X-ray source counts in the COSMOS field
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.
Cite
@article{arxiv.0704.2293,
title = {X-ray source counts in the COSMOS field},
author = {N. Cappelluti and G. Hasinger and M. Brusa and A. Comastri and G. Zamorani and H. Boehringer and H. Brunner and F. Civano and A. Finoguenov and F. Fiore and R. Gilli and R. E. Griffiths and V. Mainieri and I. Matute and T. Miyaji and J. Silverman},
journal= {arXiv preprint arXiv:0704.2293},
year = {2007}
}