VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers

Abstract

We present $\sim 1-4"$ resolution Very Large Array (VLA) observations of four CH${}_3$OH $J_2-J_1$-$E$ 25~GHz transitions ($J$=3, 5, 8, 10) along with 1.3~cm continuum toward 20 regions of active massive star formation containing Extended Green Objects (EGOs), 14 of which we have previously studied with the VLA in the Class~I 44~GHz and Class~II 6.7~GHz maser lines (Cyganowski et al. 2009). Sixteen regions are detected in at least one 25~GHz line ($J$=5), with 13 of 16 exhibiting maser emission. In total, we report 34 new sites of CH${}_3$OH maser emission and ten new sites of thermal CH${}_3$OH emission, significantly increasing the number of 25~GHz Class I CH${}_3$OH masers observed at high angular resolution. We identify probable or likely maser counterparts at 44~GHz for all 15 of the 25~GHz masers for which we have complementary data, providing further evidence that these masers trace similar physical conditions despite uncorrelated flux densities. The sites of thermal and maser emission of CH${}_3$OH are both predominantly associated with the 4.5 $\mu$m emission from the EGO, and the presence of thermal CH${}_3$OH emission is accompanied by 1.3~cm continuum emission in 9 out of 10 cases. Of the 19 regions that exhibit 1.3~cm continuum emission, it is associated with the EGO in 16 cases (out of a total of 20 sites), 13 of which are new detections at 1.3~cm. Twelve of the 1.3~cm continuum sources are associated with 6.7~GHz maser emission and likely trace deeply-embedded massive protostars.

References in corpus (42)

• The SIMBAD astronomical database
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Toward Understanding Massive Star Formation
• The Expanded Very Large Array -- a New Telescope for New Science
• 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
• 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
• The 6-GHz methanol multibeam maser catalogue II: Galactic longitudes 6 to 20
• A CH3CN and HCO+ survey towards southern methanol masers associated with star formation
• G11.92-0.61 MM1: A Keplerian disc around a massive young proto-O star
• Class I methanol masers in the outflow of IRAS 16547-4247
• Accurate rest frequencies of methanol maser and dark cloud lines
• Precise Positions of Methanol Masers
• 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
• VLA observations of ammonia in high-mass star formation regions
• VLBI study of maser kinematics in high-mass SFRs. I. G16.59-0.05
• Bipolar Molecular Outflows and Hot Cores in GLIMPSE Extended Green Objects (EGOs)
• Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: I. VLA Observations
• Simultaneous low- and high-mass star formation in a massive protocluster: ALMA observations of G11.92-0.61
• A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
• Deep Very Large Array Radio Continuum Surveys of GLIMPSE Extended Green Objects (EGOs)
• The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
• The high-mass star-forming region IRAS18182-1433
• Physical and chemical conditions in methanol maser selected hot-cores and UCHII regions
• G11.92-0.61-MM2: A Bonafide Massive Prestellar Core?
• Constraining the properties of 1.2-mm dust clumps that contain luminous water masers
• In Search of Circumstellar Disks Around Young Massive Stars
• Diversity of chemistry and excitation conditions in the high-mass star forming complex W33
• First Results from a 1.3 cm EVLA Survey of Massive Protostellar Objects: G35.03+0.35
• The Protocluster G18.67+0.03: A Test Case for Class I Methanol Masers as Evolutionary Indicators for Massive Star Formation
• A 1-mm spectral line survey toward GLIMPSE Extended Green Objects (EGOs)
• A 95 GHz Class I Methanol Maser Survey Toward A Sample of GLIMPSE Point Sources Associated with BGPS Clumps
• EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions III. The flux-limited sample
• Simultaneous observation of water and class I methanol masers toward class II methanol maser sources
• A study on subarcsecond scales of the ammonia and continuum emission toward the G16.59-0.05 high-mass star-forming region
• Ammonia and CO Outflow around 6.7 GHz Methanol Masers
• A Catalog of CH_3OH 7_0-6_1 A^+ Maser Sources in Massive Star-Forming Regions. II. Masers in NGC 6334F, G8.67-0.36, and M17
• Early-stage star forming cloud cores in GLIMPSE Extended Green Objects (EGOs) as traced by organic species

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• Online Database of Class I Methanol Masers
• The SOFIA Massive (SOMA) Star Formation Survey. II. High Luminosity Protostars
• Complex organic molecules detected in twelve high-mass star-forming regions with Atacama Large Millimeter/submillimeter Array (ALMA)
• ALMA observations of the Extended Green Object G19.01$-$0.03: I. A Keplerian disc in a massive protostellar system
• The SOMA Radio Survey. I. Comprehensive SEDs Of High-Mass Protostars From Infrared To Radio And The Emergence Of Ionization Feedback
• ATLASGAL: 3-mm class I methanol masers in high-mass star formation regions
• SOFIA {\it FORCAST} Photometry of 12 Extended Green Objects in the Milky Way
• VLA Observations of 9 Extended Green Objects in the Milky Way: Ubiquitous Weak, Compact Continuum Emission, and Multi-Epoch Emission from CH${}_3$OH, H${}_2$O, and NH${}_3$ Masers
• Modelling cosmic masers in C-type shock waves -- the coexistence of Class I CH3OH and 1720 MHz OH masers
• WISE Green Objects (WGOs): the massive star candidates in the whole Galactic Plane ($\mid b\mid <2^{\circ }$)
• The candidates for Class I methanol masers
• Broadband VLA Spectral Line Survey of a Sample of Ionized Jet Candidates