A VERY LARGE ARRAY STUDY OF ULTRACOMPACT AND HYPERCOMPACT H II REGIONS FROM 0.7 TO 3.6 cm
- Department of Physics and Astronomy, Johns Hopkins University, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States)
- Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St., Madison, WI 53706 (United States)
- Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 3-72, 58089, Morelia, Mich. (Mexico)
- National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States)
We report multi-frequency Very Large Array observations of three massive star formation regions (MSFRs) containing radio continuum components that were identified as broad radio recombination line (RRL) sources and hypercompact (HC) H II region candidates in our previous H92{alpha} and H76{alpha} study: G10.96+0.01 (component W), G28.20-0.04 (N), and G34.26+0.15 (B). An additional HC H II region candidate, G45.07+0.13, known to have broad H66{alpha} and H76{alpha} lines, small size, high electron density, and emission measure, was also included. We observed with high spatial resolution (0.''9-2.''3) the H53{alpha}, H66{alpha}, H76{alpha}, and H92{alpha} RRLs and the radio continuum at the corresponding wavelengths (0.7-3.6 cm). The motivation for these observations was to obtain RRLs over a range of principal quantum states to look for signatures of pressure broadening and macroscopic velocity structure. We find that pressure broadening contributes significantly to the linewidths, but it is not the sole cause of the broad lines. We compare radio continuum and dust emission distributions and find a good correspondence. We also discuss maser emission and multi-wavelength observations reported in the literature for these MSFRs.
- OSTI ID:
- 21560360
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 194, Issue 2; Other Information: DOI: 10.1088/0067-0049/194/2/44; ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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