Radio properties of nearby groups of galaxies (1402.5109v1)

Abstract: Much of the evolution of galaxies takes place in groups where feedback has the greatest impact on galaxy formation. By using an optically selected, statistically complete sample of 53 nearby groups (CLoGS), observed in Radio (GMRT) and in X-rays (Chandra and XMM-Newton), we aim to characterize the radio-AGN population in groups and examine their impact on the intra-group gas and member galaxies. The sensitivity to older electron populations at 240 MHz and the resolution of 610 MHz is the key to identify past and current AGN activity. Here we will present first results from three different galaxy groups analysed so far. We report an age of ~18 Myr for the radio source 3C270 in NGC 4261 implying that the expansion was supersonic over a large fraction of its lifetime. In NGC 1060 we detect a small-scale (20''/7.4 kpc) jet source with the spectral index of $\alpha_{240}^{610}$=0.9 indicating a remnant of an old outburst. Lastly in NGC 5982 the 610 and 235 MHz observations find a radio point source in the central AGN with no evidence of jets or lobes and diffuse emission from the disks (star formation).