Probing Structure in Cold Gas at $z \lesssim 1$ with Gravitationally
  Lensed Quasar Sight Lines
  Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables
study of spatial variations in the interstellar and/or circumgalactic medium of
foreground galaxies. We report observations of 4 GLQs, each with two images
separated by 0.8-3.0", that show strong absorbers at redshifts
0.4$<$$z_{abs}$$<$1.3 in their spectra, including some at the lens redshift
with impact parameters 1.5-6.9 kpc. We measure H I Lyman lines along two sight
lines each in five absorbers (10 sight lines in total) using HST STIS, and
metal lines using Magellan Echellette or Sloan Digital Sky Survey. Our data
have doubled the lens galaxy sample with measurements of H I column densities
($N_{\rm H I}$) and metal abundances along multiple sight lines. Our data,
combined with the literature, show no strong correlation between absolute
values of differences in $N_{\rm H I}$, $N_{\rm Fe II}$, or [Fe/H] and the
sight line separations at the absorber redshifts for separations of 0-8 kpc.
The estimated abundance gradients show a tentative anti-correlation with
abundances at galaxy centers. Some lens galaxies show inverted gradients,
possibly suggesting central dilution by mergers or infall of metal-poor gas.
[Fe/H] measurements and masses estimated from GLQ astrometry suggest the lens
galaxies lie below the total mass-metallicity relation for early-type galaxies
as well as measurements for quasar-galaxy pairs and gravitationally lensed
galaxies at comparable redshifts. This difference may arise in part from the
dust depletion of Fe. Higher resolution measurements of H and metals
(especially undepleted elements) for more GLQ absorbers and accurate lens
redshifts are needed to confirm these trends.
