burst indicated by one plate. There

appears to be no long-term change in minimum brightness. A

sequence finder is given by Hackney (1973).

OK 290

This object is dissimilar to the two previous ones in

that the radio spectrum rises smoothly to 10 GHz with no

maximum observed (Kraus et al. 1968). The optical counterpart

was identified with a 17th magnitude stellar object (Thompson

et al. 1968; Blake 1970), with a finder published by Blake.

A redshift of 1.620 was observed by Burbidge and Strittmatter

(1972). Medd et al. (1972) found a brightening of 1 flux unit

at 2.8 and 4.5 cm between 1967 and 1970. Stull (1972) found

a decline in flux density of 20 percent between January and

August of 1971 at 3.75 cm. Previous Rosemary Hill observa-

tions have been reported by Folsom (1970) and Hackney (1973).

Recently a comparison sequence has been calibrated by a photo-

graphic transfer from SA 54 (Brun 1957).

The data indicate that OK 290 is variable with greater

than 99.5 percent confidence. The average rms error of a

measurement is 009. The light curve in Figure 3 shows a
"wave-like" shape with maxima in late 1971 and early 1973.

There seems to be good indication of short-term activity with

variations of as much as 0.3 observed within a two-week

period. A sequence finder is given by Hackney (1973).







OQ 208

This object has a very sharply peaked radio spectrum with

a maximum at 5300 MHz (Kraus et al. 1968; Thompson et al.

1968). Blake (1970) identified the source with a 14th magni-

tude Seyfert galaxy. Medd et al. (1972) found that the

object remained at almost constant brightness at 2.8 and 4.5

cm from 1967 to 1971. Lu (1972) found that the object is an

optical variable showing a 05 peak in 1970. Craine and

Warner (1973), using the Harvard plate collection, reported

that OQ 208 was variable with a range of nearly one magnitude

between 1938 and 1953. They found no variation over a period

of four months in early 1972.

The Rosemary Hill data are shown in Figure 5. A compari-

son sequence was calibrated with a photographic transfer from

M 3 (Sandage 1953). The object is variable with greater than

99.5 percent confidence with an average rms error of 0.1.

The Florida data agree in general behavior with Lu's (1972)

results. The 1970 Florida light curve shows two peaks 0 6

above minimum with a 0.4 drop between them. In 1974 there was

a 0.5 flare followed immediately (within two weeks) by an 08

decrease. Inspection of the plates and images leads the

author to the conclusion that this change is real. The

object remained at a minimum for four weeks with one 0.4

flare occurring, rising rapidly and declining within one day.

Unfortunately, there are no 1972 observations to compare with

Craine and Warner (1973). A comparison sequence finder is

shown in Figure 4.


























Figure 4. Comparison sequence of OQ 208. This photo-
graph is reproduced from a plate taken on the
night of 13 April 1974, at Rosemary Hill.
North is at the top and east is to the left.
Comparison star photographic magnitudes are
(1) 16.40, (2) 16.52, (3) 14.77, (4) 16.56,
(5) 15.65, (6) 16.08, (7) 15.56, (8) 15.13,
(9) 15.74, (10) 15.95.






60





*
*














6*












9




*
*



3 S
... --L" 90





*4



t-
e 0

*
.* 0
0 S .0S





















Figure 5. Light curves of OQ 208, OX 074, and PKS 0202-17.






Mpg '4.5 OQ 208

15.0

15.5 *

16.0


16.5 OX 074

0
17.0
tL
17.5 0

18.0 -
16.0
0202-17
16.5

17.0

17.5 I I I I I
1969 1970 1971 1972 1973 1974







OX 074

Kraus et al. (1968) reported OX 074 to have a peaked

spectrum with a maximum at 2500 MHz. Thompson et al. (1968)

identified the source with a blue stellar object. Stull

(1972) found a flux density increase of about 35 percent at

3.75 cm in two months of 1971. Previous Rosemary Hill data

have been reported by Folsom (1970) and Hackney (1972), who

identified the object as an optically violent variable (OW).

The light curve in Figure 5 shows a l15 decrease from 1970

to 1971 with short-term bursts superimposed on the decline.

