The ensemble photometric variability of ∼25,000 quasars in the Sloan Digital Sky Survey

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dc.contributor.authorBerk, DEV
dc.contributor.authorWilhite, BC
dc.contributor.authorKron, RG
dc.contributor.authorAnderson, SF
dc.contributor.authorBrunner, RJ
dc.contributor.authorHall, PB
dc.contributor.authorIvezic, Z
dc.contributor.authorRichards, GT
dc.contributor.authorSchneider, DP
dc.contributor.authorYork, DG
dc.contributor.authorBrinkmann, JV
dc.contributor.authorLamb, DQ
dc.contributor.authorNichol, RC
dc.contributor.authorSchlegel, DJ
dc.date.accessioned2025-01-21T01:08:20Z
dc.date.available2025-01-21T01:08:20Z
dc.date.issued2004
dc.description.abstractUsing a sample of over 25,000 spectroscopically confirmed quasars from the Sloan Digital Sky Survey, we show how quasar variability in the rest-frame optical/UV regime depends on rest-frame time lag, luminosity, rest wavelength, redshift, the presence of radio and X-ray emission, and the presence of broad absorption line systems. Imaging photometry is compared with three-band spectrophotometry obtained at later epochs spanning time lags up to about 2 yr. The large sample size and wide range of parameter values allow the dependence of variability to be isolated as a function of many independent parameters. The time dependence of variability (the structure function) is well fitted by a single power law with an index gamma=0.246+/-0.008, on timescales from days to years. There is an anticorrelation of variability amplitude with rest wavelength-e.g., quasars are about twice as variable at 1000 Angstrom as at 6000 Angstrom-and quasars are systematically bluer when brighter at all redshifts. There is a strong anticorrelation of variability with quasar luminosity-variability amplitude decreases by a factor of about 4 when luminosity increases by a factor of 100. There is also a significant positive correlation of variability amplitude with redshift, indicating evolution of the quasar population or the variability mechanism. We parameterize all of these relationships. Quasars with ROSAT All-Sky Survey X-ray detections are significantly more variable (at optical/UV wavelengths) than those without, and radio-loud quasars are marginally more variable than their radio-quiet counterparts. We find no significant difference in the variability of quasars with and without broad absorption line troughs. Currently, no models of quasar variability address more than a few of these relationships. Models involving multiple discrete events or gravitational microlensing are unlikely by themselves to account for the data. So-called accretion disk instability models are promising, but more quantitative predictions are needed.
dc.fuente.origenWOS
dc.identifier.issn0004-637X
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/96456
dc.identifier.wosidWOS:000188658100008
dc.issue.numero2
dc.language.isoen
dc.pagina.final714
dc.pagina.inicio692
dc.revistaAstrophysical journal
dc.rightsacceso restringido
dc.subjectgalaxies : active
dc.subjectquasars : general
dc.subjecttechniques : photometric
dc.titleThe ensemble photometric variability of ∼25,000 quasars in the Sloan Digital Sky Survey
dc.typeartículo
dc.volumen601
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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