Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall

TL;DR

This paper models the origins of ultra-faint dwarf galaxies near the Magellanic Clouds, suggesting they are products of Galactic processing during Magellanic group infall, and predicts their distribution and properties.

Contribution

It introduces a mass model of the Local Group that links UFDs to Magellanic Clouds and predicts their locations and characteristics based on Galactic processing effects.

Findings

UFDs are consistent with being former Magellanic satellites.

Gas-rich progenitors are analogous to current gas-deficient UFDs.

Predicted HI distribution aligns with observed Magellanic Stream features.

Abstract

The recent discoveries of ultra-faint dwarf (UFD) galaxies in the vicinity of the Magellanic system supports the expectation from cosmological models that such faint objects exist and are numerous. By developing a mass model of the Local Group and backwards integrating the Magellanic Clouds' present kinematics, we find that the locations of these UFDs are consistent with those predicted if previously associated with the Large MC as part of a loose association. We further demonstrate how these satellites are likely to have been processed by the Galactic hot halo upon accretion, with the implication that ongoing detections of extremely gas-rich objects on the periphery of the Galaxy and without clear stellar counterparts are analogous to the progenitors of the gas-deficient UFDs. Our model allows us predict the locations of other putative Magellanic satellites, and propose how their distribution/kinematics provide a novel constraint on the dynamical properties of the Galaxy. We also predict that the stripped metal-poor HI, previously associated with these UFDs, lies coincident with but distinguishable from the extensive Magellanic Stream.