HARP/ACSIS: A submillimetre spectral imaging system on the James Clerk
Maxwell Telescope
ArXiv 0907.3610 (2009)
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 Programme (HARP) and
Auto-Correlation Spectral Imaging System (ACSIS) that have recently been
installed and commissioned on the James Clerk Maxwell Telescope (JCMT). 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 $\sim$120 K across the whole band and
system temperatures of $\sim$300K are reached routinely under good weather
conditions. The system includes a single-sideband filter so these are SSB
figures. 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 1 square degree can be observed in under
1 hour.
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
SMA and ALMA.
