Forming disc galaxies in ΛCDM simulations
Abstract
We used fully cosmological, high-resolution N-body + smooth particle hydrodynamic (SPH) simulations to follow the formation of disc galaxies with rotational velocities between 135 and 270kms-1 in a Λ cold dark matter (CDM) universe. The simulations include gas cooling, star formation, the effects of a uniform ultraviolet (UV) background and a physically motivated description of feedback from supernovae (SNe). The host dark matter haloes have a spin and last major merger redshift typical of galaxy-sized haloes as measured in recent large-scale N-body simulations. The simulated galaxies form rotationally supported discs with realistic exponential scalelengths and fall on both the I band and baryonic Tully-Fisher relations. An extended stellar disc forms inside the Milky Way (MW)-sized halo immediately after the last major merger. The combination of UV background and SN feedback drastically reduces the number of visible satellites orbiting inside a MW-sized halo, bringing it in fair agreement with observations. Our simulations predict that the average age of a primary galaxy's stellar population decreases with mass, because feedback delays star formation in less massive galaxies. Galaxies have stellar masses and current star formation rates as a function of total mass that are in good agreement with observational data. We discuss how both high mass and force resolution and a realistic description of star formation and feedback are important ingredients to match the observed properties of galaxies.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2007
- DOI:
- 10.1111/j.1365-2966.2006.11266.x
- arXiv:
- arXiv:astro-ph/0602351
- Bibcode:
- 2007MNRAS.374.1479G
- Keywords:
-
- methods: N-body simulations;
- galaxies: evolution;
- galaxies: formation;
- Astrophysics
- E-Print:
- Revised version after the referee's comments. Conclusions unchanged. 2 new plots. MNRAS in press. 20 plots. 21 pages