Accession Number : AD0724182

Title :   An Absorption-Line Study of the Galactic Neutral-Hydrogen at 21 CM,

Corporate Author : OWENS VALLEY RADIO OBSERVATORY PASADENA CALIF

Personal Author(s) : Hughes,M. P. ; Thompson,A. R. ; Colvin,R. S.

Report Date : 1971

Pagination or Media Count : 83

Abstract : The paper describes observations of galactic 21-cm line absorption in the spectra of ninety-seven radio sources made with the two-element interferometer at the Owens Valley Radio Observatory. Measurements of 21-cm absorption are of fundamental importance because they yield directly information on the optical depth of the galactic hydrogen. Almost all of the many studies of the 21-cm line are concerned with observations in emission, and require assumptions concerning the optical depth before the data can be interpreted in terms of the temperature or columnar density of the gas.

Descriptors :   (*INTERSTELLAR MATTER, *EXTRATERRESTRIAL RADIO WAVES), HYDROGEN, ABSORPTION SPECTRA, LINE SPECTRA, RADIO ASTRONOMY, TABLES(DATA)

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE