First-passage model fits the LMC Corona better

What the study found: The study finds that a first passage model for the Large Magellanic Cloud (LMC) better matches the present-day properties of its gaseous halo, called the Corona, than a second passage model. In this context, first passage means the LMC has only recently approached the Milky Way for the first time, while second passage means it had a previous close approach.
Why the authors say this matters: The authors say the size and gas properties of the LMC Corona can be used to distinguish between these two orbital histories. They conclude that the present-day gas properties strongly disfavor a second passage trajectory.
What the researchers tested: The researchers used constrained idealized simulations of the LMC/Milky Way interaction. They combined live circumgalactic gas particles with analytic dark matter potentials evolved along previously published orbital trajectories.
What worked and what didn't: The first passage model reproduced the observed velocity profile and column density profile of the present-day LMC Corona. In the second passage scenario, the longer interaction time led to present-day velocities and column densities around the LMC that were significantly lower than the observations. The study reports truncation radii of 16.6 ± 0.5 kpc for the first passage model and about 5.7 kpc for the second passage model.
What to keep in mind: The summary only describes the models and observational comparisons reported in the abstract. Other limitations are not described in the available summary.

Key points

• The first passage model matches the observed velocity and column density profiles of the LMC Corona.
• The second passage model produces present-day gas properties that are significantly lower than observations.
• The study reports a truncation radius of 16.6 ± 0.5 kpc for the first passage case.
• The reported truncation radius for the second passage case is about 5.7 kpc.
• The authors conclude that a second passage trajectory is strongly disfavored.