Deep XMM-Newton Images in the Fields of Dwarf Spheroidal Galaxies

Type Conference Paper
Names Nicholas Hunt-Walker, M. Orio, L. Pavan, E. Held, S. Ciroi, F. Di Mille, J. Gallagher, U. Munari
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #215, #457.06
Volume 42
Pages 480
Date January 1, 2010
Library Catalog NASA ADS
Abstract We present a new deep XMM-Newton image of the field of the dwarf spheroidal galaxy Leo I, and compare it with an archival XMM-Newton image of the dwarf spheroidal galaxy Fornax. We find 74 X-ray sources in the Leo I field, and 89 in the Fornax field. Although the spatial distribution does not increase much towards the center of the galaxies, there is an excess of X-ray sources in comparison with other low N(H) regions observed with deep X-ray pointings. Comparing with public and proprietary multi-filter optical observations, we identify a small number of candidate X-ray binaries in each galaxy, as well as several candidate AGN. The possibility to study the X-ray population in a "pristineā€ environment with known star formation history opens up new possibilities, and the Local Group offers several optimal environments for this project. An HR diagram of the candidate optical counterparts of the X-ray sources in the fields of the two galaxies, reaching visual magnitude V=25.5, is presented.
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