2020/04/01 by Douglas Boubert, Denis Erkal, Boubert, Douglas +3
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Astrophysics of Galaxies (astro-ph.GA) #Experimental and Theoretical Physics Studies #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2004.00633
openalex publication_date 2020/04/01 · openalex created_date 2022/09/14 · openalex updated_date 2026/07/28
Stars slingshotted by the supermassive black hole at the Galactic centre will\nescape the Milky Way so quickly that their trajectories will be almost straight\nlines. Previous works have shown how these `hypervelocity stars' are\nsubsequently deflected by the gravitational field of the Milky Way and the\nLarge Magellanic Cloud (LMC), but have neglected to account for the reflex\nmotion of the Milky Way in response to the fly by of the LMC. A consequence of\nthis motion is that the hypervelocity stars we see on the outskirts of the\nMilky Way today were ejected from where the Milky Way centre was hundreds of\nmillions of years ago. This change in perspective causes large apparent\ndeflections in the trajectories of the hypervelocity stars, which are of the\nsame order as the deflections caused by the gravitational force of the Milky\nWay and LMC. We quantify these deflections by simulating the production of\nhypervelocity stars in an isolated Milky Way (with a spherical or flattened\ndark matter halo), in a fixed-in-place Milky Way with a passing LMC, and in a\nMilky Way which responds to the passage of the LMC. The proper motion precision\nnecessary to measure these deflections will be possible with the combination of\nGaia with the proposed GaiaNIR successor mission, and these measurements will\nunlock the hypervelocity stars as probes of the shape of the Milky Way, the\nmass of the LMC, and of the dance of these two galaxies.\n