ADS Astronomy Abstract Service

Title:		The ensemble variability properties of faint QSOs
Authors:		TREVESE, DARIO; KRON, RICHARD G.; MAJEWSKI, STEVEN R.; BERSHADY, MATTHEW A.; KOO, DAVID C.
Affiliation:		AAUniversita degli Studi, Rome, Italy ABFermi National Accelerator Laboratory, Batavia, IL, US ACObservatories of the Carnegie Inst. of Washington, Pasadena, CA, US ADUniversity of California, Santa Cruz, CA, US AEUniversity of California, Santa Cruz, CA, US
Journal:		Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 433, no. 2, p. 494-509
Publication Date:		10/1994
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		AUTOCORRELATION, DISTANCE, GALAXIES, QUASARS, RED SHIFT, STATISTICAL ANALYSIS, STELLAR MAGNITUDE, SUBDWARF STARS, VARIABILITY, ASTRONOMICAL PHOTOGRAPHY, ASTRONOMICAL PHOTOMETRY, ASTRONOMICAL SPECTROSCOPY, LIGHT CURVE, REFLECTING TELESCOPES
Bibliographic Code:		1994ApJ...433..494T

Abstract

A refined sample of 64 variable objects with stellar image structure has been identified in SA 57 to B approximately = 22.5, over a time baseline of 15 yr, sampled at 11 distinct epochs. The photometric data typically have a root-mean-square (rms) error at B = 22 of only 0.05 mag. Thirty-five quasars in this field have already been spectroscopically confirmed, 34 of which are among the sample of variables. Of the other variables, six are known spectroscopically to be stars, 10 additional objects are stars based on reliable detection of proper motion, and one is spectroscopically a narrow emission line galaxy. Of the 13 remaining variables, it is argued that they are a mixture of distant halo subdwarfs and quasars with starlike colors. We compute the ensemble average structure function and autocorrelation function from the light curves in the respective quasar rest frames, which are used to investigate the general dependences on apparent magnitude, absolute magnitude, and redshift.