Probing the Secrets of Massive Star Birth

1. Probing the Secrets of Massive Star Birth 2” This detailed picture of the massive protoclusterNGC6334I (Brogan et al., in preparation) was obtained from a 1.3mm single-polarization observation using the eight 6m antennas of the SubmillimeterArra (SMA). Left panel: Image and contours of the 1.3 mm continuum. The magenta contours show VLA 3.6 cm continuum emission from the SMA3 HII region (NGC6334F). Right panel: A portion of the spectra from the massive protostars as indicated on the continuum image. The full bandwidth is 2 GHz x 2 sidebands with 0.8125 MHz channels. The resolution is 0.”8 x 0.”4 (1300x650 AU) and the rms noise achieved is 40 mJy/beam per channel. The individual protostellar cores exhibit different chemistry and kinematics as well as different continuum spectral indices which are not understood. ALMA Early Science with 16 antennas and 250m baselines: • Repeat SMA 1.3 mm = 220 GHz (band 6) Observation: • FOV: 28”  Single pointing needed • 2 x 2 GHz bandwidth, dual polarization with 0.5 MHz channels (mode 7) • Resolution: angular = 1.”3, spectral = 0.67 km/sec • Time to achieve same spectral rms noise (40 mJy): 61 sec • Time to achieve similar UV-coverage: 1.5 hours • New 440 micron = 680 GHz (band 9) Observation: • FOV: 9” Small mosaic with 19 pointings to cover 30” • 2 x 2 GHz bandwidth, dual polarization with 0.5 MHz channels (mode 7) • Resolution: angular = 0.”5, spectral = smoothed offline to 0.67 km/sec • Time to achieve same spectral rms noise as 1.3 mm: 0.2 hrs per FOV = 1.9 hrs total • Time to achieve similar UV-coverage: 2.0 hours