Shocks in the Stacked Sunyaev-Zel'dovich Profiles of Clusters II:
  Measurements from SPT-SZ + Planck Compton-y Map
  We search for the signature of shocks in stacked gas pressure profiles of
galaxy clusters using data from the South Pole Telescope (SPT). Specifically,
we stack the recently released Compton-y maps from the 2500 deg^2 SPT-SZ survey
on the locations of clusters identified in that same dataset. The sample
contains 516 clusters with mean mass <M200m> = 1e14.9 msol and redshift <z> =
0.55. We analyze in parallel a set of zoom-in hydrodynamical simulations from
The Three Hundred project. The SPT-SZ data show two features: (i) a pressure
deficit at R/R200m = $1.08 \pm 0.09$, measured at $3.1\sigma$ significance and
not observed in the simulations, and; (ii) a sharp decrease in pressure at
R/R200m = $4.58 \pm 1.24$ at $2.0\sigma$ significance. The pressure deficit is
qualitatively consistent with a shock-induced thermal non-equilibrium between
electrons and ions, and the second feature is consistent with accretion shocks
seen in previous studies. We split the cluster sample by redshift and mass, and
find both features exist in all cases. There are also no significant
differences in features along and across the cluster major axis, whose
orientation roughly points towards filamentary structure. As a consistency
test, we also analyze clusters from the Planck and Atacama Cosmology Telescope
Polarimeter surveys and find quantitatively similar features in the pressure
profiles. Finally, we compare the accretion shock radius (Rsh_acc) with
existing measurements of the splashback radius (Rsp) for SPT-SZ and constrain
the lower limit of the ratio, Rsh_acc/Rsp > $2.16 \pm 0.59$.