The object remained at a minimum of about 17T7 through late

1971 and 1972 with the short-term activity still present.

In 1973 the object underwent two 170 bursts accompanied by a

0.15 rise in the minimum brightness. A sequence finder is

given by Hackney (1972).

PKS 0202-17

An optical identification and finder for this source
were given by Bolton and Ekers (1966). The spectral index

between 1410 and 2650 MHz is fairly flat at 0.2 (Ekers 1969).

Kinman et al. (1967) reported a redshift of z = 0.717, thus

confirming the object as a QSO. Stull (1972) found that PKS

0202-17 is a probable variable at 8000 MHz (3.75 cm), with

flux density increases of 20 and 25 percent recorded in one-

month periods.

A comparison sequence was calibrated at Rosemary Hill
with a photographic transfer from SA 118 (Brun 1957). The







object is variable with 92 percent confidence, with an rms

error of 0l10. The Florida data typically show small ampli-

tude (<0.5) variations on a time scale of several weeks

(Folsom 1970). The brightness shows a long-term decline of

about 03 from 1969 to the present. The light curve is shown

in Figure 5. A sequence finder is shown in Figure 6.

PKS 0222-23

The source was identified as a possible QSO and a finder

was published by Bolton et al. (1965a). Ekers (1969) reported

that the spectral indices between 408 and 1410 MHz and between

1410 and 2650 MHz are -0.9 and -0.1, respectively.

A comparison sequence surrounding the source was cali-

brated with a photographic transfer from SA 119 (Brun 1957).

As the light curve in Figure 7 shows, the object had a major

flare in 1971 and has since declined 1IS. The minor flares

in the declining phase after the major outbursts are typical

of an optically violent object (Hackney 1972). The average

rms error is 015 and the variability is real with greater

than 99.5 percent confidence. A sequence finder is shown in

Figure 8.

PKS 0336-01

Bolton and Ekers (1966) identified the optical counter-

part of the radio source (also designated CTA 26) and pub-

lished a finding chart. The radio spectrum is inverted, the

spectral indices being -0.5 and 0.7 from 400 to 1410 MHz and

1410 to 2650 MHz, respectively (Ekers 1969). Kinman et al.

























Figure 6.


Comparison sequence of PKS 0202-17. This
photograph is reproduced from a plate taken
on the night of 10 December 1971, at Rosemary
Hill. North is at the top and east is to the
left. Comparison star photographic magnitudes
are (1) 16.15, (2) 16.90, (3) 16.49,
(4) 16.66, (5) 17.83, (6) 17.13, (7) 16.06,
(8) 18.14, (9) 18.10, (10) 16.18, (11) 17.05.









































* 4.


p



,4,
9


**~*


-a-



..4



It :'
* -- '-~



-. :$ .. .
;A. .V




.. -,~b

a'

i2
, rU


12* *


p*
)g


B


--











.



-a


* (




















Figure 7. Light curves of PKS 0222-23, PKS 0336-01, and PKS 0458-02.






Mpg 0222-23
15.5
*
16.0
1
16.5 -- *

17.0 -

17.5
17.0 0336-01

17.5 **

18.0

18.5 0458-02

0. 0


19.5 -

1969 1970 1971 1972 1973 1974
1969 1970 1971 1972 1973 1974

























Figure 8. Comparison sequence of PKS 0222-23. This
photograph is reproduced from a plate taken
on the night of 12 December 1971, at Rosemary
Hill. North is at the top and east is to the
left. Comparison star photographic magni-
tudes are: (1) 16.77, (2) 16.57, (3) 16.08,
(4) 15.80, (5) 15.81, (6) 15.26, (7) 15.45,
(8) 14.68, (9) 16.82, (10) 15.70, (11) 14.50,
(12) 15.59.






