GBT22B-354

SPC: Full Stokes measurements of excited OH masers

Abstract

The 4.765 GHz excited OH (exOH) maser in Mon R2 is the only source that is known to have linear polarization in this line. Many observations of exOH masers are made looking only at the circular components. Mueller matrices have been determined for the C-band system so we would like to measure the full Stokes parameters of known 4.7 and 6.0 GHz exOH masers, as well as search for new sources in star-forming regions. Several new discoveries of exOH masers have been reported in 2022 but the observations were done a few years ago so the masers have probably varied in intensity in the interim. This survey will check if these masers still exist, and determine their polarization properties. Using the VEGAS backend we will be able to look for 6.0 GHz satellite lines which have thus far not been detected, as well as checking for the elusive 4.750 and 4.660 GHz exOH lines. Planned integration times should give a 3 sigma sensitivity of ~0.1 Jy. Observations will take about 2 hr per source including setup time, and each source can be scheduled separately as filler objects.

Investigators

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

* indicates the PI