Outflowing activity in the UCHII region G045.47+0.05

ORTEGA MARTIN E.; PARON, SERGIO; CICHOWOLSKI SILVINA; RUBIO, MONICA; DUBNER GLORIA

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2012 vol. 546 p. 1 - 12

0004-6361

Aims. This work aims at investigating the molecular gas in the surroundings of the ultra-compact HII region G045.47+0.05 looking for evidence of molecular outflows. Methods. We carried out observations towards a region of 2×2 centered at RA=19 14 25.6 ,Dec =+11 09 27.6 (J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in the CO J =3?2, CO J=3?2, HCO+J=4?3, and CS J=7?6 lines with an angular resolution of 22  We complement these observations with public infrared data. Results. We characterize the physical parameters of the molecular clump where G045.47+0.0 is embedded. The detection of the CS J=7?6 line emission in the region reveals that the ultra-compact HII region G045.47+0.0 has not completely disrupted the dense gas where it was born. The HCO+ abundance observed towards G045.47+0.0 suggests there is molecular outflow activity in the region. From the analysis of the 12COJ=3?2 transition we report bipolar molecular outflows with a total mass of about 300 M. We derive a dynamical time (flow?s age) of about 105yr for the outflow gas, in agreement with the presence of an ultra-compact HII region. We identify the source 2MASS 19142564+1109283 as the massive protostar candidate to drive the molecular outflows. Based on the analysis of its spectral energy distribution, we infer that it is an early B-type star of about 15M. The results of this work support the scenario where the formation of massive stars, at least up to early B-type stars, is similar to that of low-mass stars.