Gao, L. and Theuns, T. and Springel, V. (2015) 'Star-forming filaments in warm dark matter models.', Monthly notices of the Royal Astronomical Society., 450 (1). pp. 45-52.
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 ∼ 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 ∼ 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 ∼ 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.
|Keywords:||Galaxies: formation, Intergalactic medium, Dark matter.|
|Full text:||(VoR) Version of Record|
Download PDF (1192Kb)
|Publisher Web site:||http://dx.doi.org/10.1093/mnras/stv643|
|Publisher statement:||This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Date accepted:||24 March 2015|
|Date deposited:||18 February 2016|
|Date of first online publication:||June 2015|
|Date first made open access:||No date available|
Save or Share this output
|Look up in GoogleScholar|