科研之友
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摘要
As part of our ongoing archival X-ray survey of galaxy clusters for tidal flares, we present evidence of an X-ray transient source within 1 arcmin of the core of Abell 1795. The extreme variability (a factor of nearly 50), luminosity (> 2 x 10(42) erg s(-1)), long duration (> 5 yr) and supersoft X-ray spectrum (< 0.1 keV) are characteristic signatures of a stellar tidal disruption event according to theoretical predictions and to existing X-ray observations, implying a massive greater than or similar to 10(5) M-circle dot black hole at the centre of that galaxy. The large number of X-ray source counts (similar to 700) and long temporal baseline (similar to 12 yr with Chandra and XMM-Newton) make this one of the best sampled examples of any tidal flare candidate to date. The transient may be the same EUV source originally found contaminating the diffuse intracluster medium observations of Bowyer, Berghofer and Korpela, which would make it the only tidal flare candidate with reported EUV observations and implies an early source luminosity 1-2 orders of magnitude greater. If the host galaxy is a cluster member then it must be a dwarf galaxy, an order of magnitude less massive than the quiescent galaxy Henize 2-10 which hosts a massive black hole that is difficult to reconcile with its low mass. The unusual faintness of the host galaxy may be explained by tidal stripping in the cluster core.
- 出版日期2013-11
- 单位西北大学
