Misc,
Modeling for Stellar Feedback in Galaxy Formation Simulations
(2017)cite arxiv:1701.01082Comment: Accepted for publication in the ApJ.
Abstract
Various heuristic approaches to model unresolved supernova (SN) feedback in
galaxy formation simulations exist to reproduce the formation of spiral
galaxies and the overall inefficient conversion of gas into stars. Some models,
however, require resolution dependent scalings. We present a sub-resolution
model representing the three major phases of supernova blast wave evolution
$-$free expansion, energy conserving Sedov-Taylor, and momentum conserving
snowplow$-$ with energy scalings adopted from high-resolution
interstellar-medium simulations in both uniform and multiphase media. We allow
for the effects of significantly enhanced SN remnant propagation in a
multiphase medium with the cooling radius scaling with the hot volume fraction,
$f_hot$, as $(1 - f_hot)^-4/5$. We also include winds
from young massive stars and AGB stars, Strömgren sphere gas heating by
massive stars, and a gas cooling limiting mechanism driven by radiative
recombination of dense HII regions. We present initial tests for isolated
Milky-Way like systems simulated with the GADGET based code SPHgal with
improved SPH prescription. Compared to pure thermal SN input, the model
significantly suppresses star formation at early epochs, with star formation
extended both in time and space in better accord with observations. Compared to
models with pure thermal SN feedback, the age at which half the stellar mass is
assembled increases by a factor of 2.4, and the mass loading parameter and gas
outflow rate from the galactic disk increase by a factor of 2. Simulation
results are converged for a two order of magnitude variation in particle mass
in the range (1.3$-$130)$10^4$ solar masses.
