1008.2158 (Brandon Patel et al.)

Analysis of a State Changing Supersoft X-ray Source in M31    [PDF]

Brandon Patel, Rosanne Di Stefano, Thomas Nelson, Francis A. Primini, Jifeng Liu, Sarah Scoles

We report on observations of a luminous supersoft X-ray source (SSS) in M31, r1-25, that has exhibited spectral changes to harder X-ray states. We document these spectral changes. In addition, we show that they have important implications for modeling the source. Quasisoft states in a source that has been observed as an SSS represent a newly- discovered phenomenon. We show how such state changers could prove to be examples of unusual black hole or neutron star accretors. Future observations of this and other state changers can provide the information needed to determine the nature(s) of these intriguing new sources.

View original: http://arxiv.org/abs/1008.2158