2008A&A...479..307B


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.08CET08:29:44

2008A&A...479..307B - Astronomy and Astrophysics, volume 479, 307-320 (2008/2-4)

Temperature structure of the intergalactic medium within seven nearby and bright clusters of galaxies observed. with XMM-Newton.

BOURDIN H. and MAZZOTTA P.

Abstract (from CDS):

Using a newly developed algorithm, we map, to the highest angular resolution allowed by the data, the temperature structure of the intra-cluster medium (ICM) within a nearly complete X-ray flux limited sample of galaxy clusters in the redshift range between z=0.045 and z=0.096. Our sample contains seven bright clusters of galaxies observed with XMM-Newton: Abell 399, Abell 401, Abell 478, Abell 1795, Abell 2029, Abell 2065, Abell 2256. We use a multi-scale spectral mapping algorithm especially designed to map spectroscopic observables from X-ray extended emission of the ICM. By means of a wavelet analysis, this algorithm couples spatially resolved spectroscopy with a structure detection approach. Derived from a former algorithm using Haar wavelets, our algorithm is now implemented with B-spline wavelets in order to perform a more regular analysis of the signal. Compared to other adaptive algorithms, our method has the advantage of analysing spatially the gas temperature structure itself, instead of being primarily driven by the geometry of gas brightness. For the four clusters in our sample that are major mergers, we find a rather complex thermal structure with strong thermal variations consistent with their dynamics. For two of them, A2065 and A2256, we perform a 3-d analysis of cold front-like features evidenced from the gas temperature and brightness maps. Furthermore, we detect a significant non-radial thermal structure outside the cool core region of the other 3 more ``regular'' clusters, with relative amplitudes of about about 10% and typical sizes ranging between 2 and 3-arcmin. We investigate possible implications of this thermal structure on the mass estimates, by extracting the surface brightness and temperature profiles from complementary sectors in the ``regular'' clusters A1795 and A2029, corresponding to hottest and coldest regions in the maps. For A2029, the temperature and surface brightness gradients seem to compensate each other, leading to a consistent mass profile. For A1795, however, the temperature structure leads to a significant mass discrepancy in the innermost cluster region. The third ``regular'' cluster, A478, is located in a particular sky region characterised by strong variations of neutral hydrogen column density, Nh, even on angular scales smaller than the cluster itself. For this cluster, we derive a spectroscopic Nh map and investigate the origin of Nh structure by discussing its correlation with galactic emission of dust in the infrared.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: general - galaxies: intergalactic medium - X-rays: galaxies: clusters - techniques: image processing - techniques: spectroscopic

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 ACO 399 ClG 02 57 56.4 +13 00 59           ~ 354 0
2 ACO 401 ClG 02 58 56.9 +13 34 56           ~ 525 0
3 ACO 478 ClG 04 13 20.7 +10 28 35           ~ 476 0
4 NAME North Polar Spur ISM 12 00 +00.0           ~ 311 1
5 ACO 1795 ClG 13 49 00.5 +26 35 07           ~ 1179 0
6 ACO 2029 ClG 15 10 58.7 +05 45 42           ~ 872 0
7 ACO 2065 ClG 15 22 42.6 +27 43 21           ~ 348 0
8 ACO 2142 ClG 15 58 20.00 +27 14 00.3           ~ 685 0
9 ACO 2256 ClG 17 03 43.5 +78 43 03           ~ 839 1

    Equat.    Gal    SGal    Ecl

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