  We present the results of a survey for OH maser emission at 1612 MHz from
dust-enshrouded AGB stars and supergiants in the LMC and SMC, with the Parkes
radio telescope, aimed at deriving the speed of the superwind from the
double-peaked OH maser profiles. Out of 8 targets in the LMC we detected 5, of
which 3 are new detections - no maser emission was detected in the two SMC
targets. We detected for the first time the redshifted components of the OH
maser profile in the extreme red supergiant IRAS 04553-6825, confirming the
suspicion that its wind speed had been severely underestimated. Despite a much
improved spectrum for IRAS 04407-7000, which was known to exhibit a
single-peaked OH maser, no complementary peak could be detected. The new
detection in IRAS 05003-6712 was also single-peaked, but for two other new
detections, IRAS 04498-6842 and IRAS 05558-7000, wind speeds could be
determined from their double-peaked maser profiles. The complete sample of
known OH/IR stars in the LMC is compared with a sample of OH/IR stars in the
galactic centre. The LMC sources generally show a pronounced asymmetry between
the bright blueshifted maser emission and weaker redshifted emission, which we
attribute to the greater contribution of amplification of radiation coming
directly from the star itself as the LMC sources are both more luminous and
less dusty than their galactic centre counterparts. We confirm that the OH
maser strength is a measure of the dust (rather than gas) mass-loss rate. At a
given luminosity or pulsation period, the wind speed in LMC sources is lower
than in galactic centre sources, and the observed trends confirm simple
radiation-driven wind theory if the dust-to-gas ratio is approximately
proportional to the metallicity.

Astrophysics