Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall

Abstract

The Large Magellanic Cloud is the most massive satellite galaxy of the Milky Way, with an estimated mass exceeding a tenth of the mass of the Milky Way. Just past its closest approach of about 50 kpc, and flying by the Milky Way at an astonishing speed of 327 km/s, the Large Magellanic Cloud can affect our Galaxy in a number of ways, including dislodging the Milky Way disc from the Galactic centre-of-mass. Here, we report evidence that the Milky Way disc is moving with respect to stellar tracers in the outer halo ($40<r<120$ kpc) at $v_{\mathrm{travel}}=32_{-4}^{+4}$ km/s, in the direction $(\ell ,b{)}_{\mathrm{apex}}=(56_{-9}^{+9},-34_{-9}^{+10})$ degrees, which points at an earlier location on the LMC trajectory. The resulting reflex motion is detected in the kinematics of outer halo stars and Milky Way satellite galaxies with accurate distances, proper motions and line-of-sight velocities. Our results indicate that dynamical models of our Galaxy cannot neglect gravitational perturbations induced by the Large Magellanic Cloud infall, nor can observations of the stellar halo be treated in a reference frame that does not correct for disc reflex motion. Future spectroscopic surveys of the stellar halo combined with Gaia astrometry will allow for sophisticated modelling of the Large Magellanic Cloud trajectory across the Milky Way, constraining the dark matter distribution in both galaxies with unprecedented detail.

Author's version of the paper published 23 November 2020 in Nature Astronomy

References in corpus (8)

• The mass distribution and gravitational potential of the Milky Way
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• 4MOST: Project overview and information for the First Call for Proposals
• The shape of the inner Milky Way halo from observations of the Pal 5 and GD-1 stellar streams
• Dynamics of the Magellanic Clouds in a LCDM Universe
• Revised and new proper motions for confirmed and candidate Milky Way dwarf galaxies
• Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
• The Outer Halo of the Milky Way as Probed by RR Lyr Variables from the Palomar Transient Facility

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