The Megaparsec-scale Gas-sloshing Spiral in the Remnant Cool Core
  Cluster Abell 1763
  We present a multiwavelength study of the massive galaxy cluster Abell 1763
at redshift z = 0.231. Image analysis of a 19.6 ks Chandra archival observation
reveals a cluster-wide spiral of enhanced surface brightness in the
intracluster medium (ICM). While such spirals are understood to form in
clusters with sloshing strong cool cores (SCCs), the gas comprising the
spiral's apex is of intermediate entropy ($\sim$ 110 keV cm$^{2}$) and cooling
time ($\sim$ 6.8 Gyr), indicating core disruption is occurring throughout the
spiral formation process. Two subclusters dominated by the second- and
third-ranked galaxies in the system lie along a line parallel to the elongation
axis of the primary cluster's ICM. Both subsystems appear to have fallen in
along a previously discovered intercluster filament and are each considered
candidates as the perturber responsible for initiating disruptive core
sloshing. Dynamical analysis indicates infall is occurring with a relative
radial velocity of $\sim$ 1800 km s$^{-1}$. The brightest cluster galaxy of
Abell 1763 possesses a high line-of-sight peculiar velocity (v$_{pec}$ $\sim$
650 km s$^{-1}$) and hosts a powerful (P$_{1.4}$ $\sim$ 10$^{26}$ W Hz$^{-1}$)
bent double-lobed radio source, likely shaped by the relative bulk ICM flow
induced in the merger. The cluster merger model of SCC destruction invokes low
impact parameter infall as the condition required for core transformation. In
contrast to this, the high angular momentum event occurring in Abell 1763
suggests that off-axis mergers play a greater role in establishing the non-cool
core cluster population than previously assumed.
