ar X iv : a st ro - p h / 06 12 15 6 v 1 6 D ec 2 00 6 Flaring Activity of Sgr A * : Expanding Hot Blobs

ar X iv : a st ro - p h / 06 12 37 8 v 1 1 4 D ec 2 00 6 Magnetic fields , strings and cosmology

ar X iv : a st ro - p h / 06 12 42 6 v 1 1 5 D ec 2 00 6 Heating and Cooling in the Perseus Cluster Core

ar X iv : a st ro - p h / 06 12 17 5 v 1 7 D ec 2 00 6 Global MHD instabilities : from Low Frequency to High Frequency QPOs , and to Sgr A *

In this contribution I review recent work that goes beyond our model for the Low-Frequency Quasi-Periodic Oscillation of microquasars, based on the Accretion-Ejection Instability. I show that similar instabilities, which can be viewed as strongly unstable versions of the diskoseismologic modes, provide explanations for both the High-Frequency QPO and for the quasi-periodicity observed durng the...

ar X iv : a st ro - p h / 06 12 53 0 v 1 1 9 D ec 2 00 6 High sensitivity low frequency radio observations of cD galaxies

We present the GMRT 235 MHz images of three radio galaxies and 610 MHz images of two sources belonging to a complete sample of cD galaxies in rich and poor galaxy clusters. The analysis of the spectral properties confirms the presence of aged radio emission in two of the presented sources.

ar X iv : a st ro - p h / 06 07 12 3 v 1 7 J ul 2 00 6 Accretion models of Sgr A *

The supermassive black hole in the center of our Galaxy, Sgr A*, is unique because the angular size of the black hole is the largest in the sky thus providing detailed boundary conditions on, and much less freedom for, accretion flow models. In this paper I review advection-dominated accretion flow (ADAF; another name is radiatively inefficient accretion flow) models for Sgr A*. This includes t...