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

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTIn 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 smallscale 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.

Matter power spectrum in hidden neutrino interacting dark matter models: a closer look at the collision term

“…Interacting DM effectively reduces the abundance of substructures in a galactic halo to a similar degree to that some WDM models do [27][28][29][30][31][32][33][34][35][36].…”

Constraining Dark Matter-Dark Radiation interactions with CMB, BAO, and Lyman-α

“…A class of models that has gained a lot of interest in recent years are those where DM couples to an additional relativistic dark sector, known as Dark Radiation (DR) [37][38][39][40]. Some of these models have been proposed to solve the missing satellite problem [41][42][43] or to delay reionization [44] by means of a cut-off in the matter power spectrum. Other classes of DM-DR models, with a smooth damping of the matter power spectrum, can alleviate the cosmological tensions on H 0 and/or σ 8 , as proposed in Refs.…”

Warm Dark Matter and Cosmic Reionization

“…Plenty of work has been devoted to trying to resolve these existing controversies at galactic and sub-galactic scales Lovell et al 2017;Sawala et al 2013Sawala et al , 2016Fattahi et al 2016;Polisensky & Ricotti 2014;Vogelsberger et al 2012;Schewtschenko et al 2016;Lovell et al 2012Lovell et al , 2014Lovell et al , 2016Nakama et al 2017). Among the possible solutions, a Warm Dark Matter (WDM) candidate with a ∼ keV mass will have a nonnegligible free-streaming scale, providing one of several potential explanations.…”