Dramatic long-term X-ray variability in AGNs
Abstract
Dramatic X-ray and optical variability on ∼ 10 year timescales has been discovered recently in a handful of quasars, which may provide important new insight into the issue of how luminous AGNs are fueled. We have assembled a new sample of extremely variable X-ray sources from archival Einstein and ROSAT data that could increase substantially the number of such objects known. The sources in our sample varied in X-ray flux by at least a factor of 7-8 over a 10-year span, and most exhibited significantly larger variability amplitudes (10 to over 100). We present the details of how our sample was assembled and preliminary results regarding the identifications, properties, and X-ray histories of the objects. Although a heterogeneous population is expected, some sources in the sample are associated with broad-line AGNs, including a radio-quiet quasar at z = 1.3 that decreased in X-ray luminosity by a factor of 40.
- Publication:
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AAS/High Energy Astrophysics Division #15
- Pub Date:
- April 2016
- Bibcode:
- 2016HEAD...1510607M