R. S. Furuya et al. 2005 ApJ 624 827 doi:10.1086/429286
R. S. Furuya1, R. Cesaroni2, S. Takahashi3, M. Momose4, L. Testi2, H. Shinnaga5 and C. Codella6
Show affiliationsUsing the Owens Valley and Nobeyama Radio Observatory interferometers, we carried out an unbiased search for hot molecular cores and ultracompact (UC) H II regions toward the high-mass star-forming region G19.61-0.23. In addition, we performed 1.2 mm imaging with SIMBA and retrieved 3.5 and 2 cm images from the VLA archive database. The newly obtained 3 mm image brings information on a cluster of high-mass (proto)stars located in the innermost and densest part of the parsec-scale clump detected in the 1.2 mm continuum. We identify a total of 10 high-mass young stellar objects: one hot core (HC) and nine UC H II regions, whose physical parameters are obtained from model fits to their continuum spectra. The ratio between the current and expected final radii of the UC H II regions ranges from 0.3 to 0.9, which leaves the possibility that all O-B stars formed simultaneously. Under the opposite assumption, namely, that star formation occurred randomly, we estimate that the HC lifetime is less than ~1/3 of that of UC H II regions on the basis of the source number ratio between them.
H II regions; ISM: evolution; ISM: individual (G19.61–0.23); radio continuum: ISM; stars: early-type
Issue 2 (2005 May 10)
Received 2004 November 23, accepted for publication 2005 January 28
R. S. Furuya et al. 2005 ApJ 624 827
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