The structure of the interstellar medium at the 25 AU scale

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168119· OSTI ID:6966828

Diamond, P J; Goss, W M; Romney, J D; Booth, R S; Kalberla, P M.W. ^[1]

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1. National Radio Astronomy Observatory, Charlottesville, VA (USA) Onsala Rymdobservatorium (Sweden) Bonn Universitaet (Germany, F.R.)

A three-station VLBI Galactic H I absorption experiment has been carried out with baselines up to 600 km. The large collecting area of the European VLBI Network consisting of the Lovell Telescope (Mark Ia), the 100 m telescope at Effelsberg, and the Westerbork Synthesis Radio Telescope was necessary to achieve adequate sensitivity for these high angular resolution (0.05 arcsec) and high-velocity resolution (0.5 km/s) observations. The extragalactic sources 3C 138, 3C 147, and 3C 380 were observed. Changes in the local H I apparent absorption were observed in all three sources as a function of resolution. The changes are most striking in the direction of 3C 138. The implied linear diameters are in the range 25 AU with typical H I densities of 10,000-100,000/cu cm. 19 refs.

• OSTI ID: 6966828
• Journal Information: Astrophysical Journal; (USA), Vol. 347; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERSTELLAR SPACE
MORPHOLOGY
ABSORPTION
ABSORPTION SPECTRA
COSMIC RADIO SOURCES
H1 REGIONS
INTERFEROMETRY
MILKY WAY
SPECTROSCOPY
GALAXIES
SPACE
SPECTRA
640105* - Astrophysics & Cosmology- Galaxies