70




*



0 I. 12

** *




9
2 4













.9 3




7*






0
.8 *








.0









* 0







(1967) reported an accurate optical position and the results

of photoelectric UBV photometry. Gardner and Whiteoak (1969)

found 2 percent linear polarization between 11 and 20 cm,

while Aller (1970) found 6 percent linear polarization at

3.75 cm. Wills (1971) found day-to-day variations of two to

four percent at 2700 MHz (11 cm), and derived the angular

diameter to be no more than 0.001 for 66 percent of the radi-

ation. Medd et al. (1972) observed month-to-month variability

at 2.8 and 4.5 cm. Dent and Kojoian (1972) found PKS 0336-01

to be variable at 7800 MHz (3.85 cm).

A comparison sequence in the field of PKS 0336-01 was

obtained at Rosemary Hill (Hackney 1973) by photographic

transfer from the field of SA 95 (Brun 1957). Hackney (1973)

reported the object to be variable. The up-to-date observa-

tions indicate that the object is variable with greater than

99.5 percent confidence with an average rms error of 0.13.

It is interesting to note that the general shape of the light

curve (Figure 7) through 1971 agrees with the radio curves of

Medd et al. (1972) and Dent and Kojoian (1972). Since the

maximum of 1970 the object reached an 0.8 minimum in 1972

and brightened by 04 in 1973. A sequence finder is given

by Hackney (1973).

PKS 0458-02

The optical counterpart of the radio source was identi-

fied by Bolton and Ekers (1966). The object was identified

as a QSO by Ekers (1969). The radio spectrum is fairly flat







with spectral indices of -0.3 and -0.1 between 408 and 1410

MHz and between 1410 and 2650 MHz, respectively. Medd et al.

(1972) found that the object varied 25 percent over a period

of a year at 2.8 and 4.5 cm.

A comparison sequence was calibrated at Rosemary Hill

with a photographic transfer from SA 97 (Brun 1957). The

object is variable with greater than 99.5 percent confidence

with an average 0.14 rms error. All points lie within a 03

scatter, except for one plate in November, 1973. This plate

was taken under poor sky conditions and, if eliminated, the

probability of variation is reduced to 18 percent. Thus, the

variability should be considered doubtful pending further

observations. The light curve is shown in Figure 8 and the

comparison sequence is shown in Figure 9.


PKS 0518+16

The optical counterpart of the radio source (also desig-

nated 3C 138) was identified by Clarke et al. (1966). The

spectral index is -0.7 between 408 and 1410 MHz (Ekers 1969).

The object is at low galactic latitude (-110) but a redshift

of z = 0.760 was measured by Burbidge and Kinman (1966) and

Lynds et al. (1966), confirming the object as a QSO. Aller

(1970) reported 9 percent linear polarization at 3.75 cm.

Medd et al. (1972) found little change in brightness at 2.8

and 4.5 cm. Peach (1969) measured a 0'1 optical variation

over one year.

























Figure 9. Comparison sequence of PKS 0458-02. This
photograph is reproduced from a plate taken
on the night of 13 October 1972, at Rosemary
Hill. North is at the top and east is to
the left. Comparison star photographic
magnitudes are: (1) 19.02, (2) 18.65,
(3) 19.11, (4) 19.30, (5) 18.71, (6) 17.86,
(7) 19.25, (8) 18.16, (9) 18.50, (10) 19.31.





74







PKS 0518+16 has been monitored for four years at Rosemary

Hill. A comparison sequence was obtained (Hackney 1973) by

photographic transfer from SA 74 (Brun 1957). The object is

variable with greater than 99.5 percent confidence with an

average rms error of 015. The light curve in Figure 10 indi-

cates that the object should be classified as a violent vari-

able (OW). Changes of 08 within one month were noted in

1970-1971. The object is seen to be gradually brightening

since 1970 with repeated short-term bursts superimposed on

the long-term behavior. A sequence finder is given by Hackney

(1973).

PKS 1252+11

The optical counterpart of PKS 1252+11 was identified by

Bolton et al. (1965a). The object was definitely established

as a QSO with the discovery of a redshift z = 0.871 by Lynds

et al. (1965) and Schmidt (1966). The spectral index is 0.1

between 1410 and 2650 MHz. Penston and Cannon (1970) obtained

three plates of the object and concluded that optical varia-

bility was doubtful.

