The BeppoSAX "HELLAS" survey

Authors
Fiore, F Giommi, P La Franca, F Matt, G Perola, GC Comastri, A Molendi, S Elvis, M Gioia, I Tamburelli, F Ricci, D Pompilio, F
Citation
F. Fiore et al., The BeppoSAX "HELLAS" survey, ASTROPHYS L, 39(1-6), 1999, pp. 657-660
Citations number
16
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL LETTERS & COMMUNICATIONS
ISSN journal
08886512 → ACNP
Volume
39
Issue
1-6
Year of publication
1999
Pages
657 - 660
Database
ISI
SICI code
0888-6512(1999)39:1-6<657:TB"S>2.0.ZU;2-H
Abstract
The BeppoSAX High Energy Llarge Area Survey (HELLAS) covers the 5-10 keV ba nd and has so far catalogued about 180 sources over 50 deg(2) of sky. After correction for the non uniform sky coverage we find 16 +/- 5 sources deg(- 2) with F5-10keV greater than or equal to 5 X 10(-14) erg cm(-2) s(-1) and resolve 30-40% of the hard 5-10 keV Cosmic X-ray Background (XRB). Optical identification of a first small sample of sources show that most (12 out of 14) are AGN. Seven of these AGN show evidence of absorption/extintion in X -ray/optical. These results support to the scenario in which the hard XRB i s made by obscured AGN.