We study the gas content of haloes in the early universe using high-resolution hydrodynamical simulations. We extract from the simulations and also predict, based on linear theory, the halo mass for which the enclosed baryon fraction equals half of the mean cosmic fraction. We find a rough agreement between the simulations and the predictions, which suggests that during the high-redshift era before stellar heating, the minimum mass needed for a minihalo to keep most of its baryons throughout its formation was ∼3 × 104 M⊙. We also carry out a detailed resolution analysis and show that in order to determine a halo's gas fraction even to 20 per cent accuracy, the halo must be resolved into at least 500 dark matter particles. © 2009 RAS.
Gas in simulations of high-redshift galaxies and minihaloes
MESINGER, ANDREI ALBERT
2009
Abstract
We study the gas content of haloes in the early universe using high-resolution hydrodynamical simulations. We extract from the simulations and also predict, based on linear theory, the halo mass for which the enclosed baryon fraction equals half of the mean cosmic fraction. We find a rough agreement between the simulations and the predictions, which suggests that during the high-redshift era before stellar heating, the minimum mass needed for a minihalo to keep most of its baryons throughout its formation was ∼3 × 104 M⊙. We also carry out a detailed resolution analysis and show that in order to determine a halo's gas fraction even to 20 per cent accuracy, the halo must be resolved into at least 500 dark matter particles. © 2009 RAS.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
