VLT/VIMOS Observations of an Occulting Galaxy Pair: Redshifts and
  Effective Extinction Curve
  We present VLT/VIMOS IFU observations of an occulting galaxy pair previously
discovered in HST observations. The foreground galaxy is a low-inclination
spiral disk, which causes clear attenuation features seen against the bright
bulge and disk of the background galaxy. We find redshifts of $z=0.064
\pm0.003$ and z=0.065 for the foreground and background galaxy respectively.
This relatively small difference does not rule out gravitational interaction
between the two galaxies. Emission line ratios point to a star-forming, not
AGN-dominated foreground galaxy.
  We fit the Cardelli, Clayton & Mathis (CCM) extinction law to the spectra of
individual fibres to derive slope ($R_V$) and normalization ($A_V$). The
normalization agrees with the HST attenuation map and the slope is lower than
the Milky Way relation ($R_V<3.1$), which is likely linked to the spatial
sampling of the disk. We speculate that the values of $R_V$ point to either
coherent ISM structures in the disk larger than usual ($\sim9$ kpc) or higher
starting values of $R_V$, indicative of recent processing of the dust.
  The foreground galaxy is a low stellar mass spiral ($M_* \sim 3 \times 10^9
M_\odot$) with a high dust content ($M_{\rm dust} \sim 0.5 \times 10^6
M_\odot$). The dust disk geometry visible in the HST image would explain the
observed SED properties of smaller galaxies: a lower mean dust temperature, a
high dust-to-stellar mass ratio but relatively little optical attenuation.
Ongoing efforts to find occulting pairs with a small foreground galaxies will
show how common this geometry is.
