Long Term Variability of SDSS Quasars

Abstract

We use a sample of 3791 quasars from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), and compare their photometry to historic plate material for the same set of quasars in order to study their variability properties. The time base-line we attain this way ranges from a few months to up to 50 years. In contrast to monitoring programs, where relatively few quasars are photometrically measured over shorter time periods, we utilize existing databases to extend this base-line as much as possible, at the cost of sampling per quasar. Our method, however, can easily be extended to much larger samples. We construct variability Structure Functions and compare these to the literature and model functions. From our modeling we conclude that 1) quasars are more variable toward shorter wavelengths, 2) their variability is consistent with an exponentially decaying light-curve with a typical time-scale of ~2 years, 3) these outbursts occur on typical time-scales of ~200 years. With the upcoming first data release of the SDSS, a much larger quasar sample can be used to put these conclusions on a more secure footing.

16 pages, accepted for publication in AJ, Sept issue

References in corpus (14)

• The USNO-B Catalog
• Long-term optical variability properties of the Palomar-Green quasars
• Optical Variability in Active Galactic Nuclei: Starbursts or Disk Instabilities?
• The Sloan Digital Sky Survey Quasar Catalog I. Early Data Release
• Variability in active galactic nuclei: confrontation of models with observations
• The Ensemble Variability Properties of Faint QSOs
• QSO variability: probing the Starburst model
• Quasar Spectral Slope Variability in the Optical Band
• Spectral Slope Variability of BL Lac Objects in the Optical Band
• Quasar Variability in the Framework of Poissonian Models
• Deriving the Quasar Luminosity Function from Accretion Disk Instabilities
• Long-term Optical Variability of Radio-Selected Quasars from the FIRST Survey
• The QSO variability-luminosity-redshift relation
• $JH{K}^{\prime }$ Imaging Photometry of Seyfert 1 AGNs and Quasars II: Observation of Long-Term Variability

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• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• The SDSS View of the Palomar-Green Bright Quasar Survey
• The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
• A Description of Quasar Variability Measured Using Repeated SDSS and POSS Imaging
• Structure Function Analysis of Long Term Quasar Variability
• On the variability of quasars: a link between Eddington ratio and optical variability?
• Spectral Variability of Quasars in the Sloan Digital Sky Survey. I: Wavelength Dependence
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• Observations and Theoretical Implications of the Large Separation Lensed Quasar SDSS J1004+4112
• Comparison of the X-ray emission from Tidal Disruption Events with those of Active Galactic Nuclei
• The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 Myr
• Ensemble X-ray variability of Active Galactic Nuclei from serendipitous source catalogues
• Discovery of 5000 Active Galactic Nuclei behind the Magellanic Clouds
• A long term study of AGN X-ray variability. Structure function analysis on a ROSAT-XMM quasar sample
• Timescale of variation and the size of the accretion disc in active galactic nuclei
• Variable Faint Optical Sources Discovered by Comparing POSS and SDSS Catalogs
• A Search for Kilonovae in the Dark Energy Survey
• Variability-selected active galactic nuclei from supernova search in the Chandra deep field south
• Optical Properties of faint FIRST Variable Radio Sources
• Lyman continuum leaking AGN in the SSA22 field
• Multiepoch Sky Surveys and the Lifetime of Quasars
• AGN and their host galaxies in the local Universe: two mass independent Eddington ratio distribution functions characterize black hole growth
• The ensemble photometric variability of over $10^5$ quasars in the Dark Energy Camera Legacy Survey and the Sloan Digital Sky Survey
• Spectral Variability of Quasars in the Sloan Digital Sky Survey. II: The C IV Line
• A structure function analysis of VST-COSMOS AGN
• Multicolor Variability of Young Stars in the Lagoon Nebula: Driving Causes and Intrinsic Timescales
• The Subaru/XMM-Newton Deep Survey (SXDS) - V. Optically Faint Variable Object Survey
• A Study of Quasar Selection in the Dark Energy Survey Supernova fields
• A forward modelling approach to AGN variability -- Method description and early applications
• Spitzer Observations of Long Term Infrared Variability Among Young Stellar Objects in Chamaeleon I
• Characterising the i-band variability of YSOs over six orders of magnitude in timescale
• Variable Point Sources in Sloan Digital Sky Survey Stripe 82. I. Project Description and Initial Catalog (0 h < R.A. < 4 h)
• Probing Spectroscopic Variability of Galaxies & Narrow-Line Active Galactic Nuclei in the Sloan Digital Sky Survey
• New Quasars Detected via Variability in the QUEST1 Survey
• The nature of the soft-excess and spectral variability in the Seyfert 1 galaxy Zw 229.015
• The Subaru/XMM-Newton Deep Survey (SXDS) - VI. Properties of Active Galactic Nuclei Selected by Optical Variability
• The Effect of Variability on the Estimation of Quasar Black Hole Masses
• A $1.4$ deg${}^2$ blind survey for CII], CIII] and CIV at $\mathbf{z}\sim 0.7-1.5$. I: nature, morphologies and equivalent widths
• Results of optical monitoring of 5 SDSS double QSOs with the Nordic Optical Telescope
• Quasar variability limits on cosmological density of cosmic strings
• The relation between the optical spectral slope and the luminosity for 17 Palomar-Green QSOs
• The Millennium Galaxy Catalogue: a census of local compact galaxies
• Towards an understanding of YSO variability: A multi-wavelength analysis of bursting, dipping, and symmetrically varying light curves of disc-bearing YSOs
• Ensemble Variability of Near-Infrared-Selected Active Galactic Nuclei
• Individual optical variability of Active Galactic Nuclei from the MEXSAS2 sample
• Long-term optical photometric monitoring of the quasar SDSS J153259.96-003944.1
• Observational nonstationarity of AGN variability: The only way to go is down!
• Optical monitoring of the z=4.40 quasar Q 2203+292
• Optical variability of eight FRII-type quasars with 13-yr photometric light curves
• Identification of quasars variable over long time scales from infrared surveys. Ensemble variability and structure function properties
• Exploring the Variable Sky with the Sloan Digital Sky Survey