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Fig. 2


Colourmagnitude (left) and colour–colour (right) diagrams of the SDSS9 optical counterparts of the X-ray sources. Foreground stars are labelled by red star symbols, AGNs with blue crosses, galaxies with blue squares, X-ray binary candidates with green circles, and other binary systems with green triangles. Unclassified sources are labelled by black dots. Orange dots represent the SDSS7 members (g< 23 mag) of the Draco dSph as classified by Rave et al. (2003). The violet line is the stellar isochrone for the age (1010 yr) and metalicity (0.0004) of the Draco dSph according to Girardi et al. (2004). It is obvious that most of the stars in the galaxy are already on the red giant branch.

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