# Galaxy formation in the Planck Millennium:the atomic hydrogen content of dark matter halos

Baugh, C. M. and Gonzalez-Perez, Violeta and Lagos, Claudia D. P. and Lacey, Cedric G. and Helly, John and Jenkins, Adrian and Frenk, Carlos S. and Benson, Andrew and Bower, Richard and Cole, Shaun (2019) Galaxy formation in the Planck Millennium:the atomic hydrogen content of dark matter halos. Monthly Notices of the Royal Astronomical Society, 483 (4). 4922–4937. ISSN 0035-8711

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## Abstract

We present recalibrations of the GALFORM semi-analytical model of galaxy formation in a new N-body simulation with the Planck cosmology. The Planck Millennium simulation uses more than 128 billion particles to resolve the matter distribution in a cube of $800$ Mpc on a side, which contains more than 77 million dark matter haloes with mass greater than $2.12 \times 10^{9} h^{-1} {\rm M_{\odot}}$ at the present day. Only minor changes to a very small number of model parameters are required in the recalibration. We present predictions for the atomic hydrogen content (HI) of dark matter halos, which is a key input into the calculation of the HI intensity mapping signal expected from the large-scale structure of the Universe. We find that the HI mass $-$ halo mass relation displays a clear break at the halo mass above which AGN heating suppresses gas cooling, $\approx 3 \times 10^{11} h^{-1} M_{\rm \odot}$. Below this halo mass, the HI content of haloes is dominated by the central galaxy; above this mass it is the combined HI content of satellites that prevails. We find that the HI mass - halo mass relation changes little with redshift up to $z=3$. The bias of HI sources shows a scale dependence that gets more pronounced with increasing redshift.

Item Type:
Journal Article
Journal or Publication Title:
Monthly Notices of the Royal Astronomical Society
This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version C M Baugh, Violeta Gonzalez-Perez, Claudia D P Lagos, Cedric G Lacey, John C Helly, Adrian Jenkins, Carlos S Frenk, Andrew J Benson, Richard G Bower, Shaun Cole, Galaxy formation in the Planck Millennium: the atomic hydrogen content of dark matter haloes, Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 4, March 2019, Pages 4922–4937 is available online at: https://academic.oup.com/mnras/article/483/4/4922/5251995
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
ID Code:
129740
Deposited By:
Deposited On:
25 Mar 2019 12:20
Refereed?:
Yes
Published?:
Published