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The southern maser site OH 300.969+1.147 has been studied using the Long Baseline Array of the Australia Telescope National Facility. The 1665- and 1667-MHz hydroxyl ground-state transitions were observed simultaneously. A series of maps with tenth-arcsec spatial resolution, at velocity spacing 0.09 km/s, and in both senses of circular polarization, reveal 59 small diameter maser spots. The spots are scattered over 2-arcsec, coincident with a strong ultracompact HII region, at a distance of 4.3 kpc. 17 Zeeman pairs of oppositely polarized spots were found, all yielding magnetic field estimates towards us (negative), ranging from -1.1 to -4.7 mG, with a median value of -3.5 mG. Excited state masers of OH at 6035 MHz and 6030 MHz at this site also display Zeeman pairs revealing a magnetic field of -5.0 mG. Weak methanol maser emission is intermingled with the OH masers, but there is no detectable closely related water maser. The consistent magnetic field direction found within this site is a striking feature of several other maser sites associated with strong HII regions studied in comparable detail. We interpret the site as a mature region nearing the end of the brief evolutionary stage that can support maser emission.
Our analysis of a VLBA 12-hour synthesis observation of the OH masers in a well-known star-forming region W49N has yielded valuable data that enables us to probe distributions of magnetic fields in both the maser columns and the intervening interstel
We present the results of MERLIN polarization mapping of OH masers at 1665 and 1667 MHz towards the Cepheus A star-forming region. The maser emission is spread over a region of 6 arcsec by 10 arcsec, twice the extent previously detected. In contrast
We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centres previously identified in the Southern Parkes Large-Area
We present high spatial resolution observations of ground-state OH masers, achieved using the Australia Telescope Compact Array (ATCA). These observations were conducted towards 171 pointing centres, where OH maser candidates were identified previous
We present a method for determining directions of magnetic field vectors in a spiral galaxy using two synchrotron polarization maps, an optical image, and a velocity field. The orientation of the transverse magnetic field is determined with a synchro