Grand, RJJ ORCID: 0000-0001-9667-1340, Deason, AJ
ORCID: 0000-0001-6146-2645, White, SDM
ORCID: 0000-0002-1061-6154, Simpson, CM
ORCID: 0000-0001-9985-1814, Gómez, FA, Marinacci, F
ORCID: 0000-0003-3816-7028 and Pakmor, R
ORCID: 0000-0003-3308-2420
(2019)
The effects of dynamical substructure on Milky Way mass estimates from the high-velocity tail of the local stellar halo.
Monthly Notices of the Royal Astronomical Society: Letters, 487 (1).
L720-LL76.
ISSN 1745-3925
Preview |
Text
slz092.pdf - Published Version Download (1MB) | Preview |
Abstract
We investigate the impact of dynamical streams and substructure on estimates of the local escape speed and total mass of Milky-Way-mass galaxies from modelling the high-velocity tail of local halo stars. We use a suite of high-resolution magnetohydrodynamical cosmological zoom-in simulations that resolve phase space substructure in local volumes around solar-like positions. We show that phase space structure varies significantly between positions in individual galaxies and across the suite. Substructure populates the high-velocity tail unevenly and leads to discrepancies in the mass estimates. We show that a combination of streams, sample noise, and truncation of the high-velocity tail below the escape speed leads to a distribution of mass estimates with a median that falls below the true value by ${\sim } 20 {{\ \rm per\ cent}}$, and a spread of a factor of 2 across the suite. Correcting for these biases, we derive a revised value for the Milky Way mass presented in Deason et al. of $1.29 ^{+0.37}_{-0.47} \times 10^{12}\, \rm M_{\odot }$.
Item Type: | Article |
---|---|
Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Uncontrolled Keywords: | 0201 Astronomical and Space Sciences |
Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
Divisions: | Astrophysics Research Institute |
Publisher: | Oxford University Press (OUP) |
Date of acceptance: | 3 June 2019 |
Date of first compliant Open Access: | 19 April 2023 |
Date Deposited: | 19 Apr 2023 11:52 |
Last Modified: | 05 Jul 2025 08:45 |
DOI or ID number: | 10.1093/mnrasl/slz092 |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/19321 |
![]() |
View Item |