A VLT/FORS2 Narrowband Imaging Search for MgII Emission Around z ~ 0.7
  Galaxies
  We perform a Very Large Telescope FOcal Reducer and low dispersion
Spectrograph 2 (VLT/FORS2) narrowband imaging search around 5 star-forming
galaxies at redshift z=0.67-0.69 in the Great Observatories Origins Deep Survey
South (GOODS-S) field to constrain the radial extent of large-scale outflows
traced by resonantly scattered MgII emission. The sample galaxies span star
formation rates in the range 4 $M_{\odot}/yr$ < SFR < $40\ M_{\odot}/yr$ and
have stellar masses $9.9 \lesssim \log M_{*}/M_{\odot} \lesssim 11.0$, and
exhibit outflows traced by MgII absorption with velocities ~150-420 km s$^{-1}$
. These observations are uniquely sensitive, reaching surface brightness limits
of 5.81 $\times$ $10^{-19}$ ergs sec $^{-1}$ cm$^{-2}$ arcsec$^2$ per 1
arcsec$^2$ aperture (at 5$\sigma$ significance). We do not detect any extended
emission around any of the sample galaxies, thus placing 5$\sigma$ upper limits
on the brightness of extended MgII emission of $<6.51 \times 10^{-19}$ ergs sec
$^{-1}$ cm$^{-2}$ arcsec$^2$ at projected distances $R_{\perp} > 8-21$ kpc. The
imaging also resolves the MgII absorption observed toward each galaxy
spatially, revealing approximately constant absorption strengths across the
galaxy disks. In concert with radiative transfer models predicting the surface
brightness of MgII emission for a variety of simple wind morphologies, our
detection limits suggest that either (1) the extent of the MgII-emitting
material in the outflows from these galaxies is limited to $\lesssim 20$ kpc;
or (2) the outflows are anisotropic and/or dusty.
