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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Star-formation efficiency and metal enrichment of the intracluster medium in local massive clusters of galaxies

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Autor(es):
Zhang, Y. -Y. [1, 2] ; Lagana, T. F. [1, 3] ; Pierini, D. [4] ; Puchwein, E. [5, 6] ; Schneider, P. [1] ; Reiprich, T. H. [1]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Bonn, Argelander Inst Astron, D-53121 Bonn - Germany
[2] Chinese Acad Sci, Natl Astron Observ, Beijing 100012 - Peoples R China
[3] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Astron, BR-05508090 Sao Paulo - Brazil
[4] Max Planck Inst Extraterr Phys, D-85748 Garching - Germany
[5] Max Planck Inst Astrophys, D-85741 Garching - Germany
[6] Heidelberger Inst Theoret Studien, D-69118 Heidelberg - Germany
Número total de Afiliações: 6
Tipo de documento: Artigo Científico
Fonte: Astronomy & Astrophysics; v. 535, NOV 2011.
Citações Web of Science: 26
Resumo

We have investigated the baryon-mass content in a subsample of 19 clusters of galaxies extracted from the X-ray flux-limited sample HIFLUGCS according to their positions in the sky. For these clusters, we measured total masses and characteristic radii on the basis of a rich optical spectroscopic data set, the physical properties of the intracluster medium (ICM) using XMM-Newton and ROSAT X-ray data, and total (galaxy) stellar masses utilizing the SDSS DR7 multi-band imaging. The observed (hot) gas-mass fractions are almost constant in this mass range. We confirm that the stellar mass fraction decreases as the total mass increases and shows (20 +/- 4)% scatter; in addition, we show that it decreases as the central entropy increases. The latter behavior supports a twofold interpretation, where heating from merging quenches the star-formation activity of galaxies in massive systems, and feedback from supernovae and/or radio galaxies drives a significant amount of gas to the regions beyond r(500) or, alternatively, a substantially large amount of intracluster light (ICL) is associated with galaxies in nonrelaxed systems. Furthermore, less massive clusters are confirmed to host less gas per unit total mass; however, they exhibit higher mass fractions in metals, so that their ICM is more metal-rich. This again supports the interpretation that in the potential wells of low-mass systems the star-formation efficiency of galaxies was high or, alternatively, some gas is missing from the hot phase of the ICM. The former hypothesis is preferred as the main driver of the mass-dependent metal enrichment since the total mass-to-optical luminosity ratio increases as the total mass increases. (AU)

Processo FAPESP: 08/04318-7 - Enriquecimento do gás intra-aglomerado e a eficiência de formação estelar em aglomerados de galáxias
Beneficiário:Tatiana Ferraz Laganá
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 06/56213-9 - Nova física no espaço: formação e evolução de estruturas no universo
Beneficiário:Claudia Lucia Mendes de Oliveira
Linha de fomento: Auxílio à Pesquisa - Temático