A survey for hard spectrum Rosat sources

Page, M. J.
Mittaz, J. P. D.
Carrera, Francisco J.

Open link

Publication date

September 2018

DOI

10.1063/1.1434751

Publisher

AIP Publishing

Journal

issn: 0094-243X

Abstract

We have performed a survey of 188 Rosat fields looking for sources significantly harder than the X-ray background (α∼0.5), with the aim of understanding the nature of sources that produce its remaining unresolved fraction. Our sample of 147 hard sources has a steeper-than-Euclidean log N−log S. We have spectroscopic identifications for 62 of the hard sources: 28 are broad line AGN, 12 are narrow emission line galaxies, and the remainder are galaxies without emission lines, clusters of galaxies, and Galactic stars. The properties of these sources are discussed. Contrary to currently favored theories for the production of the X-ray background, we do not find a single example of a high redshift type 2 QSO.Peer Reviewe