We have used the Australia Telescope Compact Array (ATCA) to search for a number of centimetre wavelength methanol transitions which are predicted to show weak maser emission towards star formation regions. Sensitive, high spatial and spectral resolution observations towards four high-mass star formation regions which show emission in a large number of class II methanol maser transitions did not result in any detections. From these observations we are able to place an upper limit of <~1300K on the brightness temperature of any emission from the 31A+-31A−, 17−2-18−3E (vt=1), 124-133A−, 124-133A+ and 41A+-41A− transitions of methanol in these sources on angular scales of 2 arcseconds. This upper limit is consistent with current models for class II methanol masers in high-mass star formation regions and better constraints than those provided here will likely require observations with next-generation radio telescopes.
@article{arxiv.1610.03109,
title = {A sensitive search for predicted methanol maser transitions with the Australia Telescope Compact Array},
author = {Antony Chipman and Simon Ellingsen and Andrej Sobolev and Dinah Cragg},
journal= {arXiv preprint arXiv:1610.03109},
year = {2016}
}
Comments
Accepted for publication in Publications of the Astronomical Society of Australia, 6 pages, 1 figure, 1 table