Observations of high velocity HI clouds in the Local Group
نویسندگان
چکیده
منابع مشابه
Westerbork HI observations of two High - Velocity Clouds
Westerbork HI synthesis observations are presented for the directions of the stars 4 Lac and HD 135485. Interstellar absorption lines at high velocities had been reported in the UV spectrum of 4 Lac, setting an upper limit of 1.2 kpc on the distance of the associated, small HI cloud (Bates et al. 1990, 1991). The Westerbork observations show that this cloud (l = 100o, b = −7o, vLSR = +100 km s−...
متن کاملHigh-velocity Clouds and the Local Group
I examine some of the evidence relevant to the idea that high-velocity clouds (HVCs) are gas clouds distributed throughout the Local Group, as proposed by Blitz et al. (1999) and Braun & Burton (1999). This model makes several predictions: a) the clouds have low metallicities; b) there should be no detectable Hα emission; c) analogues near other galaxies should exist; and d) many faint HVCs in ...
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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. One possibility is that HVCs are associated with the small dark matter halos seen in models of galaxy formation and distributed at distances of 150 kpc to 1 Mpc. We report on our attempts to detect the anal...
متن کاملHigh–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 and containing 5×107 solar masses of neutral gas and 3×108 solar masses of dark matter, falling onto the Local Group; altogether the HVCs contain 10 solar masses of neutral gas. Our reexamination of the Local–Group hypothesis for the HVCs connects their properties to the hierarchical structure for...
متن کاملInfrared Search for Young Stars in Hi High-velocity Clouds
We have searched the IRAS Point Source Catalog and HIRES maps for young stellar objects (YSOs) in the direction of five HI high-velocity clouds (HVCs). In agreement with optical searches in the halo, no evidence was found for extensive star-forming activity inside the high-latitude HVCs. Specifically, we have found no signs of star formation or YSOs in the direction of the A IV cloud or in the ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1978
ISSN: 0074-1809
DOI: 10.1017/s0074180900144237