[Normal Galaxies, Clusters of Galaxies -- Oral ]
AGN feedback in galaxy groups: The case of HCG 62
Myriam Gitti, SAO-CfA
E. O'Sullivan (SAO-CfA, Birmingham Univ.), S. Giacintucci (SAO-CfA), L. David (SAO-CfA), J. Vrtilek (SAO-CfA), S. Raychaudhury (Birmingham Univ.), C. Jones(SAO-CfA), W. Forman(SAO-CfA)
As a part of an ongoing study of 18 groups of galaxies showing
evidence for AGN/hot gas interaction, we report on the results of an
analysis of Chandra, XMM and GMRT data of the X-ray bright compact group
HCG 62. This is one of the few groups known to possess very clear, small
X-ray cavities in the inner regions. The ~50 ks Chandra image combined
with the new ~100 ks XMM exposure of HCG 62 allow us to derive with
unprecedented accuracy the radial profiles and 2-D distribution of
temperature, density and metal abundances. At higher frequency (1.4 GHz
or above) the cavities show minimal if any radio emission, but the radio
is clearly detected in the cavities with the new GMRT data at lower
frequency (610 MHz and below). By means of the synergy of X-ray and
low-frequency radio observations we compare and discuss the morphology,
luminosity and pressure of the gas and of the radio source. We find that
the cavities are close to pressure balance, and that the jets have a
"light" hadronic content. Thanks to the high spatial resolution of the
Chandra surface brightness and temperature profiles, we also identify a
shock front located around 35 kpc to the south-west of the group center,
with a Mach number ~1.45 and E_shock ~ 3 x E_cavities. Such a shock may
have significantly heated the gas close to the southern cavity, as
indicated by the temperature map.