2008A&A...484...51C


Query : 2008A&A...484...51C

2008A&A...484...51C - Astronomy and Astrophysics, volume 484, 51-65 (2008/6-2)

Warming rays in cluster cool cores.

COLAFRANCESCO S. and MARCHEGIANI P.

Abstract (from CDS):

Cosmic rays are confined in the atmospheres of galaxy clusters and, therefore, they can play a crucial role in the heating of their cool cores. We discuss here the thermal and non-thermal features of a model of cosmic ray heating of cluster cores that can provide a solution to the cooling-flow problems. To this aim, we generalize a model originally proposed by Colafrancesco, Dar & DeRujula (2004A&A...413..441C) and we show that our model predicts specific correlations between the thermal and non-thermal properties of galaxy clusters and enables various observational tests. The model reproduces the observed temperature distribution in clusters by using an energy balance condition in which the X-ray energy emitted by clusters is supplied, in a quasi-steady state, by the hadronic cosmic rays, which act as ``warming rays'' (WRs). The temperature profile of the intracluster (IC) gas is strictly correlated with the pressure distribution of the WRs and, consequently, with the non-thermal emission (radio, hard X-ray and gamma-ray) induced by the interaction of the WRs with the IC gas and the IC magnetic field. The temperature distribution of the IC gas in both cool-core and non cool-core clusters is successfully predicted from the measured IC plasma density distribution. Under this contraint, the WR model is also able to reproduce the thermal and non-thermal pressure distribution in clusters, as well as their radial entropy distribution, as shown by the analysis of three clusters studied in detail: Perseus, A2199 and Hydra. The WR model provides other observable features of galaxy clusters: a correlation of the pressure ratio (WRs to thermal IC gas) with the inner cluster temperature (PWR/Pth)~(kTinner)–2/3, a correlation of the gamma-ray luminosity with the inner cluster temperature Lγ~(kTinner)4/3, a substantial number of cool-core clusters observable with the GLAST-LAT experiment, a surface brightness of radio halos in cool-core clusters that recovers the observed one, a hard X-ray ICS emission from cool-core clusters that is systematically lower than the observed limits and yet observable with the next generation high-sensitivity and spatial resolution HXR experiments like Simbol-X. The specific theoretical properties and the multi-frequency distribution of the e.m. signals predicted in the WR model render it quite different from the other models so far proposed for the heating of clusters' cool-cores. Such differences make it possible to prove or disprove our model as an explanation for the cooling-flow problems on the basis of multi-frequency observations of galaxy clusters.

Abstract Copyright:

Journal keyword(s): cosmology: theory - galaxies: clusters: general - ISM: cosmic rays

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 ACO 133 ClG 01 02 39.0 -21 57 15           ~ 350 1
2 ACO 262 ClG 01 52 50.4 +36 08 46           ~ 675 1
3 ACO 426 ClG 03 19 47.2 +41 30 47           ~ 2093 1
4 RX J0821.0+0752 ClG 08 21 02.4 +07 51 47           ~ 56 1
5 NAME HYA SUPERCL SCG 08 57.9 +03 10           ~ 163 0
6 ACO 1650 ClG 12 58 36.76 -01 43 34.2           ~ 279 0
7 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4501 2
8 ClG J1347-1145 ClG 13 47 33.5 -11 45 42           ~ 503 0
9 ACO 1795 ClG 13 49 00.5 +26 35 07           ~ 1201 0
10 ACO 2163 ClG 16 15 34.1 -06 07 26           ~ 540 0
11 ACO 2199 ClG 16 28 37.0 +39 31 28           ~ 1128 1
12 ACO 2244 ClG 17 02 34.01 +34 04 41.1           ~ 255 0
13 ACO 2390 ClG 21 53 34.6 +17 40 11           ~ 651 2

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2022.05.20-23:56:19

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