A Powerful AGN Outburst in RBS 797
  Utilizing $\sim 50$ ks of Chandra X-ray Observatory imaging, we present an
analysis of the intracluster medium (ICM) and cavity system in the galaxy
cluster RBS 797. In addition to the two previously known cavities in the
cluster core, the new and deeper X-ray image has revealed additional structure
associated with the active galactic nucleus (AGN). The surface brightness
decrements of the two cavities are unusually large, and are consistent with
elongated cavities lying close to our line-of-sight. We estimate a total AGN
outburst energy and mean jet power of $\approx 3 - 6 \times 10^{60}$ erg and
$\approx 3 - 6 \times 10^{45}$ erg s$^{-1}$, respectively, depending on the
assumed geometrical configuration of the cavities. Thus, RBS 797 is apparently
among the the most powerful AGN outbursts known in a cluster. The average mass
accretion rate needed to power the AGN by accretion alone is $\sim 1 M_{\odot}$
yr$^{-1}$. We show that accretion of cold gas onto the AGN at this level is
plausible, but that Bondi accretion of the hot atmosphere is probably not. The
BCG harbors an unresolved, non-thermal nuclear X-ray source with a bolometric
luminosity of $\approx 2 \times 10^{44}$ erg s$^{-1}$. The nuclear emission is
probably associated with a rapidly-accreting, radiatively inefficient accretion
flow. We present tentative evidence that star formation in the BCG is being
triggered by the radio jets and suggest that the cavities may be driving weak
shocks ($M \sim 1.5$) into the ICM, similar to the process in the galaxy
cluster MS 0735.6+7421.
