Optical and near-infrared observations of hard serendipitous Chandra sources

Abstract

We have been carrying out a successful observational programme targeted at finding the highly obscured quasars that are thought to be the main contributors to the hard X-ray background. Out of 56 sources so far studied with optical and near-infrared imaging and spectroscopy, we have found three definite and a further twelve possible Type II quasars. Few sources show significant line emission, suggesting that the line photons are depleted by the large columns of obscuring matter. The redshift distribution of our sources shows a distinct peak at z~1. The broad-band colours and magnitudes of the optical/near-infrared counterparts indicate that the light in these bands is dominated by the continuum of a massive bright galaxy.

Astron. Nachr. in press, issue dedicated to the proceedings of the workshop "X-ray Surveys in the light of New Observatories", Sep. 2002, Santander, Spain

References in corpus (6)

• The Chandra Deep Field South: the 1 Million Second
• A Classic Type 2 QSO
• Chandra Detection of a TypeII Quasar at z=3.288
• The Chandra Deep Survey of the Hubble Deep Field North Area. IV. An Ultradeep Image of the HDF-N
• 2-8 keV X-ray number counts determined from Chandra blank field observations
• Multi-wavelength observations of serendipitous Chandra X-ray sources in the field of A2390

Cited by in corpus (1)

• The (un)resolved X-ray background in the Lockman Hole