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Published 2008 | public
Journal Article

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 ^(12)CO(1–0) line to map the molecular gas in the Large Magellanic Cloud. For some regions we also obtained interferometric maps of the high density gas tracers HCO^+ and HCN with the Australia Telescope Compact Array. Here we discuss the properties of the elongated molecular complex that stretches about 2 kpc southward from 30 Doradus. Our data suggest 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 triggers of molecular-cloud formation are shocks and shearing forces that are present in the surrounding south-eastern H_I 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 ^(12)CO(1–0) and H_I emission peaks in the molecular ridge are typically near each other but never coincide. A likely explanation is the conversion of warmer, low-opacity H_I to colder, high-opacity H_I from which H_2 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.

Additional Information

© Astronomical Society of Australia 2008. Received 2007 December 20, accepted 2008 May 10. Published: 29 September 2008. Jürgen Ott is a Jansky Fellow of the National Radio Astronomy Observatory. Erik Muller is a Bolton Fellow. The Australia Telescope Compact Array is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023