The Molecular Ridge Close to 30 Doradus in the Large Magellanic Cloud

Abstract

With the ATNF Mopra telescope we are performing a survey in the 12CO(1-0) line to map the molecular gas in the Large Magellanic Cloud (LMC). For some regions we also obtained interferometric maps of the high density gas tracers HCO+ and HCN with the Australia Telescope Compact Array (ATCA). Here we discuss the properties of the elongated molecular complex that stretches about 2 kpc southward from 30 Doradus. Our data suggests that the complex, which we refer to as the ``molecular ridge,'' is not a coherent feature but consists of many smaller clumps that share the same formation history. Likely molecular cloud formation triggers are shocks and shearing forces that are present in the surrounding south-eastern HI overdensity region, a region influenced by strong ram pressure and tidal forces. The molecular ridge is at the western edge of the the overdensity region where a bifurcated velocity structure transitions into a single disk velocity component. We find that the 12CO(1-0) and HI emission peaks in the molecular ridge are typically near each other but never coincide. A likely explanation is the conversion of warmer, low-opacity HI to colder, high-opacity HI from which H2 subsequently forms. On smaller scales, we find that very dense molecular gas, as traced by interferometric HCO+ and HCN maps, is associated with star formation along shocked filaments and with rims of expanding shell-like structures, both created by feedback from massive stars.

arXiv commentaccepted for publication in the Publications of the Astronomical Society of Australia

References in corpus (12)

• Magellanic Cloud Structure from Near-IR Surveys I: The Viewing Angles of the LMC
• The Origin of the Magellanic Stream and Its Leading Arm
• A New Look at the Large-Scale HI Structure of the LMC
• A FUSE Survey of Interstellar Molecular Hydrogen in the Small and Large Magellanic Clouds
• The gravitational and hydrodynamical interaction between the LMC and the Galaxy
• N-body simulations of the Magellanic Stream
• Dust and Atomic Gas in Dwarf Irregular Galaxies of the M81 Group: The SINGS and THINGS view
• Dynamical Influences of the Last Magellanic Interaction On the Magellanic Clouds
• Extinction in the Large Magellanic Cloud
• Spitzer IRAC Observations of Star Formation in N159 in the LMC
• A Catalog of HI Clouds in the Large Magellanic Cloud
• Synthesis Imaging of Dense Molecular Gas in the N113 HII Region of the Large Magellanic Cloud

Cited by in corpus (24)

• Physical Properties of Giant Molecular Clouds in the Large Magellanic Cloud
• The Structure of a Low-Metallicity Giant Molecular Cloud Complex
• Molecular and Atomic Gas in the Large Magellanic Cloud II. Three-dimensional Correlation between CO and HI
• Spitzer View of Young Massive Stars in the LMC HII Complexes. II. N159
• Spitzer View of Young Massive Stars in the LMC HII Complex N44
• Detection of a hot molecular core in the Large Magellanic Cloud with ALMA
• Molecular and Atomic Gas in the Large Magellanic Cloud - I. Conditions for CO Detection
• Characterizing the Low-Mass Molecular Component in the Northern Small Magellanic Cloud
• Supernova Remnants and Star Formation in the Large Magellanic Cloud
• Warm and Dense Molecular Gas in the N159 Region: 12CO J=4-3 and 13CO J=3-2 Observations with NANTEN2 and ASTE
• Dense Clumps in Giant Molecular Clouds in the Large Magellanic Cloud: Density and Temperature Derived from ${}^{13}$CO($J=3-2$) Observations
• A multi-wavelength look at the young plerionic supernova remnant 0540-69.3
• The Influence of Far-Ultraviolet Radiation on the Properties of Molecular Clouds in the 30 Dor Region of the Large Magellanic Cloud
• The thermal dust emission in the N158-N159-N160 (LMC) star forming complex mapped by Spitzer, Herschel and LABOCA
• First Detection of Ammonia in the Large Magellanic Cloud: The Kinetic Temperature of Dense Molecular Cores in N159W
• Evolution of dust and molecular hydrogen in the Magellanic System
• Deep GeMS/GSAOI near-infrared observations of N159W in the Large Magellanic Cloud
• The VMC Survey XXII. Hierarchical Star Formation in the 30 Doradus-N158-N159-N160 Star-Forming Complex
• From Gas to Stars in Energetic Environments: Dense Gas Clumps in the 30 Doradus Region Within the Large Magellanic Cloud
• An environmental analysis of the fast transient AT2018cow and implications for its progenitor and late-time brightness
• A view of Large Magellanic Cloud HII regions N159, N132, and N166 through the 345 GHz window
• Maps of the Magellanic Clouds from Combined South Pole Telescope and Planck Data
• Discovery of a dense molecular cloud towards a young massive embedded star in 30 Doradus
• Near-Infrared Polarimetric Study of N159/N160 Star-Forming Complex in the Large Magellanic Cloud