Fundación Galileo Galilei - INAF Telescopio Nazionale Galileo 28°45'14.4N 17°53'20.6W 2387.2m A.S.L.

Seminars at FGG

Galaxy Clusters with Radio Halos/Relics: their Internal Dynamics and Constrains on Cluster Evolution.

Speaker: Marisa Girardi (Dipart. di Fisica, Universitá di Trieste)

Date and time: 2011-11-24 11:30

Extended, diffuse radio emissions (halos and relics) embedded in galaxy clusters are rare phenomena. Here I present the results of the DARC program, aimed to study the internal Dynamics Analysis of "Radio"-Clusters mainly based on a TNG program (spectroscopic data for 20 clusters at z=0.1-0.3). The study of kinematics of member galaxies prove that DARC clusters are examples of very massive (>10EXP15 solar masses), substructured systems likely catched during their formation via a cluster-cluster merger. Optical data allow to detect and weight the intervening subclusters as well as to determine their relative motions and projected geometry. The observational scenario agrees with a short time (a few Gy) elapsed after the core-core passage as expected in the case of a radio emission generated by the shock waves or turbulence related to the cluster-cluster merger.