Other
Scientific paper
Jan 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995phdt.........5h&link_type=abstract
PhD Dissertation, Wisconsin Univ. Madison, WI United States
Other
Molecular Gases, Ionized Gases, High Temperature Gases, H Ii Regions, Continuums, Masers, Stellar Mass, Star Formation, Massive Stars, Line Spectra
Scientific paper
The first high resolution observation of the recently discovered NH3 (5,5) maser in G9.62 + 0.19 shows that the size of the emitting region is less than 0.5double prime and the brightness temperature of the new maser thus exceeds 104 K. Star formation in G9.62 + 0.19 occurs along a narrow linear structure of length 0.6 pc, outlined by maser emission in several molecular lines, highly excited ammonia and ultracompact HII regions. Our VLA study of four objects in the NH3 (4,4) line shows that the regions traced by this line are molecular clumps with sizes approx. 0.1 pc, densities of approx. 107 cm-3 and temperatures of 100 K or higher. In three of the four cases studied the hot dense molecular clumps are not coincident with the ionized gas in the region. The most likely interpretation for these objects are massive young stellar objects which are still highly embedded in the molecular gas from which they formed. A detailed study of the massive star forming region G9.62 + 0.19 in the CH3CN(6-6) and Cl80(1-0) rotational lines and the 2.7 mm continuum shows that three centers of star formation are embedded in a molecular core of mass 1700 M(solar mass). The derived gas temperatures in the centers of star formation range from 50 to 300 K and the associated H2 column densities range from 1024-1023 cm2. Continuum emission at 2.7 mm is detected at all three positions and can be explained by a constant density Hll region or a photoevaporating disk for the southernmost source and by emission from partially ionized winds or from hot dust at the other two positions. The molecular core shows a smooth velocity gradient of 9 km s-1 pc-1 along its major axis. High velocity gas is detected coincident with the molecular clump imaged in the NH3(4,4) line. The results of a high resolution survey toward 20 ultracompact HII regions in the 22 GHz water maser line show that strong maser emission is usually located in front of the ionized arc in the case of the cometary class of ultracompact HII regions. Also, in all cases where high resolution ammonia maps exist, the water masers are coincident with the hot, dense molecular clumps.
No associations
LandOfFree
A study of the hot molecular gas associated with ultra-compact ionized regions 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 A study of the hot molecular gas associated with ultra-compact ionized regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A study of the hot molecular gas associated with ultra-compact ionized regions will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-837147