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Related papers: Where are the high velocity clouds?

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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

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

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…

Astrophysics of Galaxies · Physics 2017-08-24 Asger Grønnow , Thor Tepper-García , Joss Bland-Hawthorn , Naomi McClure-Griffiths

We model the kinematics of the high- and intermediate- velocity clouds (HVCs and IVCs) observed in absorption towards a sample of 55 Galactic halo stars with accurate distance measurements. We employ a simple model of a thick disc whose…

Astrophysics of Galaxies · Physics 2022-05-25 A. Marasco , F. Fraternali , N. Lehner , J. C. Howk

A head-tail high-velocity cloud (HVC) is a neutral hydrogen halo cloud that appears to be interacting with the diffuse halo medium as evident by its compressed head trailed by a relatively diffuse tail. This paper presents a sample of 116…

Astrophysics of Galaxies · Physics 2015-05-30 M. E. Putman , D. R. Saul , E. Mets

We suggest that the high--velocity clouds (HVCs) are large clouds, with typical diameters of 25 kpc and containing 5e7 solar masses of neutral gas and 3e8 solar masses of dark matter, falling onto the Local Group; altogether the HVCs…

Astrophysics · Physics 2010-11-23 Leo Blitz , David N. Spergel , Peter J. Teuben , Dap Hartmann , W. Butler Burton

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…

Astrophysics · Physics 2007-05-23 B. P. Wakker

We present new observational results on high-velocity clouds (HVCs) based on an analysis of the Leiden/Dwingeloo HI survey. We cataloged all HVCs with NHI > 1 10^19 cm^-2 and found 252 clouds that form a representative flux limited sample.…

Astrophysics · Physics 2007-05-23 C. Bruens , J. Kerp , P. M. W. Kalberla , U. Mebold

The origin of our Galaxy's high-velocity clouds (HVCs) remains a mystery after many decades of effort. In this paper, we use the TNG50 simulation of the IllustrisTNG project to identify cool, dense clouds that match observations of Galactic…

Astrophysics of Galaxies · Physics 2024-10-21 Scott Lucchini , Jiwon Jesse Han , Lars Hernquist , Charlie Conroy

Three-dimensional simulations of the disk-halo interaction show the formation of a thick HI and HII gas disk with different scale heights. The thick HI disk prevents the disk gas from expanding freely upwards, unless some highly energetic…

Astrophysics · Physics 2009-10-31 Miguel A. de Avillez

We use spectroscopic data from HST and FUSE to study the wide range of ionization states of the "highly ionized high-velocity clouds". Studied extensively in OVI absorption, these clouds are usually assumed to be infalling gas in the…

Astrophysics · Physics 2009-11-10 J. A. Collins , J. M. Shull , M. L. Giroux

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…

Astrophysics of Galaxies · Physics 2015-06-04 N. Lehner , J. C. Howk , C. Thom , A. J. Fox , J. Tumlinson , T. M. Tripp , J. D. Meiring

High Velocity Clouds (HVCs) have recently attracted renewed attention as being long lived, massive dark matter dominated clouds of primordial composition distributed throughout the Local Group. In this picture the HVCs would contain a few…

Astrophysics · Physics 2007-05-23 Martin A. Zwaan

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 have recently identified several high velocity (V < -100 km/s) clouds in the directions of Mrk 509 and PKS 2155-304 that have unusual ionization properties. The clouds exhibit strong C IV absorption with little or no detectable low ion…

Astrophysics · Physics 2009-10-30 Kenneth R. Sembach , Blair D. Savage , Limin Lu , Edward M. Murphy

We present hydrodynamic simulations of high-velocity clouds (HVCs) traveling through the hot, tenuous medium in the Galactic halo. A suite of models was created using the FLASH hydrodynamics code, sampling various cloud sizes, densities,…

Astrophysics of Galaxies · Physics 2015-05-28 Kyujin Kwak , David B. Henley , Robin L. Shelton

We study the interaction of galactic wind with hot halo gas using hydrodynamical simulations. We find that the outcome of this interaction depends crucially on the wind injection density and velocity. Various phases of the extraplanar media…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Mahavir Sharma , Biman B. Nath , Indranil Chattopadhyay , Yuri Shchekinov

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

The high-velocity clouds (HVCs) in the outer Milky Way at $20^{\circ} < l < 190^{\circ}$ have similar spatial locations, metallicities, and kinematics. Moreover, their locations and kinematics are coincident with several extraplanar stellar…

Astrophysics of Galaxies · Physics 2022-10-21 Todd M. Tripp

From an analysis of the sky and velocity distributions of the high-velocity clouds (HVCs) we show that the majority of the HVCs has a common origin. We conclude that the HVCs surround the Galaxy, forming a metacloud of 300 kpc in size and…

Astrophysics · Physics 2009-11-11 Carlos A. Olano
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