2010MNRAS.408.1438H

We present wide-area radio (12 mm) Mopra telescope observations of the complex and rich massive star-forming region G305. Our goals are to determine the reservoir for star formation within G305 using NH₃ to trace the dense molecular content, and thus the gas available to form stars; estimate physical parameters of detected NH₃ clumps (temperature, column density, mass, etc.); locate current areas of active star formation via the presence of H₂ O and methanol masers and the distribution of young stellar objects (YSOs) and ultra-compact HII regions associated with this region. This paper details the NH₃( J, K), (1,1), (2,2) and (3,3) inversion transition and 22 GHz H₂ O maser observations. We observed a ∼ region with ∼2 arcmin angular resolution and a sensitivity of ∼60 mK per 0.4 km/s channel. We identify 15 NH₃(1,1), 12 NH₃(2,2) and 6 NH₃(3,3) clumps surrounding the central HII region. The sizes of the clumps vary between <2.6 and 10.1 pc; the average kinetic temperature of the gas is 25K. We calculate clump masses of and find the total molecular mass of the complex to be. We note the positions of 56 star formation tracers, and discover a high degree of correlation with detected NH₃clumps. We have detected 16 H₂ O masers and find they correlate with the detected ammonia clumps. In general, they are found closer to the NH₃ clump cores than star formation tracers of later evolutionary stages.