HARP/ACSIS: a submillimetre spectral imaging system on the James Clerk Maxwell Telescope
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 399:2 (2009) 1026-1043
Authors:
JV Buckle, RE Hills, H Smith, WRF Dent, G Bell, EI Curtis, R Dace, H Gibson, SF Graves, J Leech, JS Richer, R Williamson, S Withington, G Yassin, R Bennett, P Hastings, I Laidlaw, JF Lightfoot, T Burgess, PE Dewdney, G Hovey, AG Willis, R Redman, B Wooff, DS Berry, B Cavanagh, GR Davis, J Dempsey, P Friberg, T Jenness, R Kackley, NP Rees, R Tilanus, C Walther, W Zwart, TM Klapwijk, M Kroug, T Zijlstra
Abstract:
This paper describes a new Heterodyne Array Receiver Program (HARP) and Auto-Correlation Spectral Imaging System (ACSIS) that have recently been installed and commissioned on the James Clerk Maxwell Telescope. The 16-element focal-plane array receiver, operating in the submillimetre from 325 to 375 GHz, offers high (three-dimensional) mapping speeds, along with significant improvements over single-detector counterparts in calibration and image quality. Receiver temperatures are ∼120 K across the whole band, and system temperatures of ∼300 K are reached routinely under good weather conditions. The system includes a single-sideband (SSB) filter so these are SSB values. Used in conjunction with ACSIS, the system can produce large-scale maps rapidly, in one or more frequency settings, at high spatial and spectral resolution. Fully sampled maps of size can be observed in under 1 h. The scientific need for array receivers arises from the requirement for programmes to study samples of objects of statistically significant size, in large-scale unbiased surveys of galactic and extra-galactic regions. Along with morphological information, the new spectral imaging system can be used to study the physical and chemical properties of regions of interest. Its three-dimensional imaging capabilities are critical for research into turbulence and dynamics. In addition, HARP/ACSIS will provide highly complementary science programmes to wide-field continuum studies and produce the essential preparatory work for submillimetre interferometers such as the Submillimeter Array (SMA) and Atacama Large Millimeter/Submillimeter Array (ALMA).
