Prevalence of Complex Organic Molecules in Starless and Prestellar Cores
  within the Taurus Molecular Cloud
  The detection of complex organic molecules (COMs) toward dense, collapsing
prestellar cores has sparked interest in the fields of astrochemistry and
astrobiology, yet the mechanisms for COM formation are still debated. It was
originally believed that COMs initially form in ices which are then irradiated
by UV radiation from the surrounding interstellar radiation field as well as
forming protostars and subsequently photodesorbed into the gas-phase. However,
starless and prestellar cores do not have internal protostars to heat-up and
sublimate the ices. Alternative models using chemical energy have been
developed to explain the desorption of COMs, yet in order to test these models
robust measurements of COM abundances are needed toward representative samples
of cores. We've conducted a large-sample survey of 31 starless and prestellar
cores in the Taurus Molecular Cloud, detecting methanol (CH$_3$OH) in 100$\%$
of the cores targeted and acetaldehyde (CH$_3$CHO) in 70$\%$. At least two
transition lines of each molecule were measured, allowing us to place tight
constraints on excitation temperature, column density and abundance. Additional
mapping of methanol revealed extended emission, detected down to A$_\mathrm{V}$
as low as $\sim$ 3 mag. We find complex organic molecules are detectable in the
gas-phase and are being formed early, at least hundreds of thousands of years
prior to star and planet formation. The precursor molecule, CH$_3$OH, may be
chemically linked to the more complex CH$_3$CHO, however higher spatial
resolution maps are needed to further test chemical models.
