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A&A 365, L80-L86 (2001)
DOI: 10.1051/0004-6361:20000017

Measuring cluster temperature profiles with XMM/EPIC

M. Arnaud¹, D. M. Neumann¹, N. Aghanim², R. Gastaud³, S. Majerowicz¹ and J. P. Hughes^1,4.

¹  CEA/DSM/DAPNIA Saclay, Service d'Astrophysique, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France
²  IAS-CNRS, Université Paris Sud, Bât. 121, 91405 Orsay Cedex, France
³  CEA/DSM/DAPNIA Saclay, Service d'Électronique et d'Informatique, 91191 Gif-sur-Yvette, France
⁴  Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019, USA

(Received 2 October 2000 / Accepted 4 November 2000)

Abstract
Using the PV observation of A1795, we illustrate the capability of XMM-EPIC to measure cluster temperature profiles, a key ingredient for the determination of cluster mass profiles through the equation of hydrostatic equilibrium. We develop a methodology for spatially resolved spectroscopy of extended sources, adapted to XMM background and vignetting characteristics. The effect of the particle induced background is discussed. A simple unbiased method is proposed to correct for vignetting effects, in which every photon is weighted according to its energy and location on the detector. We were able to derive the temperature profile of A1795 up to 0.4 times the virial radius. A significant and spatially resolved drop in temperature towards the center ( ) is observed, which corresponds to the cooling flow region of the cluster. Beyond that region, the temperature is constant with no indication of a fall-off at large radii out to 1.2 Mpc.

Key words: galaxies: clusters: individual: A1795 - galaxies: intergalactic medium - Cosmology: observations - Cosmology: dark matter - X-rays: general

Offprint request: M. Arnaud, marnaud@discovery.saclay.cea.fr

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