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OATS-UNI/TS SEMINAR
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Speaker: Mariangela Bernardi (Dept. Physics & Astronomy, Univ. of Pennsylvania)

Title: Massive galaxies in massive datasets
Date: Wednesday, February 23rd, 2011
Time: 15:00
Venue: Villa Bazzoni

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Abstract: Understanding why massive early-type galaxies are red and dead has proved to be difficult. This has been the source of tension with hierarchical formation models, such as the Cold Dark Matter model, in which massive objects are formed from mergers of smaller ones which existed at early times. The problem is to arrange for star formation to occur at higher redshift than the actual assembly of the stars into a single massive galaxy. The most recent galaxy formation models arrange for this to happen by a combination of two processes: dry mergers and AGN feedback (or other mechanisms of quenching star formation). I will discuss a number of results on massive galaxies in the SDSS which suggest that two mass scales, M* = 3 10^10 and 2 10^11 Msun, are special. The smaller scale could mark the transition between wet and dry mergers, or it could be related to the interplay between SNe and AGN feedback; the larger scale could mark the transition above which major dry mergers dominate the assembly histories of early-type galaxies. I will also discuss how the Brightest Cluster Galaxies and other extreme objects in the SDSS and other recent astrophysical datasets fit into this picture.
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contact: Valentina D'Odorico (INAF - OAT)