학술논문
The XMM-Newton Serendipitous Survey V. Optical identification of the XMM-Newton Medium sensitivity Survey (XMS)
Document Type
Working Paper
Author
Barcons, X.; Carrera, F. J.; Ceballos, M. T.; Page, M. J.; Bussons-Gordo, J.; Corral, A.; Ebrero, J.; Mateos, S.; Tedds, J. A.; Watson, M. G.; Birkinshaw, M.; Boller, T.; Borisov, N.; Bremer, M.; Bromage, G. E.; Brunner, H.; Caccianiga, A.; Crawford, C. S.; Cropper, M. S.; Della Ceca, R.; Derry, P.; Fabian, A. C.; Guillout, P.; Hashimoto, Y.; Hasinger, G.; Hassall, B. J. M.; Lamer, G.; Loaring, N. S.; Maccacaro, T.; Mason, K. O.; McMahon, R. G.; Mirioni, L.; Mittaz, J. P. D.; Motch, C.; Negueruela, I.; Osborne, J. P.; Panessa, F.; Perez-Fournon, I.; Pye, J. P.; Roberts, T. P.; Rosen, S.; Schartel, N.; Schurch, N.; Schwope, A.; Severgnini, P.; Sharp, R.; Stewart, G. C.; Szokoly, G.; Ullan, A.; Ward, M. J.; Warwick, R. S.; Wheatley, P. J.; Webb, N. A.; Worrall, D.; Yuan, W.; Ziaeepour, H.
Source
Subject
Language
Abstract
We present the XMM-Newton Medium sensitivity Survey (XMS), including a total of 318 X-ray sources found among the serendipitous content of 25 XMM-Newton target fields. The XMS comprises four largely overlapping source samples selected at soft (0.5-2 keV), intermediate (0.5-4.5 keV), hard (2-10 keV) and ultra-hard (4.5-7.5 keV) bands, the first three of them being flux-limited. We report on the optical identification of the XMS samples, complete to 85-95%. At the intermediate flux levels sampled by the XMS we find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard selected samples. We find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~35-45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN.
Comment: A&A, accepted
Comment: A&A, accepted