Volume 424, Number 1, September II 2004
|Page(s)||133 - 143|
|Section||Galactic structure, stellar clusters, and populations|
|Published online||17 August 2004|
X-ray sources and their optical counterparts in the globular cluster M 22
Centre d'Étude Spatiale des Rayonnements, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 04, France e-mail: Natalie.Webb@cesr.fr
2 Istituto di Astrofisica Spaziale e Fisica Cosmica, CNR, via Fosso del Cavaliere, Roma, Italy
3 Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
4 INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padua, Italy
Accepted: 26 May 2004
Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where of these sources are likely to be related to the cluster. Using differential optical photometry, we have identified probable counterparts to those sources belonging to the cluster. Using X-ray spectroscopic and timing studies, supported by the optical colours, we propose that the most central X-ray sources in the cluster are cataclysmic variables, millisecond pulsars, active binaries and a blue straggler. We also identify a cluster of galaxies behind this globular cluster.
Key words: Galaxy: globular clusters: individual: M 22 / X-rays: general / stars: binaries: general / galaxies: clusters: general
© ESO, 2004
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