Low Mass Group Environments have no Substantial Impact on the
  Circumgalactic Medium Metallicity
  We explore how environment affects the metallicity of the circumgalactic
medium (CGM) using 13 low mass galaxy groups (2-5 galaxies) at $\langle
z_{abs}\rangle=0.25$ identified near background quasars. Using quasar spectra
from HST/COS and from Keck/HIRES or VLT/UVES we measure column densities of, or
determine limits on, CGM absorption lines. We use a Markov chain Monte Carlo
approach with Cloudy to estimate metallicities of cool ($T\sim10^4$K) CGM gas
within groups and compare them to CGM metallicities of 47 isolated galaxies.
Both group and isolated CGM metallicities span a wide range ($-2<$[Si/H]$<0$),
where the mean group ($-0.54\pm0.22$) and isolated ($-0.77\pm0.14$) CGM
metallicities are similar. Group and isolated environments have similar
distributions of {\HI} column densities as a function of impact parameter.
However, contrary to isolated galaxies, we do not find an anti-correlation
between {\HI} column density and the nearest group galaxy impact parameter. We
additionally divided the groups by member luminosity ratios (i.e.,
galaxy-galaxy and galaxy-dwarf groups). While there was no significant
difference in their mean metallicities, a modest increase in sample size should
allow one to statistically identify a higher CGM metallicity in galaxy-dwarf
groups compared to galaxy-galaxy groups. We conclude that either environmental
effects have not played an important role in the metallicity of the CGM at this
stage and expect that this may only occur when galaxies are strongly
interacting or merging, or that some isolated galaxies have higher CGM
metallicities due to past interactions. Thus, environment does not seem to be
the cause of the CGM metallicity bimodality.
