Argus: a new 16-pixel millimeter-wave spectroscopic instrument for star formation studies at the Green Bank Telescope

Argus is a new 16-pixel W-band focal plane array for millimeter spectroscopy at the Green Bank Telescope (GBT). Built by a consortium led by Sarah Church at Stanford, this new instrument provides fast astronomical imaging over the 75-116 GHz band and at high spatial resolution. The frequency range covered by Argus is of particular interest for star formation studies and will be excellent at probing cold, dense cores within star-forming regions, along with constraining the dynamics of filamentary structures withing giant molecular cloud complexes. In particular, the 3mm band covers a large number of important spectral lines, including CO (J=1-0) and its isotopologues, as well as HCO+, H13CO+, SiO, N2H+, HCN and HNC. These molecular transitions trace a combination of dense cold gas, shocked emission from jets and outflows as well as the signatures of infall, all of which are imperative constituents in the early stages of star formation. Argus on the GBT will provide the high sensitivity of a filled aperture along with a high angular resolution of 6-10", this resolution is well-matched to the mid- and far-infrared observations from the Spitzer, SOFIA, and Herschel telescopes. We report on the current status of Argus and present recent commissioning and early science highlights from Argus of 12CO, 13CO and HCO+ emission towards the massive star forming region, DR 21. Argus, currently under commissioning, is expected to be in full science mode in the winter semester of 2016.