The diversity of methanol maser morphologies from VLBI observations

  title={The diversity of methanol maser morphologies from VLBI observations},
  author={Anna Bartkiewicz and Marian Szymczak and Huib Jan van Langevelde and A. M. S. Richards and Yale Center for Astronomy and Nicolaus Copernicus University and Poland Joint Institute for Vlbi in Europe and Dwingeloo and The Netherlands Sterrewacht Leiden and Leiden University and Theoretical Institute for Advanced Research in Astrophysics and Alan Turing Building and University of Manchester and UK Department of Physics and Astronomy and University of New Mexico and USA. National Radio Astronomy Observatory and Socorro and Usa},
  journal={Astronomy and Astrophysics},
Context. The 6.7 GHz methanol maser marks an early stage of high-mass star formation, but the origin of this maser is currently a matter of debate. In particular it is unclear whether the maser emission arises in discs, outflows or behind shocks running into rotating molecular clouds. Aims. We investigated which structures the methanol masers trace in the environment of high-mass protostar candidates by observing a homogenous sample of methanol masers selected from Torun surveys. We also probed… Expand
European VLBI Network observations of 6.7 GHz methanol masers in clusters of massive young stellar objects
Methanol masers at 6.7 GHz are associated with high-mass star-forming regions (HMSFRs) and often have mid-infrared (MIR) counterparts characterized by extended emission at 4.5 $\mu$m, which likelyExpand
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Methanol masers at 6.7 GHz are well known tracers of high-mass star-forming regions. However, their origin is still not clearly understood. We aimed to determine the morphology and velocity structureExpand
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Context. The 22.2 GHz water masers are often associated with the 6.7 GHz methanol masers but owing to the different excitation conditions they likely probe independent spatial and kinematic regionsExpand
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Context. Both 22 GHz water and 6.7 GHz methanol masers are usually interpreted as signposts of early stages of high-mass star formation but little is known about their associations and the physicalExpand
Study unreachable — Imaging the milliarcsecond structures of the methanol masers using the European VLBI Network
The maser emission of methanol molecule at 6668.519 MHz (ca. 4.5 cm) is exclusively associated with high-mass star forming regions. It is an excellent tracer of still accreting high-mass protostarsExpand
Dynamics of the 6.7 and 12.2 GHz methanol masers around Cepheus A HW2
Context. The 6.7 GHz methanol maser is exclusively associated with high-mass star formation. However, it remains unclear what structures harbour the methanol masers. Cepheus A is one of the closestExpand
VLBI study of maser kinematics in high-mass SFRs. I. G16.59-0.05
Aims. To study the high-mass star-forming process, we have started a large project to unveil the gas kinematics close to young stellar objects (YSOs) through the Very Long Baseline InterferometryExpand
Studies of methanol maser rings
We present the results of studies of a new class of 6.7 GHz methanol maser sources with a ring-like emission structure discovered recently with the EVN. We have used the VLA to search for waterExpand
Periodic methanol masers: from a colliding wind binary (CWB) perspective
Since the discovery of periodic class II methanol masers at 6.7 and 12.2 GHz associated with high-mass star formation regions (HMSFRs), a number of possible driving mechanisms have been proposed toExpand
Probing the magnetic fields of massive star-forming regions with methanol maser polarization
Methanol masers can provide valuable insight into the processes involved in high mass star formation; however, the local environment in which they form is still unclear. Four primary, yetExpand


Class II methanol masers and their environment at high resolution
Observations of the 6. 7- and 12.2-GHz masing transitions of methanol by Norris et al. (1988; 1993) using the Australia Telescope Compact Array (ATCA) and the Parkes-Tidbinbilla InterferometerExpand
A multi-transition molecular line study of candidate massive young stellar objects associated with methanol masers
Aims. We characterize the molecular environment of candidate massive young stellar objects (MYSOs) signposted by methanol masers. Methods. Single pixel observations of 10 transitions of HCO + , COExpand
SiO outflow signatures toward massive young stellar objects with linearly distributed methanol masers
Context. Methanol masers are often found in linear distributions, and it has been hypothesized that these masers trace circumstellar accretion disks around young massive stars. However, recentExpand
Methanol Masers as Tracers of Circumstellar Disks
We show that in many methanol maser sources the masers are located in lines, with a velocity gradient along them which suggests that the masers are situated in edge-on circumstellar, orExpand
Methanol Masers: Reliable Tracers of the Early Stages of High-Mass Star Formation
The GLIMPSE and MSX surveys have been used to examine the mid-infrared properties of a statistically complete sample of 6.7 GHz methanol masers. The GLIMPSE point sources associated with methanolExpand
Water masers in the massive protostar IRAS 20126+4104: ejection and deceleration
Received date; accepted date Abstract. We report on the first multi-epoch, phase referenced VLBI observations of the H2O maser emission in a high-mass protostar associated with a disk-jet system. TheExpand
Ring shaped 6.7 GHz methanol maser emission around a young high-mass star
We report on EVN imaging of the 6.7 GHz methanol maser emission from the candidate high-mass protostar G23.657-0.127. The masers originate in a nearly circular ring of 127 mas radius and 12 masExpand
Masers as signposts of high-mass protostars A water maser survey of methanol maser sources
The 22 GHz H2O maser line was observed towards 79 candidate high-mass protostellar objects from a flux-limited sample of 6.7 GHz methanol sources. The emission was detected in 41 sources, towards 28Expand
Inferences from the kinematic properties of 6.7 GHz methanol masers
Context. It is now well established that the strong and widespread 6.7 GHz methanol masers are associated with young high mass stars. A still unsolved question is where in the circumstellarExpand
Kinematics of the 12 GHz Methanol Masers toward W3(OH)
In this paper, two epochs (1994 February and 1998 December) of Very Long Baseline Array observations of the 12 GHz CH3OH masers toward the ultracompact (UC) H II region W3(OH) are compared. The 12Expand