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J/A+A/361/429       Baryon content of groups and clusters    (Roussel+, 2000)

The baryon content of groups and clusters of galaxies Roussel H., Sadat R., Blanchard A. <Astron. Astrophys. 361, 429 (2000)> =2000A&A...361..429R
ADC_Keywords: Clusters, galaxy ; X-ray sources Keywords: cosmology: observations - galaxies: clusters: general - X-rays: general Abstract: 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. Description: Tables 1 and 2 summarize the data taken from the literature (except for A665, whose X-ray parameters were derived by us) used for our study. Tables 3 and 5 present some dynamical quantities for each cluster or group, in the frame of two different normalizations of the scaling law used to compute the virial radius (EMN : Evrard, Metzler & Navarro, 1996ApJ...469..494E ; BN : Bryan & Norman , 1998ApJ...495...80B) Tables 4 and 6 contain average quantities, as a function of temperature category (groups, cool clusters and hot clusters) and at three different density contrasts, again with either EMN or BN normalization. Results emphasize differences arising from the use of two mass estimators, SLM (for scaling law model) and IHE (for isothermal hydrostatic equilibrium). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 100 35 X-ray data. Parameters refer to Eq. 8 and 9 of the paper. table2.dat 80 33 Optical data. The first part corresponds to the galaxy spatial distribution and the second part to the luminosity function (Eq. 5). table3.dat 51 33 Dynamical quantities for the whole sample, at the limiting radius r200 and with the r500-TX normalization of EMN (the redshift is taken into account in this relationship). table4.dat 75 12 Average dynamical quantities for the objects with the most reliable data (details on those that have been discarded can be found in the paragraph ``notes on individual clusters''), using the EMN normalization and at various limiting radii. table5.dat 51 33 Same as Table 3, but with the r200-TX normalization of BN table6.dat 75 12 Same as Table 4, but using the BN normalization. refs.dat 52 44 References
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Name Name(s) of cluster (abbreviated) 11- 17 F7.5 --- z ? Redshift 20- 24 F5.2 keV TX ? Intracluster gas temperature 27- 30 F4.2 keV E_TX ? Upper error on TX (1) 33- 36 F4.2 keV e_TX ? Lower error on TX (1) 39- 43 A5 --- r_TX Reference code for TX (2) 46- 49 F4.2 Mpc RXlim ? Limiting radius of X-ray emission (3) 52- 56 F5.3 --- beta Slope of gas profile (4) 59- 63 F5.3 Mpc rcX Core radius (4) 66- 70 F5.2 10-3cm-3 ne0 Central electron density (4) 73- 83 A11 --- r_beta Reference codes for gas profile (2) 86-100 A15 --- Names Other name or complete name for RXJ
Note (1): When only E_TX is given, the error bar is symmetric. Temperature error bars of clusters are computed from different reliable references (taking into account or not a cooling flow) as the maximum of two estimates : the dispersion among the measures and the quadratic mean of the quoted uncertainties (this procedure produces a large uncertainty when there exists a possibility for a strong temperature gradient). They are given at a 90% confidence level, multiplying when necessary 1σ errors by 1.64 (the errors of Fornax and RX J1340.6 given by I96 and PA94, which confidence levels are not stated, are assumed to be 1σ). Note (2): Codes are explicited in refs.dat file. Note (3): When no limiting radius is given, we assumed RXlim(Mpc)=TX/3(keV), a relationship calibrated on other clusters. Note (4): Fornax and HCG 62 have got a two-component gas density profile, parameters of the second entry corresponding to the core.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Name Name of cluster (abbreviated) 10- 12 A3 --- TOP [(1-4)] Type of optical profile (1) 15- 21 F7.2 --- sigma0 Normalization of optical profile (2) 24- 30 F7.5 Mpc rc Scale radius (3) 33- 37 F5.3 --- epsilon ? Slope (4) 40- 45 F6.2 --- MBlim ? Limiting blue magnitude of observations 48- 58 A11 --- r_sigma0 References for optical profile (5) 62- 67 F6.2 --- MB* ? Charac. B magnitude of luminosity function 70- 73 F4.2 --- alpha ? Slope of luminosity function 76- 80 A5 --- r_TOP Reference code for luminosity function (5)
Note (1): the types are designated by: (1) : King form (Eq. 2 of the paper) (2) : de Vaucouleurs form (Eq. 3) (3) : integrated luminosity profile (Eq. 7) (4) : de Vaucouleurs projected luminosity density profile (cf Eq. 3) Note (2): normalizations are defined, depending on TOP value: for TOP = (1) or (2) : sigma0 (unit : number of galaxies Mpc-2) for TOP = (3) : L0 (unit : 1011LBsun) for TOP = (4) : sigmaL0_ (unit : 1011LB(sun)/Mpc2) Note (3): for TOP = (2) or (4), corresponds to the parameter rV (Eq. 3) Note (4): for TOP = (2) or (4), corresponds to the parameter gamma (Eq. 3) Note (5): Codes are explicited in refs.dat file.
Byte-by-byte Description of file: table3.dat table5.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Name Name of cluster (abbreviated) 10- 13 F4.2 Mpc r200 Virial radius 16- 21 F6.2 10+13solMass Mtot Total gravitating mass at r200 (1) 24- 28 F5.2 10+13solMass Mgas Gas mass at r200 (1) 31- 34 F4.2 10+13solMass M* Stellar mass at r200 (1) 37- 40 F4.1 % fb Baryon fraction at r200 43- 45 I3 solMass/solLum M/LB Mass to blue luminosity ratio at r200 (1) 48- 51 F4.2 --- MIHE/MSLM Comparison of the two estimators
Note (1): The scalings with the Hubble constant are : M_tot and M_* ∝ h-1, Mgas ∝ h-5/2 and L ∝ h-2.
Byte-by-byte Description of file: table4.dat table6.dat
Bytes Format Units Label Explanations
1- 13 A13 --- Class Category according to TX (1) 16- 21 A6 --- rdelta Limit in density contrast (2) 24- 27 F4.1 % fgas(SLM) Gas fraction (SLM estimator) 30- 33 F4.1 % fb(SLM) Baryon fraction 36- 39 F4.1 --- Mgas/M*(SLM) Gas to stellar mass ratio 42- 46 F5.1 --- Mtot/M*(SLM) Total to stellar mass ratio 49- 51 I3 solMass/solLum M/LB(SLM) Mass to blue luminosity ratio 54- 57 F4.1 % fgas(IHE) Gas fraction (IHE estimator) 60- 63 F4.1 % fb(IHE) Baryon fraction 66- 70 F5.1 --- Mtot/M*(IHE) Total to stellar mass ratio 73- 75 I3 solMass/solLum M/LB(IHE) Mass to blue luminosity ratio
Note (1): Groups are defined by TX<2keV and hot clusters by TX>5keV. Note (2): Dynamical quantities are given at the virial radius r200 (from SLM) but also at two other ones : r500, the radius within which EMN claim that the hydrostatic equilibrium is universally reached ; r2000 which we preferred to use because this represents the maximal extent of X-ray observations that is valid for the whole sample, including groups.
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Code Reference code 9- 27 A19 --- Bibcode Bibcode 29- 52 A24 --- Aut Author's name
Acknowledgements: Helene ROUSSEL
(End) Patricia Bauer [CDS] 05-Oct-2000
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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