A comparison sequence (shown in Figure 11) was established

in the field of the object with a photographic transfer from

SA 81 (Brun 1957). The data indicate that the object is vari-

able with 98 percent confidence. The rms error is 0.09.

The light curve (Figure 10) shows a total range of 055 with

changes of 035 occurring within six weeks. There seem to be

no long-term trends.





















Figure 10. Light curves of PKS 0518+16, PKS 1252+11, and PKS 1347+21.





Mpg 18.0 0518+16


18.5 0

19.0 0" "
0- O* O

19.5 -
*

20.0
15.5
1252+11
0 0
16.0 -
: w *
16.5 -

14.5 -
: 1347+21
15.0 o *
*
15.5

970 1971 193 1974
1969 1970 1971 1972 1973 1974


























Figure 11.


Comparison sequence of PKS 1252+11. This
photograph is reproduced from a plate
taken on the night of 3 March 1974, at
Rosemary Hill. North is at the top and
east is to the left. Comparison star
photographic magnitudes are: (1) 15.67,
(2) 15.56, (3) 16.56, (4) 17.36, (5) 16.81,
(6) 14.89, (7) 15.41, (8) 15.29, (9) 16.40,
(10) 18.05, (11) 17.77.













































" ~ i ~:15







PKS 1347+21

Shimmins and Day (1968) reported that the object shows

a departure from a power law spectrum at 400 MHz and concluded

that the object is a possible QSO. The photographic observa-

tions of Folsom et al. (1971) indicated that the object had

shown a brightness change between the Palomar Sky Survey plate

and 1970 but was not variable during their observations.

A photographic transfer from SA 82 (Brun 1957) was used

to calibrate a comparison sequence for PKS 1347+21 at Rose-

mary Hill. The object is variable at a confidence level of

89 percent with an average rms of 0.12. The light curve in

Figure 10 indicates that the object is slowly varying with a

04 decline observed between 1969 and 1972. A sequence

finder is shown in Figure 12.


PKS 1607+26

Shimmins and Day (1968) reported that the radio source

has a spectral index of 0.4 at 400 MHz. An optical identifi-

cation was published by Merkelijn (1968). Folsom et al.

(1971) reported that the object is moderately variable

optically.

A comparison sequence in the field of PKS 1607+26 was

established at Rosemary Hill (Folsom 1970) with a photographic

transfer from SA 61 (Brun 1957). The object is variable with

95 percent confidence with an average rms error of 0.10. The

object shows a total range of about 065 with one change of

0.5 observed. The average brightness increased 0.2 from

























Figure 12.


Comparison sequence of PKS 1347+21. This
photograph is reproduced from a plate taken
on the night of 29 April 1974, at Rosemary
Hill. North is at the top and east is to
the left. Comparison star photographic
magnitudes are: (1) 17.02, (2) 16.07,
(3) 13.88, (4) 16.69, (5) 16.37, (6) 13.37,
(7) 15.98, (8) 15.71, (9) 15.57, (10) 14.40.



















































































0' C


I"'* 9
bas


C_
\ ,' '''?
r
.. .-
k
';5 ;;;
''


.I ,
;R







1969 to 1974. The light curve is shown in Figure 13. A

sequence finder is given by Folsom (1970).

PKS 2209+08

The optical counterpart of the radio source was identi-

fied by Clarke et al. (1966). Ekers reported the spectral

indices to be -0.6 and -0.2 between 408 and 1410 MHz and

between 1410 and 2650 MHz, respectively. Miley (1971) con-

firmed the object as a QSO. Hackney (1973) gave an optical

light curve.

A comparison sequence in the field of PKS 2209+08 was

established by photographic transfer from SA 114 (Brun 1957).

The object is variable with greater than 99.5 percent confi-

dence with an average rms error of 013. The light curve is

shown in Figure 13. There is evidence of one major flare of

about 05s in 1970 and an indication of another in 1973. This

object also seems to experience antiflares in which the bright-

ness drops below the average value by as much as OT6. In 1970

and 1973 this sudden drop immediately preceded a flare or

possible flare. A sequence finder is given by Hackney (1973).

