Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-02-04
Astronomy and Astrophysics
Astrophysics
8 pages, 6 figures, to appear in the Proceedings of the Symposium "New Visions of the X-ray Universe in the XMM-Newton and Cha
Scientific paper
We have been monitoring M31 with HRC and ACIS onboard \chandra regularly in the past two years. By combining eight \chandra ACIS-I observations taken between 1999 to 2001, we have identified 204 X-ray sources within the central $\sim 17\arcmin\times17\arcmin$ region of M31, with a detection limit of $\sim 1.6\times10^{35}$\lum. Of these 204 sources, 21 are identified with globular clusters, 2 with supernova remnants (one of them is spatially resolved with \chandra), and 8 with planetary nebula. By comparing individual images, about 50% of the sources are variable in time scales of months. We also found 14 transients. Combining all the available transients found in literatures, there are 25 transients in M31 and M32 detected by \chandra and \xmm; we present some of the long-term lightcurves by using the HRC, ACIS and \xmm data. The spectral shape of 12 sources is shown to be variable, suggesting that they went through state changes. The luminosity function of all the point sources is consistent with previous observations (a broken power-law with a luminosity break at $1.7\times10^{37}$\lum). However, when the X-ray sources in different regions are considered separately, different luminosity functions are obtained. This indicates that the star formation history might be different in different regions.
Di Stefano Rosanne
Garcia Murillo R.
Kong Albert K. H.
Murray Stephen S.
Primini Francis A.
No associations
LandOfFree
Two Years of the X-ray Sky in M31 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 Two Years of the X-ray Sky in M31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two Years of the X-ray Sky in M31 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-346063