X-ray spectral study of hot gas in three clusters of galaxies

¹ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: y.g.grange@sron.nl
² Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands
³ ASI Science Data Center, ESRIN, 00044 Frascati(RM), Italy

Received: 4 September 2009
Accepted: 12 January 2010

Abstract

Aims. We studied the physical properties of three clusters of galaxies, selected from a BeppoSAX wide field camera (WFC) survey. These sources are identified as 1RXS J153934.7–833535, 1RXS J160147.6–754507, and 1RXS J081232.3–571423 in the ROSAT All-Sky Survey catalogue. We obtained XMM-Newton follow-up observations for these three clusters.

Methods. We fitted single and multi-temperature models to spectra obtained with the EPIC-pn camera to determine the temperature, the chemical composition of the gas and their radial distribution. Since two observations were contaminated by a high soft-proton background, we developed a new method to estimate the effect of this background on the data.

Results. We present the temperature and iron abundance of two of these three clusters for the first time. The iron abundance of 1RXS J153934.7–833535 decreases with radius. The fits to the XMM-Newton and Chandra data show that the radial temperature profile within 3' towards the centre either flattens or lowers. A Chandra image of the source suggests the presence of X-ray cavities. The gas properties in 1RXS J160147.6–754507 are consistent with a flat radial distribution of iron and temperature within 2' from the centre. 1RXS J081232.3–571423 is a relatively cool cluster with a temperature of about 3 keV.

Conclusions. The radial temperature and iron profiles suggest that 1RXS J153934.7–833535 is a cool core cluster. The Chandra image shows substructure which points toward active galactic nuclei (AGN) feedback in the core. The flat radial profiles of the temperature and iron abundance in 1RXS J160147.6–754507 are similar to the profiles of non-cool-core clusters.