Satellite galaxies as better tracers of the Milky Way halo mass

Abstract The inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, deviations from steady-state in the tracer dist...

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Bibliographic Details
Published inProceedings of the International Astronomical Union Vol. 14; no. S353; pp. 109 - 112
Main Authors Han, Jiaxin, Wang, Wenting, Li, Zhaozhou
Format Journal Article
LanguageEnglish
Published Cambridge Cambridge University Press 01.06.2019
Subjects
Astronomy
Bias
Dark matter
Galaxies
Galaxy distribution
Milky Way
Stars
Stars & galaxies
Steady state models
Tracers
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Summary:Abstract The inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, deviations from steady-state in the tracer distribution lead to an irreducible stochastic bias. This bias is small for satellite galaxies and dark matter particles, but as large as a factor of 2 for halo stars. This is consistent with the picture that satellite galaxies closely trace the underlying phase space distribution of dark matter particles, while halo stars are less phase-mixed. As a result, the use of only ~100 satellite galaxies can achieve a significantly higher accuracy than that achievable with a much larger sample of halo stars.
ISSN:1743-9213
1743-9221
DOI:10.1017/S1743921319008020