44 GHz Class I Methanol (CH${}_3$OH) Maser Survey in the Galactic Center

Abstract

We report on a large 44 GHz ($7_0-6_1$ A${}^{+}$) methanol (CH${}_3$OH) maser survey of the Galactic Center (GC). The Karl G. Jansky Very Large Array was used to search for CH${}_3$OH maser emission covering a large fraction of the region around Sgr A. In 25 pointings, over 300 CH${}_3$OH maser sources ($>10\sigma$) were detected. The majority of the maser sources have a single peak emission spectrum with line of sight velocities that range from about $-$13 km\,s${}^{-1}$ to 72 km\,s${}^{-1}$. Most maser sources were found to have velocities around 35$-$55 km\,s${}^{-1}$, closely following velocities of neighboring interacting molecular clouds. The full width half maximum of each individual spectral feature is very narrow ($\sim$0.85 km\,s${}^{-1}$ on average). In the north, where Sgr A East is known to be interacting with the 50 km\,s${}^{-1}$ molecular cloud, more than 100 44 GHz CH${}_3$OH masers were detected. In addition, three other distinct concentrations of masers were found, which appear to be located closer to the interior of the interacting molecular clouds. Possibly a subset of masers are associated with star formation, although conclusive evidence is lacking.

References in corpus (10)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• A new modified-rate approach for gas-grain chemical simulations
• Class I methanol masers in the outflow of IRAS 16547-4247
• Abundant Methanol Masers but no New Evidence for Star Formation in GCM0.253+0.016
• Massive Star Formation in the Molecular Ring Orbiting the Black Hole at the Galactic Center
• A Catalog of Methanol Masers in Massive Star-forming Regions. III. The Molecular Outflow Sample
• Very Large Array Observations of Galactic Center OH 1720 MHz Masers in Sagittarius A East and in the Circumnuclear Disk
• Class I Methanol (CH${}_3$OH) Maser Conditions near Supernova Remnants
• The environment of the strongest galactic methanol maser
• Excited-state OH Masers and Supernova Remnants

Cited by in corpus (7)

• Class I methanol masers in NGC253: Alcohol at the end of the bar
• A catalog of 44 GHz methanol masers in massive star-forming regions. IV. The high-mass protostellar object sample
• Diagnostics of a Nuclear Starburst: Water and Methanol Masers
• Molecular Cloud Cores in the Galactic Center 50 $\mathrm{km}{\mathrm{s}}^{-1}$ Molecular Cloud
• Modelling cosmic masers in C-type shock waves -- the coexistence of Class I CH3OH and 1720 MHz OH masers
• Hot Molecular Core Candidates in the Galactic Center 50 km/s Molecular Cloud
• Parsec-scale SiO emission in the Galactic Center