XMM observation of the dynamically young galaxy cluster CL 0939+4713

¹ Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD, UK
² Center for Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Building 37, Cambridge, MA 02139, USA
³ Institut für Astrophysik, Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
⁴ Dpto. Física Teórica y del Cosmos, Universidad de Granada, Avda. Fuentenueva s/n, 18002 Granada, Spain

Corresponding author: E. De Filippis, bdf@space.mit.edu

Received: 13 August 2002
Accepted: 24 March 2003

Abstract

We present an XMM observation of the distant galaxy cluster CL 0939+4713. The X-ray image shows pronounced substructure, with two main subclusters which have even some internal structure. This is an indication that the cluster is a dynamically young system. This conclusion is supported by the temperature distribution: a hot region is found between the two main subclusters indicating that they are at the beginning of a major merger, and that they will probably collide in a few hundreds of Myr. The intra-cluster gas of CL 0939+4713 shows inhomogeneities in the metal distribution, with the optically richer subcluster having a higher metallicity.