Tackling the Soft X-ray Excess in AGN with Variability Studies
Abstract
The origin of the soft X-ray excess in AGN has been a mystery ever since its discovery. We present how the time variability of this spectral component can point towards its origin. Using the powerful technique of multi-epoch fitting, we study how the soft excess in a given object depends on other parameters of the continuum and the accretion disk possibly hinting at its nature. As an example, we present results from this technique applied to the Seyfert galaxy Mrk 841, the source in which the soft excess was originally discovered. We study 3 XMM and 2 of the Suzaku pointings available and find that the source displays an impressive variability in the soft X-ray band on the timescale of years. We explore several common soft excess models and their ability to physically consistently explain this spectral variability. We find that the shape and strength of the soft excess correlates with the general X-ray continuum shape and flux, implying a connection between the two. Possible scenarios for such a connection will be discussed.
- Publication:
-
AAS/High Energy Astrophysics Division #13
- Pub Date:
- April 2013
- Bibcode:
- 2013HEAD...1310811L