Simulation of the Cosmic Evolution of Atomic and Molecular Hydrogen in Galaxies

Journal article

We present a simulation of the cosmic evolution of the atomic and molecular phases of the cold hydrogen gas in about 3e7 galaxies, obtained by post-processing the virtual galaxy catalog produced by (De Lucia et al. 2007) on the Millennium Simulation of cosmic structure (Springel et al. 2005). Our method uses a set of physical prescriptions to assign neutral atomic hydrogen (HI) and molecular hydrogen (H2) to galaxies, based on their total cold gas masses and a few additional galaxy properties. These prescriptions are specially designed for large cosmological simulations, where, given current computational limitations, individual galaxies can only be represented by simplistic model-objects with a few global properties. Our recipes allow us to (i) split total cold gas masses between HI, H2, and Helium, (ii) assign realistic sizes to both the HI- and H2-disks, and (iii) evaluate the corresponding velocity profiles and shapes of the characteristic radio emission lines. The results presented in this paper include the local HI- and H2-mass functions, the CO-luminosity function, the cold gas mass--diameter relation, and the Tully-Fisher relation (TFR), which all match recent observational data from the local Universe. We also present high-redshift predictions of cold gas diameters and the TFR, both of which appear to evolve markedly with redshift.

Authors: Obreschkow, D; Croton, D; Lucia, G; Khochfar, S; Rawlings, S

• Publication status: Published
• Journal: Astrophys.J.
• Volume: 698
• Issue: 2
• Pages: 1467-1484
• Publication date: 2009-04-15
• DOI: 10.1088/0004-637X/698/2/1467
• EISSN: 1538-4357
• ISSN: 0004-637X
• Keywords: astro-ph.CO; astro-ph.GA