2009MNRAS.394L..70W

Observations of H₂ O masers towards the post-asymptotic-giant-branch star and water fountain source OH 009.1-0.4 were made as part of The H₂O southern galactic Plane Survey, with the Mopra radiotelescope. Together with followup observations using the Australia Telescope Compact Array (ATCA), we have identified H₂ O maser emission over a velocity spread of nearly 400 km/s (-109 to +289km/s). This velocity spread appears to be the largest of any known maser source in our Galaxy. High-resolution observations with the ATCA indicate that the maser emission is confined to a region 0.3 x0.3 arcsec and shows weak evidence for a separation of the red- and blueshifted maser spots. We are unable to determine if the water fountain is projected along the line of sight, or is inclined, but either way OH 009.1-0.4 is an interesting source, worthy of followup observations.