PKS 2345-16

Bolton and Ekers (1966) gave an optical identification

of the radio source. A redshift of z = 0.6 was determined by

Schmidt (Ekers 1969). The radio spectrum is flat, with a

spectral index of -0.05 between 11 and 21 cm,and the object

is variable at radio wavelengths (Kellerman and Pauliny-Toth

1968). Folsom (1970) described two 1.5 flares occurring in




















Figure 13. Light curves of PKS 1607+26, PKS 2209+08, and PKS 2345-16.





Mpg 1607+26
17.5 0
0.. 0
,.4 *0 *.* .
18.0 00 0

18.5
17.5- 2209+08

18:0 *
a *
18.5 -

2345-16
15.5 -
1*1
16.0
-0
16.5 *
: o*o
17.0 *
: *y'* 0""
17.5 5 ,
-9 1I 19 I I1972 9I I19
1969 1970 1971 1972 1973 1974C







late 1969 and early 1970. Hackney (1972) described a one-

magnitude flare seen in the fall of 1971 and postulated two

components. The first corresponds to long period (months or

years) changes in brightness and the second corresponds to

rapid (days or weeks) changes of slightly smaller amplitude.

Medd et al. (1972) found the source to be variable at 2.8 and

4.5 cm with one large peak observed at a time corresponding

to the optical flares observed by Folsom (1970).

A comparison sequence was calibrated at Rosemary Hill

(Folsom 1970) with a photographic transfer from SA 116 (Brun

1957) and it is shown by Hackney (1972). The light curve is

shown in Figure 13. The confidence level for variability is

greater than 99.5 percent with an average error of 010.

Computer refinement of the comparison sequence leads to the

conclusion that the peak observed by Hackney (1972) in 1971

was not as large as previously indicated. The source reached

minimum brightness in 1971 and began a long-term brightening

which continued through 1972 and 1973. Short-term activity

seems to be superimposed on the long-term behavior most of

the time. A peak of about 05 was observed in September of

1973.

NRAO 140

The optical counterpart of NRAO 140 was identified by

Kristian and Sandage (1970). An alternate designation is OE

355. A redshift of z = 1.263 was measured by Burbidge and

Strittmatter (1972). Kraus et al. (1968) reported a radio







spectrum peaked at about 700 MHz at a level of 4.1 flux units.

Medd et al. (1972) reported the radio intensity to be variable

at 2.8 and 4.5 cm with a peak occurring in 1969.

A comparison sequence in the field of the object was

established by photographic transfer from SA 48 (Brun 1957)

and is shown in Figure 14. The object is variable with

greater than 99.5 percent confidence with an rms error of

O11. The light curve is shown in Figure 15. It should be

noted that only seven plates have been taken, thus leaving

some uncertainty about the validity of the variability.

NRAO 512

The optical counterpart of the radio source NRAO 512 was

identified by Folsom (1970) from the radio position. Locke

et al. (1969) reported that the source was faint (less than

two flux units) at 2.8 and 4.6 cm. These authors observed

that the flux density declined by a factor of two in a five-

month period in 1968 at both wavelengths after being constant

for eight months. Stull (1972) observed a 0.5 flux unit

increase in 1971 at 8000 MHz (3.75 cm). Medd et al. (1972)

observed a one flux unit peak in 1970 at 2.8 and 4.5 cm in

addition to the decline previously reported by Locke et al.

(1969).

The observations at Rosemary Hill show that the source

is a violent optical variable. The light curve is shown in

Figure 15. The object is variable with greater than 99.5

percent confidence with an average rms error of 011. The


























Figure 14. Comparison sequence of NRAO 140. This
photograph is reproduced from a plate taken
on the night of 30 October 1973, at Rosemary
Hill. North is at the top and east is to
the left. Comparison star photographic
magnitudes are: (1) 17.64, (2) 16.79,
(3) 18.08, (4) 18.24, (5) 17.71, (6) 15.42,
(7) 16.03, (8) 17.01, (9) 16.15, (10) 17.41.






89



AMA





















Figure 15. Light curves of NRAO 140 and NRAO 512.




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