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We present a 21cm line HI self-absorption (HISA) survey of cold atomic gas within Galactic longitudes 75 to 146 degrees and latitudes -3 to +5 degrees. We identify HISA as spatially and spectrally confined dark HI features and extract it…

We present a 93' by 93' map of the area near the Local Group dwarf galaxy LGS 3, centered on an HI cloud 30' away from the galaxy. Previous authors associated this cloud with LGS 3 but relied on observations made with a 36' beam. Our…

Astrophysics · Physics 2009-11-07 Timothy Robishaw , Joshua D. Simon , Leo Blitz

We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously…

Astrophysics · Physics 2009-11-13 T. Oosterloo , R. Morganti , E. M. Sadler , J. M. van der Hulst , P. Serra

The low column density gas at the outskirts of galaxies as traced by the 21 cm hydrogen line emission (HI) represents the interface between galaxies and the intergalactic medium, i.e., where galaxies are believed to get their supply of gas…

Astrophysics of Galaxies · Physics 2018-05-23 Roger Ianjamasimanana , Fabian Walter , W. J. G. de Blok , George H. Heald , Elias Brinks

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

While studying extraplanar neutral hydrogen in the disk-halo transition of the inner Galaxy we have discovered what appears to be a huge superbubble centered around l ~ 30 deg, whose top extends to latitudes > 25 deg at a distance of about…

Astrophysics · Physics 2008-11-26 Yurii Pidopryhora , Felix J. Lockman , Joseph C. Shields

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 have conducted an HI 21 cm emission-line survey using the Parkes 20cm multibeam instrument and the Australia Telescope Compact Array (ATCA) of six loose groups of galaxies chosen to be analogs to the Local Group. The goal of this survey…

Astrophysics · Physics 2011-02-11 D. J. Pisano , D. G. Barnes , B. K. Gibson , L. Staveley-Smith , K. Freeman , V. A. Kilborn

We present a second catalog of HI sources detected in the Arecibo Legacy Fast ALFA Survey. We report 488 detections over 135 square degrees, within the region of the sky having 22h<RA<03h and +26deg<Dec<+28deg. We present here the…

We present results from MUSE observations of a 21-cm HI absorption system detected with the Australian Square Kilometre Array Pathfinder radio telescope at redshift $z = 0.4503$ towards the $z = 1.71$ quasar PKS 1610-771. We identify four…

We present Australia Telescope Compact Array (ATCA) observations of a galaxy-sized intergalactic HI cloud (the Vela Cloud) in the NGC 3256 galaxy group. The group contains the prominent merging galaxy NGC 3256, which is surrounded by a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Jayanne English , Baerbel Koribalski , Joss Bland-Hawthorn , Ken Freeman , Claudia McCain

The extra-planar H I in the inner parts of the Milky Way has been discovered to contain numerous cloud-like structures when observed in the 21cm line with the Green Bank Telescope (GBT). These halo clouds have motions consistent with…

Astrophysics · Physics 2009-09-29 Felix J. Lockman , Yurii Pidopryhora

High-velocity clouds (HVCs) are neutral or ionised gas clouds in the vicinity of the Milky Way that are characterised by high radial velocities inconsistent with participation in the regular rotation of the Galactic disc. Previous attempts…

Astrophysics of Galaxies · Physics 2017-12-05 Tobias Westmeier

In this study, we analyze molecular gas formation in neutral atomic hydrogen (HI) clouds using the latest CO data obtained from the four-beam receiver system on a 45-m telescope (FOREST) unbiased Galactic plane imaging survey with the…

The search for ``dark galaxies,'' a key prediction of the lambda cold dark matter, has yielded few viable candidates. Recently, FAST J0139+4328 was reported as the first isolated dark galaxy in the nearby universe, based on a neutral…

Cosmological galaxy formation models predict the existence of dark matter minihalos surrounding galaxies and in filaments connecting groups of galaxies. The more massive of these minihalos are predicted to host HI gas that should be…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Katie M. Chynoweth , Glen I. Langston , Kelly Holley-Bockelmann

We present the results of a new sensitive survey of neutral hydrogen above and below the Galactic Center with the Green Bank Telescope. The observations extend up to Galactic latitude | b | < 10 deg with an effective angular resolution of…

Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…

Astrophysics · Physics 2009-11-07 Felix J. Lockman , Edward M. Murphy , Sara Petty-Powell , Vincent J. Urick

We have mapped the emission from atomic hydrogen at 21 cm from the galaxy NGC 3783 with the Australia Telescope Compact Array. Our main results are: a) the HI morphology is irregular and perturbed, gathered in three blobs apparently…

Astrophysics · Physics 2007-05-23 J. A. Garcia-Barreto , F. Combes , B. Koribalski , J. Franco

Most detected neutral atomic hydrogen (HI) at low redshift is associated with optically bright galaxies. However, a handful of HI clouds are known which appear to be optically dark and have no nearby potential progenitor galaxies, making…

Astrophysics of Galaxies · Physics 2018-05-23 Rhys Taylor , Richard Wünsch , Jan Palouš