Description
Galactic-scale outflows are thought to be the primary mechanism in the removal of cool gas from star-forming galaxies. Presently, the mass and energy of these flows remain poorly constrained. One way to better constrain these parameters is to measure the spatial extent of the outflow; however, measuring this quantity via spectral methods has been traditionally very difficult due to the faintness of emission lines tracing outflowing material. We perform a VLT/FORS2 narrowband imaging of 5 star-forming galaxies at redshift z = 0.67 − 0.69 in the GOODS-S field as part of an effort to spatially resolve and constrain the radial extent of large-scale outflows traced by Mg II emission. These observations probe Mg II to unmatched surface brightness limits of 5.74 × 10−19 ergs sec −1 cm−2 arcsec2 (5σ). We do not detect any extended Mg II emission in any of our galaxies, suggesting that the wind material does not extend beyond the galaxies’ stellar component. Our observations also allow us to create the first ever spatially-resolved map of Mg II absorption, revealing approximately constant absorption strengths across the galaxy disks.
