2000A&A...361..429R


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.18CET06:38:57

2000A&A...361..429R - Astronomy and Astrophysics, volume 361, 429-443 (2000/9-2)

The baryon content of groups and clusters of galaxies.

ROUSSEL H., SADAT R. and BLANCHARD A.

Abstract (from CDS):

We have analyzed the properties of a sample of 33 groups and clusters of galaxies for which both optical and X-ray data were available in the literature. This sample was built to examine the baryon content and to check for trends over a decade in temperature down to 1keV. We examine the relative contribution of galaxies and ICM to baryons in clusters through the gas-to-stellar mass ratio (Mgas/M*). We find that the typical stellar contribution to the baryonic mass is between 5 and 20%, at the virial radius. The ratio (Mgas/M*) is found to be roughly independent of temperature. Therefore, we do not confirm the trend of increasing gas-to-stellar mass ratio with increasing temperature as previously claimed. We also determine the absolute values and the distribution of the baryon fraction with the density contrast δ with respect to the critical density. Virial masses are estimated from two different mass estimators: one based on the isothermal hydrostatic equation (IHE), the other based on scaling law models (SLM), the calibration being taken from numerical simulations. Comparing the two methods, we find that SLM lead to less dispersed baryon fractions over all density contrasts and that the derived mean absolute values are significantly lower than IHE mean values: at δ=500, the baryon fractions (gas fractions) are 11.5-13.4% (10.3-12%) and ∼20% (17%) respectively. We show that this is not due to the uncertainties on the outer slope β of the gas density profile but is rather indicating that IHE masses are less reliable. Examining the shape of the baryon fraction profiles, we find that cluster baryon fractions estimated from SLM follow a scaling law. Moreover, we do not find any strong evidence of increasing baryon (gas) fraction with temperature: hotter clusters do not have a higher baryon fraction than colder ones, neither do we find the slope β to increase with temperature. The absence of clear trends between fb and Mgas/M* with temperature is consistent with the similarity of baryon fraction profiles and suggests that non-gravitational processes such as galaxy feedback, necessary to explain the observed luminosity-temperature relationship, do not play a dominant role in heating the intra-cluster gas on the virial scale.

Abstract Copyright:

Journal keyword(s): cosmology: observations - galaxies: clusters: general - X-rays: general

VizieR on-line data: <Available at CDS (J/A+A/361/429): refs.dat table1.dat table2.dat table3.dat table4.dat table5.dat>

Simbad objects: 34

goto View the reference in ADS

Number of rows : 34

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 76 ClG 00 40 16.1031 +06 52 46.226           ~ 127 2
2 ACO 85 ClG 00 41 37.8 -09 20 33           ~ 798 0
3 ACO 119 ClG 00 56 16.8 -01 15 00           ~ 523 2
4 NAME NGC 533 Group GrG 01 25 29.1 +01 48 17           ~ 56 0
5 NGC 533 GiG 01 25 31.432 +01 45 33.57   13.1 14.11     ~ 208 0
6 2MAXI J0254+416 ClG 02 54 32.2 +41 35 10           ~ 298 1
7 ACO 401 ClG 02 58 56.9 +13 34 56           ~ 523 0
8 ACO 426 ClG 03 19 47.2 +41 30 47           ~ 1988 1
9 ACO S 373 ClG 03 38 30 -35 27.3           ~ 1581 0
10 ACO 576 ClG 07 21 24.1 +55 44 20           ~ 286 1
11 NGC 2300 IG 07 32 20.486 +85 42 31.90   12.2       ~ 317 0
12 ACO 665 ClG 08 30 45.2 +65 52 55           ~ 403 0
13 ACO 780 ClG 09 18 30 -12 15.7           ~ 437 0
14 NAME Hydra I Cluster ClG 10 36 36.0 -27 31 04           ~ 781 1
15 ACO 1377 ClG 11 47 15.66 +55 43 01.6           ~ 137 1
16 ACO 1413 ClG 11 55 18.0 +23 24 19           ~ 384 0
17 NGC 4261 LIN 12 19 23.2160630 +05 49 29.700024   13.92 12.87     ~ 1130 0
18 HCG 62 CGG 12 53 05.6 -09 12 21           ~ 295 0
19 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4298 2
20 ACO 1689 ClG 13 11 29.5 -01 20 28           ~ 1034 0
21 NGC 5044 BiC 13 15 23.969 -16 23 08.00   11.9   10.74   ~ 459 0
22 RX J1340.6+4018 G 13 40 33.4 +40 17 48           ~ 41 1
23 ACO 1775 ClG 13 41 55.6 +26 21 53           ~ 277 0
24 ACO 2029 ClG 15 10 58.7 +05 45 42           ~ 866 0
25 ACO 2052 ClG 15 16 45.5 +07 00 01           ~ 684 1
26 ACO 2063 ClG 15 23 01.8 +08 38 22           ~ 372 2
27 ACO 2163 ClG 16 15 34.1 -06 07 26           ~ 523 0
28 ACO 2199 ClG 16 28 37.0 +39 31 28           ~ 1111 1
29 ACO 2218 ClG 16 35 54.0 +66 13 00           ~ 782 1
30 ACO 2256 ClG 17 03 43.5 +78 43 03           ~ 836 1
31 HCG 94 CGG 23 17 16.5 +18 43 11           ~ 76 0
32 ACO 2634 ClG 23 38 18.4 +27 01 37           ~ 485 2
33 ACO 2657 ClG 23 44 51.0 +09 08 40           ~ 262 3
34 ACO 2670 ClG 23 54 13.64 -10 25 08.7           ~ 338 0

    Equat.    Gal    SGal    Ecl

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2021.01.18-06:38:57

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