LOW-VELOCITY HALO CLOUDS
نویسندگان
چکیده
منابع مشابه
Low-Velocity Halo Clouds
Models that reproduce the observed high-velocity clouds (HVCs) also predict clouds at lower radial velocities that may easily be confused with Galactic disk (|z| < 1 kpc) gas. We describe the first search for these low-velocity halo clouds (LVHCs) using IRAS data and the initial data from the Galactic Arecibo L-band Feed Array survey in Hi (GALFA-Hi). The technique is based upon the expectation...
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In the five years since its launch, the Far Ultraviolet Spectroscopic Explorer has given the astronomical community a marvelous glimpse into the realm of previously unexplored regions of the Milky Way and its surroundings. Absorption lines produced by gas along entire paths through the nearby universe have now been recorded in the spectra of distant QSOs and active galactic nuclei. Of the lines...
متن کاملA FUSE Survey of Molecular Hydrogen in Intermediate-Velocity Clouds in the Milky Way Halo
Far Ultraviolet Spectroscopic Explorer (FUSE) data is used to investigate the molecular hydrogen (H2) content of intermediate-velocity clouds (IVCs) in the lower halo of the Milky Way. We analyze interstellar absorption towards 56 (mostly extragalactic) background sources to study H2 absorption in the Lymanand Werner bands in 61 IVC components at H i column densities ≥ 10 cm. For data with good...
متن کاملOptical Emission from High Velocity Clouds and the Ionization Sources in the Galactic Halo
Optical emission lines have now been detected from about 20 high velocity clouds. These emission lines – primarily Hα, secondarily [N ii] and [S ii] – are very faint and diffuse, spread over the surfaces of the clouds. We compile emission line measurements and present a model in which the Hα is recombination caused by photoionizing radiation escaping the Milky Way. In such a model, we infer HVC...
متن کاملCompact High Velocity Clouds
We summarize the observed properties of the CHVC population, which provide strong evidence for source distances in the range 200– 1000 kpc. At these distances, the population corresponds to strongly dark-matter dominated sub-dwarf galaxies still accreting onto the more massive Local Group systems. Recent searches for faint associated stellar populations have revealed red-giant candidates for wh...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2009
ISSN: 0004-637X,1538-4357
DOI: 10.1088/0004-637x/692/1/827