LARGE-SCALE STAR-FORMATION-DRIVEN OUTFLOWS AT 1 < z < 2 IN THE 3D-HST SURVEY

We present evidence of large-scale outflows from three low-mass (log(M-*/M-circle dot) similar to 9.75) star-forming (SFR > 4 M-circle dot yr(-1)) galaxies observed at z = 1.24, z = 1.35, and z = 1.75 in the 3D-HST Survey. Each of these galaxies is located within a projected physical distance of 60 kpc around the sight line to the quasar SDSS J123622.93+621526.6, which exhibits well-separated strong (W-r(lambda 2796) greater than or similar to 0.8 angstrom) Mg II absorption systems matching precisely to the redshifts of the three galaxies. We derive the star formation surface densities from the Ha emission in the WFC3 G141 grism observations for the galaxies and find that in each case the star formation surface density well exceeds 0.1 M-circle dot yr(-1) kpc(-2), the typical threshold for starburst galaxies in the local universe. From a small but complete parallel census of the 0.65 < z < 2.6 galaxies with H-140 less than or similar to 24 proximate to the quasar sight line, we detect Mg II absorption associated with galaxies extending to physical distances of 130 kpc. We determine that the W-r > 0.8 angstrom Mg II covering fraction of star-forming galaxies at 1 < z < 2 may be as large as unity on scales extending to at least 60 kpc, providing early constraints on the typical extent of starburst-driven winds around galaxies at this redshift. Our observations additionally suggest that the azimuthal distribution of W-r > 0.4 angstrom Mg II absorbing gas around star-forming galaxies may evolve from z similar to 2 to the present, consistent with recent observations of an increasing collimation of star-formation-driven outflows with time from z similar to 3.