Publication Date:
2015-06-12
Description:
We present polarimetric maser observations with the Australia Telescope Compact Array of excited-state hydroxyl (OH) masers. We observed 30 fields of OH masers in full Stokes polarization with the Compact Array Broadband Backend at both the 6030 and 6035 MHz excited-state OH transitions, and the 6668 MHz methanol maser transition, detecting 70 sites of maser emission. Amongst the OH we found 112 Zeeman pairs, of which 18 exhibited candidate components. This is the largest single full polarimetric study of multiple sites of star formation for these frequencies, and the rate of 16 per cent components clearly indicates that the component exists, and is comparable to the percentage recently found for ground-state transitions. This significant percentage of components, with consistent proportions at both ground- and excited-state transitions, argues against Faraday rotation suppressing the component emission. Our simultaneous observations of methanol found the expected low level of polarization, with no circular detected, and linear only found at the ≤10 per cent level for the brightest sources.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
