ﻻ يوجد ملخص باللغة العربية
We use cosmological hydrodynamical galaxy formation simulations from the NIHAO project to investigate the response of cold dark matter (CDM) haloes to baryonic processes. Previous work has shown that the halo response is primarily a function of the ratio between galaxy stellar mass and total virial mass, and the density threshold above which gas is eligible to form stars, $n [{rm cm}^{-3}]$. At low $n$ all simulations in the literature agree that dwarf galaxy haloes are cuspy, but at high $nge 100$ there is no consensus. We trace halo contraction in dwarf galaxies with $nge 100$ reported in some previous simulations to insufficient spatial resolution. Provided the adopted star formation threshold is appropriate for the resolution of the simulation, we show that the halo response is remarkably stable for $nge 5$, up to the highest star formation threshold that we test, $n=500$. This free parameter can be calibrated using the observed clustering of young stars. Simulations with low thresholds $nle 1$ predict clustering that is too weak, while simulations with high star formation thresholds $nge 5$, are consistent with the observed clustering. Finally, we test the CDM predictions against the circular velocities of nearby dwarf galaxies. Low thresholds predict velocities that are too high, while simulations with $nsim 10$ provide a good match to the observations. We thus conclude that the CDM model provides a good description of the structure of galaxies on kpc scales provided the effects of baryons are properly captured.
We use cosmological hydrodynamical galaxy formation simulations from the NIHAO project to investigate the impact of the threshold for star formation on the response of the dark matter (DM) halo to baryonic processes. The fiducial NIHAO threshold, $n=
We address the issue of numerical convergence in cosmological smoothed particle hydrodynamics simulations using a suite of runs drawn from the EAGLE project. Our simulations adopt subgrid models that produce realistic galaxy populations at a fiducial
The formation of supermassive stars has generally been studied under the assumption of rapid accretion of pristine metal-free gas. Recently it was found, however, that gas enriched to metallicities up to $Z sim 10^{-3}$ Z$_{odot}$ can also facilitate
Photoheating of the gas in low-mass dark matter (DM) haloes prevents baryons from cooling, leaving the haloes free of stars. Gas in these dark haloes remains exposed to the ultraviolet background (UVB), and so is expected to emit via fluorescent reco
We use ~100 cosmological galaxy formation zoom-in simulations using the smoothed particle hydrodynamics code {sc gasoline} to study the effect of baryonic processes on the mass profiles of cold dark matter haloes. The haloes in our study range from d