The Space Density of Primordial Gas Clouds near Galaxies and Groups and their Relation to Galactic High-Velocity Clouds.

  title={The Space Density of Primordial Gas Clouds near Galaxies and Groups and their Relation to Galactic High-Velocity Clouds.},
  author={Zwaan and Briggs},
  journal={The Astrophysical journal},
  volume={530 2},
  • Zwaan, Briggs
  • Published 3 January 2000
  • Physics, Medicine
  • The Astrophysical journal
The Arecibo H i Strip Survey probed the halos of approximately 300 cataloged galaxies and the environments of approximately 14 groups with sensitivity to neutral hydrogen masses >/=107 M middle dot in circle. The survey detected no objects with properties resembling the high-velocity clouds (HVCs) associated with the Milky Way or Local Group. If the HVCs were typically MHi=107.5 M middle dot in circle objects distributed throughout groups and galaxy halos at distances of approximately 1 Mpc… Expand

Topics from this paper

Where are the high-velocity clouds in local group analogs?
High-velocity clouds (HVCs) are clouds of H I seen around the Milky Way with velocities inconsistent with Galactic rotation; they have unknown distances and masses and controversial origins. OneExpand
A targeted survey for H i clouds in galaxy groups
Five galaxy groups with properties similar to those of the Local Group have been surveyed for H I clouds with the Arecibo Telescope. In total 300 pointings have been observed on grids ofExpand
Free–Floating HI Clouds in the M 81 Group
Abstract Recent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~ 105 M⊙) HI clouds with no obvious opticalExpand
The abundance of dark galaxies
We show that gas in a large fraction of low-mass dark matter haloes may form Toomre-stable discs, if angular momentum is conserved when the gas contracts. Such haloes would be stable to starExpand
An HI survey of the Centaurus and Sculptor Groups - Constraints on the space density of low mass galaxies
We present results of two 21-cm Hi surveys performed with the Australia Telescope Compact Array in the nearby Centaurus A and Sculptor galaxy groups. These surveys are sensitive to compact Hi cloudsExpand
▪ Abstract ROSAT observations indicate that approximately half of all nearby groups of galaxies contain spatially extended X-ray emission. The radial extent of the X-ray emission is typically 50–500Expand
An H i view of galaxy conformity: H i-rich environment around H i-excess galaxies
Using data taken as part of the Bluedisk project, we study the connection between neutral hydrogen (H I) in the environment of spiral galaxies and that in the galaxies themselves. We measure theExpand
The H i detection of low column density clouds and galaxies
The HIDEEP survey was carried out in an attempt to find objects having low inferred neutral hydrogen column densities, yet it found a distribution that was strongly peaked at 10(20.65) cm(−2). In anExpand
Properties of Galaxy Dark Matter Halos from Weak Lensing
We present the results of a study of weak lensing by galaxies based on 45.5 deg2 of RC-band imaging data from the Red-Sequence Cluster Survey (RCS). We define a sample of lenses with 19.5 < RC < 21Expand
Astrophysics in 2000
It was a year in which some topics selected themselves as important through the sheer numbers of papers published. These include the connection(s) between galaxies with active central engines andExpand


A confirmed location in the Galactic halo for the high-velocity cloud ‘chain A’
The high-velocity clouds of atomic hydrogen, discovered about 35 years ago,, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky WayExpand
High-Velocity Clouds: Building Blocks of the Local Group
We suggest that the high-velocity clouds (HVCs) are large clouds, with typical diameters of 25 kpc, containing 3×107 M☉ of neutral gas and 3×108 M☉ of dark matter, falling onto the Local Group;Expand
Galaxies Discovered behind the Milky Way by the Dwingeloo Obscured Galaxies Survey
Our Galaxy blocks a significant portion of the extragalactic sky from view, hampering studies of large-scale structure. This produces an incomplete knowledge of the distribution of galaxies and,Expand
We report results from a 21 cm survey of fields in the Perseus-Pisces supercluster and a foreground void, which was designed to find gas-rich dwarf galaxies or optically faint H I clouds with massesExpand
The H I Mass Function of Galaxies from a Deep Survey in the 21 Centimeter Line
The H I mass function (HIMF) for galaxies in the local universe is constructed from the results of the Arecibo H I Strip Survey, a blind extragalactic survey in the 21 cm line. The survey, consistingExpand
The Escape of Ionizing Photons from the Galaxy
The Magellanic Stream and several high-velocity clouds have now been detected in optical line emission. The observed emission measures and kinematics are most plausibly explained by photoionizationExpand
Tidal disruption of the Magellanic Clouds by the Milky Way
Interactions between galaxies are common, and influence physical properties such as the global morphology and star-formation rate (Hubble type). Galaxies can interact in many different ways: they canExpand
▪ Abstract The Local Group dwarf galaxies offer a unique window to the detailed properties of the most common type of galaxy in the Universe. In this review, I update the census of Local Group dwarfsExpand
The Shape of the H i Mass Function for Late-Type Galaxies over the Range M H I 10 7--10 10 M sub sun
An analysis of two large catalogs of H I observations of nearby galaxies (Fisher & Tully and Hoffman et al.) does not yield evidence for either (1) a sharp rise in the number of low-mass- H I-richExpand
A deep survey of H I-selected galaxies: The sample and the data
In a 21 cm neutral hydrogen survey of approximately 55 deg2 out to a redshift of cz = 8340 km s-1, we have identified 75 extragalactic H I sources. These objects comprise a well-defined sample ofExpand