A&A 442, 827-839 (2005)

DOI: 10.1051/0004-6361:20053306

## XMM-Newton study of the two-dimensional structure of the REFLEX-DXL galaxy clusters

**A. Finoguenov, H. Böhringer and Y.-Y. Zhang**

Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany

e-mail: alexis@xray.mpe.mpg.de

(Received 25 April 2005 / Accepted 20 June 2005 )

** Abstract **

We carry out a two-dimensional study of temperature, entropy, and
pressure distributions in a nearly volume-limited subsample of REFLEX
clusters at redshift 0.3, the REFLEX-DXL. We use the observations gained by
XMM-Newton, which cover the central
. We define the
substructure in both entropy and pressure as a deviation from the mean
profile of the sample. The non-parametric locally weighted regression
suggests a broken power-law approximation to the entropy profile with inner
and outer slopes of 0.78 and 0.52, respectively, and a break at
0.5*r*_{500}. Characterization of the pressure profile is more complex,
requiring three power laws, with slopes -0.64 at
*r*<0.3*r*_{500}, -2.47
at
*r*>0.5*r*_{500} and a slope of -1.50 in between. Analysis of the
substructure in the pressure and entropy maps reveals somewhat larger
fluctuations around the mean pressure profile compared to the
entropy. Typically, pressure fluctuations are found at the 30% level, while
the entropy fluctuations are at the 20% level (rms). We compare the
cumulative distribution of the substructure level in the REFLEX-DXL sample
with the results of numerical simulation, and by means of KS test, show that
they are in agreement. A discussion of the origin of the substructure is
provided on an individual cluster basis.

**Key words:**cosmology: observations

**--**galaxies: clusters: general

SIMBAD Objects

**©**

*ESO 2005*