The radial dependence of temperature and iron abundance

Galaxy clusters from z = 0.14 to z = 0.89

¹ Max-Planck-Institut für Kernphysik, PO Box 103980, 69029 Heidelberg, Germany e-mail: Steven.Ehlert@mpi-hd.mpg.de
² Department of Physics and Astronomy, Northwestern University, 2131 Sheridan Road, Evanston, IL 60208-2900, USA
³ LAM, Pôle de l'Etoile Site de Château-Gombert, 38, rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France e-mail: m-ulmer2@northwestern.edu

Received: 19 March 2008
Accepted: 3 June 2009

Abstract

Context. The origin and evolution of the intracluster medium (ICM) are still not fully understood. A better understanding is not only interesting in its own right, but it is also important for modeling hierarchical structure growth and for using cluster surveys to determine cosmological parameters.

Aims. To determine if there exists any evidence for evolution in the temperature or iron abundance gradients between z 0.14 and z 0.8, therefore elucidating the origin of energy and metal input to the ICM.

Methods. By using a sample of 35 observations of 31 clusters of galaxies found in the archival data of Chandra and XMM-Newton with redshifts between 0.14 and 0.89, we derived the temperature and iron abundance radial profiles. To compare clusters with similar properties, the data were divided into comparable subsets.

Results. There is no substantial evidence to suggest that the iron abundance radial profiles in galaxy clusters evolve with redshift in any of the chosen subsets. Temperature radial profiles also do not appear to be changing with redshift once selection effects are taken into account.

Conclusions. The lack of evolution in the iron profiles is consistent with scenarios where the galaxies in clusters are stripped of their gas at higher redshifts. The temperature and iron abundance profiles also suggest that the primary source of heating in high redshift clusters is the gravitational infall of mass. These findings further emphasize the importance of modeling the local environment of clusters in cosmological studies and have important implications for studies that go to larger redshifts.