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Title
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Star-forming filaments in warm dark matter models
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Author
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Abstract
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| We performed a hydrodynamical cosmological simulation of the formation of a Milky Way-like galaxy in a warm dark matter (WDM) cosmology. Smooth and dense filaments, several comoving mega parsec long, form generically above z similar to 2 in this model. Atomic line cooling allows gas in the centres of these filaments to cool to the base of the cooling function, resulting in a very striking pattern of extended Lyman-limit systems (LLSs). Observations of the correlation function of LLSs might hence provide useful limits on the nature of the dark matter. We argue that the self-shielding of filaments may lead to a thermal instability resulting in star formation. We implement a sub-grid model for this, and find that filaments rather than haloes dominate star formation until z similar to 6, although this depends on how stars form in WDM. Reionization decreases the gas density in filaments, and the more usual star formation in haloes dominates below z similar to 6, although star formation in filaments continues until z = 2. 15 per cent of the stars of the z = 0 galaxy formed in filaments. At higher redshift, these stars give galaxies a stringy appearance, which, if observed, might be a strong indication that the dark matter is warm. |
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Language
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English
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Source (journal)
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Monthly notices of the Royal Astronomical Society. - Oxford, 1983, currens
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Publication
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Oxford
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2015
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ISSN
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0035-8711
[print]
1365-2966
[online]
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DOI
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10.1093/MNRAS/STV643
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Volume/pages
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450
:1
(2015)
, p. 45-52
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ISI
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000356311600005
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Full text (Publisher's DOI)
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Full text (open access)
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