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Related papers: Neutral hydrogen in galactic fountains

200 papers

Nonlinear behaviour of galactic dynamos is studied, allowing for magnetic helicity removal by the galactic fountain flow. A suitable advection speed is estimated, and a one-dimensional mean-field dynamo model with dynamic alpha-effect is…

Astrophysics · Physics 2007-05-23 Anvar Shukurov , Dmitry Sokoloff , Kandaswamy Subramanian , Axel Brandenburg

Here I briefly highlight our studies of the gas content, kinematics and star formation in nearby dwarf galaxies (D < 10 Mpc) based on the `Local Volume HI Survey' (LVHIS, Koribalski et al. 2018), which was conducted with the Australia…

Astrophysics of Galaxies · Physics 2020-02-19 B. S. Koribalski

The Square Kilometre Array mid-frequency array will enable high-redshift detections of neutral hydrogen (HI) emission in galaxies, providing important constraints on the evolution of cold gas in galaxies over cosmic time. Strong…

Astrophysics of Galaxies · Physics 2024-09-12 Roger P. Deane , Tariq Blecher , Danail Obreschkow , Ian Heywood

Parkes neutral hydrogen 21 cm line (HI) observations of the surroundings of 9 early-type Local Group dwarfs are presented. We detected numerous HI clouds in the general direction of those dwarfs and these clouds are often offset from the…

Astrophysics · Physics 2008-11-26 A. Bouchard , C. Carignan , L. Staveley-Smith

The recent discovery of an enriched metallicity for the Smith high-velocity HI cloud (SC) lends support to a Galactic origin for this system. We use a dynamical model of the galactic fountain to reproduce the observed properties of the SC.…

Astrophysics of Galaxies · Physics 2016-09-22 Antonino Marasco , Filippo Fraternali

Neutral hydrogen clouds are found in the Milky Way and Andromeda halo both as large complexes and smaller isolated clouds. Here we present a search for Hi clouds in the halo of M33, the third spiral galaxy of the Local Group. We have used…

We have detected over 400 HI clouds in the lower halo of the Galaxy within the pilot region of the Galactic All-Sky Survey (GASS), a region of the fourth quadrant that spans 18 degrees in longitude, 40 degrees in latitude and is centered on…

Neutral atomic hydrogen (HI) observations are fundamental to understand the dynamics of galaxies, their assembly, the fuelling of their star formation and environmental interactions. HI studies have so far been limited by the capabilities…

Astrophysics of Galaxies · Physics 2024-08-16 F. M. Maccagni , W. J. G. de Blok

Using data taken as part of the Bluedisk project we study the connection between neutral hydrogen (HI) in the environment of spiral galaxies and that in the galaxies themselves. We measure the total HI mass present in the environment in a…

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

Galaxies in the local Universe are thought to require ongoing replenishment of their gas reservoir in order to maintain the observed star formation rates. Cosmological simulations predict that such accretion can occur in both a dynamically…

We present a comparison of the leftover satellites at z=0 in a cold dark matter dominated simulation of the formation of the Local Group to the distribution of observed neutral hydrogen high-velocity clouds and compact high-velocity clouds.…

Astrophysics · Physics 2007-05-23 M. E. Putman , B. Moore

Gas that escapes from the Galactic disk, rises into the halo, cools and falls back, constitutes a "Galactic Fountain". Three-Dimensional simulations show that such a fountain model reproduces many of the features that have been observed in…

Astrophysics · Physics 2007-05-23 Miguel A. de Avillez

Many of the baryons in our Galaxy probably lie outside the well known disk and bulge components. Despite a wealth of evidence for the presence of some gas in galactic halos, including absorption line systems in the spectra of quasars, high…

Astrophysics of Galaxies · Physics 2017-04-10 Huanian Zhang , Dennis Zaritsky

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

We measure the neutral atomic hydrogen (HI) gas content of field galaxies at intermediate redshifts of z ~ 0.1 and z ~ 0.2 using hydrogen 21-cm emission lines observed with the Westerbork Synthesis Radio Telescope (WSRT). In order to make…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jonghwan Rhee , Martin A. Zwaan , Frank H. Briggs , Jayaram N. Chengalur , Philip Lah , Tom Oosterloo , Thijs van der Hulst

The neutral hydrogen line profiles along the major axis of the nearby spiral galaxy NGC 2403 show a wing towards the sytemic velocity. This asymmetry can be explained with the presence of an abnormally thick HI disk (FWHM ~ 5 kpc) or with a…

Astrophysics · Physics 2007-05-23 W. E. Schaap , R. Sancisi , R. A. Swaters

We present a study of the filamentary structure in the atomic hydrogen (HI) emission at the 21 cm wavelength toward the Galactic plane using the observations in the HI4PI survey. Using the Hessian matrix method across radial velocity…

It is argued that galaxies like ours sustain their star formation by transferring gas from an extensive corona to the star-forming disc. The transfer is effected by the galactic fountain -- cool clouds that are shot up from the plane to…

Astrophysics of Galaxies · Physics 2015-05-18 F. Marinacci , J. Binney , F. Fraternali , C. Nipoti , L. Ciotti , P. Londrillo

We study the properties of low-column density gas clumps in the halo of the Milky Way based on high-resolution 21-cm observations. Using interferometric data from the WSRT and the VLA we study HI emission at low-, intermediate- and high…

Astrophysics of Galaxies · Physics 2015-05-13 N. Ben Bekhti , P. Richter , B. Winkel , F. Kenn , T. Westmeier