Cosmic Reionization On Computers: The Galaxy-Halo Connection between $5 leq z leq10$. (arXiv:2001.02233v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_H/0/1/0/all/0/1">Hanjue Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Avestruz_C/0/1/0/all/0/1">Camille Avestruz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gnedin_N/0/1/0/all/0/1">Nickolay Y. Gnedin</a>
We explore the connection between the stellar component of galaxies and their
host halos during the epoch of reionization ($5 leq zleq10$) using the CROC
(Cosmic Reionization on Computers) simulations. We compare simulated galaxies
with observations and find that CROC underpredicts the abundance of luminous
galaxies when compared to observed UV luminosity functions, and analogously the
most massive galaxies when compared to observed stellar mass functions. We can
trace the deficit of star formation to high redshifts, where the slope of the
star formation rate to stellar mass relation is consistent with observations,
but the normalization is systematically low. This results in a star formation
rate density and stellar mass density that is systematically offset from
observations. However, the less luminous or lower stellar mass objects have
luminosities and stellar masses that agree fairly well with observational data.
We explore the stellar-to-halo mass ratio, a key quantity that is difficult to
measure at high redshifts and that models do not consistently predict. In CROC,
the stellar-to-halo mass ratio {it decreases} with redshift, a trend opposite
to some abundance matching studies. These discrepancies uncover where future
effort should be focused in order to improve the fidelity of modeling cosmic
reionization. We also compare the CROC galaxy bias with observational
measurements using Lyman-Break Galaxy (LBG) samples. The good agreement of
simulation and data shows that the clustering of dark matter halos is properly
captured in CROC.
We explore the connection between the stellar component of galaxies and their
host halos during the epoch of reionization ($5 leq zleq10$) using the CROC
(Cosmic Reionization on Computers) simulations. We compare simulated galaxies
with observations and find that CROC underpredicts the abundance of luminous
galaxies when compared to observed UV luminosity functions, and analogously the
most massive galaxies when compared to observed stellar mass functions. We can
trace the deficit of star formation to high redshifts, where the slope of the
star formation rate to stellar mass relation is consistent with observations,
but the normalization is systematically low. This results in a star formation
rate density and stellar mass density that is systematically offset from
observations. However, the less luminous or lower stellar mass objects have
luminosities and stellar masses that agree fairly well with observational data.
We explore the stellar-to-halo mass ratio, a key quantity that is difficult to
measure at high redshifts and that models do not consistently predict. In CROC,
the stellar-to-halo mass ratio {it decreases} with redshift, a trend opposite
to some abundance matching studies. These discrepancies uncover where future
effort should be focused in order to improve the fidelity of modeling cosmic
reionization. We also compare the CROC galaxy bias with observational
measurements using Lyman-Break Galaxy (LBG) samples. The good agreement of
simulation and data shows that the clustering of dark matter halos is properly
captured in CROC.
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