Signatures of large-scale cold fronts in the optically-selected merging
  cluster HSC J085024+001536
  We represent a joint X-ray, weak-lensing, and optical analysis of the
optically-selected merging cluster, HSC J085024+001536, from the Subaru HSC-SSP
survey. Both the member galaxy density and the weak-lensing mass map show that
the cluster is composed of southeast and northwest components. The
two-dimensional weak-lensing analysis shows that the southeast component is the
main cluster, and the sub- and main-cluster mass ratio is
$0.32^{+0.75}_{-0.23}$. The northwest subcluster is offset by $\sim700$ kpc
from the main cluster center, and their relative line-of-sight velocity is
$\sim1300\,{\rm km s^{-1}}$ from spectroscopic redshifts of member galaxies.
The X-ray emission is concentrated around the main cluster, while the gas mass
fraction within a sphere of $1'$ radius of the subcluster is only
$f_{\mathrm{gas}}=4.0^{+2.3}_{-3.3}\%$, indicating that the subcluster gas was
stripped by ram pressure. X-ray residual image shows three arc-like excess
patterns, of which two are symmetrically located at $\sim550$ kpc from the
X-ray morphological center, and the other is close to the X-ray core. The
excess close to the subcluster has a cold-front feature where dense-cold gas
and thin-hot gas contact. The two outer excesses are tangentially elongated
about $\sim 450-650$ kpc, suggesting that the cluster is merged with a non-zero
impact parameter. Overall features revealed by the multi-wavelength datasets
indicate that the cluster is at the second impact or later. Since the
optically-defined merger catalog is unbiased for merger boost of the
intracluster medium, X-ray follow-up observations will pave the way to
understand merger physics at various phases.
