Milky Way mass constraints from the Galactic satellite gap

Abstract

We use the distribution of maximum circular velocities, $V_{max}$, of satellites in the Milky Way (MW) to constrain the virial mass, $M_{200}$, of the Galactic halo under an assumed prior of a $\Lambda$CDM universe. This is done by analysing the subhalo populations of a large sample of halos found in the Millennium II cosmological simulation. The observation that the MW has at most three subhalos with $V_{max}\ge 30km/s$ requires a halo mass $M_{200}\le 1.4\times 10^{12}{M}_{\odot }$, while the existence of the Magellanic Clouds (assumed to have $V_{max}\ge 60km/s$) requires $M_{200}\ge 1.0\times 10^{12}{M}_{\odot }$. The first of these conditions is necessary to avoid the "too-big-to-fail" problem highlighted by Boylan-Kolchin et al., while the second stems from the observation that massive satellites like the Magellanic Clouds are rare. When combining both requirements, we find that the MW halo mass must lie in the range $0.25\le M_{200}/(10^{12}{M}_{\odot })\le 1.4$ at $90\%$ confidence. The gap in the abundance of Galactic satellites between $30km/s\le V_{max}\le 60km/s$ places our galaxy in the tail of the expected satellite distribution.

13 pages, 9 figures, updated to match published version in MNRAS

References in corpus (14)

• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• The RAVE Survey: Constraining the Local Galactic Escape Speed
• A common mass scale for satellite galaxies of the Milky Way
• Bent by baryons: the low mass galaxy-halo relation
• The Cold Dark Matter Halos of Local Group Dwarf Spheroidals
• SubHaloes going Notts: The SubHalo-Finder Comparison Project
• Dark matter subhalos and the dwarf satellites of the Milky Way
• The abundance of (not just) dark matter haloes
• The Mass Profile of the Galaxy to 80 kpc
• The velocity dispersion and mass profile of the Milky Way
• The mass and velocity anisotropy of the Carina, Fornax, Sculptor and Sextans dwarf spheroidal galaxies
• Dynamics of the Magellanic Clouds in a LCDM Universe
• Balancing mass and momentum in the Local Group

Cited by in corpus (11)

• Lyman-alpha Constraints on Ultralight Scalar Dark Matter: Implications for the Early and Late Universe
• The local high velocity tail and the Galactic escape speed
• Alignments between galaxies, satellite systems and haloes
• Subhalo statistics of galactic halos: beyond the resolution limit
• Constraining the mass of the Local Group
• Using Galaxy Pairs to Probe Star Formation During Major Halo Mergers
• Re-examining the Too-Big-To-Fail Problem for Dark Matter Haloes with Central Density Cores
• Not a Copernican observer: biased peculiar velocity statistics in the local Universe
• An Accurate Comprehensive Approach to Substructure: II. Stripped Subhaloes
• An Accurate Comprehensive Approach to Substructure: III. Masses and Formation Times of the Host Haloes
• The outskirts of M33: Tidally induced distortions versus signatures of gas accretion