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A mid-IR study of Hickson Compact Groups I : Probing the Effects of Environment in Galaxy Interactions

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 نشر من قبل Bitsakis Theodoros
 تاريخ النشر 2010
  مجال البحث فيزياء
والبحث باللغة English
 تأليف T. Bitsakis




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Hickson Compact Groups (HCGs) are among the densest galaxy environments of the local universe. To examine the effects of the environment on the infrared properties of these systems, we present an analysis of Spitzer and ISO mid-infrared imaging as well as deep ground based near-infrared imaging of 14 HCGs containing a total of 69 galaxies. Based on mid-infrared color diagnostics we identify the galaxies which appear to host an active nucleus, while using a suite of templates, we fit the complete infrared spectral energy distribution for each group member. We compare our estimates of galaxy mass, star formation rate, total infrared luminosities, and specific star formation rates (sSFR) for our HCG sample, to samples of isolated galaxies and interacting pairs and find that overall there is no discernible difference among them. However, HCGs which can be considered as dynamically old, host late-type galaxies with a slightly lower sSFR than the one found in dynamically young groups. This could be attributed to multiple past interactions among the galaxies in old groups, that have led to the build up of their stellar mass. It is also consistent with our prediction for the presence of diffuse cold dust in the intergalactic medium of 9 of the dynamically old groups.



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