Significant H I and Metal Differences around the z = 0.83 Lens Galaxy
  Towards the Doubly Lensed Quasar SBS 0909+532
  We report a large difference in neutral hydrogen (H I) and metal column
densities between the two sight lines probing opposite sides of the lensing
galaxy at $z_\mathrm{lens}$ = 0.83 toward the doubly lensed quasar SBS
0909+532. Using archival HST-STIS and Keck HIRES spectra of the lensed quasar
images, we measure log $N_\mathrm{H\;I}$ = 18.77 $\pm$ 0.12 cm$^{-2}$ toward
the brighter image ($A$) at an impact parameter of $r_A$ = 3.15 kpc and log
$N_\mathrm{H\;I}$ = 20.38 $\pm$ 0.20 cm$^{-2}$ toward the fainter image ($B$)
at an impact parameter of $r_B$ = 5.74 kpc. This difference by a factor of
$\sim$41 is the highest difference between sight lines for a lens galaxy in
which H I has been measured, suggesting patchiness and/or anisotropy on these
scales. We estimate an average Fe abundance gradient between the sight lines to
be $\geq$ +0.35 dex kpc$^{-1}$. The $N_\mathrm{Fe\;II}$/$N_\mathrm{Mg\;II}$
ratios for the individual components detected in the Keck HIRES spectra have
supersolar values for all components in sight line $A$ and for 11 out of 18
components in sight line $B$, suggesting that Type Ia supernovae may have
contributed to the chemical enrichment of the galaxy's environment.
Additionally, these observations provide complementary information to
detections of cold gas in early-type galaxies and the tension between these and
some models of cloud survival.
