HI Observations Towards the Sagittarius Dwarf Spheroidal Galaxy

We have measured the 21-cm line of Galactic HI over more than 50 square degrees in the direction of the Sagittarius dwarf spheroidal galaxy. The data show no evidence of HI associated with the dwarf spheroidal which might be consider analogous to the Magellanic Stream as it is associated in both position and velocity with the Large Magellanic Cloud. Nor do the HI data show evidence for any disturbance in the Milky Way disk gas that can be unambiguously assigned to interaction with the dwarf galaxy. The data shown here limit the HI mass at the velocity of the Sagittarius dwarf to <7000 solar masses over some 18 square degrees between Galactic latitudes -13 degrees and -18 degrees.Comment: 5 pages, 4 figures; accepted for publication in Astronomy & Astrophysic

The Milky and its Gas: Cold Fountains and Accretion

The Milky Way is acquiring gas from infalling high-velocity clouds. The material enters a disk-halo interface that in many places is populated with HI clouds that have been ejected from the disk through processes linked to star formation. The Smith Cloud is an extraordinary example of a high-velocity cloud that is bringing $>10^6$ M$_{\odot}$ of relatively low metallicity gas into the Milky Way. It may be part of a larger stream, components of which are now passing through the disk.Comment: Presented at "Assembling the Puzzle of the Milky Way", Grand Bornand, April 201