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Title: THE CORRELATIONS BETWEEN OPTICAL VARIABILITY AND PHYSICAL PARAMETERS OF QUASARS IN SDSS STRIPE 82

Abstract

We investigate the optical variability of 7658 quasars from SDSS Stripe 82. Taking advantage of a larger sample and relatively more data points for each quasar, we estimate variability amplitudes and divide the sample into small bins of redshift, rest-frame wavelength, black hole mass, Eddington ratio, and bolometric luminosity, respectively, to investigate the relationships between variability and these parameters. An anti-correlation between variability and rest-frame wavelength is found. The variability amplitude of radio-quiet quasars shows almost no cosmological evolution, but that of radio-loud ones may weakly anti-correlate with redshift. In addition, variability increases as either luminosity or Eddington ratio decreases. However, the relationship between variability and black hole mass is uncertain; it is negative when the influence of Eddington ratio is excluded, but positive when the influence of luminosity is excluded. The intrinsic distribution of variability amplitudes for radio-loud and radio-quiet quasars are different. Both radio-loud and radio-quiet quasars exhibit a bluer-when-brighter chromatism. Assuming that quasar variability is caused by variations of accretion rate, the Shakura-Sunyaev disk model can reproduce the tendencies of observed correlations between variability and rest-frame wavelength, luminosity as well as Eddington ratio, supporting that changes of accretion rate play an important role in producing the observedmore » optical variability. However, the predicted positive correlation between variability and black hole mass seems to be inconsistent with the observed negative correlation between them in small bins of Eddington ratio, which suggests that other physical mechanisms may still need to be considered in modifying the simple accretion disk model.« less

Authors:
; ; ;  [1]
  1. Department of Astronomy, Peking University, Beijing 100871 (China)
Publication Date:
OSTI Identifier:
22086515
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 758; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; AMPLITUDES; ASTROPHYSICS; BLACK HOLES; BOLOMETERS; CORRELATIONS; GALAXIES; GALAXY NUCLEI; LUMINOSITY; MASS; QUASARS; RADIOASTRONOMY; RED SHIFT; STAR EVOLUTION; WAVELENGTHS

Citation Formats

Zuo Wenwen, Wu Xuebing, Liu Yiqing, and Jiao Chengliang. THE CORRELATIONS BETWEEN OPTICAL VARIABILITY AND PHYSICAL PARAMETERS OF QUASARS IN SDSS STRIPE 82. United States: N. p., 2012. Web. doi:10.1088/0004-637X/758/2/104.
Zuo Wenwen, Wu Xuebing, Liu Yiqing, & Jiao Chengliang. THE CORRELATIONS BETWEEN OPTICAL VARIABILITY AND PHYSICAL PARAMETERS OF QUASARS IN SDSS STRIPE 82. United States. doi:10.1088/0004-637X/758/2/104.
Zuo Wenwen, Wu Xuebing, Liu Yiqing, and Jiao Chengliang. Sat . "THE CORRELATIONS BETWEEN OPTICAL VARIABILITY AND PHYSICAL PARAMETERS OF QUASARS IN SDSS STRIPE 82". United States. doi:10.1088/0004-637X/758/2/104.
@article{osti_22086515,
title = {THE CORRELATIONS BETWEEN OPTICAL VARIABILITY AND PHYSICAL PARAMETERS OF QUASARS IN SDSS STRIPE 82},
author = {Zuo Wenwen and Wu Xuebing and Liu Yiqing and Jiao Chengliang},
abstractNote = {We investigate the optical variability of 7658 quasars from SDSS Stripe 82. Taking advantage of a larger sample and relatively more data points for each quasar, we estimate variability amplitudes and divide the sample into small bins of redshift, rest-frame wavelength, black hole mass, Eddington ratio, and bolometric luminosity, respectively, to investigate the relationships between variability and these parameters. An anti-correlation between variability and rest-frame wavelength is found. The variability amplitude of radio-quiet quasars shows almost no cosmological evolution, but that of radio-loud ones may weakly anti-correlate with redshift. In addition, variability increases as either luminosity or Eddington ratio decreases. However, the relationship between variability and black hole mass is uncertain; it is negative when the influence of Eddington ratio is excluded, but positive when the influence of luminosity is excluded. The intrinsic distribution of variability amplitudes for radio-loud and radio-quiet quasars are different. Both radio-loud and radio-quiet quasars exhibit a bluer-when-brighter chromatism. Assuming that quasar variability is caused by variations of accretion rate, the Shakura-Sunyaev disk model can reproduce the tendencies of observed correlations between variability and rest-frame wavelength, luminosity as well as Eddington ratio, supporting that changes of accretion rate play an important role in producing the observed optical variability. However, the predicted positive correlation between variability and black hole mass seems to be inconsistent with the observed negative correlation between them in small bins of Eddington ratio, which suggests that other physical mechanisms may still need to be considered in modifying the simple accretion disk model.},
doi = {10.1088/0004-637X/758/2/104},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 758,
place = {United States},
year = {2012},
month = {10}
}