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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)