Milky Way mass constraints from the Galactic satellite gap

Cautun, M.; Frenk, C.S.; van de Weygaert, R.; Hellwing, W.A.; Jones, B.J.T.

doi:10.1093/mnras/stu1849

Milky Way mass constraints from the Galactic satellite gap

Cautun, M.; Frenk, C.S.; van de Weygaert, R.; Hellwing, W.A.; Jones, B.J.T.

Authors

M. Cautun

C.S. Frenk

R. van de Weygaert

W.A. Hellwing

B.J.T. Jones

Abstract

We use the distribution of maximum circular velocities, Vmax, of satellites in the Milky Way (MW) to constrain the virial mass, M200, of the Galactic halo under an assumed prior of a Λ cold dark matter universe. This is done by analysing the subhalo populations of a large sample of haloes found in the Millennium II cosmological simulation. The observation that the MW has at most three subhaloes with Vmax ≥ 30 km s−1 requires a halo mass M200 ≤ 1.4 × 1012 M⊙, while the existence of the Magellanic Clouds (assumed to have Vmax ≥ 60 km s−1) requires M200 ≥ 1.0 × 1012 M⊙. 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 ≤ M200/(1012 M⊙) ≤ 1.4 at 90 per cent confidence. The gap in the abundance of Galactic satellites between 30 km s−1 ≤ Vmax ≤ 60 km s−1 places our galaxy in the tail of the expected satellite distribution.

Citation

Cautun, M., Frenk, C., van de Weygaert, R., Hellwing, W., & Jones, B. (2014). Milky Way mass constraints from the Galactic satellite gap. Monthly Notices of the Royal Astronomical Society, 445(2), 2049-2060. https://doi.org/10.1093/mnras/stu1849

Journal Article Type	Article
Acceptance Date	Sep 4, 2014
Publication Date	Dec 1, 2014
Deposit Date	Oct 21, 2014
Publicly Available Date	Apr 15, 2015
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	445
Issue	2
Pages	2049-2060
DOI	https://doi.org/10.1093/mnras/stu1849
Keywords	Galaxy: abundances, Galaxy: halo, Dark matter.

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This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.