Demographics and Physical Properties of Gas Out/Inflows at 0.4 < z < 1.4
  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 FeII absorption greater than 200 km/s (100 km/s) towards 2.5%
(20%) of the galaxies. The fraction of blueshifted spectra does not vary
significantly with stellar mass, color, or luminosity but does decline at
specific star formation rates less than roughly 0.8 Gyr^{-1}. The insensitivity
of the blueshifted fraction to galaxy properties requires collimated outflows
at these redshifts, while the decline in outflow fraction with increasing
blueshift might reflect the angular dependence of the outflow velocity. The low
detection rate of infalling gas, 3 to 6% of the spectra, suggests an origin in
(enriched) streams favorably aligned with our sightline. We find 4 of these 9
infalling streams have projected velocities commensurate with the kinematics of
an extended disk or satellite galaxy. The strength of the MgII absorption
increases with stellar mass, B-band luminosity, and U-B color, trends arising
from a combination of more interstellar absorption at the systemic velocity and
less emission filling in more massive galaxies. Our results provides a new
quantitative understanding of gas flows between galaxies and the circumgalactic
medium over a critical period in galaxy evolution.
