The X-ray luminosity function of galaxies in the Coma cluster

¹ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
² Space Research Institute, Profsoyuznaya 84/32, Moscow 117810, Russia
³ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, Hawaii 96822, USA
⁴ Universitá degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁵ Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille, France

Corresponding author: A. Finoguenov, alexis@xray.mpe.mpg.de

Received: 28 November 2003
Accepted: 27 January 2004

Abstract

The XMM-Newton survey of the Coma cluster of galaxies covers an area of 1.86 square degrees with a mosaic of 16 pointings and has a total useful integration time of 400 ks. Detected X-ray sources with extent less than were correlated with cataloged galaxies in the Coma cluster region. The redshift information, which is abundant in this region of the sky, allowed us to separate cluster members from background and foreground galaxies. For the background sources, we recover a typical in the flux range  ergs s^-1 cm^-2 in the 0.5-2.0 keV band. The X-ray emission from the cluster galaxies exhibits X-ray colors typical of thermal emission. The luminosities of Coma galaxies lie in the ergs s^-1 interval in the  keV band. The luminosity function of Coma galaxies reveals that their X-ray activity is suppressed with respect to the field by a factor of 5.6, indicating a lower level of X-ray emission for a given stellar mass.