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 \ion Mg2 emission .
The sample galaxies span star formation rates in the range 4 { M _ { \odot } yr ^ { -1 } } < \mathrm { SFR } < 40 { M _ { \odot } yr ^ { -1 } } and have stellar masses 9.9 \lesssim \log M _ { * } / M _ { \odot } \lesssim 11.0 , and exhibit outflows traced by MgII absorption with velocities \sim 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 \ion Mg2-emitting material in the outflows from these galaxies is limited to \lesssim 20 kpc ; or ( 2 ) the outflows are anisotropic and/or dusty .