GBT25A-001

Full Stokes polarization of rare 4.660 GHz OH masers in W51 and IRAS 18460-0151

Abstract

Our submission is for two once-off observations that can be used as filler sources. Only twelve 4.660 GHz OH masers have been reported to date and there are no linear polarisation observations. A survey for excited OH masers using the Hartebeesthoek Radio Astronomy Observatory 26-m dish discovered a rare 4.660 GHz maser in source W51. Gaussian fits to the line suggest a single spot of emission and ongoing monitoring since 2016 shows a steady increase in the flux. Another 4.660 GHz OH maser was reported recently in IRAS 18460-0151. We would like to do full Stokes GBT observations towards W51 and IRAS 18460-0151 to see if there is any polarization. In addition, using the GBT sensitivity, we would also like to look for weak 4.765 and 4.750 GHz as well as 6.035 and 6.031 GHz OH masers. Any new discoveries of these masers could help elucidate why these masers are so rare.

Investigators

Name	Institution
Paul Fallon *	South Africa, University of ; North-West University
Derck Smits	South Africa, University of

* indicates the PI