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Title: SOURCE IDENTIFICATION IN THE IGR J17448-3232 FIELD: DISCOVERY OF THE SCORPIUS GALAXY CLUSTER

We use a 43 ks XMM-Newton observation to investigate the nature of sources first distinguished by a follow-up Chandra observation of the field surrounding INTEGRAL source IGR J17448-3232, which includes extended emission and a bright point source previously classified as a blazar. We establish that the extended emission is a heretofore unknown massive galaxy cluster hidden behind the Galactic bulge. The emission-weighted temperature of the cluster within the field of view is 8.8 keV, with parts of the cluster reaching temperatures of up to 12 keV; no cool core is evident. At a redshift of 0.055, the cluster is somewhat under-luminous relative to the X-ray luminosity-temperature relation, which may be attributable to its dynamical state. We present a preliminary analysis of its properties in this paper. We also confirm that the bright point source is a blazar, and we propose that it is either a flat spectrum radio quasar or a low-frequency peaked BL Lac object. We find four other fainter sources in the field, which we study and tentatively identify. Only one, which we propose is a foreground Galactic X-ray binary, is hard enough to contribute to IGR J17448-3232, but it is too faint to be significant. We thusmore » determine that IGR J17448-3232 is in fact the galaxy cluster up to ≈45 keV and the blazar beyond.« less
Authors:
;  [1] ;  [2] ; ;  [3]
  1. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
  2. Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  3. CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d'Astrophysique, Centre de Saclay, F-91191 Gif-sur-Yvette (France)
Publication Date:
OSTI Identifier:
22364541
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BL LACERTAE OBJECTS; BLACK HOLES; GALAXY CLUSTERS; KEV RANGE; LUMINOSITY; MILKY WAY; QUASARS; RED SHIFT; X RADIATION