Massive, long-duration, soft X-ray flares from galactic nuclei
Abstract
During the ROSAT and XMM-Newton sky surveys a very small number of giant (factor >100), soft, X-ray flares have been seen in galactic nuclei. Their very rarity shows that they are not produced by a common AGN process. While they all tend to show similar decay curves, the rise and plateau sections of the flare vary considerably between sources. Flares which rise and decay on a timescale of weeks to months fit easily into the category of Tidal Disruption Events (TDE) where the black hole is temporarily fueled by stellar debris. But what about events, such as NGC 3599 and GSN 069 which have a peak flux lasting for years or IC 3599 where the flare repeated after 20 years ? The behavior of these three galaxies is similar to that of black hole binaries such as GRS 1915+105, where the flare is commonly attributed to an accretion disc instability, leading to an emptying and refilling of the inner disc. However, recent numerical simulations indicate that TDE occurring in galaxies with M_{BH}<6×10{6} solar masses, may also have light curves which take years to reach peak flux. We explore both of these possibilities in detail.
- Publication:
-
The Extremes of Black Hole Accretion
- Pub Date:
- July 2015
- Bibcode:
- 2015ebha.confE..61S