Bibcode
Garcia, M. R.
Bibliographical reference
American Astronomical Society, 200th AAS Meeting, #84.03; Bulletin of the American Astronomical Society, Vol. 34, p.785
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5
2002
Citations
0
Refereed citations
0
Description
Between Oct 1999 and Jun 2001 Chandra observed M31 on a nearly monthly
schedule. These observations allowed the discovery of 14 X-ray
transients, a few of which were followed up with HST in an attempt to
find contemporaneous optical counterparts. The transient most luminous
in X-rays shows a possible U ~23 counterpart in HST imaging. The ratio
of the X-ray to optical luminosity implies a rather long orbital period
for this transient. By adding the Chandra observations together we are
able to measure the luminosity function within the bulge region down to
~ 3 x 1035erg s-1. This luminosity function shows
a break whose position increases monotonically as we move out from the
bulge into the disk. The slope of the luminosity function becomes
steeper as we move towards the disk, which is surprising given that
elliptical galaxies tend to have steeper luminosity functions than
spiral disks. A hint as to what is causing this surprising behavior may
be found in the variability of sources with M31, which also shows a
monotonic trend, decreasing with increasing radius. This work supported
in part by NASA grant GO-9087 and contract NAS8-38248.