The Magellanic Stream at 20 kpc: A New Orbital History for the Magellanic Clouds

We present new simulations of the formation of the Magellanic Stream based on an updated first-passage interaction history for the Magellanic Clouds, including both the Galactic and Magellanic Coronae and a live dark matter halo for the Milky Way. This new interaction history is needed because previ...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2021-11, Vol.921 (2), p.L36
Main Authors: Lucchini, Scott, D’Onghia, Elena, Fox, Andrew J.
Format: Article
Language:English
Subjects:
Clouds
Corona
Dark matter
Galactic halos
Galaxy dynamics
Galaxy physics
H alpha line
Magellanic Clouds
Magellanic Stream
Mass distribution
Milky Way
Orbits
Tidal power
Ultraviolet absorption
Ultraviolet radiation
Velocity distribution
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Summary:We present new simulations of the formation of the Magellanic Stream based on an updated first-passage interaction history for the Magellanic Clouds, including both the Galactic and Magellanic Coronae and a live dark matter halo for the Milky Way. This new interaction history is needed because previously successful orbits need updating to account for the Magellanic Corona and the loosely bound nature of the Magellanic Group. These orbits involve two tidal interactions over the last 3.5 Gyr and reproduce the Stream’s position and appearance on the sky, mass distribution, and velocity profile. Most importantly, our simulated Stream is only ∼20 kpc away from the Sun at its closest point, whereas previous first-infall models predicted a distance of 100–200 kpc. This dramatic paradigm shift in the Stream’s 3D position would have several important implications. First, estimates of the observed neutral and ionized masses would be reduced by a factor of ∼5. Second, the stellar component of the Stream is also predicted to be
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ac3338