XMM–NEWTON observation of Abell 1835: Temperature, mass and gas mass fraction profiles

¹ CEA/Saclay, Service d'Astrophysique, L'Orme des Merisiers, Bât. 709, 91191 Gif–sur–Yvette Cedex, France
² Max–Planck Institut für extraterrestrische Physik, PO Box 1312, 85741 Garching, Germany
³ Department of Astronomy, University of Virginia, PO Box 3818, 530 McCormick Road, Charlottesville, VA 22903-0818, USA

Corresponding author: S. Majerowicz, smajerowicz@cea.fr

Received: 19 February 2002
Accepted: 1 August 2002

Abstract

We present a study of the medium distant cluster of galaxies Abell 1835 based on Xmm–newton data. The high quality of Xmm–newton data enable us to perform spectro-imaging of the cluster up to large radii. We determine the gas and total mass profiles based on the hydrostatic approach using the β-model and the temperature profile. For the determination of the temperature profile of the icm, which is needed for the mass determination, we apply a double background subtraction, which accounts for the various kinds of background present (particle and astrophysical background). We find a basically flat temperature profile up to 0.75 r₂₀₀ with a temperature decrease towards the center linked to the cooling flow. We obtain a gas mass fraction of ()%, which is a lower limit on the baryon fraction in this cluster. Using this value as baryon fraction for the entire Universe, we obtain by combining our results with results based on primordial nucleosynthesis, an upper limit for , which is in good agreement with other recent studies.