Cited by 285Stellar, planetary, and galactic studiesGalaxies: Formation, Evolution, PhenomenaAstrophysical Phenomena and Observations

Tango for three: Sagittarius, LMC, and the Milky Way

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Vasiliev, Eugene, Belokurov, Vasily, Erkal, Denis·2021·Monthly Notices of the Royal Astronomical Society

Abstract

We assemble a catalogue of candidate Sagittarius stream members with 5D and 6D phase-space information, using astrometric data from Gaia DR2, distances estimated from RR Lyrae stars, and line-of-sight velocities from various spectroscopic surveys. We find a clear misalignment between the stream track and the direction of the reflex-corrected proper motions in the leading arm of the stream, which we interpret as a signature of a time-dependent perturbation of the gravitational potential. A likely cause of this perturbation is the recent passage of the most massive Milky Way satellite – the Large Magellanic Cloud (LMC). We develop novel methods for simulating the Sagittarius stream in the presence of the LMC, using specially tailored N-body simulations and a flexible parametrization of the Milky Way halo density profile. We find that while models without the LMC can fit most stream features rather well, they fail to reproduce the misalignment and overestimate the distance to the leading arm apocentre. On the other hand, models with an LMC mass in the range $(1.3\pm 0.3)\times 10^{11}\, \mathrm{M}_\odot$ rectify these deficiencies. We demonstrate that the stream can not be modelled adequately in a static Milky Way. Instead, our Galaxy is required to lurch toward the massive in-falling Cloud, giving the Sgr stream its peculiar shape and kinematics. By exploring the parameter space of Milky Way potentials, we determine the enclosed mass within 100 kpc to be $(5.6\pm 0.4)\times 10^{11}\, \mathrm{M}_\odot$, and the virial mass to be $(9.0\pm 1.3)\times 10^{11}\, \mathrm{M}_\odot$, and find tentative evidence for a radially-varying shape and orientation of the Galactic halo.

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Research works printed but not linked: 9

  1. Bland-Hawthorn J., Tepper-García T., 2020, arXiv:2009.02434 · arXiv
  2. Deason A., Erkal D., Belokurov V., et al., 2020, arXiv:2010.13801 · arXiv
  3. Emami R., Genel S., Hernquist L., et al., 2020, arXiv:2009.09220 · arXiv
  4. Erkal D., Deason A., Belokurov V., et al., 2020b, arXiv:2010.13789 · arXiv
  5. Garavito-Camargo N., Besla G., Laporte C., Price-Whelan A., Cunningham E., Johnston K., Weinberg M., Gómez F., 2020, arXiv:2010.00816 · arXiv
  6. Iorio G., Belokurov V., 2020, arXiv:2008.02280 · arXiv
  7. Li T. S., Koposov S., Erkal D., et al., 2020, arXiv:2006.10763 · arXiv
  8. Shao S., Cautun M., Deason A., Frenk C., 2020, arXiv:2005.03025 · arXiv
  9. Valluri M., Price-Whelan A., Snyder S., 2020, arXiv:2009.09004 · arXiv

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Authors
Vasiliev, E., Belokurov, V., & Erkal, D.
Affiliations
  • P.N. Lebedev Physical Institute of the Russian Academy of Sciences (RU)
  • University of Cambridge (GB)
  • University of Surrey (GB)
Corresponding author
Vasiliev, Eugene
Venue
Monthly Notices of the Royal Astronomical Society
Published
2020-11-25
Volume
501
Issue
2
Pages
2279-2304
ISSN
  • 0035-8711 (ISSN-L)
  • 1365-2966
OpenAlex
W3087827168
Cited by
285
References
136
Citations by year
2026: 39 · 2025: 60 · 2024: 48 · 2023: 47 · 2022: 47 · 2021: 42 · 2020: 2
FWCI
15.47
Type
journal article
Language
en
Open access
Locations
  • Monthly Notices of the Royal Astronomical Society (publishedVersion)
  • arXiv (Cornell University) (publishedVersion)
  • arXiv (Cornell University)
Funders
Science and Technology Facilities Council
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Astrophysical Phenomena and Observations
Keywords
Sagittarius stream, Large Magellanic Cloud, Galactic halo, gravitational perturbations, N-body simulations, Milky Way potential, halo mass, halo shape, stream kinematics, Gaia DR2 astrometry

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