The first high-resolution observations of 37.7-, 38.3- and 38.5-GHz methanol masers

Abstract

We have used the Australia Telescope Compact Array (ATCA) to undertake the first high angular resolution observations of 37.7-GHz ($7_{-2}-8_{-1}E$) methanol masers towards a sample of eleven high-mass star formation regions which host strong 6.7-GHz methanol masers. The 37.7-GHz methanol sites are coincident to within the astrometric uncertainty (0.4 arcseconds) with the 6.7-GHz methanol masers associated with the same star formation region. However, spatial and spectral comparison of the 6.7- and 37.7-GHz maser emission within individual sources shows that the 37.7-GHz masers are less often, or to a lesser degree co-spatial than are the 12.2-GHz and 6.7-GHz masers. We also made sensitive, high angular resolution observations of the 38.3- and 38.5-GHz class II methanol transitions ($6_2-5_3{A}^{-}$ and $6_2-5_3{A}^{+}$, respectively) and the 36.2-GHz ($4_{-1}-3_{0}E$) class I methanol transition towards the same sample of eleven sources. The 37.7-, 38.3- and 38.5-GHz methanol masers are unresolved in the current observations, which implies a lower limit on the brightness temperature of the strongest masers of more than $10^6$K. We detected the 38.3-GHz methanol transition towards 7 sources, 5 of which are new detections and detected the 38.5-GHz transition towards 6 sources, 4 of which are new detections. We detected 36.2-GHz class I methanol masers towards all eleven sources, 6 of these are new detections for this transition, of which 4 sources do not have previously reported class I methanol masers from any transition.

arXiv commentAccepted for publication in MNRAS, 34 pages, 20 figures

References in corpus (36)

• Models of class II methanol masers based on improved molecular data
• A Parallax-based Distance Estimator for Spiral Arm Sources
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Methanol masers : Reliable tracers of the early stages of high-mass star formation
• 12.2-GHz methanol masers associated with 1.2-mm dust clumps: Quantifying high-mass star formation evolutionary schemes
• The 6-GHz methanol multibeam maser catalogue II: Galactic longitudes 6 to 20
• The 6-GHz methanol multibeam maser catalogue IV: Galactic longitudes 186 to 330 including the Orion-Monoceros region
• Confirmation of the exclusive association between 6.7-GHz methanol masers and high-mass star formation regions
• {Millimeter Multiplicity in NGC 6334 I and I(N)
• Southern class I methanol masers at 36 and 44 GHz
• Class I methanol masers in the outflow of IRAS 16547-4247
• Trigonometric Parallaxes of Massive Star Forming Regions: IV. G35.20-0.74 and G35.20-1.74
• The Arecibo Methanol Maser Galactic Plane Survey--I: Data
• A Survey of the Galactic Plane for 6.7-GHz Methanol Masers I: l = 325.0 - 335.0 ; b = -0.53 - 0.53
• The Relationship between Class I and Class II Methanol Masers
• New 9.9-GHz methanol masers
• Multi-transition study and new detections of class II methanol masers
• Statistical properties of 12.2 GHz methanol masers associated with a complete sample of 6.7 GHz methanol masers
• Search for Class I methanol masers in low-mass star formation regions
• Investigating high-mass star formation through maser surveys
• 12.2-GHz methanol maser MMB follow-up catalogue - I. Longitude range 330 to 10 degrees
• First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259
• High-spatial-resolution observations of NH3 and CH3OH towards the massive twin cores NGC6334 I & I(N)
• Ground-state OH observations towards NGC 6334
• Discovery of new 19.9-GHz methanol masers in star forming regions
• 12.2-GHz methanol maser MMB follow-up catalogue - II. Longitude range 186 to 330 degrees
• Class I methanol masers in NGC253: Alcohol at the end of the bar
• MALT-45: A 7 mm survey of the southern Galaxy - I. Techniques and spectral line data
• Search for class II methanol masers at 23.1 GHz
• A search for water masers associated with class II methanol masers - I. Longitude range 6 to 20 degrees
• High-velocity feature of the class I methanol maser in G309.38-0.13
• A search for 85.5- and 86.6-GHz methanol maser emission
• 12.2-GHz methanol maser MMB follow-up catalogue - III. Longitude range 10 to 20 degrees
• MALT-45: A 7mm survey of the southern Galaxy - II. ATCA follow-up observations of 44GHz class I methanol masers
• Testing maser-based evolutionary schemes: A new search for 37.7-GHz methanol masers
• The first high-resolution observations of 19.9-GHz methanol masers

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• MAGMO: Polarimetry of 1720-MHz OH Masers towards Southern Star Forming Regions
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