DISCOVERY OF H2O MASER EMISSION FROM THE RED SUPERGIANT IRAS04553-6825 IN THE LARGE-MAGELLANIC-CLOUD

We report the detection of 22 GHz H2O maser emission from the red supe rgiant IRAS04553-6825 in the Large Magellanic Cloud. It is the first k nown source of circumstellar H2O maser emission outside the Milky Way. The measured flux density is comparable to that expected from scaling the galactic red supergiant NML Cyg. The peak velocity agrees with th e SiO maser peak velocity. A near-infrared spectrum indicates that IRA S04553-6825 has a typical LMC metallicity. We argue that, possibly as a result of the low metallicity, the H2O emission probably occurs near or within the dust formation radius, rather than further out as appea rs to be the case in NML Cyg and galactic OH/IR stars.