Figure 1.
Left panel: The velocity
of galaxies within the 10
GCLASS clusters relative
to the velocity dispersion
of each cluster versus the
position of each galaxy
relative to the virial radius.
Quiescent galaxies are
plotted as red triangles,
star-forming galaxies as
inverted blue triangles,
and post-starburst
galaxies as encircled
green stars. Strikingly, the
post-starbust galaxies
form a “ring” structure
at high velocities and
intermediate radius.
Right panel: Galaxies in a
simulated set of clusters
(black points). Green
stars show galaxies that
are “quenched” in the
simulation on a timescale
of 0.1 — 0.5 Gyr after
they first cross about
half the virial radius.
The distribution of the
simulated quenched
galaxies is statistically
consistent with the
observed post-starburst
population suggesting
this is where and when
cluster galaxies are first
quenched.
4
The GCLASS Survey at z ~ 1
One additional challenge in observing this
quenching process in action is that until very
recently we’ve only been able F