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Related papers: Compact High-Velocity Clouds at High Resolution

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We employ three-band Spitzer-MIPS observations to search for cold dust emission in three neutral hydrogen compact high-velocity clouds (CHVCs) in the vicinity of the Milky Way. Far-infrared emission correlated with HI column density was…

Astrophysics of Galaxies · Physics 2012-03-06 Rik J. Williams , Smita Mathur , Shawn Poindexter , Martin Elvis , Fabrizio Nicastro

We present a catalog of 59 ultra-compact high velocity clouds (UCHVCs) extracted from the 40% complete ALFALFA HI-line survey. The ALFALFA UCHVCs have median flux densities of 1.34 Jy km/s, median angular diameters of 10', and median…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-18 Elizabeth A. K. Adams , Riccardo Giovanelli , Martha P. Haynes

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

Hierarchical structure formation models predict the existence of large numbers of low velocity dispersion dark halos. Galaxy surveys find far fewer galaxies than predicted by analytical estimates and numerical simulations. In this paper, we…

Astrophysics · Physics 2007-05-23 Leo Blitz , David N. Spergel , Peter J. Teuben , Dap Hartman

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

Because isolated high-velocity clouds (HVCs) are found at great distances from the Galactic radiation field and because they have subsolar metallicities, there have been no detections of dust in these structures. A key problem in this…

Astrophysics of Galaxies · Physics 2016-02-10 Daniel Lenz , Lars Flöer , Jürgen Kerp

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

High-velocity clouds (HVCs) are composed of neutral hydrogen (HI) moving at velocities that deviate from the general rotational motion of the Milky Way. Currently, the origins of the HVCs remain poorly known due to the difficulty in…

Astrophysics of Galaxies · Physics 2025-04-15 Xiao-Lan Liu , Jin-Long Xu , Peng Jiang , Ming Zhu , Chuan-Peng Zhang , Naiping Yu , Ye Xu , Xin Guan , Jun-Jie Wang

We describe an automated search through the Leiden/Dwingeloo HI Survey (LDS) for high-velocity clouds north of Dec=-28 deg. From the general catalog we extract a sample of isolated high-velocity clouds, CHVCs: anomalous-velocity HI clouds…

Astrophysics · Physics 2009-11-07 V. de Heij , R. Braun , W. B. Burton

Arecibo mapping is reported of the neutral hydrogen distribution along selected directions out from the centers of two small High Velocity Clouds (HVC), W486 and W491. Both HVCs have a small inner region where the neutral hydrogen column…

Astrophysics · Physics 2009-11-07 G. L. Hoffman , E. E. Salpeter , M. G. Pocceschi

Growing evidence supports the suggestion that the compact high-velocity clouds of HI (CHVCs) are located throughout the Local Group and continue to fuel galactic evolution. Recent distance estimates to individual objects lie in the range…

Astrophysics · Physics 2009-10-31 Robert Braun , W. Butler Burton

Recent observations of high velocity clouds (HVCs) have revealed compression fronts and tail shaped features of HI suggesting that they are interacting with external medium. We perform 3-D hydro-dynamical simulations of HVCs moving through…

Astrophysics · Physics 2009-11-06 Vicent Quilis , Ben Moore

We study the hypothesis that high-velocity clouds (HVCs) may originate from instabilities within the gaseous phase of the Galactic halo. According to the hydrostatic equilibrium model of Kalberla & Kerp (1998), we determine the probability…

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

High-velocity clouds (HVCs), which are gas clouds moving at high velocity relative to the galactic disk, may play a critical role in galaxy evolution, potentially supplying gas to the disk and triggering star formation. In this study, we…

Astrophysics of Galaxies · Physics 2025-07-02 Maki Nagata , Fumi Egusa , Fumiya Maeda , Kazuki Tokuda , Kotaro Kohno , Kana Morokuma-Matsui , Jin Koda

We present new HI observations of the high-velocity cloud (HVC) that we resolved near the Local Group dwarf galaxy LGS 3. The cloud is rotating, with an implied mass that makes it dark matter-dominated no matter what its distance from the…

Astrophysics · Physics 2007-05-23 Joshua D. Simon , Timothy Robishaw , Leo Blitz

We present dark-matter minihalo models for the Ultra-Compact High Velocity HI Clouds (UCHVCs) recently discovered in the 21 cm ALFALFA survey. We assume gravitational confinement of 10^4 K HI gas by flat-cored dark-matter subhalos within…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-06 Yakov Faerman , Amiel Sternberg , Christopher F. McKee

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

High-latitude ($|b|>30^{\circ}$) molecular clouds have virial parameters that exceed 1, but whether these clouds can form stars has not been studied systematically. Using JCMT SCUBA-2 archival data, we surveyed 70 fields that target…

One of the predictions of the standard CDM is that dark haloes have centrally divergent density profiles. An extensive body of rotation curve observations of dwarf and low surface brightness galaxies shows the dark haloes of those systems…

Astrophysics · Physics 2009-10-31 C. Firmani , E. D'Onghia , G. Chincarini , X. Hernandez , V. Avila-Reese

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