PATT Travel Grant request to support observations for the Programme 'Switched on Water Masers' at the Parkes 60 metre Telescope, Australia

We propose a sensitive Parkes Programme to search a statistically robust sample of young massive prestellar cores to measure the onset of the 22 GHz water maser-emitting phase. The sceince objective of this proposal is to detect the very earliest stages of the 'switch-on' of the maser emitting phase that occurs in (most ?) massive young stars, and differs in objective to the more usual maser detection surveys that have been commonly carried out towards many star formation regions in the galaxy. Using the latest accurate positions/bolometric luminosities/distances from our HERSCHEL Guaranteed time programmes, we will search a carefully selected sample of about nearby cores, mostly in Corona Australis, Chamaeleon, Musca, Lupus, Ophiuchus, Vela and RCW120, to achieve a final sensitivity L(H2O) ~ a few 10-9 - 10-8 Lsun. Our three tiered observing strategy will focus on for nearby (< 1 kpc) protostellar cores with well characterised distances and evolutionary phases, to provide good sampling of far-IR colour/luminosity/evolutionary state parameter space of a statistically robust sample that will answer the question of exactly when maser emission first switches on, comparing this with its natal environment as shown by the far-infrared properties, and from simultaneous measurements of temperature using the 23 GHz NH3 lines.