44 GHz methanol masers: Observations toward 95 GHz methanol masers

Abstract

We report a simultaneous 44 and 95 GHz class I methanol maser survey toward 144 sources from the 95 GHz class I methanol maser catalog. The observations were made with the three telescopes of the Korean very long baseline interferometry network operating in single-dish mode. The detection rates are 89% at 44 GHz and 77% at 95 GHz. There are 106 new discoveries at 44 GHz. Comparing the previous 95 GHz detections with new observations of the same transitions made using the Purple Mountain Observatory 13.7 m radio telescope shows no clear evidence of variability on a timescale of six years. Emission from the 44 and 95 GHz transitions shows strong correlations in peak velocity, peak flux density, and integrated flux density, indicating that they are likely cospatial. We found that the peak flux density ratio Spk,95/Spk,44 decreases as the 44 GHz peak flux density increases. We found that some class I methanol masers in our sample could be associated with infrared dark clouds, while others are associated with H II regions, indicating that some sources occur at an early stage of high-mass star formation, while others are located toward more evolved sources.

arXiv comment26 pages, including 10 figures and 8 tables. Accepted for publication in ApJS

References in corpus (54)

• The NumPy array: a structure for efficient numerical computation
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• High-Mass Star and Massive Cluster Formation in the Milky Way
• High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Infrared Dark Clouds: precursors to star clusters
• The WISE Catalog of Galactic HII Regions
• The initial conditions of stellar protocluster formation. I. A catalogue of Spitzer dark clouds
• Models of class II methanol masers based on improved molecular data
• The 6-GHz methanol multibeam maser catalogue I: Galactic Centre region, longitudes 345 to 6
• Ammonia in Infrared Dark Clouds
• The Bolocam Galactic Plane Survey -- II. Catalog of the Image Data
• A general catalogue of 6.7 GHz methanol masers. I: data
• A Catalog of MSX Infrared Dark Cloud Candidates
• 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
• Trigonometric Parallaxes of 6.7 GHz Methanol Masers
• Southern class I methanol masers at 36 and 44 GHz
• Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm
• Class I and Class II methanol masers in high-mass star forming regions
• Triggered star formation on the borders of the Galactic HII region RCW 82
• Triggered massive-star formation on the borders of Galactic HII regions. IV- Star formation at the periphery of Sh2-212
• The Arecibo Methanol Maser Galactic Plane Survey--I: Data
• A 95 GHz Class I Methanol Maser Survey Toward GLIMPSE Extended Green Objects (EGOs)
• Detection of new sources of methanol emission at 95 GHz with the Mopra telescope
• Physical characteristics of bright Class I methanol masers
• The Relationship between Class I and Class II Methanol Masers
• Different Evolutionary Stages in the Massive Star Forming Region S255 Complex
• Infrared Nebulae Around Young Stellar Objects
• Online Database of Class I Methanol Masers
• A Green Bank Telescope Survey of Large Galactic HII Regions
• The Initial Conditions of Stellar Protocluster Formation: III. The Herschel counterparts of the Spitzer Dark Cloud catalogue
• A Multi-Epoch, Simultaneous Water and Methanol Maser Survey toward Intermediate-Mass Young Stellar Objects
• A New 95 GHz Methanol Maser Catalog: I. Data
• Evidence for a Massive Protocluster in S255N
• A Catalog of Methanol Masers in Massive Star-forming Regions. III. The Molecular Outflow Sample
• A 95 GHz Class I Methanol Maser Survey Toward A Sample of GLIMPSE Point Sources Associated with BGPS Clumps
• The detection of Class I methanol masers towards regions of low-mass star formation
• MALT-45: A 7 mm survey of the southern Galaxy - I. Techniques and spectral line data
• A catalog of 44 GHz methanol masers in massive star-forming regions. IV. The high-mass protostellar object sample
• A search for 95 GHz class I methanol masers in molecular outflows
• Simultaneous observation of water and class I methanol masers toward class II methanol maser sources
• The Detection of New Methanol Masers in the 5_{-1}-4_0E Line
• 84-GHz methanol masers, their relationship to 36-GHz methanol masers and their molecular environments
• Untangling the Recombination Line Emission from HII Regions with Multiple Velocity Components
• Simultaneous Survey of Water and Class I Methanol Masers toward Red MSX Sources
• MALT-45: A 7mm survey of the southern Galaxy - II. ATCA follow-up observations of 44GHz class I methanol masers
• Linear Polarization of Class I Methanol Masers in Massive Star-Forming Regions
• Class I methanol masers in low-mass star formation regions
• The relationship between Class I and Class II methanol masers at high angular resolution
• Water and Methanol Maser Activities in the NGC 2024 FIR 6 Region
• Improved Selection Criteria for HII Regions, based on IRAS Sources

Cited by in corpus (6)

• Methanol masers in NGC 253 with ALCHEMI
• ATLASGAL: 3-mm class I methanol masers in high-mass star formation regions
• The physical parameters of clumps associated with class I methanol masers
• Probing the electron-to-proton mass ratio gradient in the Milky Way with class I methanol masers
• Modelling cosmic masers in C-type shock waves -- the coexistence of Class I CH3OH and 1720 MHz OH masers
• Discovery of widespread non-metastable ammonia masers in the Milky Way