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dc.contributor.authorSesar, Branimir
dc.contributor.authorIvezic, Zeljko
dc.contributor.authorLupton, Robert
dc.contributor.authorJuric, Mario
dc.contributor.authorGunn, James
dc.contributor.authorKnapp, Gillian
dc.contributor.authorDe Lee, Nathan
dc.contributor.authorSmith, Allyn
dc.contributor.authorMiknaitis, Gajus
dc.contributor.authorLin, Huan
dc.contributor.authorTucker, Douglas
dc.contributor.authorDoi, Mamoru
dc.contributor.authorTanaka, Masayuki
dc.contributor.authorFukugita, Masataka
dc.contributor.authorHoltzman, Jon
dc.contributor.authorKent, Steve
dc.contributor.authorYanny, Brian
dc.contributor.authorSchlegel, David
dc.contributor.authorFinkbeiner, Douglas
dc.contributor.authorPadmanabhan, Nikhil
dc.contributor.authorRockosi, Constance
dc.contributor.authorBond, Nicholas
dc.contributor.authorLee, Brian
dc.contributor.authorStoughton, Chris
dc.contributor.authorJester, Sebastian
dc.contributor.authorHarris, Hugh
dc.contributor.authorHarding, Paul
dc.contributor.authorBrinkmann, Jon
dc.contributor.authorSchneider, Donald
dc.contributor.authorYork, Donald
dc.contributor.authorRichmond, Michael
dc.contributor.authorVanden Berk, Daniel
dc.identifier.citationThe Astronomical Journal 134 (2007) 2236-2251en_US
dc.descriptionRIT community members may access full-text via RIT Libraries licensed databases:
dc.description.abstractWe quantify the variability of faint unresolved optical sources using a catalog based on multiple SDSS imaging observations. The catalog covers SDSS Stripe 82, which lies along the celestial equator in the Southern Galactic Hemisphere (22h 24m < J2000 < 04h 08m, −1.27◦ < J2000 < +1.27◦, ∼ 290 deg2), and contains 58 million photometric observations in the SDSS ugriz system for 1.4 million unresolved sources that were observed at least 4 times in each of the gri bands (with a median of 10 observations obtained over ∼5 years). In each photometric bandpass we compute various low-order lightcurve statistics such as root-mean-square scatter (rms), 2 per degree of freedom, skewness, minimum and maximum magnitude, and use them to select and study variable sources. We find that 2% of unresolved optical sources brighter than g = 20.5 appear variable at the 0.05 mag level (rms) simultaneously in the g and r bands. The majority (2/3) of these variable sources are low-redshift (< 2) quasars, although they represent only 2% of all sources in the adopted flux-limited sample. We find that at least 90% of quasars are variable at the 0.03 mag level (rms) and confirm that variability is as good a method for finding low-redshift quasars as is the UV excess color selection (at high Galactic latitudes). We analyze the distribution of lightcurve skewness for quasars and find that is centered on zero. We find that about 1/4 of the variable stars are RR Lyrae stars, and that only 0.5% of stars from the main stellar locus are variable at the 0.05 mag level. The distribution of lightcurve skewness in the g − r vs. u − g color-color diagram on the main stellar locus is found to be bimodal (with one mode consistent with Algol-like behavior). Using over six hundred RR Lyrae stars, we demonstrate rich halo substructure out to distances of 100 kpc. We extrapolate these results to expected performance by the Large Synoptic Survey Telescope and estimate that it will obtain well-sampled 2% accurate, multi-color lightcurves for ∼ 2 million low-redshift quasars, and will discover at least 50 million variable stars.en_US
dc.publisherAmerican Astronomical Society - The Astronomical Journalen_US
dc.relation.ispartofseriesvol. 134en_US
dc.relation.ispartofseriesno. 6en_US
dc.relation.ispartofseriespps. 2236-2251en_US
dc.subjectGalaxy - haloen_US
dc.subjectGalaxy - stellar contesten_US
dc.subjectQuasars - generalen_US
dc.subjectRR Lyraeen_US
dc.titleExploring the variable sky with the Sloan Digital Sky Surveyen_US

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