Star forming filaments in warm dark matter models
arXiv:1403.2475 · doi:10.1093/mnras/stv643
Abstract
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 co-moving 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. Reionisation 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. Fifteen 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.
8 pages, 7 figures. Accepted to MNRAS. Minor revision apart from adding more comparisons with CDM
References in corpus (9)
- Too big to fail? The puzzling darkness of massive Milky Way subhaloes
- Massloss of galaxies due to a UV-background
- The Observed properties of Dark Matter on small spatial scales
- Dark matter and cosmic structure
- Discreteness effects in simulations of Hot/Warm dark matter
- Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds
- Through Thick and Thin - HI Absorption in Cosmological Simulations
- Lighting the Universe with filaments
- The phase space density of fermionic dark matter haloes