SF-03-0023

Which spectral lines trace what physical processes in the Galactic Center? First results: line list and LTE modeling results

Alyssa Bulatek, Adam Ginsburg, Katharina Immer, Desmond Jeff, Christian Henkel, Karl Menten, Jeremy Darling

The presences of certain molecules in the interstellar medium (ISM) are used as "fingerprints" to trace specific physical processes. However, the chemical complexity of the Central Molecular Zone (CMZ) in the Milky Way serves as evidence for the non-universality of these traditional tracers in extreme environments like CMZs. We present a wideband spectral line survey of the CMZ molecular cloud G0.253+0.015 ("The Brick") acquired with ALMA. We aim to use The Brick to build a toolkit to study molecular processes in the ISM that can be applied to CMZ-like environments, where traditional tracers fail. We are building this toolkit by associating the observed lines with 4 phases we know are present in The Brick (protostellar outflows, hot star-forming cores, shocks, and diffuse molecular gas). We present a catalog of spectral lines detected at small (1", ~8000 AU) scales in the only star-forming region in The Brick. We detect CO, HCO+, SO2, HNCO, H2CO, H2CS, HC3N, CH3OH, CH3CN, and other molecules in the extended phases and we present LTE modeling results for these. Using line-specific morphologies, we present preliminary interpretations of the processes traced by each species. As part of the survey, we present the first clear evidence that the 107 GHz line of methanol is dasing. We also present a preliminary comparison to JWST observations that show signs of CO ice absorption in this region.