Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-10-26
Astrophys.J.660:945-958,2007
Astronomy and Astrophysics
Astrophysics
37 pages, 11 figures. Accepted to ApJ. Additional numerical tests of the internal parameters of the galactic wind model are pr
Scientific paper
10.1086/513001
We present the results of a numerical study of a galactic wind model and its implications on the properties of damped Lyman-alpha absorbers (DLAs) using cosmological hydrodynamic simulations. We vary both the wind strength and the internal parameters of the the wind model in a series of cosmological SPH simulations that include radiative cooling and heating by a UV background, star formation, and feedback from supernovae and galactic winds. To test our simulations, we examine the DLA `rate-of-incidence' as a function of halo mass, galaxy apparent magnitude, and impact parameter. We find that the statistical distribution of DLAs does not depend on the exact values of internal numerical parameters that control the decoupling of hydrodynamic forces when the gas is ejected from starforming regions. The DLA rate-of-incidence in our simulations at z=3 is dominated by the faint galaxies with apparent magnitude R_AB < 25.5. However, interestingly in a `strong wind' run, the differential distribution of DLA sight-lines is peaked at Mhalo = 10^{12} Msun/h (R_AB~27), and the mean DLA halo mass is Mmean=10^{12.4} Msun/h (R_AB ~ 26). These mass-scales are much larger than those if we ignore winds, because galactic wind feedback suppresses the DLA cross section in low-mass halos and increases the relative contribution to the DLA incidence from more massive halos. The DLAs in our simulations are more compact than the present-day disk galaxies, and the impact parameter distribution is very narrow unless we limit the search for the host galaxy to only bright LBGs. The comoving number density of DLAs is higher than that of LBGs down to R_AB=30 mag if the physical radius of each DLA is smaller than 5 kpc/h_70. We discuss conflicts between current simulations and observations, and potential problems with simulations based on the CDM model.
Hernquist Lars
Nagamine Kentaro
Springel Volker
Wolfe Arthur M.
No associations
LandOfFree
Distribution of Damped Lyman-alpha Absorbers in a Lambda Cold Dark Matter Universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Distribution of Damped Lyman-alpha Absorbers in a Lambda Cold Dark Matter Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Distribution of Damped Lyman-alpha Absorbers in a Lambda Cold Dark Matter Universe will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-554710