Polycyclic Aromatic Hydrocarbons (PAHs)
have been implicated as a large reservoir of reactive carbon
in the interstellar medium since the 1980s. PAHs have
been widely attributed as the carriers of the unidentified
infrared bands where their aggregate vibrational emission
spectra are extremely well matched to the observed line
signals. Only in the last year have individual PAHs been
detected in the ISM for the first time, however, allowing us
to begin to investigate the detailed chemical pathways for the
formation and destruction of these molecules. In this
talk, I will discuss our detections of PAH molecules via their
rotational transitions using Green Bank Telescope observations
of TMC-1 from the GOTHAM collaboration. I will discuss
the efforts to model the chemistry of these PAHs, the
necessity of complementary laboratory kinetics work, our
application of novel machine learning approaches to exploring
the chemical inventory in TMC-1, and finally the benefits of
unbiased reaction screening studies in the laboratory with
Microwave Spectral Taxonomy.
About the Speaker:
Brett McGuire received his B.S. in
Chemistry from the University of Illinois at Urbana-Champaign
in 2009 and his Ph.D. in Physical Chemistry from the
California Institute of Technology in 2014. He was a
National Radio Astronomy Observatory (NRAO) Jansky Fellow and
then a NASA Hubble Fellow from 2014-2020 at the NRAO and the
Center for Astrophysics | Harvard & Smithsonian. In
2020, he started a faculty position at the Massachusetts
Institute of Technology where he is now the Class of 1943
Career Development Assistant Professor of Chemistry.
Research in the McGuire Group uses the tools of physical
chemistry, molecular spectroscopy, and observational
astrophysics to understand how the chemical ingredients for
life evolve with and help shape the formation of stars and
planets.