scholarly journals Periodicity in Class II methanol masers in high-mass star-forming regions

2013 ◽  
Vol 437 (2) ◽  
pp. 1808-1820 ◽  
Author(s):  
S. Goedhart ◽  
J. P. Maswanganye ◽  
M. J. Gaylard ◽  
D. J. van der Walt
Keyword(s):  
Class Ii ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Methanol Masers

scholarly journals Class I and Class II methanol masers in high-mass star-forming regions

2010 ◽  
Vol 517 ◽  
pp. A56 ◽  
Author(s):  
F. Fontani ◽  
R. Cesaroni ◽  
R. S. Furuya
Keyword(s):  
Class Ii ◽  
Class I ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Methanol Masers

scholarly journals 44 GHz Methanol Maser Surveys

2012 ◽  
Vol 8 (S287) ◽  
pp. 133-140
Author(s):  
S. E. Kurtz
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Class Ii ◽  
Class I ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
Star Forming Regions ◽  
Methanol Masers

AbstractClass I 44 GHz methanol masers are not as well-known, as common, or as bright as their more famous Class II cousins at 6.7 and 12.2 GHz. Nevertheless, the 44 GHz masers are commonly found in high-mass star forming regions. At times they appear to trace dynamically important phenomena; at other times they show no obvious link to the star formation process. Here, we summarize the major observational efforts to date, including both dedicated surveys and collateral observations. The principal results are presented, some that were expected, and others that were unexpected.

scholarly journals New class I methanol masers

2012 ◽  
Vol 8 (S287) ◽  
pp. 433-440 ◽  
Author(s):  
M. A. Voronkov ◽  
J. L. Caswell ◽  
S. P. Ellingsen ◽  
S. L. Breen ◽  
T. R. Britton ◽  
...  
Keyword(s):  
Class I ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
New Class ◽  
Star Forming Regions ◽  
Rare Class ◽  
New Type ◽  
Methanol Masers

AbstractWe review properties of all known collisionally pumped (class I) methanol maser series based on observations with the Australia Telescope Compact Array (ATCA) and the Mopra radio telescope. Masers at 36, 84, 44 and 95 GHz are most widespread, while 9.9, 25, 23.4 and 104 GHz masers are much rarer, tracing the most energetic shocks. A survey of many southern masers at 36 and 44 GHz suggests that these two transitions are highly complementary. The 23.4 GHz maser is a new type of rare class I methanol maser, detected only in two high-mass star-forming regions, G357.97-0.16 and G343.12-0.06, and showing a behaviour similar to 9.9, 25 and 104 GHz masers. Interferometric positions suggest that shocks responsible for class I masers could arise from a range of phenomena, not merely an outflow scenario. For example, some masers might be caused by interaction of an expanding Hii region with its surrounding molecular cloud. This has implications for evolutionary sequences incorporating class I methanol masers if they appear more than once during the evolution of the star-forming region. We also make predictions for candidate maser transitions in the ALMA frequency range.

scholarly journals Methanol masers: Evolutionary and kinematic tracers of massive star formation

2002 ◽  
Vol 206 ◽  
pp. 147-150
Author(s):  
Vincent Minier ◽  
Roy Booth ◽  
John Conway ◽  
Michele Pestalozzi
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
Methanol Masers ◽  
Maser Sources

We summarise our recent VLBI observations of a large sample of methanol maser sources associated with high-mass star-forming regions.

Understanding high-mass star formation through KaVA observations of water and methanol masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 259-262
Author(s):  
Kee-Tae Kim ◽  
Tomoya Hirota ◽  
Koichiro Sugiyama ◽  
Jungha Kim ◽  
Do-Young Byun ◽  
...  
Keyword(s):  
Dynamical Evolution ◽  
Young Stellar Objects ◽  
High Mass ◽  
Mass Star ◽  
Stellar Objects ◽  
Star Forming ◽  
3 Dimensional ◽  
Star Forming Regions ◽  
Large Program ◽  
Methanol Masers

AbstractDespite their importance in the formation and evolution of stellar clusters and galaxies, the formation of high-mass stars remains poorly understood. We recently started a systematic observational study of the 22 GHz water and 44 GHz class I methanol masers in high-mass star-forming regions as a four-year KaVA large program. Our sample consists of 87 high-mass young stellar objects (HM-YSOs) in various evolutionary phases, many of which are associated with two or more different maser species. The primary scientific goals are to measure the spatial distributions and 3-dimensional velocity fields of multiple maser species, and understand the dynamical evolution of HM-YSOs and their circumstellar structures, in conjunction with follow-up observations with JVN/EAVN (6.7 GHz class II methanol masers), VERA, and ALMA. In this paper we present details of our KaVA large program, including the first-year results and observing/data analysis plans for the second year and beyond.

