Flux densities of ultracompact H II regions at 7 millimeters

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166145· OSTI ID:6995524

Wood, D O.W.; Churchwell, E; Handa, T; Fukui, Y; Sofue, Y

Observations of the 7-mm continuum are reported for 29 suspected ultracompact (UC) H II regions. Twenty-seven sources were detected, most of which had not previously been observed at 7 mm. These sources were found to be small (only eight were fully resolved by the 43-arcsec beam) and bright at mm wavelengths (greater than 0.5 Jy), making them easy to distinguish from associated diffuse free-free emission which can confuse single-dish observations made at cm wavelengths. The ionizing stars are mostly O5-O6, consistent with the detection limit of 0.5 Jy. It is found that dust in UC H II regions typically absorbs more than 50 percent of the stellar ionizing photons. Some of the sources reported here might also serve as flux and pointing calibrators at mm wavelengths. 19 references.

• Research Organization: Washburn Observatory, Madison, WI (USA); Nobeyama Radio Observatory, Minamimaki (Japan); Nagoya Univ. (Japan); Tokyo Astronomical Observatory, Mitaka (Japan)
• OSTI ID: 6995524
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 326; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC DUST
COSMIC RADIO SOURCES
DUSTS
ELECTROMAGNETIC RADIATION
FLUX DENSITY
H2 REGIONS
IONIZATION
MICROWAVE RADIATION
RADIATIONS