The Impact of Galactic Outflows Across Cosmic Scales

Romeel Dave
University of Arizona

Feedback from supernova-driven winds is an important driver of galaxy
evolution, particularly at early times when systems were smaller.
Quantifying such feedback is challenging both observationally and
theoretically.  We present new cosmological SPH simulations incorporating
various models of superwind feedback, and study their impact on the
properties of galaxies and intergalactic gas during the heydey of
galaxy formation at z~2-6.  Our models can reproduce the constancy of
CIV absorption at those epochs seen in quasar absorption line studies,
despite an order of magnitude increase in the overall IGM metallicity,
due to the importance of energy input accompanying metal injection.
We compare to observed CIV line and pixel optical depth properties
and early galaxy data, and find that they put significant constraints
on outflow properties.  A particularly interesting result is that
momentum-driven wind scenarios, favored by observations of local
starbursts, also provides our best fit to observations of IGM enrichment
and galaxy properties at these distant epochs.  While these conclusions
are preliminary and further tests are in the works, it appears that
we are making significant progress towards understanding the impact of
galactic outflows on galaxy formation and evolution.