EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 424/1 Article
Free access article

Issue A&A
Volume 424, Number 1, September II 2004
Page(s) 133 - 143
Section Galactic structure, stellar clusters and populations
DOI http://dx.doi.org/10.1051/0004-6361:20040399



A&A 424, 133-143 (2004)
DOI: 10.1051/0004-6361:20040399

X-ray sources and their optical counterparts in the globular cluster M 22

N. A. Webb1, D. Serre1, B. Gendre1, 2, D. Barret1, J.-P. Lasota3 and L. Rizzi4

1  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

(Received 5 March 2004 / Accepted 26 May 2004)

Abstract
Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where $5\pm3$ 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

SIMBAD Objects



© ESO 2004


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.