2007A&A...464.1015V


Query : 2007A&A...464.1015V

2007A&A...464.1015V - Astronomy and Astrophysics, volume 464, 1015-1022 (2007/3-4)

Inferences from the kinematic properties of 6.7 GHz methanol masers.

VAN DER WALT D.J., SOBOLEV A.M. and BUTNER H.

Abstract (from CDS):

It is now well established that the strong and widespread 6.7GHz methanol masers are associated with young high mass stars. A still unsolved question is where in the circumstellar environment the masers arise. We address this question by considering an ensemble of rest frame maser velocities of 337 maser features. The CS(2-1) spectra of 63 methanol maser sources were used to derive systemic velocities and velocity dispersion of the thermal gas. Using the systemic velocities and the velocities of the 337 maser features in the 63 sources, a single distribution of rest frame maser velocities was constructed. This distribution as well as other kinematic information about the masers are used to evaluate four proposed scenarios for where the masers might arise in the circumstellar environment. It is shown that kinematically the masers are not associated with hot cores. We also argue that the scenario in which the masers are associated with an external generated planar shock that propagates into a rotating core cannot explain the observed kinematic properties of the masers. It was found that a simple Keplerian-like disk model is consistent with the observed distribution of rest frame maser velocities. Although outflows have the potential to explain the data, it was not possible to fully test this possibility due to the diverse nature of outflows.

Abstract Copyright:

Journal keyword(s): masers - stars: formation - ISM: molecules

Simbad objects: 18

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Number of rows : 18
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME W 3 OH HII 02 27 04.1 +61 52 22           ~ 997 2
2 GAL 174.20-00.08 Cld 05 30 45.9 +33 47 56           ~ 198 2
3 GAL 009.62+00.19 HII 18 06 13.9 -20 31 44           ~ 198 0
4 GAL 008.67-00.30 HII 18 06 19.027 -21 37 32.32           ~ 69 0
5 W 31 SFR 18 10 28.6 -19 55 51           ~ 252 0
6 W 31c HII 18 10 29.1 -19 56 05           ~ 330 0
7 GRS G012.21 -00.10 Rad 18 12 39.70 -18 24 20.1           ~ 5 0
8 GRS G011.94 -00.62 HII 18 14 01.3 -18 53 34           ~ 10 0
9 IRAS 18321-0820 Y*O 18 34 51.5650 -08 18 21.305           ~ 40 0
10 GAL 024.78+00.08 HII 18 36.2 -07 13           ~ 81 0
11 CORNISH G029.9559-00.0168 Y*O 18 46 04.18 -02 39 21.3           ~ 360 0
12 IRAS 18449-0115 cor 18 47 34.29 -01 12 44.5           ~ 366 0
13 OH 34.26 +0.15 SFR 18 53 18.54 +01 14 57.9           ~ 490 0
14 GAL 037.55-00.11 HII 19 00 15.7 +04 03 13           ~ 40 0
15 GRS G045.07 +00.13 Rad 19 13 22 +10 50.9           ~ 21 0
16 GRS G043.89 -00.78 Rad 19 14 26.2 +09 22 34           ~ 4 0
17 IRAS 20126+4104 Y*O 20 14 25.8816769656 +41 13 36.879427236           B2.5-B0.5 421 0
18 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 1018 0

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2023.02.01-21:10:05

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