Understanding extreme quasar optical variability with CRTS: I. Major AGN flares

Abstract

There is a large degree of variety in the optical variability of quasars and it is unclear whether this is all attributable to a single (set of) physical mechanism(s). We present the results of a systematic search for major flares in AGN in the Catalina Real-time Transient Survey as part of a broader study into extreme quasar variability. Such flares are defined in a quantitative manner as being atop of the normal, stochastic variability of quasars. We have identified 51 events from over 900,000 known quasars and high probability quasar candidates, typically lasting 900 days and with a median peak amplitude of $\Delta m=1.25$ mag. Characterizing the flare profile with a Weibull distribution, we find that nine of the sources are well described by a single-point single-lens model. This supports the proposal by Lawrence et al. (2016) that microlensing is a plausible physical mechanism for extreme variability. However, we attribute the majority of our events to explosive stellar-related activity in the accretion disk: superluminous supernovae, tidal disruption events, and mergers of stellar mass black holes.

25 pages, 18 figures, accepted for publication by MNRAS

References in corpus (14)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• An ultraviolet-optical flare from the tidal disruption of a helium-rich stellar core
• The Catalina Surveys Periodic Variable Star Catalog
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• A possible close supermassive black-hole binary in a quasar with optical periodicity
• Starbursts near supermassive black holes: young stars in the Galactic Center, and gravitational waves in LISA band
• SDSS Standard Star Catalog for Stripe 82: the Dawn of Industrial 1% Optical Photometry
• The Superluminous Transient ASASSN-15lh as a Tidal Disruption Event from a Kerr Black Hole
• Intermediate mass black holes in AGN disks II. Model predictions & observational constraints
• Super-luminous supernovae at redshifts of 2.05 and 3.90
• A milliparsec supermassive black hole binary candidate in the galaxy SDSS J120136.02+300305.5
• Measuring Quasar Variability with Pan-STARRS1 and SDSS
• Spectral analysis of four 'hypervariable' AGN: a microneedle in the haystack?

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• Discovery of late-time X-ray flare and anomalous emission line enhancement after the nuclear optical outburst in a narrow-line Seyfert 1 Galaxy
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