Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-07-21
Astron.Astrophys.409:65-78,2003
Astronomy and Astrophysics
Astrophysics
16 pages, 10 figures, accepted for publication in Astronomy & Astrophysics (aa.cls included)
Scientific paper
10.1051/0004-6361:20031107
We present extensive optical, radio and infrared follow-up observations of a sample of 35 hard X-ray (2-10 keV) selected sources discovered serendipitously in the PV XMM-Newton observation of the radio-loud quasar PKS 0312-77 field, for which also an archival Chandra observation is available. The observations have been carried out as part of the HELLAS2XMM survey, a program aimed to understand the nature of the sources responsible for the bulk of the hard X-ray Background (XRB). The identification of the optical counterparts greatly benefits from the positional accuracy obtained from Chandra and radio observations. As a consequence, the spectroscopic completeness of the present sample (80%) is limited only by the faintness of the optical counterparts. The multiwavelength coverage of our survey allows us to unveil a large spread in the overall properties of hard X-ray selected sources. At low redshift (z<1), the source breakdown includes Broad Line AGN, Narrow Emission-Line Galaxies, and optically ``normal'' galaxies. All the ten sources at z>1 are spectroscopically classified as Broad Line AGNs. A few of them show significant intrinsic X-ray absorption (N(H)>10^22 cm^-2), further supporting previous evidence of a decoupling between optical and X-ray properties at high luminosities and redshifts. Finally, a non negligible fraction (15%) of the hard X-ray sources are not detected down to the limiting magnitude of the optical images. The corresponding high X-ray to optical flux ratio, X-ray and optical-infrared colors strongly suggest that they are high redshift, obscured AGN.
Baldi Alessandro
Brusa Marcella
Ciliegi Paolo
Cocchia Filomena
Comastri Andrea
No associations
LandOfFree
The Hellas2XMM survey: III. Multiwavelength observations of hard X-ray selected sources in the PKS 0312-77 field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Hellas2XMM survey: III. Multiwavelength observations of hard X-ray selected sources in the PKS 0312-77 field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Hellas2XMM survey: III. Multiwavelength observations of hard X-ray selected sources in the PKS 0312-77 field will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-340607