The AGN outburst and merger in HCG 62

We report on an analysis of new Chandra data of the galaxy group HCG 62, well
known for possessing cavities in its intragroup medium (IGM) inflated by the radio lobes of
its central active galactic nucleus (AGN). With the new data, a factor of three deeper than
previous Chandra data, we re-examine the energetics of the cavities and determine new
constraints on their contents. We confirm that the ratio of radiative to mechanical power
of the AGN outburst that created the cavities is less than 10-4, among the lowest of any
known cavity system, implying that the relativistic electrons in the lobes can supply only a
tiny fraction of the pressure required to support the cavities. This finding implies additional
pressure support in the lobes from heavy particles or thermal gas, and we place new constraints
on the presence of thermal gas in the cavities. Lastly, we report additional evidence
for a recent merger in the surface brightness, temperature, and metallicity structure of the
ICM.