2010A&A...517A..71S


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.16CEST19:17:45

2010A&A...517A..71S - Astronomy and Astrophysics, volume 517, A71-71 (2010/7-1)

VLBI study of maser kinematics in high-mass star-forming regions. I. G16.59-0.05.

SANNA A., MOSCADELLI L., CESARONI R., TARCHI A., FURUYA R.S. and GODDI C.

Abstract (from CDS):

To study the high-mass star-forming process, we started a large project to unveil the gas kinematics close to young stellar objects (YSOs) through the Very Long Baseline Interferometry (VLBI) of maser associations. By comparing the high spatial resolution maser data that traces the inner kinematics of the (proto)stellar cocoon with interferometric thermal data that traces the large-scale environment of the hot molecular core (HMC) harboring the (proto)stars, we can investigate the nature and identify the sources of large-scale motions. The present paper focuses on the high-mass star-forming region G16.59-0.05. Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G16.59-0.05: H2O at 22.2GHz (4 epochs), CH3OH at 6.7GHz (3 epochs), and OH at 1.665GHz (1 epoch). In addition, we performed high-resolution (≥0.1"), high-sensitivity (<0.1mJy) VLA observations of the radio continuum emission from the star-forming region at 1.3 and 3.6cm. This is the first work to report accurate measurements of the relative proper motions of the 6.7GHz CH3OH masers. The different spatial and 3-D velocity distributions clearly indicate that the 22GHz water and 6.7GHz methanol masers trace different kinematic environments. The bipolar distribution of 6.7GHz maser line-of-sight velocities and the regular pattern of observed proper motions suggest that these masers are tracing rotation around a central mass of about 35M. The flattened spatial distribution of the 6.7GHz masers, oriented NW-SE, suggests that they can originate in a disk/toroid rotating around the massive YSO that drives the 12CO (2-1) outflow, oriented NE-SW, observed on an arcsec scale. The extended, radio continuum source observed close to the 6.7 GHz masers could be excited by a wide-angle wind emitted from the YSO associated with the methanol masers, and such a wind has proven to be energetic enough to drive the NE-SW 12CO (2-1) outflow. The H2O masers are distributed across a region offset about 0.''5 to the NW of the CH3OH masers, in the same area as where the emission of high-density molecular tracers, typical of HMCs, was detected. We postulate that a distinct YSO, possibly in an earlier evolutionary phase than what excites the methanol masers, is responsible for the excitation of the water masers and the HMC molecular lines.

Abstract Copyright:

Journal keyword(s): masers - techniques: high angular resolution - ISM: kinematics and dynamics - stars: formation - stars: individual: IRAS 18182-1433 - stars: individual: G16.59-0.05

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2497 2
2 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3716 1
3 3C 345 QSO 16 42 58.8100340220 +39 48 36.999540578   16.81 16.59 16.84   ~ 1554 2
4 QSO B1730-130 QSO 17 33 02.70578476 -13 04 49.5481484   18 18.5 18.78 17.39 ~ 983 1
5 4C 09.57 BLL 17 51 32.81857318 +09 39 00.7284829   17.46 16.78 15.57   ~ 811 1
6 7C 175844.60+384828.00 QSO 18 00 24.76536125 +38 48 30.6975330   17.8 17.8 17.04   ~ 130 1
7 IRAS 18182-1433 mul 18 21 07.9 -14 31 53           ~ 95 0
8 OH 16.59 -0.05 cor 18 21 09.2137 -14 31 45.484           ~ 116 0
9 PMN J1825-1718 Rad 18 25 36.53244 -17 18 49.8521           ~ 30 1
10 PMN J1832-1028 Rad 18 32 11.4 -10 28 13           ~ 12 0
11 QSO B2059+034 QSO 21 01 38.83416420 +03 41 31.3209577   18.13 17.78 17.68   ~ 149 1
12 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2507 2

    Equat.    Gal    SGal    Ecl

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2020.07.16-19:17:45

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