Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2011-09-07
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
Accepted by Astronomy and Astrophysics. 6 pages, 8 figures
Scientific paper
We seek clarification of the nature of X-ray sources detected in M 31. Here we focus on CXOM31 J004253.1+411422, the brightness of which suggests that it belongs to the class of ultraluminous X-ray sources. We determine the X-ray properties of sources detected in the XMM-Newton Chandra monitoring program. We investigate spectral properties and search for periodic or quasi-periodic oscillations. A multi-component model is applied to the spectra obtained from XMM-Newton data to evaluate the relative contributions from thermal and non-thermal emission. The time dependence of this ratio is evaluated over a period of forty days. We simultaneously fit data from XMM-Newton EPIC-pn, MOS1 and MOS2 detectors with (non-thermal) powerlaw and (thermal) multicolored blackbody. The X-ray spectrum is best fit by the combination of a thermal component with kT ~ 1 keV and a powerlaw component with photon index approximately 2.6. From combined analysis of Chandra, Swift and XMM-Newton data, the unabsorbed total luminosity of this source decreases from ~ 3.8 x 10^{39} erg s^{-1} in the first observation to ~ 0.5 x 10^{39} ergs s^{-1} over a period of three months. The decay closely follows an exponential decline with a time constant of 32 days. The source spectrum evolves significantly, exhibiting a faster decline of the thermal component. We do not find evidence of any significant temporal features in the power density spectrum. The presence of a thermal component at kT ~ 1 keV in conjunction with a non-thermal high energy tail, is also consistent with spectral properties of other ULXs in the "high state". Our analysis indicates that the underlying source of this first ULX in M~31 is a black hole of mass, M > 13 M_{sun}, accreting near the Eddington limit, that underwent a transient outburst followed by an exponential decay reminiscent of transients associated with galactic X-ray novae.
Greiner Jochen
Haberl Franck
Hartmann Dieter H.
Henze Matthias
Hernanz Margarida
No associations
LandOfFree
CXOM31 J004253.1+411422: The first ultra-luminous X-ray transient in M 31 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with CXOM31 J004253.1+411422: The first ultra-luminous X-ray transient in M 31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and CXOM31 J004253.1+411422: The first ultra-luminous X-ray transient in M 31 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-306919