The anatomy of the NGC 5044 group -- II. Stellar populations and
  star-formation histories
  The distribution of galaxy properties in groups and clusters holds important
information on galaxy evolution and growth of structure in the Universe. While
clusters have received appreciable attention in this regard, the role of groups
as fundamental to formation of the present day galaxy population has remained
relatively unaddressed. Here we present stellar ages, metallicities and
alpha-element abundances derived using Lick indices for 67 spectroscopically
confirmed members of the NGC 5044 galaxy group with the aim of shedding light
on galaxy evolution in the context of the group environment.
  We find that galaxies in the NGC 5044 group show evidence for a strong
relationship between stellar mass and metallicity, consistent with their
counterparts in both higher and lower mass groups and clusters. Galaxies show
no clear trend of age or alpha-element abundance with mass, but these data form
a tight sequence when fit simultaneously in age, metallicity and stellar mass.
In the context of the group environment, our data support the tidal disruption
of low-mass galaxies at small group-centric radii, as evident from an apparent
lack of galaxies below ~10^9 M_sun within ~100 kpc of the brightest group
galaxy. Using a joint analysis of absorption- and emission-line metallicities,
we are able to show that the star-forming galaxy population in the NGC 5044
group appears to require gas removal to explain the ~1.5 dex offset between
absorption- and emission-line metallicities observed in some cases. A
comparison with other stellar population properties suggests that this gas
removal is dominated by galaxy interactions with the hot intragroup medium.
