An XMM-Newton view of M101: I. The luminous X-ray source population

Details An XMM-Newton view of M101: I. The luminous X-ray source population An XMM-Newton view of M101: I. The luminous X-ray source population

2003-12-17

arxiv.org/abs/astro-ph/0312457v1

Mon.Not.Roy.Astron.Soc. 349 (2004) 404

Astronomy and Astrophysics

Astrophysics

23 pages, 8 figures. Accepted for publication in MNRAS

Scientific paper

10.1111/j.1365-2966.2004.07546.x

We present the first results of an XMM-Newton EPIC observation of the luminous X-ray source population in the supergiant spiral galaxy M101. We have studied the properties of the fourteen most luminous sources, all of which have intrinsic X-ray luminosities exceeding the Eddington limit for a 1.4 solar mass neutron star, with a subset in the ultraluminous X-ray source (ULX) regime. Eleven sources show evidence of short-term variability, and most vary by a factor of ~2-4 over a baseline of 11-24 yrs, providing strong evidence that these sources are accreting X-ray binary (XRB) systems. The sources show a variety of spectral shapes, with no apparent spectral distinction between those above and below the ULX threshold. Nine are well-fit with either simple absorbed disc blackbody/powerlaw models. However for three of the four sources best-fit with powerlaw models, we cannot exclude the disc blackbody fits and therefore conclude that, coupled with their high luminosities, eight out of nine single-component sources are possibly high state XRBs. The nuclear source has the only unambiguous powerlaw spectrum (photon index~2.3), which may be evidence for a low-luminosity AGN. The remaining five sources require at least two-component spectral fits. We have compared the spectral shapes of nine sources covered by both this observation and an archival 100ks Chandra observation of M101; the majority show behaviour typical of Galactic XRBs i.e. softening with increasing luminosity. We find no definitive spectral signatures to indicate that these sources contain neutron star primaries, and conclude that they are likely to be stellar-mass black hole XRBs, with black hole masses of ~2-23 solar masses if accreting at the Eddington limit (abridged).

Affiliated with

Also associated with

No associations

Rating

An XMM-Newton view of M101: I. The luminous X-ray source population 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 An XMM-Newton view of M101: I. The luminous X-ray source population, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An XMM-Newton view of M101: I. The luminous X-ray source population will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-592031