Related papers: GCN: a gaseous Galactic halo stream?
New 21cm observations with the Green Bank Telescope show that a significant fraction of the HI in the inner Galaxy's halo 1 kpc from the midplane exists in the form of discrete clouds. Some look very much like a Spitzer ``standard'' diffuse…
Stellar streams are key players in many aspects of Milky Way studies and, in particular, studying their orbital dynamics is crucial for furthering our understanding of the Milky Way's gravitational potential. Although this is not a trivial…
An all high-latitude sky survey for cool carbon giant stars in the Galactic halo has revealed 75 such stars, of which the majority are new detections. Of these, more than half are clustered on a Great Circle on the sky which intersects the…
The Orphan Stream is one of the most prominent tidal streams in the Galactic halo. Using data on red giants, RR Lyrae, and horizontal branch stars from Gaia and other surveys, we determine the proper motion of the Orphan Stream over a path…
The Magellanic Stream is a 100\deg x 10\deg filament of gas which lies within the Galactic halo and contains ~ 2 x 10^8 \Msun of neutral hydrogen. We present data from the HI Parkes All Sky Survey (HIPASS) in the first complete survey of…
Recent, high sensitivity, HI observations of nearby spiral galaxies show that their thin `cold' disks are surrounded by thick layers (halos) of neutral gas with anomalous kinematics. We present results for three galaxies viewed at different…
We present two sets of grid-based hydrodynamical simulations of high-velocity clouds (HVCs) traveling through the diffuse, hot Galactic halo. These HI clouds have been suggested to provide fuel for ongoing star formation in the Galactic…
Using Blue Horizontal Branch stars identified in the Dark Energy Survey Year 1 data, we report the detection of an extended and lumpy stellar debris distribution around the Magellanic Clouds. At the heliocentric distance of the Clouds,…
High velocity gas that does not conform to Galactic rotation is observed throughout the Galaxy's halo. One component of this gas, HI high velocity clouds (HVCs), have attracted attention since their discovery in the 1960s and remain…
We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and…
In this contribution the current state of knowledge about the high-velocity clouds (HVCs) is summarized. Recent progress has shown that the HVCs are a diverse phenomenon. The intermediate-velocity clouds (IVCs) are likely to be part of a…
The high- and intermediate-velocity interstellar clouds (HVCs/IVCs) are tracers of energetic processes in and around the Milky Way. Clouds with near-solar metallicity about one kpc above the disk trace the circulation of material between…
A population of discrete HI clouds in the halo of the inner Galaxy has been discovered in 21cm observations made with the Green Bank Telescope. The halo clouds are seen up to 1.5 kpc from the Galactic plane at many longitudes. Their…
The dominant gaseous structure in the Galactic halo is the Magellanic Stream, an extended network of neutral and ionized filaments surrounding the Large and Small Magellanic Clouds (LMC/SMC), the two most massive satellite galaxies of the…
The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic…
Various scenarios have been proposed to explain the origin of the Galactic high-velocity clouds, predicting different distances and implying widely varying properties for the Galaxy's gaseous halo. To eliminate the difficulties of studying…
Tidal streams of globular clusters are ideal tracers of the Galactic gravitational potential. Compared to the few known, complex and diffuse dwarf-galaxy streams, they are kinematically cold, have thin morphologies and are abundant in the…
Neutral hydrogen observations of the nearby, edge-on spiral galaxy NGC 891 reveal the presence of an HI halo extending up to at least 5 kpc from the plane. This halo gas appears to rotate 25 to 100 km/s more slowly than the gas in the…
The possibility of a gaseous halo stream which was stripped from the Sagittarius dwarf galaxy is presented. The total mass of the neutral hydrogen along the orbit of the Sgr dwarf in the direction of the Galactic anticenter is 4-10 x 10^6…
High-velocity clouds (HVC), fast-moving ionized and neutral gas clouds found at high galactic latitudes, may play an important role in the evolution of the Milky Way. The extent of this role depends sensitively on their distances and total…