The Arizona Radio Observatory: Surveying the ISM through Millimeter and Sub-millimeter Spectroscopy

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This award under the University Radio Observatories (URO) program supports scientific research, technical developments, operations, student training and public outreach at the Arizona Radio Observatory (ARO). The ARO operates the 10 m Sub-millimeter Telescope (SMT) on Mt. Graham and the 12 m millimeter-wave antenna at Kitt Peak. The ARO facility offers wide frequency coverage from 65 to 720 GHz utilizing state-of-the-art ALMA-type heterodyne sideband-separating (SBS) receivers. This provides the high sensitivity and stability needed for spectroscopy with broad intermediate frequency (IF) bandwidths (16 GHz) to do large Galactic and extragalactic surveys in the spatial and frequency domains supported by this instrumentation. Further, the ARO capabilities allow for a wide range of observations requiring maximum sensitivity, such as Very Long Baseline Interferometry (VLBI). The single-dish programs serve as both ALMA preparatory and ALMA complementary science investigations. The ARO complements spectroscopic studies across the ALMA frequency range and provides a venue for path-finding observations for the ALMA array. The investigators plan to develop and construct receivers and a new digital spectrometer will be fabricated for maximum utilization of the receivers. The support from the URO program permits that 50% of the time on both ARO telescopes will be available to outside observers. The ARO supports users with trained telescope operators, on-site visitor facilities, and remote observing capabilities. The telescopes are closely connected to laboratory spectroscopy facilities, which allows the measurement and astronomical verification of crucial molecular data.The research by the investigators addresses the processes whereby stars and planetary systems are created from interstellar material and the feedback effects on the dynamical and chemical state of the interstellar medium (ISM). Studies include: (a) an extensive survey of starless cores and Class 0 protostars (b) large scale mapping in CO and other molecules to probe star formation in Bok globules and giant molecular clouds, (c) a broad molecular line survey of the circumstellar shell of NML Cygnus to document the dynamical and chemical properties of massive supergiant stars; (d) exploration of the morphology and chemical composition of planetary nebulae to better understand their connection to the diffuse ISM and the formation of dense clouds; (e) molecular line studies of refractory gas-phase molecules to elucidate dust grain composition; and (f) documentation of the properties of sub-mm galaxies through surveys of transitions of species such as H2O and CI that offer great diagnostic power. In addition, ARO will continue to play a key role in the international millimeter/sub-millimeter VLBI studies of the environs of black holes (e.g. Sgr A*). Among the broader impacts of the ARO program are undergraduate and graduate student training opportunities in multi -disciplinary science involving observations, instrumentation development and laboratory research. This program will strengthen student engagement and STEM education and to diversify the population of students and researchers in STEM fields.