15/09/2004 – Auditório Principal Bloco G – IAG/USP
Dra. Florence Durret
Instituto de Astrofísica de Paris (IAP) – França
Título/Title: Diffuse sources and stellar populations in clusters of galaxies
Resumo/Abstract:
| I will present two
recent papers concerning clusters of galaxies. The first one concerns the search for large scale diffuse emission in the Coma cluster, performed with a new method based on an iterative multi scale wavelet analysis and reconstruction technique which allows to model all the sources (stars and galaxies) and subtract them from the original images. Four concentrations of diffuse emission have been found in the central zone around the two giant galaxies. We characterize their properties and discuss their star formation rates and possible origins, and use these characteristics to trace the cluster dynamics. In the second work, we have analyzed spectroscopically 54 galaxies in the direction of the cluster Cl 0048-2942 (at redshift z ~0.64), out of which 23 are in the cluster. Stellar population synthesis shows population gradients in the cluster with intermediate/old populations in the centre and younger populations in the outskirts; field galaxies seem to host less evolved stellar populations. The percentage of K+A galaxies in our sample, based on stellar population synthesis results, is consistent with other estimates. |
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