A Complete Spectroscopic Census of Abell 2029: A Tale of Three Histories
  A rich spectroscopic census of members of the local massive cluster Abell
2029 includes 1215 members of A2029 and its two infalling groups, A2033 and a
Southern Infalling Group (SIG). The two infalling groups are identified in
spectroscopic, X-ray and weak lensing maps. We identify active galactic nuclei
(AGN), star-forming galaxies, E+A galaxies, and quiescent galaxies based on the
spectroscopy. The fractions of AGN and post-starburst E+A galaxies in A2029 are
similar to those of other clusters. We derive the stellar mass
($M_{*}$)-metallicity of A2029 based on 227 star-forming members; A2029 members
within $10^{9} M_{\odot} < M _{*} < 10^{9.5} M_{\odot}$ are more metal rich
than SDSS galaxies within the same mass range. We utilize the spectroscopic
index $D_{n}4000$, a strong age indicator, to trace past and future evolution
of the A2029 system. The median $D_{n}4000$ of the members decreases as the
projected clustercentric distance increases for all three subsystems. The
$D_{n}4000 - M_{*}$ relations of the members in A2029 and its two infalling
groups differ significantly indicating the importance of stochastic effects for
understanding the evolution of cluster galaxy populations. In the main cluster,
an excess around $D_{n}4000 \sim 1.8$ indicates that some A2029 members became
quiescent galaxies 2-3 Gyr ago consistent with the merger epoch of the X-ray
sloshing pattern.
