# The COpernicus COmplexio: Statistical Properties of Warm Dark Matter Haloes

Source: [The COpernicus COmplexio: Statistical Properties of Warm Dark Matter Haloes](<https://www.sota2.com/research/paper/68fa32901e209131ce8891f8>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T19:35:08.481Z

Authors: Sownak Bose, Wojciech A. Hellwing, Carlos S. Frenk, Adrian Jenkins, Mark R. Lovell, John C. Helly, Baojiu Li

Published: 2015-07-08T00:44:30.000Z

## Abstract

The recent detection of a 3.5 keV X-ray line from the centres of galaxies and clusters by Bulbul et al. (2014a) and Boyarsky et al. (2014a) 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 $\\sim13.4$bn particles, each of mass $\\sim 10^5\\, h^{-1} M\_\\odot$, providing detailed information about halo structure and evolution down to dwarf galaxy mass scales. Non-linear structure formation on small scales ($M\_{200}\\, \\leq\\, 2 \\times 10^9\\,h^{-1}\\,M\_\\odot$) 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 $\\sim 2 \\times 10^{9}\\,h^{-1}\\,M\_\\odot$ and declines very rapidly towards lower masses so that there are five times fewer haloes of mass $M\_{200}= 10^{8}\\,h^{-1}\\,M\_\\odot$ 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.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1507.01998>)

[PDF](<https://arxiv.org/pdf/1507.01998.pdf>)