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Produced by the NASA Center for Aerospace Information (CASI)
FINAL TECHNICAL, REPORT

"Luminosity Calibration of Low Redshift Quasars"

Grant No. NAG S-17S

Period of Grant: April 1S, 1981 through July 31, 1983

Dr. E. Joseph Wampler, Principal Investigator

Grantee: Tt... Regents of the University of California

University of California, Santa Cruz 95064

(NASA—C8-175372) LUHIMOSITY CALISHATION QF 584-18120

LOV REDSHIFT QUASARS Final Technical

Report, 15 Apr. 1981 - 31 Jul. 1983

(California Univ.) 4 p HC A02/MF A01 Unclas

CSCL 03A G3/89 15147
- i

Final Technical Report for Grant NAG 5-175

"Luminosity Calibration of Low Redshift Quasars"

E. Joseph Wampler

Despite the title this Grant has supported research on two separate

projects. The first was a-collaboration between myself and Dr. Martin Gaskell

at the Institute of Astronomy in Cambridge, England. We combined European

(SERC) and U.S. shifts on the IUE in order to obtain the long integration time

required to record spectra of faint (-16th magnitude) quasars. The second

project was an attempt to obtain LWR spectra of the nearby giant radio galaxy

Centarus A (NGC 5548) in an attempt to determine the chemical composition and

stellar populations in this unusual galaxy.

The IUE results from the low redshift quasar study have been combined with

the data from an extensive ground based survey. The results are described in

the attached preprint. This paper has been accepted for publication in the

January 1984 issue of the Astrophysical Journal.

We have been very pleased with the performance of the IUE spacecraft.

It has proven to be surprisingly sensitive and the spectra were of high quality

despite the faintness of the sources. The IUE spectra of the low redshift

quasars form a very important section of the attached preprint. They showed

that the correlation we found in high redshift quasar spectra between the

strength of the C IV X1550 feature and the continuum luminosity is also valid

for low redshift objects. Once a model for luminosity evolution is established

these data can be used to determine q o . Under the simplest assumption: that

the luminosity calibration is independent of z the data suggest that go w.l. O

The Centarus A project has proven to be much more difficult. I had hoped

to obtain a series of spectra as a function of distance from the galactic

nucleus in order to study metallicity and population gradients for the stars

in Cen A. However it was possible to obtain IUE spectra for only the bright

nuclear region of Cen A as the surface brightness of the galaxy and the

population of early type stars fell off rapidly with distance from the nuclear

region. Ground based spectra obtained during the Spring observing periods in

1981 and 1982 are available much further out in the envelope. It will be

possible to compare these spectra to the nuclear spectra which have been

extended into the UV by IUE and obtain crude limits to the fraction of blue

stars in the envelope. However these limits will not be as good as they might

have been if UV spectra had been available further out in the envelope.

Even the reduction of the ground based data has been difficult. The surface

brightness of the outer regions of Cen A is quite faint and great care had to be

exercised in removing the contamination of the sky background. Consequently,

the reduction procedure has proceeded slowly. Also to model the observed Cen A

spectrum in the UV it was necessary to obtain the IUE catalog of UV spectra of

standard stellar types. Because of personal changes at the IUE observatory
-1/ i

Spectrophotometry of Two Complete Samples of Flat Radio Spectrum Quasars

1- 2

-E. Joseph Wampler., C. Martin Gaskell , William L. Burke

Lick Observatory

Jack A. Baldwin

3

Cerro Tololo Interamerican Observatory

Submitted to Astrophysical Journal

1. Visiting Astronomer, European Southern Observatory, Garching, Germany

2. Present address: Institute of Astronomy, Cambridge, U.K.

3. Supported by the National Science Foundation
0

•

2

a magnetic tape copy of this catalog was not received until July 1983.

Despite these difficulties a preliminary examination of the now largely

reduced data suggests that it will be sufficient for our purposes and the

main objectives of the program will be met. As the interpretation of the

uata has been slow the results will probably not be written up until the

end of 1983.