Statistical properties of 12.2 GHz methanol masers associated with a complete sample of 6.7 GHz methanol masers

Abstract

We present definitive detection statistics for 12.2 GHz methanol masers towards a complete sample of 6.7 GHz methanol masers detected in the Methanol Multibeam survey south of declination -20 degrees. In total, we detect 250 12.2 GHz methanol masers towards 580 6.7 GHz methanol masers. This equates to a detection rate of 43.1%, which is lower than that of previous significant searches of comparable sensitivity. Both the velocity ranges and the flux densities of the target 6.7 GHz sources surpass that of their 12.2 GHz companion in almost all cases. 80 % of the detected 12.2 GHz methanol maser peaks are coincident in velocity with the 6.7 GHz maser peak. Our data support an evolutionary scenario whereby the 12.2 GHz sources are associated with a somewhat later evolutionary stage than the 6.7 GHz sources devoid of this transition. Furthermore, we find that the 6.7 GHz and 12.2 GHz methanol sources increase in luminosity as they evolve. In addition to this, evidence for an increase in velocity range with evolution is presented. This implies that it is not only the luminosity, but also the volume of gas conducive to the different maser transitions, that increases as the sources evolve. Comparison with GLIMPSE mid-infrared sources has revealed a coincidence rate between the locations of the 6.7 GHz methanol masers and GLIMPSE point sources similar to that achieved in previous studies. Overall, the properties of the GLIMPSE sources with and without 12.2 GHz counterparts are similar. There is a higher 12.2 GHz detection rate towards those 6.7 GHz methanol masers that are coincident with extended green objects.

Accepted to ApJ March 2011. 28 pages, 9 figures

References in corpus (7)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• The 6-GHz Multibeam Maser Survey I. Techniques
• Multi-wavelength observations of Southern Hot Molecular Cores traced by methanol masers - I. Ammonia and 24 GHz Continuum Data
• Physical and chemical conditions in methanol maser selected hot-cores and UCHII regions
• A multi-transition molecular line study of candidate massive young stellar objects associated with methanol masers

Cited by in corpus (37)

• ATLASGAL --- Environments of 6.7\,GHz methanol masers
• Confirmation of the exclusive association between 6.7-GHz methanol masers and high-mass star formation regions
• A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
• The almost ubiquitous association of 6.7 GHz methanol masers with dust
• Online Database of Class I Methanol Masers
• Periodicity in Class II methanol masers in high mass star forming regions
• Constraining the properties of 1.2-mm dust clumps that contain luminous water masers
• SPLASH: The Southern Parkes Large-Area Survey in Hydroxyl - First Science from the Pilot Region
• 12.2-GHz methanol maser MMB follow-up catalogue - I. Longitude range 330 to 10 degrees
• New Periodic 6.7 GHz Class II Methanol Maser Associated with G358.460-0.391
• 37 GHz methanol masers : Horsemen of the Apocalypse for the class II methanol maser phase?
• European VLBI Network imaging of 6.7 GHz methanol masers
• A search for water masers associated with class II methanol masers - II. Longitude range 341${}^{\circ }$ to 6${}^{\circ }$
• 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
• A Global View on Star Formation: The GLOSTAR Galactic Plane Survey V. 6.7 GHz Methanol Maser Catalogue
• Methanol masers in NGC 253 with ALCHEMI
• 6.7GHz Methanol Maser Associated Outflows: An evolutionary sequence
• A search for 95 GHz class I methanol masers in molecular outflows
• A search for water masers associated with class II methanol masers - I. Longitude range 6 to 20 degrees
• Practical Limitations on Astrophysical Observations of Methanol to Investigate Variations in the Proton-to-Electron Mass Ratio
• A global view on star formation: The GLOSTAR Galactic plane survey III. 6.7 GHz methanol maser survey in Cygnus X
• 12.2-GHz methanol maser MMB follow-up catalogue - III. Longitude range 10 to 20 degrees
• ATLASGAL -- physical parameters of dust clumps associated with 6.7 GHz methanol masers
• Testing maser-based evolutionary schemes: A new search for 37.7-GHz methanol masers
• The 6-GHz multibeam maser survey III: comparison between the MMB and HOPS
• The mid-infrared environments of 6.7 GHz Methanol Masers from the Methanol Multi-Beam Survey
• The first high-resolution observations of 19.9-GHz methanol masers
• The relationship between Class I and Class II methanol masers at high angular resolution
• The first high-resolution observations of 37.7-, 38.3- and 38.5-GHz methanol masers
• The RMS Survey: Ammonia mapping of the environment of young massive stellar objects II
• Variability in extragalactic class I methanol masers: New maser components toward NGC4945 and NGC253
• Long-term Variability of H${}_2$CO Masers in Star-forming Regions
• SCOTCH Search for Clandestine Optically Thick Compact HII regions II
• Environmental conditions shaping star formation: The Carina Nebula
• Observations of 12.2 GHz methanol masers towards northern high-mass protostellar objects
• Masers in star forming regions