Polarization maser observations of late-type stars at OH 1665 and 1667 MHz

VLBI astrometry of the stellar image of U Herculis, amplified by the 1667 MHz OH maser

The OH 1667 MHz maser in the circumstellar shell around the Mira variable U Her has been observed with the NRAO Very Long Baseline Array (VLBA) at 6 epochs, spread over 4 years. Using phase referencing techniques the position of the most blue-shifted maser spot was monitored with respect to two extra-galactic radio sources. The absolute radio positions of the maser can be compared with the stel...

The Magnetic Field toward the Young Planetary Nebula K 3 - 35

K 3-35 is a planetary nebula (PN) where H2O maser emission has been detected, suggesting that it departed from the proto-PNe phase only some decades ago. Interferometric VLA observations of the OH 18 cm transitions in K 3-35 are presented. OH maser emission is detected in all four ground state lines (1612, 1665, 1667, and 1720 MHz). All the masers appear blueshifted with respect to the systemic...

Maser Observations of Planetary Nebulae Precursors

We present OH maser observations at 1612, 1665, 1667, and 1720 MHz for 86 post-asymptotic giant branch (post-AGB) stars selected from a survey of 1612 MHz maser sources in the Galactic Plane. The observations were taken with the Parkes Telescope and the Australia Telescope Compact Array between 2002 September and 2003 August. Post-AGB stars are the precursors to planetary nebulae, the diverse m...

Robert Hooke's Micrographia of 1665 and 1667.

VLBA polarization observations of the J=7/2, 13.44 GHz OH maser in W3(OH)

We have obtained the first polarization images of the J = 7/2, F = 4−4 OHmaser emission fromW3(OH) at 13.44 GHz with high dynamic range and resolution. The emission has been imaged with a spectral resolution of 0.087 km s−1 and with a spatial resolution of 670μarcsec, the highest ever achieved in any image of the OH radical. The 13.44 GHz OH maser emission lies within an extremely compact area ...