Results are presented of a search for 22 GHz H _ { 2 } O 6 _ { 16 } \rightarrow 5 _ { 23 } , 43 GHz SiO _ { v = 1 } ( J = 1 \rightarrow 0 ) , 86 GHz SiO _ { v = 1 } ( J = 2 \rightarrow 1 ) and 129 GHz SiO _ { v = 1 } ( J = 3 \rightarrow 2 ) maser emission from bright IRAS point sources in the Small and Large Magellanic Clouds — mostly circumstellar envelopes around obscured red supergiants and Asymptotic Giant Branch stars ( OH/IR stars ) .
The aim of this effort was to test whether the kinematics of the mass loss from these stars depends on metallicity . H _ { 2 } O maser emission was detected in the red supergiants IRAS04553 - 6825 and IRAS05280 - 6910 , and tentatively in the luminous IR object IRAS05216 - 6753 and the AGB star IRAS05329 - 6708 , all in the LMC .
SiO _ { v = 1 } ( J = 2 \rightarrow 1 ) maser emission was detected in IRAS04553 - 6825 . The double-peaked H _ { 2 } O maser line profiles of IRAS04553 - 6825 and IRAS05280 - 6910 , in combination with the OH ( and SiO ) maser line profiles , yield the acceleration of the outflows from these stars .
The outflow velocity increases between the H _ { 2 } O masing zône near the dust-formation region and the more distant OH masing zône from v \sim 18 to 26 km for IRAS04553 - 6825 and from v \sim 6 to 17 km s ^ { -1 } for IRAS05280 - 6910 . The total sample of LMC targets is analysed in comparison with circumstellar masers in the Galactic Centre .
The photon fluxes of circumstellar masers in the LMC are found to be very similar to those in the Galactic Centre .
The expansion velocities in the LMC appear to be \sim 20 % lower than for similarly bright OH masers in the Galactic Centre , but the data are still consistent with no difference in expansion velocity .
OH/IR stars in the LMC appear to have slower accelerating envelopes than OH/IR stars in the Galactic Centre . The masers in the LMC have blue-asymmetric emission profiles .
This may be due to the amplification of stellar and/or free-free radiation , rather than the amplification of dust emission , and may be more pronounced in low metallicity envelopes . The SiO maser strength increases with the photometric amplitude at 2.2 \mu m but is independent of the photometric amplitude at 10 \mu m. This suggests a strong connection between shocks in the dust-free SiO masing zône and the dust formation process .
The LMC masers obey the same trend as the Galactic Centre masers . Appendices describe H _ { 2 } O maser emission from the moderately mass-losing AGB star R Dor in the Milky Way , optical echelle spectroscopy of IRAS04553 - 6825 , and the properties of circumstellar masers in the Galactic Centre .