QUANTIFYING QUASAR VARIABILITY AS PART OF A GENERAL APPROACH TO CLASSIFYING CONTINUOUSLY VARYING SOURCES

By S. Kozłowski, C. Kochanek, A. Udalski, Ł. Wyrzykowski, Igor Soszynski, M. Szymański, M. Kubiak, G. Pietrzyński, O. Szewczyk, K. Ulaczyk and 1 more. 2009

224 citations recorded by the source corpus.

Robust fast methods to classify variable light curves in large sky surveys are becoming increasingly important. While it is relatively straightforward to identify common periodic stars and particular transient events (supernovae, novae, microlensing events), there is no equivalent for non-periodic continuously varying sources (quasars, aperiodic stellar variability). In this paper, we present a fast method for modeling and classifying such sources. We demonstrate the method using ∼86, 000 variable sources from the OGLE-II survey of the LMC and ∼2700 mid-IR-selected quasar candidates from the OGLE-III survey of the LMC and SMC. We discuss the location of common variability classes in the parameter space of the model. In particular, we show that quasars occupy a distinct region of variability space, providing a simple quantitative approach to the variability selection of quasars.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c2a38c8d6993972e3c135a6fe7036b100a4cb99f

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Citations in the corpus

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: TECHNICAL OVERVIEW (2014, methodology): “…process) model to generate quasar continuum LCs (Kelly et al. 2009, 2014), which has been demonstrated to provide a reasonably good description of stochastic quasar continuum variability on the timescales of interest here (e.g., Kozłowski et al. 2010; MacLeod et al. 2010; Zu et al. 2013).”
THE MAN BEHIND THE CURTAIN: X-RAYS DRIVE THE UV THROUGH NIR VARIABILITY IN THE 2013 ACTIVE GALACTIC NUCLEUS OUTBURST IN NGC 2617 (2013, methodology): “…the continuum light curve using a damped ran om walk (DRW) model, which has been demonstrated to be a good statistical model of optical quasar variability using large (∼ 104) samples of quasar light curves (e.g., Kelly et al. 2009; Kozłowski et al. 2010; MacLeod et al. 2010; Zu et al. 2013b).”
THINK OUTSIDE THE COLOR BOX: PROBABILISTIC TARGET SELECTION AND THE SDSS-XDQSO QUASAR TARGETING CATALOG (2010, background): “…al. 2002; Morgan et al. 2008), LSST (Ivezić et al. 2008; Abell et al. 2009), Skymapper (Keller et al. 2007), and WFIRST, the selection of quasars based on their variability has recently received some attention (Kozłowski et al. 2010; Schmidt et al. 2010; Butler & Bloom 2010; MacLeod et al. 2011).”
CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION (2010, background): “Kelly et al. (2009a) found that quasar optical light curves on timescales 7 yr in the rest frame of the quasar are well described by a Gaussian process on the logarithmic scale (see also Kozłowski et al. 2010), with characteristic timescale consistent with accretion disk thermal timescales.”
False periodicities in quasar time-domain surveys (2016, methodology): “The means of each lognormal prior were set based on the geometric mean τ of 200 d from quasar samples in MacLeod et al. (2010), Kozłowski et al. (2010) and Andrae et al. (2013), and to give σ T = (cτ/2)1/2 ∼ 0.1 mag.”