X-ray source counts in the COSMOS field

N. Cappelluti; G. Hasinger; M. Brusa; A. Comastri; G. Zamorani; H. Boehringer; H. Brunner; F. Civano; A. Finoguenov; F. Fiore; R. Gilli; R. E. Griffiths; V. Mainieri; I. Matute; T. Miyaji; J. Silverman

arXiv · 0704.2293

X-ray source counts in the COSMOS field

N. Cappelluti·G. Hasinger·M. Brusa·A. Comastri·G. Zamorani·H. Boehringer·H. Brunner·F. Civano·A. Finoguenov·F. Fiore·R. Gilli·R. E. Griffiths·V. Mainieri·I. Matute·T. Miyaji·J. Silverman

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Abstract

We present the analysis of the source counts in the XMM-COSMOS survey using data of the first year of XMM-Newton observations. The survey covers ~2 deg^2 within the region of sky bounded by 9^h57.5^m<R.A.<10^h03.5^m; 1^d27.5^m<DEC<2^d57.5^m with a total net integration time of 504 ks. Using a maximum likelihood algorithm we detected a total of 1390 sources at least in one band. Using Monte Carlo simulations to estimate the sky coverage we produced the logN-logS relations. These relations have been then derived in the 0.5--2 keV, 2--10 keV and 5--10 keV energy bands, down to flux limits of 7.2x10^-16 erg cm^-2 s^-1, 4.0x10^-15 erg cm^-2 s^-1 and 9.7x10^-15 erg cm^-2 s^-1, respectively. These relations have been compared to previous X-ray survey and to the most recent X-ray background model finding an excellent agreement. The slightly different normalizations observed in the source counts of COSMOS and previous surveys can be largely explained as a combination of low counting statistics and cosmic variance introduced by the large scale structure.

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N. Cappelluti, G. Hasinger, M. Brusa, A. Comastri, G. Zamorani, H. Boehringer, H. Brunner, F. Civano, A. Finoguenov, F. Fiore, R. Gilli, R. E. Griffiths, V. Mainieri, I. Matute, T. Miyaji, J. Silverman. 2007-04-18. X-ray source counts in the COSMOS field. https://arxiv.org/abs/0704.2293

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