SEMINAR ANNOUNCEMENT: OATs-DAUT Seminar on Wednesday March 26th (tomorrow) at 12:00 noon, Villa Bazzoni

[Gabriella Schiulaz]

*********************************************************** 
                     OATS-DAUT SEMINAR 
*********************************************************** 


Speaker: Elena RASIA (Univ. of Michingan) 

Title: Studying scaling relation of galaxy clusters and their scatter. 

Date: Wednesday, March 26th, 2008 
Time: 12:00 
Venue: Villa Bazzoni 

*********************************************************** 
Abstract: In next few years large sky surveys will be underway with the aim of identifying and characterizing galaxy clusters over large portion of the sky. The astronomical community will deal with tens thousands of clusters observed in optical (e.g., with DES survey), millimetric (e.g., with South Pole Telescope survey) or X-ray (e.g., with e-Rosita mission). With this ambitious and promising expectation in mind, now it is the right time to investigate the systematics that could affect the analysis of real data and provide a concrete framework for the statistical studies we will performed. To address questions both of cosmology and the smaller-scale astrophysics, we are deciphering the various connections among observable cluster properties, the intrinsic quantities, and the underlying mass distribution including this evolution with redshift. I will present some first result based on one single bullet-like cluster and on a large cosmological sample. 
*********************************************************** 
contact: Stefano Borgani (DAUT) 



Next week seminar:

*********************************************************** 
OATS-DAUT SEMINAR 
*********************************************************** 
Speaker: Pavel Kroupa (Argelander-Institut fuer Astronomie (AIfA), Bonn University) 

Title: Are the dSph satellite galaxies tidal-dwarfs? 

Date: Wednesday, April 2nd, 2008 
Time: 12:00 
Venue: Villa Bazzoni 

*********************************************************** 
Abstract: 
The Milky Way has about 15 low-mass dwarf-spheroidal (dSph) satellites. These have luminosities and internal velocity dispersions similar to globular clusters but are about 100 times larger. The usual interpretation is that these objects are dark-matter dominated: the stars are located in the innermost regions of 10-100 times more massive dark-matter sub-halos. However, many of the dSph satellites are sub-structured and appear to be distorted. Such distortions are most readily explained if the satellites are significantly affected by the Milky Way tide such that dark matter does not significantly shield them. Furthermore, the satellites are distributed in a relatively thin plane extending to 250 kpc which is highly inclined to the disk of the Milky Way. This plane appears to be rotationally supported. This is most readily explained if the dSph satellites are causally related, i.e. if they share a common orbital angular momentum vector. All of this can be understood within a conservative framework, in which early galaxy-galaxy encounters produce tidal-dwarf galaxies. Applied to the Milky Way this suggests an early (about 10 Gyr ago) encounter which left a population of related TDGs in orbit. 
*********************************************************** 
contact: Simone Recchi (OATS) 



 
For additional information on OAT seminars see:
http://adlibitum.oats.inaf.it/seminari/ 

Gabriella Schiulaz
segreteria OAT
Phone: 040-3199241
schiulaz at oats.inaf.it
segreteria at oats.inaf.it