2010A&A...517A..78S


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.23CET00:52:08

2010A&A...517A..78S - Astronomy and Astrophysics, volume 517, A78-78 (2010/7-1)

VLBI study of maser kinematics in high-mass star-forming regions. II. G23.01-0.41.

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

Abstract (from CDS):

We performed a detailed study of maser and radio continuum emission toward the high-mass star-forming region G23.01-0.41. This study aims at improving our knowledge of the high-mass star-forming process by comparing the gas kinematics near a newly born young stellar object (YSO), analyzed through high spatial resolution maser data, with the large-scale environment of its native hot molecular core (HMC), identified in previous interferometric observations of thermal continuum and molecular lines. Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G23.01-0.41: 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 HMC at 1.3 and 3.6cm. We have detected H2O, CH3OH, and OH maser emission clustered within 2000AU from the center of a flattened HMC, oriented SE-NW, from which emerges a massive 12CO outflow, elongated NE-SW, extended up to the pc-scale. Although the three maser species show a clearly different spatial and velocity distribution and sample distinct environments around the massive YSO, the spatial symmetry and velocity field of each maser specie can be explained in terms of expansion from a common center, which possibly denotes the position of the YSO driving the maser motion. Water masers trace both a fast shock (up to 50km/s) closer to the YSO, powered by a wide-angle wind, and a slower (20km/s) bipolar jet, at the base of the large-scale outflow. Because the compact free-free emission is found offset from the putative location of the YSO along a direction consistent with that of the maser jet axis, we interpret the radio continuum in terms of a thermal jet. The velocity field of methanol masers can be explained in terms of a composition of slow (4km/s in amplitude) motions of radial expansion and rotation about an axis approximately parallel to the maser jet. Finally, the distribution of line-of-sight velocities of the hydroxyl masers suggests that they can trace gas less dense (nH2≤106cm–3) and more distant from the YSO than that traced by the water and methanol masers, which is expanding toward the observer. A few pairs of OH masers, with different circular polarization, are well aligned in position on the sky and we interpret them as Zeeman pairs. From Zeeman splitting, the derived typical values of the magnetic field are of a few mG.

Abstract Copyright:

Journal keyword(s): masers - techniques: high angular resolution - ISM: kinematics and dynamics - stars: individual: G23.01-0.41 - stars: formation

Simbad objects: 15

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Number of rows : 15

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2550 2
2 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3816 2
3 3C 345 QSO 16 42 58.8100340220 +39 48 36.999540578   16.81 16.59 16.84   ~ 1568 2
4 QSO B1730-130 QSO 17 33 02.70578476 -13 04 49.5481484   18 18.5 18.78 17.39 ~ 999 1
5 4C 09.57 BLL 17 51 32.81857318 +09 39 00.7284829   17.46 16.78 15.57   ~ 825 1
6 7C 175844.60+384828.00 QSO 18 00 24.76536125 +38 48 30.6975330   17.8 17.8 17.04   ~ 133 1
7 IRAS 18182-1433 mul 18 21 07.9 -14 31 53           ~ 97 0
8 OH 16.59 -0.05 cor 18 21 09.2137 -14 31 45.484           ~ 118 0
9 PMN J1825-0737 Rad 18 25 37.60955203 -07 37 30.0129436           ~ 18 1
10 PMN J1832-1028 Rad 18 32 11.4 -10 28 13           ~ 12 0
11 EGO G023.01-0.41 of? 18 34 40.2 -09 00 38           ~ 19 0
12 MSX5C G023.0126-00.4177 IR 18 34 42.2 -09 00 41           ~ 47 0
13 IRAS 20126+4104 Y*O 20 14 25.8816186803 +41 13 36.869078243           B2.5-B0.5 403 0
14 QSO B2059+034 QSO 21 01 38.83416420 +03 41 31.3209577   18.13 17.78 17.68   ~ 152 1
15 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2545 2

    Equat.    Gal    SGal    Ecl

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