Bibcode
Servillat, M.; Dieball, A.; Webb, N. A.; Knigge, C.; Maccarone, C.; Barret, D.; Cornelisse, R.; Long, K. S.; Shara, M. M.; Zurek, D. R.
Bibliographical reference
"SF2A-2008: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics Eds.: C. Charbonnel, F. Combes and R. Samadi. Available online at http://proc.sf2a.asso.fr, p.283"
Advertised on:
11
2008
Citations
0
Refereed citations
0
Description
We aim to detect and identify the faint X-ray sources belonging to Galactic
globular clusters in order to understand their role in the evolution of
globular clusters. We present a new Chandra X-ray observation of the Galactic
globular cluster NGC 2808. Previous observations with XMM-Newton and
ultraviolet observations with the Hubble Space Telescope are re-investigated to
help identify the Chandra sources associated with the cluster. From
statistical analysis, 16 sources are very likely to be linked to NGC 2808. We
found one likely neutron star low-mass X-ray binary in quiescence and 8
cataclysmic variable candidates in the core of NGC 2808. The other core sources
are also cataclysmic variable candidates, but some of the faintest could
possibly be chromospherically active binaries or millisecond pulsars. This
significant population of close binaries is likely to play an important role
in slowing down the core collapse of this cluster. We found a possible deficit
of X-ray sources compared to 47 Tuc which could be related to the metallicity
content and the complexity of the evolution of NGC 2808. From X-rays and radio
(ATCA) oobservations, we found no evidence of an intermediate mass black hole
in NGC 2808 and derived mass constraints of several hundreds solar masses.