AST 9622569 ABSTRACT The University of Arizona proposes to build an 11- element, SIS heterodyne array receiver for use on the 10 meter University of Arizona/Max Planck Institute for Radioastronomy (MPIfR) Heinrich Hertz Telescope (HHT). The array will be designed for operation in the 870 pm atmospheric window, with a tuning range from 315 to 380 Ghz, one of the richest regions in the submillimeter portion of the spectrum. The 870 pm window also has the highest atmospheric transmission of any submillimeter band. An array designed for this wavelength range will make excellent use of the telescope, the available atmospheric transmission, and provide a new perspective on stellar, chemical, and galaxy evolution in the present as well as past epochs. The array receiver will use SIS waveguide receivers in an efficient, compact optical system. The array is divided into two, independently tuned, hexagonally packed subarrays with orthogonal polarizations. The subarrays are physically arranged so that their beams, when combined on a wire grid, appear interleaved on the sky. The field-of-view of the array is 76" x 88". The separation between adjacent pixels is at most ~ 19". The tuning and control of the array receiver will be completely automated. Funding will be used to build the array receiver "front-end", which includes the optics, mixers, cryostat, local oscillators, and cooled I.F. amplifiers. Each array channel will have from 500 MHz (435 km/s) to 2 GHz (1740 km/s) of available bandwidth. The corresponding spectral resolutions are 0.053 and 0.85 km/s respectively. Such a large range in instantaneous bandwidth and spectral resolution will make the array an excellent probe of velocity fields in a wide range of astronomical objects, from cold clouds to edge-on, high-redshift galaxies.
