The spatial distribution of an aromatic molecule, C6H5CN, in the cold dark cloud TMC-1

Abstract

We present a highly sensitive 2D line survey of TMC-1 obtained with the Yebes 40 m radio telescope in the Q-band (31.13–49.53 GHz). These maps cover a region of 320″×320″ centred on the position of the QUIJOTE line survey with a spatial sampling of 20″. The region covering 240″×240″, where a longer integration time was used, shows a homogenous sensitivity of 2–4 mK across the band. We present in this work the first determination of the spatial extent of benzonitrile (C6H5CN), which follows that of cyanopolyynes rather well, but differs significantly from that of the radicals CnH and CnN. We definitively conclude that aromatic species in TMC-1 are formed from chemical reactions involving smaller species in the densest zones of the cloud.