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Discipine of Physics
Faculty of Science, Engineering & Technology

Astrophysics Research

Interstellar Masers

UTas People Involved
Stars form deep within dense clouds of gas and dust which absorb light at most wavelengths.  However, these clouds are transparent at radio wavelengths enabling radio telescopes to probe the star formation process.  Molecular masers (Microwave Amplification by Stimulated Emission of Radiation) are the radio analogue of lasers and occur naturally in some astrophysical environments, including near where high-mass stars are forming.  Masers indicate the presence of specific physical conditions and are potentially very powerful probes of the star formation environment.  However, the processes which produce masers are complex and cannot easily be determined from a single observation.  Fortunately some molecules exhibit masers from a number of transitions at different frequencies.  Where these masers are found in the same source models are constrained by the requirement that they produce emission from each of the transitions in the observed intensity ratio.

A team consisting of observational astronomers from the University of Tasmania and the Australia Telescope National Facility and theoreticians from Monash University and Ural State University have been successfully using the method described above to improve our understanding of the early stages of the formation of high-mass stars. A project funded by the Australian Research Council is underway to collecting data on a range of methanol and OH masers towards many sources to better understand the physical conditions during the evolutionary phase of star formation corresponding to the presence of these masers.  As part of the same project we are also undertaking detailed modelling of a small number of sources that show maser emission in a large number of transitions as in these cases we are able to tightly constrain the maser models.

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Dr Simon Ellingsen
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Created: September 2009 by Tammy Riley
Last modified: September 2007
Copyright School of Mathematics & Physics, University of Tasmania Australia, 2009