The spatial distribution of Milky Way satellites, gaps in streams and the nature of dark matter

Abstract

The spatial distribution of Milky Way (MW) subhaloes provides an important set of observables for testing cosmological models. These include the radial distribution of luminous satellites, planar configurations, and the abundance of dark subhaloes whose existence or absence is key to distinguishing amongst dark matter models. We use the COCO $N$-body simulations of cold dark matter (CDM) and 3.3keV thermal relic warm dark matter (WDM) to predict the satellite spatial distribution in the limit that the impact of baryonic physics is minimal. We demonstrate that the radial distributions of CDM and 3.3keV-WDM luminous satellites are identical if the minimum pre-infall halo mass to form a galaxy is $>10^{8.5}{\mathrm{M}}_{\odot }$. The distribution of dark subhaloes is significantly more concentrated in WDM due to the absence of low mass, recently accreted substructures that typically inhabit the outer parts of a MW halo in CDM. We show that subhaloes of mass $[10^7,10^8]{\mathrm{M}}_{\odot }$ and within 30kpc of the centre are the stripped remnants of larger haloes in both models. Therefore their abundance in WDM is $3\times$ higher than one would anticipate from the overall WDM subhalo population. We estimate that differences between CDM and WDM concentration-mass relations can be probed for subhalo-stream impact parameters $<2$kpc. Finally, we find that the impact of WDM on planes of satellites is likely negligible. Comprehensive comparisons with observations will require further work with high resolution, self-consistent hydrodynamical simulations.

15 pages, 4 figures. Accepted version of paper. Contact: [email protected]

References in corpus (20)

• Sterile neutrino dark matter as a consequence of nuMSM-induced lepton asymmetry
• SubHaloes going Notts: The SubHalo-Finder Comparison Project
• Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies
• The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites
• The abundance of (not just) dark matter haloes
• Shaken and Stirred: The Milky Way's Dark Substructures
• Joint constraints on thermal relic dark matter from strong gravitational lensing, the Lyman-$\alpha$ forest, and Milky Way satellites
• Dark Matter Constraints from a Unified Analysis of Strong Gravitational Lenses and Milky Way Satellite Galaxies
• The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2
• Lighting the Universe with filaments
• Discs of Satellites: the new dwarf spheroidals
• Constraints on the properties of warm dark matter using the satellite galaxies of the Milky Way
• Gaps in globular cluster streams: giant molecular clouds can cause them too
• Satellite Systems around Galaxies in Hydrodynamic Simulations
• The asymptotic tidal remnants of cold dark matter subhalos
• Can cosmological simulations capture the diverse satellite populations of observed Milky Way analogues?
• Evolution of galactic planes of satellites in the EAGLE simulation
• The Role of Baryons in Creating Statistically Significant Planes of Satellites around Milky Way-Mass Galaxies
• Magellanic satellites in $\Lambda$CDM cosmological hydrodynamical simulations of the Local Group
• An updated detailed characterization of planes of satellites in the MW and M31

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• The Effects of Dark Matter and Baryonic Physics on the Milky Way Subhalo Population in the Presence of the Large Magellanic Cloud
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