Probing Early Phases of High Mass Stars with 6.7 GHz Methanol Masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 323-324
Author(s):  
Sonu Tabitha Paulson ◽  
Jagadheep D. Pandian
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Dust Emission ◽  
Black Body ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Methanol Masers ◽  
Early Phases

AbstractMethanol masers at 6.7 GHz are the brightest of class II methanol masers and have been found exclusively towards massive star forming regions. These masers can thus be used as a unique tool to probe the early phases of massive star formation. We present here the SED studies of 284 methanol masers chosen from the MMB catalogue, which falls in the Hi-GAL range (|l| ≤ 60°, |b| ≤ 1°). The masers are studied using the ATLASGAL, MIPSGAL and Hi-GAL data at wavelengths ranging from 24−870 micrometers. A single grey body component fit was used to model the cold dust emission whereas the emission from the warm dust is modelled by a black body. The clump properties such as isothermal mass, FIR luminosity and MIR luminosity were obtained using the best fit parameters of the SED fits. We discuss the physical properties of the sources and explore the evolutionary stages of the sources having 6.7 GHz maser emission in the timeline of high mass star formation.

The Relationship between 6.7 GHz Methanol Masers and Radio Recombination Lines in High-mass Star-forming Regions

2019 ◽  
Vol 245 (1) ◽  
pp. 12 ◽  
Author(s):  
Xu-Jia Ouyang ◽  
Xi Chen ◽  
Zhi-Qiang Shen ◽  
Kai Yang ◽  
Xiao-Qiong Li ◽  
...  
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Radio Recombination Lines ◽  
Star Forming Regions ◽  
Methanol Masers ◽  
The Relationship

scholarly journals Where methanol masers spring

2007 ◽  
Vol 3 (S242) ◽  
pp. 178-179
Author(s):  
Karl J. E. Torstensson ◽  
Huib Jan van Langevelde ◽  
Stephen Bourke
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
Star Forming Regions ◽  
Surrounding Environment ◽  
First Results ◽  
Vlbi Data ◽  
Methanol Masers ◽  
Cepheus A

AbstractWe are carrying out a program to observe the 6.7 GHz methanol maser emission in high-mass star-forming regions using large FOV (~2'), astrometric, VLBI data. Here we report on the first results of the inner few arc seconds in Cepheus A East. We find a maser filament extending over ~1.7” (1200 AU), straddling the waist of Cep A HW2. The region in which the CH3OH masers are found contains several YSO's and it is not clear whether the CH3OH masers are associated with several different objects or rather the larger scale surrounding environment.

scholarly journals Anomalous peculiar motions of high-mass young stars in the Scutum spiral arm

2019 ◽  
Vol 632 ◽  
pp. A123 ◽  
Author(s):  
K. Immer ◽  
J. Li ◽  
L. H. Quiroga-Nuñez ◽  
M. J. Reid ◽  
B. Zhang ◽  
...  
Keyword(s):  
Spiral Structure ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Trigonometric Parallax ◽  
Motion Measurements ◽  
Methanol Masers ◽  
Galactic Longitude ◽  
Spiral Arm

We present trigonometric parallax and proper motion measurements toward 22 GHz water and 6.7 GHz methanol masers in 16 high-mass star-forming regions. These sources are all located in the Scutum spiral arm of the Milky Way. The observations were conducted as part of the Bar and Spiral Structure Legacy (BeSSeL) survey. A combination of 14 sources from a forthcoming study and 14 sources from the literature, we now have a sample of 44 sources in the Scutum spiral arm, covering a Galactic longitude range from 0° to 33°. A group of 16 sources shows large peculiar motions of which 13 are oriented toward the inner Galaxy. A likely explanation for these high peculiar motions is the combined gravitational potential of the spiral arm and the Galactic bar.

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