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The mass profile of the Milky Way to the virial radius from the Illustris simulation

Taylor, Corbin and Boylan-Kolchin, Michael and Torrey, Paul and Vogelsberger, Mark and Hernquist, Lars (2016) The mass profile of the Milky Way to the virial radius from the Illustris simulation. Monthly Notices of the Royal Astronomical Society, 461 (4). pp. 3483-3493. ISSN 0035-8711.

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We use particle data from the Illustris simulation, combined with individual kinematic constraints on the mass of the Milky Way (MW) at specific distances from the Galactic Centre, to infer the radial distribution of the MW's dark matter halo mass. Our method allows us to convert any constraint on the mass of the MW within a fixed distance to a full circular velocity profile to the MW's virial radius. As primary examples, we take two recent (and discrepant) measurements of the total mass within 50 kpc of the Galaxy and find that they imply very different mass profiles and stellar masses for the Galaxy. The dark-matter-only version of the Illustris simulation enables us to compute the effects of galaxy formation on such constraints on a halo-by-halo basis; on small scales, galaxy formation enhances the density relative to dark-matter-only runs, while the total mass density is approximately 20 per cent lower at large Galactocentric distances. We are also able to quantify how current and future constraints on the mass of the MW within specific radii will be reflected in uncertainties on its virial mass: even a measurement of M(<50 kpc) with essentially perfect precision still results in a 20 per cent uncertainty on the virial mass of the Galaxy, while a future measurement of M(<100 kpc) with 10 per cent errors would result in the same level of uncertainty. We expect that our technique will become even more useful as (1) better kinematic constraints become available at larger distances and (2) cosmological simulations provide even more faithful representations of the observable Universe.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Boylan-Kolchin, Michael0000-0002-9604-343X
Torrey, Paul0000-0002-5653-0786
Vogelsberger, Mark0000-0001-8593-7692
Hernquist, Lars0000-0001-6950-1629
Additional Information:© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 June 21. Received 2016 June 21. In original form 2015 October 21. First published online June 26, 2016. We thank Joss Bland-Hawthorn, Nitya Kallivayalil, Julio Navarro, and Annalisa Pillepich for helpful conversations. The analysis of the Illustris data sets for this paper was done using the Odyssey cluster, which is supported by the FAS Division of Science, Research Computing Group at Harvard University. MB-K acknowledges support provided by NASA through a Hubble Space Telescope theory grant (programme AR-12836) from the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. PT acknowledges support from NASA ATP Grant NNX14AH35G. LH acknowledges support from NASA grant NNX12AC67G and NSF grant AST-1312095.
Funding AgencyGrant Number
NASA Hubble FellowshipAR-12836
Subject Keywords:Galaxy: fundamental parameters Galaxy: halo Galaxy: structure dark matter
Issue or Number:4
Record Number:CaltechAUTHORS:20161017-111754731
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Official Citation:Corbin Taylor, Michael Boylan-Kolchin, Paul Torrey, Mark Vogelsberger, and Lars Hernquist The mass profile of the Milky Way to the virial radius from the Illustris simulation MNRAS (October 01, 2016) Vol. 461 3483-3493 doi:10.1093/mnras/stw1522 first published online June 26, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:71175
Deposited By: Ruth Sustaita
Deposited On:17 Oct 2016 18:37
Last Modified:09 Mar 2020 13:19

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