Dark matter–radiation interactions: the structure of Milky Way satellite galaxies

Schewtschenko, J.A.; Baugh, C.M.; Wilkinson, R.J.; Boehm, C.; Pascoli, S.; Sawala, T.

Abstract

In the thermal dark matter (DM) paradigm, primordial interactions between DM and Standard Model particles are responsible for the observed DM relic density. In Boehm et al. (2014), we showed that weak-strength interactions between DM and radiation (photons or neutrinos) can erase small-scale density fluctuations, leading to a suppression of the matter power spectrum compared to the collisionless cold DM (CDM) model. This results in fewer DM subhaloes within Milky Way-like DM haloes, implying a reduction in the abundance of satellite galaxies. Here we use very high resolution N-body simulations to measure the dynamics of these subhaloes. We find that when interactions are included, the largest subhaloes are less concentrated than their counterparts in the collisionless CDM model and have rotation curves that match observational data, providing a new solution to the “too big to fail” problem.

Citation

Schewtschenko, J., Baugh, C., Wilkinson, R., Boehm, C., Pascoli, S., & Sawala, T. (2016). Dark matter–radiation interactions: the structure of Milky Way satellite galaxies. Monthly Notices of the Royal Astronomical Society, 461(3), 2282-2287. https://doi.org/10.1093/mnras/stw1078

• Journal Article Type: Article
• Acceptance Date: May 4, 2016
• Online Publication Date: May 6, 2016
• Publication Date: Sep 21, 2016
• Deposit Date: Jun 10, 2016
• Publicly Available Date: Jun 16, 2016
• 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: 461
• Issue: 3
• Pages: 2282-2287
• DOI: https://doi.org/10.1093/mnras/stw1078
• Public URL: https://durham-repository.worktribe.com/output/1409754
• Related Public URLs: https://arxiv.org/abs/1512.06774