Astronomy and Astrophysics – Astronomy
Scientific paper
Aug 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992phdt.........5k&link_type=abstract
Ph.D. Thesis Boston Univ., MA.
Astronomy and Astrophysics
Astronomy
1
H I Regions, Interstellar Matter, Neutral Gases, Dust, H Ii Regions, Hydrogen Atoms, Infrared Astronomy Satellite, Infrared Radiation, Kinematics, Molecular Clouds, Optical Thickness, Spin Temperature, Star Formation, Thermodynamic Properties
Scientific paper
A new, high resolution survey of neutral atomic hydrogen (H I) emission has been conducted at the Arecibo Observatory. The survey investigated the thermal and kinematic properties of H I associated with objects of astronomical interest. The small beamwidth of the telescope (4') allowed the detection of absorption features and small scale structures that were unresolved in other large scale surveys. The survey consists of a 30 square degree map of the first galactic quadrant and smaller maps of 40 targeted objects. The first quadrant survey was used to examine the global kinematics of H I and the atomic properties for a subfield of molecular clouds. The spin temperatures and optical depths were determined for H I clouds seen in absorption toward H II regions (areas of ionized gas which surround young, hot stars). These temperatures appear strongly correlated with the measured optical depths. Kinematic distances were determined for 70 H II regions, 45 of which for the first time. A comparison between the Survey and other galactic-scale surveys can reveal additional physical properties of the interstellar medium. This was done in part by examining infrared emission from the H II region sample. The dust opacity and color temperatures were determined using data from the Infrared Astronomy Satellite. The luminosity distribution of the H II regions was calculated using the previously derived kinematic distances. One of the targeted fields was the Rosette Molecular Complex, a giant molecular cloud and a site of recent star formation. The total (atomic and molecular) mass of the complex was found to be 1.43 x 105 solar mass of which 60 percent is in the atomic phase. The complex contains 30 molecular 'clumps' embedded in a low density gas. The clumps range from a few to several hundred solar masses and from 2 to 7 pc in diameter. An expanding shell, centered on the nebula, was detected in both the atomic and molecular gas. The dynamical age for the shell is approximately 4 million years, which is consistent with the age of the central star cluster NGC 2244.
No associations
LandOfFree
The Boston University-Arecibo galactic HI survey: The galaxy at 4 arcminute resolution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Boston University-Arecibo galactic HI survey: The galaxy at 4 arcminute resolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Boston University-Arecibo galactic HI survey: The galaxy at 4 arcminute resolution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1168530