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A semi-analytic model comparison – gas cooling and galaxy mergers

De Lucia, Gabriella and Boylan-Kolchin, Michael and Benson, Andrew J. and Fontanot, Fabio and Monaco, Pierluigi (2010) A semi-analytic model comparison – gas cooling and galaxy mergers. Monthly Notices of the Royal Astronomical Society, 406 (3). pp. 1533-1552. ISSN 0035-8711. doi:10.1111/j.1365-2966.2010.16806.x.

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We use stripped-down versions of three semi-analytic galaxy formation models to study the influence of different assumptions about gas cooling and galaxy mergers. By running the three models on identical sets of merger trees extracted from high-resolution cosmological N-body simulations, we are able to perform both statistical analyses and halo-by-halo comparisons. This paper demonstrates that there is a good statistical agreement between the three models used here, when operating on the same merger trees, reflecting a general agreement in the underlying framework for semi-analytic models. We also show, however, that various assumptions that are commonly adopted to treat gas cooling and galaxy mergers can lead to significantly different results, at least in some regimes. In particular, we find that the different models adopted for gas cooling lead to similar results for mass scales comparable to that of our own Galaxy. Significant differences, however, arise at larger mass scales. These are largely (but not entirely) due to different treatments of the ‘rapid cooling’ regime, and different assumptions about the hot gas distribution. At this mass regime, the predicted cooling rates can differ up to about one order of magnitude, with important implications on the relative weight that these models give to feedback from active galactic nuclei in order to counteract excessive gas condensation in relatively massive haloes at low redshift. Different assumptions in the modelling of galaxy mergers can also result in significant differences in the timings of mergers, with important consequences for the formation and evolution of massive galaxies.

Item Type:Article
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URLURL TypeDescription
Boylan-Kolchin, Michael0000-0002-9604-343X
Benson, Andrew J.0000-0001-5501-6008
Additional Information:© 2010 The Authors. Journal compilation © 2010 RAS. Accepted 2010 April 3. Received 2010 March 30; in original form 2010 March 12. Article first published online: 5 July 2010. GDL acknowledges financial support from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 202781. AJB acknowledges the support of the Gordon & Betty Moore Foundation. GDL, AJB and FF acknowledge the hospitality of the Kavli Institute for Theoretical Physics of Santa Barbara, where the initial calculations that led to this paper were carried out. The Millennium and Millennium-II Simulation data bases used in this paper and the web application providing online access to them were constructed as part of the activities of the German Astrophysical Virtual Observatory. We are grateful to Gerard Lemson for setting up an internal data base that greatly facilitated the exchange of data and information needed to carry out this project. We are grateful to Carlton Baugh, Richard Bower, Shaun Cole, Carlos Frenk and Cedric Lacey for making available the Galform code for this project.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
European Research Council (ERC)202781
Gordon and Betty Moore FoundationUNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: formation; galaxies: interactions
Issue or Number:3
Record Number:CaltechAUTHORS:20100903-105425904
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Official Citation:De Lucia, G., Boylan-Kolchin, M., Benson, A. J., Fontanot, F. and Monaco, P. (2010), A semi-analytic model comparison – gas cooling and galaxy mergers. Monthly Notices of the Royal Astronomical Society, 406: 1533–1552. doi: 10.1111/j.1365-2966.2010.16806.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19783
Deposited On:08 Sep 2010 15:04
Last Modified:08 Nov 2021 23:55

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