The Copernicus Complexio: Statistical Properties of Warm Dark Matter Haloes

Bose, S.; Hellwing, W.A.; Frenk, C.S.; Jenkins, A.; Lovell, M.R.; Helly, J.C.; Li, B.

Abstract

The recent detection of a 3.5 keV X-ray line from the centres of galaxies and clusters by Bulbul et al. and Boyarsky et al. has been interpreted as emission from the decay of 7 keV sterile neutrinos which could make up the (warm) dark matter (WDM). As part of the Copernicus Complexio (COCO) programme, we investigate the properties of dark matter haloes formed in a high-resolution cosmological N-body simulation from initial conditions similar to those expected in a universe in which the dark matter consists of 7 keV sterile neutrinos. This simulation and its cold dark matter (CDM) counterpart have ∼13.4 bn particles, each of mass ∼105 h−1 M⊙, providing detailed information about halo structure and evolution down to dwarf galaxy mass scales. Non-linear structure formation on small scales (M200 ≲ 2 × 109 h−1 M⊙) begins slightly later in COCO-WARM than in COCO-COLD. The halo mass function at the present day in the WDM model begins to drop below its CDM counterpart at a mass ∼2 × 109 h−1 M⊙ and declines very rapidly towards lower masses so that there are five times fewer haloes of mass M200 = 108 h−1 M⊙ in COCO-WARM than in COCO-COLD. Halo concentrations on dwarf galaxy scales are correspondingly smaller in COCO-WARM, and we provide a simple functional form that describes its evolution with redshift. The shapes of haloes are similar in the two cases, but the smallest haloes in COCO-WARM rotate slightly more slowly than their CDM counterparts.

Citation

Bose, S., Hellwing, W., Frenk, C., Jenkins, A., Lovell, M., Helly, J., & Li, B. (2016). The Copernicus Complexio: Statistical Properties of Warm Dark Matter Haloes. Monthly Notices of the Royal Astronomical Society, 455(1), 318-333. https://doi.org/10.1093/mnras/stv2294

• Journal Article Type: Article
• Acceptance Date: Oct 1, 2015
• Online Publication Date: Nov 2, 2015
• Publication Date: Jan 1, 2016
• Deposit Date: Aug 17, 2015
• Publicly Available Date: Nov 5, 2015
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 455
• Issue: 1
• Pages: 318-333
• DOI: https://doi.org/10.1093/mnras/stv2294
• Keywords: Methods: numerical dark matter
• Related Public URLs: http://arxiv.org/abs/1507.01998