Measuring cluster temperature profiles with XMM/EPIC *,**
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
Corresponding author: M. Arnaud, marnaud@discovery.saclay.cea.fr
Received:
2
October
2000
Accepted:
4
November
2000
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
Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).
EPIC was developed by the EPIC Consortium led by the Principal Investigator, Dr. M. J. L. Turner. The consortium comprises the following Institutes: University of Leicester, University of Birmingham, (UK); CEA/Saclay, IAS Orsay, CESR Toulouse, (France); IAAP Tuebingen, MPE Garching, (Germany); IFC Milan, ITESRE Bologna, IAUP Palermo, Italy. EPIC is funded by: PPARC, CEA, CNES, DLR and ASI.
© ESO, 2001