A robust estimate of the Milky Way mass from rotation curve data
File(s)
Working paper
Author(s)
Karukes, Ekaterina V
Benito, Maria
Iocco, Fabio
Trotta, Roberto
Geringer-Sameth, Alex
Type
Working Paper
Abstract
We present a new estimate of the mass of the Milky Way, inferred via a
Bayesian approach from tracers of the circular velocity in the disk plane and
stars in the stellar halo. We use the rotation curve method to determine the
dark matter density profile, together with the total stellar mass, which is
constrained by surface stellar density and microlensing measurements. We also
include uncertainties on the baryonic morphology via Bayesian model averaging,
thus converting a potential source of systematic error into a more manageable
statistical uncertainty. We evaluate the robustness of our result against
various possible systematics, including rotation curve data selection,
uncertainty on the Sun's velocity $V_0$, dependence on the dark matter profile
assumptions, and choice of priors. We find the Milky Way's virial mass to be
$\log_{10}M_{200}/ {\rm M_\odot} =
11.92^{+0.06}_{-0.05}{\rm(stat)}\pm{0.28}\pm0.27{\rm(syst)}$ and the total mass
to be $\log_{10}M_{\rm tot}/ {\rm M_\odot} =
11.95^{+0.04}_{-0.04}{\rm(stat)}\pm{0.25}\pm0.25{\rm(syst)}$
($M_{200}=8.3^{+1.2}_{-0.9}{\rm(stat)}\times10^{11}\,{\rm M_\odot}$ and $M_{\rm
tot}=8.9^{+1.0}_{-0.8}{\rm(stat)}\times10^{11}\,{\rm M_\odot}$). We also apply
our framework to Gaia DR2 rotation curve data and find good statistical
agreement with the above results.
Bayesian approach from tracers of the circular velocity in the disk plane and
stars in the stellar halo. We use the rotation curve method to determine the
dark matter density profile, together with the total stellar mass, which is
constrained by surface stellar density and microlensing measurements. We also
include uncertainties on the baryonic morphology via Bayesian model averaging,
thus converting a potential source of systematic error into a more manageable
statistical uncertainty. We evaluate the robustness of our result against
various possible systematics, including rotation curve data selection,
uncertainty on the Sun's velocity $V_0$, dependence on the dark matter profile
assumptions, and choice of priors. We find the Milky Way's virial mass to be
$\log_{10}M_{200}/ {\rm M_\odot} =
11.92^{+0.06}_{-0.05}{\rm(stat)}\pm{0.28}\pm0.27{\rm(syst)}$ and the total mass
to be $\log_{10}M_{\rm tot}/ {\rm M_\odot} =
11.95^{+0.04}_{-0.04}{\rm(stat)}\pm{0.25}\pm0.25{\rm(syst)}$
($M_{200}=8.3^{+1.2}_{-0.9}{\rm(stat)}\times10^{11}\,{\rm M_\odot}$ and $M_{\rm
tot}=8.9^{+1.0}_{-0.8}{\rm(stat)}\times10^{11}\,{\rm M_\odot}$). We also apply
our framework to Gaia DR2 rotation curve data and find good statistical
agreement with the above results.
Date Issued
2019-12-09
Citation
2019
Publisher
arXiv
Copyright Statement
© 2019 The Author(s)
Sponsor
European Commission
Science and Technology Facilities Council
Science and Technology Facilities Council (STFC)
Identifier
http://arxiv.org/abs/1912.04296v1
Grant Number
H2020-MSCA-RISE-2015-691164
ST-N000838
ST/N000838/1
Subjects
astro-ph.GA
astro-ph.GA
hep-ph
Notes
31 pages, 9 figures, 6 tables
Publication Status
Published