  The simplest cyanobenzene, benzonitrile (c-C6H5CN) have been possibly
detected toward the cyanopolyyne peak in TMC-1. We used the results of the 8.8
-- 50 GHz spectral survey of TMC-1 by Kaifu et al. (2004) and stacked the lines
of benzonitrile that fall within the range of this survey. The obtained
spectrum strongly suggests the presence of this molecule. Benzonitrile is a
derivative of the simplest aromatic hydrocarbon benzene. Aromatic hydrocarbons
are thought to be ubiquitous in the ISM, but it is difficult to study them in
molecular cloud interiors, since they are nonpolar and have no allowed
transitions at radio frequencies. Therefore it is important to search for their
derivatives, such as cyanobenzenes. Thus, the detection of benzonitrile might
be important for astrochemistry, but additional sensitive observations are
necessary in order to confirm it.
