Accession Number : AD0683213

Title :   OBSERVATIONS OF FOUR H II REGIONS AT A WAVELENGTH OF 2.8 CENTIMETERS,

Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) RADIO AND ELECTRICAL ENGINEERING DIV

Personal Author(s) : MacLeod,John M. ; Doherty,Lorne H.

Report Date : 01 APR 1968

Pagination or Media Count : 15

Abstract : Contour maps of the H 2 regions W12, Orion A, W43, and W51 are presented. These were derived from observations at 2.8 cm with a beam of 2.'.8. With this resolution, W12 consists of a single component, Orion A of two components, W43 of four components plus a large extended source, and W51 of eight components plus a large extended source. Flux densities and angular sizes of the components are listed, as are electron densities, emission measures, and masses. Identifications of the emission nebulae and the exciting stars are considered, and in the case of Orion A the data suggest that the main source is density-bounded on the north. The spectra of the sources are presented and discussed. It has previously been suggested that W51 contains a non-thermal source, but no evidence for this component has been found. W51 and W43 are shown to have certain similarities in structure which may be related to their positions at tangential points of spiral arms. (Author)

Descriptors :   (*INTERSTELLAR MATTER, *EXTRATERRESTRIAL RADIO WAVES), FREE RADICALS, HYDROGEN, ELECTRON DENSITY, NEBULAE, STARS, MAPPING, CANADA

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE