A Lower Limit on the Mass of Our Galaxy from the H3 Survey

The timing argument provides a lower limit on the mass of the Milky Way. Using a sample of 32 stars at R > 60 kpc drawn from the H3 Spectroscopic Survey and mock catalogs created from published numerical simulations, we find that M200 > 0.91 × 1012 M with 90% confidence. We recommend using thi...

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Bibliographic Details
Published in:The Astrophysical journal 2020-01, Vol.888 (2), p.114
Main Authors: Zaritsky, Dennis, Conroy, Charlie, Zhang, Huanian, Naidu, Rohan P., Bonaca, Ana, Caldwell, Nelson, Cargile, Phillip A., Johnson, Benjamin D.
Format: Article
Language:English
Subjects:
Astrophysics
Computer simulation
Confidence
Galaxies
Milky Way
Milky Way dark matter halo
Milky Way Galaxy
Milky Way stellar halo
Numerical simulations
Polls & surveys
Stars
Stars & galaxies
Uncertainty analysis
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Summary:The timing argument provides a lower limit on the mass of the Milky Way. Using a sample of 32 stars at R > 60 kpc drawn from the H3 Spectroscopic Survey and mock catalogs created from published numerical simulations, we find that M200 > 0.91 × 1012 M with 90% confidence. We recommend using this limit to refine the allowed prior mass range in more complex and sophisticated statistical treatments of Milky Way dynamics. The use of such a prior would have significantly reduced many previously published uncertainty ranges. Our analysis suggests that the most likely value of M200 is 1.5 × 1012 M , but establishing this as the Milky Way mass requires a larger sample of outer halo stars and a more complete analysis of the inner halo stars in H3. The imminent growth in the sample of outer halo stars due to ongoing and planned surveys will make this possible.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ab5b93