Stellar feedback from HMXBs in cosmological hydrodynamical simulations
  We explored the role of X-ray binaries composed by a black hole and a massive
stellar companion (BHXs) as sources of kinetic feedback by using hydrodynamical
cosmological simulations. Following previous results, our BHX model selects low
metal-poor stars ($Z = [0,10^{-4}]$) as possible progenitors. The model that
better reproduces observations assumes that a $\sim 20\%$ fraction of
low-metallicity black holes are in binary systems which produce BHXs. These
sources are estimated to deposit $\sim 10^{52}$ erg of kinetic energy per
event. With these parameters and in the simulated volume, we find that the
energy injected by BHXs represents $\sim 30\%$ of the total energy released by
SNII and BHX events at redshift $z\sim7$ and then decreases rapidly as baryons
get chemically enriched. Haloes with virial masses smaller than $\sim 10^{10}
\,M_{\odot}$ (or $T_{\rm vir} \lesssim 10^5 $ K) are the most directly affected
ones by BHX feedback. These haloes host galaxies with stellar masses in the
range $10^7 - 10^8$ M$_\odot$. Our results show that BHX feedback is able to
keep the interstellar medium warm, without removing a significant gas fraction,
in agreement with previous analytical calculations. Consequently, the
stellar-to-dark matter mass ratio is better reproduced at high redshift. Our
model also predicts a stronger evolution of the number of galaxies as a
function of the stellar mass with redshift when BHX feedback is considered.
These findings support previous claims that the BHXs could be an effective
source of feedback in early stages of galaxy evolution.
