Abstract
We have undertaken a search for complex organic molecules by searching for their molecular
line transitions in the interstellar medium (ISM), using the Australia National Telescope
Facility (ATNF) Mopra single-dish radio telescope and the new Compact Array Broadband
Backend (CABB) capabilities of the Australia Telescope Compact Array (ATCA). A selection
of 10 “mm-only” radio sources suspected of being candidates for hot core star-forming
regions were observed using the ATCA, searching over a total of 4 GHz in the 7-mm and 4
GHz in the 3-mm bandwidth. Over 1 500 molecular transitions have been detected, of which
only a small percentage can be assigned to previous detections in the ISM. This is partly due
to the extended coverage provided by the ATCA’s CABB upgrade, which allows a sixteen-fold
improvement to simultaneously observable bandwidth in comparison to previous capabilities.
We have been able to identify numerous known transitions belonging to previously discovered
species as well as observe many new transitions of complex organic molecules known to exist
in the ISM. We have been able to identify at least one line frequency that has not previously
been catalogued and which may belong to an undiscovered interstellar species. We also
record several 100s of transitions that we cannot yet assign with confidence to potentially
new transitions, of which a portion may originate from yet to be discovered molecules.