How well is angular momentum accretion modelled in semi-analytic galaxy formation models?

Hou, Jun; Lacey, Cedric G; Frenk, Carlos S

Abstract

Gas cooling and accretion in haloes delivers mass and angular momentum on to galaxies. In this work, we investigate the accuracy of the modelling of this important process in several different semi-analytic (SA) galaxy formation models (GALFORM, L-GALAXIES, and MORGANA) through comparisons with a hydrodynamical simulation performed with the moving-mesh code AREPO. Both SA models and the simulation were run without any feedback or metal enrichment, in order to focus on the cooling and accretion process. All of the SA models considered here assume that gas cools from a spherical halo. We found that the assumption that the gas conserves its angular momentum when moving from the virial radius, rvir, to the central region of the halo, r ∼ 0.1rvir, is approximately consistent with the results from our simulation. We also found that, compared to the simulation, the MORGANA model tends to overestimate the mean specific angular momentum of cooled-down gas, the L-GALAXIES model also tends to overestimate this in low-redshift massive haloes, while the two older GALFORM models tend to underestimate the angular momentum. In general, the predictions of the new GALFORM cooling model developed by Hou et al. agree the best with the simulation.

Citation

Hou, J., Lacey, C. G., & Frenk, C. S. (2021). How well is angular momentum accretion modelled in semi-analytic galaxy formation models?. Monthly Notices of the Royal Astronomical Society, 507(3), 4241-4261. https://doi.org/10.1093/mnras/stab2454

• Journal Article Type: Article
• Acceptance Date: Aug 24, 2021
• Online Publication Date: Aug 28, 2021
• Publication Date: 2021-11
• Deposit Date: Nov 15, 2021
• Publicly Available Date: Nov 15, 2021
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 507
• Issue: 3
• Pages: 4241-4261
• DOI: https://doi.org/10.1093/mnras/stab2454