Deep surveys with XMM and CXO: comparison of HDF-N results and comments on the X-ray evolution of galaxies

A comparison is made of the results of the 1Ms CXO and the 160ks XMM-Newton deep surveys of the HDF-N. The confusion of sources in the XMM image is assessed as a function of energy. Source spectra are compared and the optical ids. of many XMM sources are aided by the CXO positions. The XMM spectra are summed for each broad optical classification. The harder response of XMM is highlighted with respect to the nature of sources contributing to the bulk of the XRB, i.e. AGN with heavy absorption. Comments are made on the nature of sources contributing to the log(N) - log(S) at fluxes between 10-16 and 10-17 ergs cm-2 s-1 (0.5 - 2kev), where the number counts are constrained by fluctuation analysis (Miyaji and Griffiths ApJ 564, L5 (2002). We may be observing the X-ray evolution of normal galaxies, as predicted from the expected evolution in numbers of low-mass X-ray binaries (Ghosh &White ApJ 559, L97 (2001)) and applied to galaxy X-ray fluxes by Ptak et al. (ApJ 559, L91 (2001)). Finally, we comment on the cosmic variance across different XMM fields.