Aperture synthesis observations of star forming regions: compact HII regions and masers

Thesis/Dissertation · Sat Jan 01 00:00:00 EST 1983

OSTI ID:5094520

Garay, G A

Radio observations have been made of the emission from regions of star formation due to spectral lines of hydrogen, OH and H/sub 2/O and free-free continuum using Haystack, VLA and VLBI Network. The purpose was to provide new observations, to help to understand the early stages of star formation. VLA radio recombination line observations have been made of various compact HII regions towards regions of star formation. In addition aperture synthesis mapping of the OH maser emission towards those regions have been made. The OH maser spots are always projected on the face of a compact HII region. It was found that the OH masers have radial velocities which are reshifted from the associated HII region velocity. This is simply explained if the OH maser sources are part of a remnant accreting envelope which is still collapsing towards the newly formed star. Aperture synthesis observations have also been made of the Orion Nebula in search of compact radio sources which would help to establish which of the infrared sources in the molecular cloud might contain primary energy sources. Radio emission was detected from the BN object and five other sources in the molecular cloud. In addition, fifteen ultracompact HII regions associated with the Trapezium OB stars were found. Some of these objects may correspond to neutral condensation surrounded by externally ionized envelopes. Finally, the polarization characteristics of the strong water vapor maser emission towards the Orion Nebula was mapped and monitored. Energy requirements suggest that the maser source is internally excited. It is suggested that the maser cloud is probably associated with very early stages of star formation in which no radio or infrared continuum emission is detected.

• Research Organization: Harvard Univ., Cambridge, MA (USA)
• OSTI ID: 5094520
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
H2 REGIONS
RADIOWAVE RADIATION
STAR EVOLUTION
COSMIC GASES
COSMIC RADIO SOURCES
HYDROGEN
HYDROXYL RADICALS
MASERS
RADIAL VELOCITY
WATER
AMPLIFIERS
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FLUIDS
GASES
HYDROGEN COMPOUNDS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
NONMETALS
OXYGEN COMPOUNDS
RADIATIONS
RADICALS
VELOCITY
640103* - Astrophysics & Cosmology- Quasi-Stellar
Radio
& X-Ray Sources- (-1987)
640102 - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources