Astronomy & Astrophysics

Free access article

A&A 433, 101-111 (2005)
DOI: 10.1051/0004-6361:20041888

Temperature and entropy profiles of nearby cooling flow clusters observed with XMM-Newton

R. Piffaretti^{1, 2}, Ph. Jetzer¹, J. S. Kaastra³ and T. Tamura^{3, 4}

¹ Institute of Theoretical Physics, University of Zürich, Winterthurerstrasse, 190, 8057 Zürich, Switzerland
e-mail: piff@physik.unizh.ch
² Laboratory for Astrophysics, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
³ SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
⁴ Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan

(Received 24 August 2004 / Accepted 1 December 2004 )

Abstract
We investigate temperature and entropy profiles of 13 nearby cooling flow clusters observed with the EPIC cameras of XMM-Newton. When normalized and scaled by the virial radius the temperature profiles turn out to be remarkably similar. At large radii the temperature profiles show a clear decline starting from a break radius at ~ $0.1 \, r_{{\rm vir}}$ . The temperature decreases by ~ $30 \%$ between $0.1 \, r_{{\rm vir}}$ and $0.5 \, r_{{\rm vir}}$ . As expected for systems where non-gravitational processes are of great importance, the scale length characterizing the central temperature drop is not found to be proportional to the virial radius of the system. The entropy of the plasma increases monotonically moving outwards almost proportional to the radius and the central entropy level is tightly correlated with the core radius of the X-ray emission. The dispersion in the entropy profiles is smaller if the empirical relation $S \propto T^$ is used instead of the standard self-similar relation $S \propto T$ and, as expected for cooling flow clusters, no entropy cores are observed.

Key words: galaxies: clusters: general -- cooling flows -- X-rays: galaxies: clusters

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