Abundant Methanol Masers but no New Evidence for Star Formation in GCM0.253+0.016

Abstract

We present new observations of the quiescent giant molecular cloud GCM0.253+0.016 in the Galactic center, using the upgraded Karl G. Jansky Very Large Array. Observations were made at wavelengths near 1 cm, at K (24 to 26 GHz) and Ka (27 and 36 GHz) bands, with velocity resolutions of 1-3 km/s and spatial resolutions of ~0.1 pc, at the assumed 8.4 kpc distance of this cloud. The continuum observations of this cloud are the most sensitive yet made, and reveal previously undetected emission which we attribute primarily to free-free emission from external ionization of the cloud. In addition to the sensitive continuum map, we produce maps of 12 molecular lines: 8 transitions of NH3 -- (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7) and (9,9), as well as the HC3N (3-2) and (4-3) lines, and CH3OH 4(-1) - 3(0) the latter of which is known to be a collisionally-excited maser. We identify 148 CH3OH 4(-1) - 3(0) (36.2 GHz) sources, of which 68 have brightness temperatures in excess of the highest temperature measured for this cloud (400 K) and can be confirmed to be masers. The majority of these masers are concentrated in the southernmost part of the cloud. We find that neither these masers nor the continuum emission in this cloud provide strong evidence for ongoing star formation in excess of that previously inferred by the presence of an H2O maser.

33 pages, 4 tables, 9 figures; ApJ Accepted

References in corpus (17)

• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• ATLASGAL --- towards a complete sample of massive star forming clumps
• Magnetic Fields in High-Mass Infrared Dark Clouds
• Desorption From Interstellar Ices
• Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores
• A cluster in the making: ALMA reveals the initial conditions for high-mass cluster formation
• Turbulence sets the initial conditions for star formation in high-pressure environments
• G0.253+0.016: A centrally condensed, high-mass protocluster
• APEX mapping of H3O+ in the Sgr B2 region
• The dynamics and star-forming potential of the massive Galactic centre cloud G0.253+0.016
• A multi-wavelength view of the Galactic center dust ridge reveals little star formation
• ALMA view of G0.253+0.016: Can cloud-cloud collision form the cloud?
• Detection of Star Formation in the Unusually Cold Giant Molecular Cloud G216
• Class I Methanol (CH${}_3$OH) Maser Conditions near Supernova Remnants
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: 278 GHz Class I Methanol Masers
• Absorption Filaments Towards the Massive Clump G0.253+0.016
• Prospects for Detection of Synchrotron Emission from Secondary Electrons and Positrons in Starless Cores: Application to G0.216+0.016

Cited by in corpus (20)

• The link between turbulence, magnetic fields, filaments, and star formation in the Central Molecular Zone cloud G0.253+0.016
• 'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016
• Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds
• Ubiquitous velocity fluctuations throughout the molecular interstellar medium
• CMZoom: Survey Overview and First Data Release
• Star Formation Rates of Massive Molecular Clouds in the Central Molecular Zone
• Star formation in 'the Brick': ALMA reveals an active proto-cluster in the Galactic centre cloud G0.253+0.016
• Origins of Scatter in the Relationship Between HCN 1-0 and Dense Gas Mass in the Galactic Center
• Kinematics and properties of the Central Molecular Zone as probed with [C II]
• A Large--Scale Spectroscopic Survey of Methanol and OH Line Emission from the Galactic Center: Observations and Data
• The CARMA 3mm Survey of the Inner $0.7^{\circ }\times 0.4^{\circ }$ of the Central Molecular Zone
• IRTF/TEXES Observations of the HII Regions H1 and H2 in the Galactic Centre
• The initial conditions for young massive cluster formation in the Galactic Centre: convergence of large-scale gas flows
• Evidence for an interaction between the Galactic Center clouds M0.10-0.08 and M0.11-0.11
• Modelling cosmic masers in C-type shock waves -- the coexistence of Class I CH3OH and 1720 MHz OH masers
• Towards a multi-scale understanding of the gas-star formation cycle in the Central Molecular Zone
• Star Formation in the Galactic Center
• Molecular gas kinematics of the CMZ: Great oaks from little acorns grow
• Molecular and ionized gas kinematics in the GC Radio Arc
• The 107 GHz methanol transition is a dasar in G0.253+0.016