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An XMM-Newton Study of the Hard X-ray Sky

E. Piconcelli·M. Cappi·L. Bassani·G. Di Cocco·M. Dadina
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Abstract

We report on the spectral properties of a sample of 90 hard X-ray selected serendipitous sources detected in 12 XMM observations with 1 ~1.55 over the whole sample. We also find that the mean slope of the QSOs in our sample turns out to remain nearly constant ( ~1.8-1.9) between 0 ~10^(22) cm^(-2)) is ~30%, with little evolution in the range 2<F(2-10)<80 10^(-14) erg/cm2/s. Interestingly, this value is a factor ~2 lower than predicted by the synthesis models of the CXB. This finding, detected for the first time in this survey, therefore suggests that most of the heavily obscured objects which make up the bulk of the CXB will be found at lower fluxes (F(2-10)< 10^(-14) erg/cm2/s). This mismatch together with other recent observational evidences which contrast with CXB model predictions suggest that one (or more) of the assumptions usually included in these models need to be revised.

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E. Piconcelli, M. Cappi, L. Bassani, G. Di Cocco, M. Dadina. 2003-09-23. An XMM-Newton Study of the Hard X-ray Sky. https://doi.org/10.1051/0004-6361%3A20031490

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