Speaker
Description
In recent years, two ultra-long (>1000 hr) single-dish spectral surveys toward the cold and quiescent molecular cloud TMC-1 have identified over 20 molecules containing five- and six-membered carbon rings, from benzonitrile (1 ring) to cyanocoronene (7 rings). These species are the simplest representatives of polycyclic aromatic hydrocarbons (PAHs), believed to account for a significant fraction of interstellar carbon. Despite their importance, their formation remains poorly understood. Distinguishing between top-down and bottom-up pathways requires detecting aromatic species across diverse interstellar environments, where physical conditions (e.g. Galactic location, evolutionary stage, temperature, turbulence, and cosmic-ray ionisation rate) leave distinct chemical signatures. The recent detection of benzonitrile in turbulent Galactic Center clouds shows that aromatic chemistry can survive harsh conditions, suggesting that it may be widespread throughout the entire Galaxy. To confirm this hypothesis, we need to detect large samples of aromatic species towards multiple of Galactic molecular clouds, achievable only with a single dish facility with significantly improved line sensitivity (< 0.1 mK). In this talk I will demonstrate how AtLAST observations in Band 1 (30-50 GHz) will enable the detection of several aromatic species within a few hours, enabling a systematic exploration of the Galaxy’s aromatic content.