Evolutionary phases of gas-rich galaxies in a galaxy cluster at z=1.46
  We report a survey of molecular gas in galaxies in the XMMXCS J2215.9-1738
cluster at $z=1.46$. We have detected emission lines from 17 galaxies within a
radius of $R_{200}$ from the cluster center, in Band 3 data of the Atacama
Large Millimeter/submillimeter Array (ALMA) with a coverage of 93 -- 95 GHz in
frequency and 2.33 arcmin$^2$ in spatial direction. The lines are all
identified as CO $J$=2--1 emission lines from cluster members at $z\sim1.46$ by
their redshifts and the colors of their optical and near-infrared (NIR)
counterparts. The line luminosities reach down to $L'_{\rm
CO(2-1)}=4.5\times10^{9}$ K km s$^{-1}$ pc$^2$. The spatial distribution of
galaxies with a detection of CO(2--1) suggests that they disappear from the
very center of the cluster. The phase-space diagram showing relative velocity
versus cluster-centric distance indicates that the gas-rich galaxies have
entered the cluster more recently than the gas-poor star-forming galaxies and
passive galaxies located in the virialized region of this cluster. The results
imply that the galaxies have experienced ram-pressure stripping and/or
strangulation during the course of infall towards the cluster center and then
the molecular gas in the galaxies at the cluster center is depleted by star
formation.
