High-redshift halo-galaxy connection via constrained simulations

The evolution of halos with masses around $M_{\text{h}}\approx {10}^{11}{\text{M}}_{\odot }$ and $M_{\text{h}}\approx {10}^{12}{\text{M}}_{\odot }$ at redshifts $z>9$ is examined using constrained N-body simulations. {The average specific mass accretion rates, ${\dot{M}}_{\text{h}}\mathrm{/}{M}_{\text{h}}$, exhibit minimal mass dependence and generally agree with existing literature. Individual halo accretion histories, however, vary substantially. } About one-third of simulations reveal an increase in ${\dot{M}}_{\text{h}}$ around $z\approx 13$. Comparing simulated halos with observed galaxies having spectroscopic redshifts, we find that for galaxies at $z\gtrsim 9$, the ratio between observed star formation rate (SFR) and ${\dot{M}}_{\text{h}}$ is approximately $2\mathrm{\%}$. This ratio remains consistent for the stellar-to-halo mass ratio (SHMR) but only for $z\gtrsim 10$. At $z\simeq 9$, the SHMR is notably lower by a factor of a few. At $z\gtrsim 10$, there is an agreement between specific star formation rates (sSFRs) and ${\dot{M}}_{\text{h}}\mathrm{/}{M}_{\text{h}}$. However, at $z\simeq 9$, observed sSFRs exceed simulated values by a factor of two. It is argued that the mildly elevated SHMR in high-$z$ halos with $M_{\text{h}}\approx {10}^{11}{M}_{\odot }$, can be achieved by assuming the applicability of the local Kennicutt-Schmidt law and a reduced effectiveness of stellar feedback due to deeper gravitational potential of high-$z$ halos of a fixed mass.