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 active galactic nucleus (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 d 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. 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 disc: superluminous supernovae, tidal disruption events and mergers of stellar mass black holes.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/625731 |
| Date | 10 1900 |
| Creators | Graham, Matthew J., Djorgovski, S. G., Drake, Andrew J., Stern, Daniel, Mahabal, Ashish A., Glikman, Eilat, Larson, Steve, Christensen, Eric |
| Contributors | Univ Arizona, Dept Planetary Sci, Lunar & Planetary Lab |
| Publisher | OXFORD UNIV PRESS |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society |
| Relation | https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stx1456 |
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