Source identification in the IGR J17448-3232 field: discovery of the Scorpius galaxy cluster
arXiv:1411.1677 · doi:10.1088/0004-637X/799/1/24
Abstract
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 thus determine that IGR J17448-3232 is in fact the galaxy cluster up to 45 keV and the blazar beyond.
arXiv commentAccepted for publication in the Astrophysical Journal
References in corpus (21)
- On the Absorption of X-rays in the Interstellar Medium
- The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
- Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
- The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
- The Milky Way in Molecular Clouds: A New Complete CO Survey
- Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
- The Mass Function of an X-Ray Flux-Limited Sample of Galaxy Clusters
- The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
- The 70 Month Swift-BAT All-Sky Hard X-Ray Survey
- A Catalog of Galaxy Clusters Observed by XMM-Newton
- X-ray background measurements with XMM-Newton EPIC
- The 3rd IBIS/ISGRI soft gamma-ray survey catalog
- The 4th IBIS/ISGRI soft gamma-ray survey catalog
- RXTE Measurement of the Diffuse X-ray Emission From the Galactic Ridge: Implications for the Energetics of the Interstellar Medium
- Self-similar scaling and evolution in the galaxy cluster X-ray Luminosity-Temperature relation
- A Sample-oriented Catalogue of BL Lacertae Objects
- Chandra Multiwavelength Project X-ray Point Source Number Counts and the Cosmic X-ray Background
- X-ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti-Galactic Center Fields
- Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic Plane: The Cycle 9 Sample
- High Resolution XMM-Newton Spectroscopy of the Cooling Flow Cluster A3112
- Discovery of the infrared counterpart of CXOU J174437.3-323222 in the field of IGR J17448-3232: a blazar candidate viewed through the Galactic centre?