The Magellanic Stream to Halo Interface: Processes that shape our nearest gaseous Halo Stream

TL;DR

This study investigates the small-scale hydrodynamical processes at the interface between the Magellanic Stream and the Galactic halo, using high-resolution HI observations to understand gas dynamics, transfer, and enrichment.

Contribution

It introduces a high-sensitivity HI observational program with advanced spatial analysis techniques to better understand the MS-halo interface processes.

Findings

Enhanced detection of low-density gas components near the halo

Identification of cold gas cores in the Magellanic Stream

Insights into gas transfer and metal enrichment processes

Abstract

Understanding the hydrodynamical processes and conditions at the interface between the Magellanic Stream (MS) and the Galactic halo is critical to understanding the MS and by extension, gaseous tails in other interacting galaxies. These processes operate on relatively small scales and not only help shape this clumpy stream, but also affect the neutral gas dynamics and transfer of mass from the stream to the halo, thus affecting metal enrichment and gas replenishment of the Galaxy. We describe an observational program to place constraints on these processes through high-resolution measurements of HI emission, HI absorption and Halpha emission with unprecedented sensitivity. Methods will include structural analysis, searching for cold gas cores in clumps and analyzing gas kinematics as it transitions to the halo. The latter method includes sophisticated spatial integration techniques to deeply probe the neutral gas, which we apply to a new HI map obtained from the Green Bank Telescope with the highest sensitivity HI observations of the MS to date. We demonstrate that the integration techniques enhance sensitivity even further, thus allowing detection of apparent MS gas components with density approaching that of the Galactic halo.