Demographics and Physical Properties of Gas Out/Inflows at 0.4 < z < 1.4. (arXiv:1206.5552v2 [astro-ph.CO] UPDATED)

Demographics and Physical Properties of Gas Out/Inflows at 0.4 < z < 1.4. (arXiv:1206.5552v2 [astro-ph.CO] UPDATED):
We present Keck/LRIS spectra of over 200 galaxies with well-determined
redshifts between 0.4 and 1.4. We combine new measurements of near-ultraviolet,
low-ionization absorption lines with previously measured masses, luminosities,
colors, and star formation rates to describe the demographics and properties of
galactic flows. Among star-forming galaxies with blue colors, we find a net
blueshift of the Fe II absorption greater than 200 km/s (100 km/s) towards 2.5%
(20%) of the galaxies. The fraction of spectra with blueshifts decreases
significantly among galaxies with specific star formation rates less than
roughly 0.8 Gyr^{-1} and does not vary significantly with stellar mass, color,
or luminosity. The insensitivity of the blueshifted fraction to galaxy
properties favors collimated outflows, and in this context we demonstrate how
the solid angle of the outflow declines with increasing outflow velocity. We
also detect enriched infall towards 3-6% of the galaxies, apparently observed
at an optimal viewing angle. At least 3 (1) of the 9 infalling streams have a
large cross section and velocities commensurate with an extended disk
(satellite galaxy). We explain the strong dependence of the Mg II absorption
equivalent width on stellar mass, B-band luminosity, and U-B color by resonance
emission partially filling in the intrinsic absorption troughs; emission
filling can also explain the significant differences often observed between the
shape of the Mg II line profile and the absorption troughs of those Fe II
transitions that decay primarily by fluorescence. This study provides a new
quantitative understanding of gas flows between galaxies and the circumgalactic
medium over a critical period in galaxy evolution.