Star forming filaments in warm dark matter models

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.

arXiv comment8 pages, 7 figures. Accepted to MNRAS. Minor revision apart from adding more comparisons with CDM

References in corpus (35)

• The cosmological simulation code GADGET-2
• Particle Dark Matter: Evidence, Candidates and Constraints
• Where are the missing galactic satellites?
• The Aquarius Project: the subhalos of galactic halos
• Radiative Transfer in a Clumpy Universe: II. The Utraviolet Extragalactic Background
• The Formation of the First Star in the Universe
• Sterile Neutrinos as Dark Matter
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Cold collapse and the core catastrophe
• Halo Formation in Warm Dark Matter Models
• Cosmological Simulations with TreeSPH
• The physics driving the cosmic star formation history
• How supernova feedback turns dark matter cusps into cores
• The Milky Way's bright satellites as an apparent failure of LCDM
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• Star formation thresholds and galaxy edges: why and where
• Massloss of galaxies due to a UV-background
• On the evolution of the HI column density distribution in cosmological simulations
• The Observed properties of Dark Matter on small spatial scales
• The properties of warm dark matter haloes
• The Effects of Photoionization on Galaxy Formation - I: Model and Results at z=0
• The haloes of bright satellite galaxies in a warm dark matter universe
• Dark matter and cosmic structure
• Quantifying the heart of darkness with GHALO - a multi-billion particle simulation of our galactic halo
• Smoothed Particle Hydrodynamics in Astrophysics
• Discreteness effects in simulations of Hot/Warm dark matter
• Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds
• The Missing Massive Satellites of the Milky Way
• Kinematics of Milky Way Satellites in a Lambda Cold Dark Matter Universe
• Through Thick and Thin - HI Absorption in Cosmological Simulations
• Lighting the Universe with filaments
• The phase space density of fermionic dark matter haloes
• Model independent analysis of dark matter points to a particle mass at the keV scale
• Physical properties of simulated galaxy populations at z=2 - I. Effect of metal-line cooling and feedback from star formation and AGN
• Physical properties of simulated galaxy populations at z=2 - II. Effects of cosmology, reionization and ISM physics

Cited by in corpus (11)

• Sterile Neutrino Dark Matter
• Formation of the first star clusters and massive star binaries by fragmentation of filamentary primordial gas clouds
• The halo mass function and filaments in full cosmological simulations with fuzzy dark matter
• Impact of filaments on galaxy formation in their residing dark matter haloes
• Reionisation in sterile neutrino cosmologies
• 21-cm observations and warm dark matter models
• The galaxy population in cold and warm dark matter cosmologies
• The impact of filaments on dwarf galaxy properties in the Auriga simulations
• Modeling Post-Reionization HI Distributions in Fuzzy Dark Matter Cosmologies Using Conditional Normalizing Flows
• Prospects for detecting cosmic filaments in Lyman-alpha emission across redshifts $z=2-5$
• Kolmogorov complexity in the Milky Way and its reduction with warm dark matter