Stellar and total baryon mass fractions in groups and clusters since redshift 1 Export

@article{citeulike:4269378, abstract = {We investigate if the discrepancy between estimates of the total baryon mass fraction obtained from observations of the cosmic microwave background (CMB) and of galaxy groups/clusters persists when a large sample of groups is considered. To this purpose, 91 candidate X-ray groups/poor clusters at redshift 0.1\<z\<1 are selected from the COSMOS 2 deg^2 survey, based only on their X-ray luminosity and extent. This sample is complemented by 27 nearby clusters for which robust analogous determinations of the total and stellar mass inside R\_500 are available. The total sample of 118 groups and clusters with z\<1 spans a range in M\_500 of \~{}10^{13}-10^{15} Msun. We find that the stellar massfraction enclosed in galaxies at R\_500 decreases with increasing total mass as M\_500^{-0.37\pm 0.04},independent of redshift. Estimating the total gas mass fraction from a recently derived, high quality scaling relation, the total baryon mass fraction(f\_500^{stars+gas}=f\_{500}^{stars}+f\_{500}^{gas}) is found to increase by \~{}25\% when M{500} increases from \<M\>=5x10^{13} Msun to \<M\>= 7 x 10^14 Msun. After consideration of a plausible contribution due to intra--cluster light (16\% of the total stellar mass), and gas depletion through the hierarchical assembly process (10\% of the gas mass), the estimated values of the total baryon mass fraction are still lower than the latest CMB measure of the same quantity (WMAP5), at a significance level of 3.7 sigma for groups of \<M\>=5x10^13 Msun. The discrepancy decreases towards higher total masses, such that it is 1sigma at \<M\>= 7x10^{14} Msun. We discuss this result in terms of non-gravitational processes such as feedback and filamentary heating.}, archivePrefix = {arXiv}, author = {Giodini, S. and Pierini, D. and Finoguenov, A. and Pratt, G. W. and Boehringer, H. and Leauthaud, A. and Guzzo, L. and Aussel, H. and Bolzonella, M. and Capak, P. and Elvis, M. and Hasinger, G. and Ilbert, O. and Kartaltepe and Koekemoer, A. M. and Lilly, S. J. and Mccracken, H. J. and Salvato, M. and Sanders, D. B. and Scoville, N. Z. and Sasaki, S. and Smolcic, V. and Taniguchi, Y. and Thompson, D. and Collaboration, Cosmos}, citeulike-article-id = {4269378}, citeulike-linkout-0 = {http://arxiv.org/abs/0904.0448}, citeulike-linkout-1 = {http://arxiv.org/pdf/0904.0448}, day = {2}, eprint = {0904.0448}, keywords = {baryon, cosmos, stellar}, month = {Apr}, posted-at = {2009-04-03 08:59:41}, priority = {2}, title = {Stellar and total baryon mass fractions in groups and clusters since redshift 1}, url = {http://arxiv.org/abs/0904.0448}, year = {2009} }

TY - JOUR ID - citeulike:4269378 L3 - citeulike-article-id:4269378 N2 - We investigate if the discrepancy between estimates of the total baryon mass fraction obtained from observations of the cosmic microwave background (CMB) and of galaxy groups/clusters persists when a large sample of groups is considered. To this purpose, 91 candidate X-ray groups/poor clusters at redshift 0.1<z<1 are selected from the COSMOS 2 deg^2 survey, based only on their X-ray luminosity and extent. This sample is complemented by 27 nearby clusters for which robust analogous determinations of the total and stellar mass inside R_500 are available. The total sample of 118 groups and clusters with z<1 spans a range in M_500 of ~10^{13}-10^{15} Msun. We find that the stellar massfraction enclosed in galaxies at R_500 decreases with increasing total mass as M_500^{-0.37\pm 0.04},independent of redshift. Estimating the total gas mass fraction from a recently derived, high quality scaling relation, the total baryon mass fraction(f_500^{stars+gas}=f_{500}^{stars}+f_{500}^{gas}) is found to increase by ~25% when M{500} increases from <M>=5x10^{13} Msun to <M>= 7 x 10^14 Msun. After consideration of a plausible contribution due to intra--cluster light (16% of the total stellar mass), and gas depletion through the hierarchical assembly process (10% of the gas mass), the estimated values of the total baryon mass fraction are still lower than the latest CMB measure of the same quantity (WMAP5), at a significance level of 3.7 sigma for groups of <M>=5x10^13 Msun. The discrepancy decreases towards higher total masses, such that it is 1sigma at <M>= 7x10^{14} Msun. We discuss this result in terms of non-gravitational processes such as feedback and filamentary heating. TI - Stellar and total baryon mass fractions in groups and clusters since redshift 1 KW - baryon KW - cosmos KW - stellar AU - Giodini, S AU - Pierini, D AU - Finoguenov, A AU - Pratt, GW AU - Boehringer, H AU - Leauthaud, A AU - Guzzo, L AU - Aussel, H AU - Bolzonella, M AU - Capak, P AU - Elvis, M AU - Hasinger, G AU - Ilbert, O AU - Kartaltepe AU - Koekemoer, AM AU - Lilly, SJ AU - Mccracken, HJ AU - Salvato, M AU - Sanders, DB AU - Scoville, NZ AU - Sasaki, S AU - Smolcic, V AU - Taniguchi, Y AU - Thompson, D AU - Collaboration, Cosmos PY - 2009/Apr/02/ UR - http://arxiv.org/abs/0904.0448 ER -