English
Related papers

Related papers: How was the mushroom-shaped GW 123.4--1.5 formed i…

200 papers

We present deep HI 21-cm and optical observations of the face-on spiral galaxy M 83 obtained as part of a project to search for high-velocity clouds (HVCs) in nearby galaxies. Anomalous-velocity neutral gas is detected toward M 83, with…

Astrophysics · Physics 2011-02-11 Eric D. Miller , Joel N. Bregman , Bart P. Wakker

High-velocity clouds (HVCs) in the Galactic center have garnered significant attention due to their mysterious formation, potentially linked to starburst events or supermassive black hole activity in the region. However, it remains…

Astrophysics of Galaxies · Physics 2025-02-25 Mengfei Zhang , Miao Li , Peixin Zhu

We present the germ of a new model for High Velocity Clouds, derived from the idea that the dark matter halo of our Galaxy is in the form of cold, planetary-mass gas clouds. In this picture HVCs arise as a result of disruptive collisions…

Astrophysics · Physics 2007-05-23 Mark Walker , Mark Wardle

We report the discovery of eleven high-velocity HI clouds at Galactic latitudes of 25-30 degrees, likely embedded in the Milky Way's nuclear wind. The clouds are detected with deep Green Bank Telescope 21 cm observations of a $3.2^\circ…

Astrophysics of Galaxies · Physics 2025-07-08 Rongmon Bordoloi , Andrew J. Fox , Felix J. Lockman

Numerical simulations have explored the possibility to form molecular clouds through either a quasi-static, self-gravitating mechanism or the collision of gas streams or lower-density clouds. They also quantitatively predict the…

We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusually large velocity dispersions of more than 100 km/s (FWHM)…

Astrophysics · Physics 2015-06-24 Harald Riffert , Pawan Kumar , W. K. Huchtmeier

We present the results of a study of simulated Giant Molecular Clouds (GMCs) formed in a Milky Way-type galactic disk with a flat rotation curve. This simulation, which does not include star formation or feedback, produces clouds with…

Astrophysics of Galaxies · Physics 2015-06-16 Samantha M. Benincasa , Elizabeth J. Tasker , Ralph E. Pudritz , James Wadsley

A recent discovery of two stellar clusters associated with the diffuse high-latitude cloud HRK 81.4-77.8 has important implications for star formation in the Galactic halo. We derive a plausible distance estimate to HRK 81.4-77.8 primarily…

Astrophysics of Galaxies · Physics 2016-05-04 J. Kerp , D. Lenz , T. Roehser

In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study…

Astrophysics of Galaxies · Physics 2014-11-20 Kyujin Kwak , Robin L. Shelton , Elizabeth A. Raley

We investigate the Hi envelope of the young, massive GMCs in the star-forming regions N48 and N49, which are located within the high column density Hi ridge between two kpc-scale supergiant shells, LMC 4 and LMC 5. New long-baseline Hi 21…

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…

Astrophysics of Galaxies · Physics 2011-02-11 Fabian Heitsch , Mary E. Putman

High-velocity clouds consist of cold gas that appears to be raining down from the halo to the disc of the Milky Way. Over the past fifty years, two competing scenarios have attributed their origin either to gas accretion from outside the…

Astrophysics of Galaxies · Physics 2015-06-23 F. Fraternali , A. Marasco , L. Armillotta , F. Marinacci

We investigate the effect of star formation and diffuse photoelectric heating on the properties of giant molecular clouds (GMCs) formed in high resolution (~< 10 pc) global (~ 20 kpc) simulations of isolated Milky Way-type galaxy disks. The…

Astrophysics of Galaxies · Physics 2015-05-27 Elizabeth J. Tasker

We investigate the formation and evolution of giant molecular clouds (GMCs) in a Milky-Way-like disk galaxy with a flat rotation curve. We perform a series of 3D adaptive mesh refinement (AMR) numerical simulations that follow both the…

Astrophysics · Physics 2009-07-22 Elizabeth J. Tasker , Jonathan C. Tan

Dense, star-forming gas is believed to form at the stagnation points of large-scale ISM flows, but observational examples of this process in action are rare. We here present a giant molecular cloud (GMC) sandwiched between two colliding…

Astrophysics of Galaxies · Physics 2015-06-23 J. R. Dawson , E. Ntormousi , Y. Fukui , T. Hayakawa , K. Fierlinger

FAST HI observations reveal unprecedented internal structures of the high-velocity cloud AC-III, which is found to consist of several coherent subclumps (D1-D6) with nearly constant line widths of $\sim 20~\mathrm{km~s^{-1}}$, while the…

Astrophysics of Galaxies · Physics 2025-10-31 Xunchuan Liu

[Abridged] The interstellar medium is observed to be organised in filamentary structures, as well as neutral (HI) and ionized (HII) bubbles. The expanding nature of these bubbles makes them shape their surroundings and possibly play a role…

We study the properties of all major HVC complexes from a sample compiled 1991 by Wakker & van Woerden (WvW). We use the Leiden/Argentine/Bonn all sky 21-cm line survey and decompose the profiles into Gaussian components. We find a well…

Astrophysics · Physics 2009-11-11 Peter M. W. Kalberla , Urmas Haud

New 21 cm HI observations have revealed a giant HI cloud in the Galactic plane that has unusual properties. It is quite well defined, about 150 pc in diameter at a distance of 5 kpc, and contains as much as 100,000 Solar Masses of atomic…

Astrophysics · Physics 2009-11-06 Anthony H. Minter , Felix J. Lockman , Glen I. Langston , Jennifer A. Lockman

We present a catalogue of Giant Molecular Clouds (GMCs) in M33, extracted from cold dust continuum emission. Our GMCs are identified by computing dendrograms. We measure the spatial distribution of these clouds, and characterise their dust…

Astrophysics of Galaxies · Physics 2018-12-31 Thomas G. Williams , Walter K. Gear , Matthew W. L. Smith