2018ApJ...866...32T

We have carried out interferometric observations of cyanopolyynes, HC₃N, HC₅N, and HC₇N, in the 36 GHz band toward the G28.28-0.36 high-mass star-forming region using the Ka-band receiver of the Karl G. Jansky Very Large Array. The spatial distributions of HC₃N and HC₅N are obtained. HC₅N emission is coincident with a 450 µm dust continuum emission, and this clump with a diameter of ∼0.2 pc is located at a position ∼0.15 pc east of the 6.7 GHz methanol maser. HC₇N is tentatively detected toward the clump. The HC₃N:HC₅N:HC₇N column density ratios are estimated to be 1.0:∼0.3:∼0.2 at an HC₇N peak position. We discuss possible natures of the 450 µm continuum clump associated with the cyanopolyynes. This clump seems to contain deeply embedded low- or intermediate-mass protostellar cores, and the most likely formation mechanism of the cyanopolyynes is the mechanism of warm carbon-chain chemistry. In addition, HC₃N and compact HC₅N emission is detected at the edge of the 4.5 µm emission, which possibly implies that such emission has a shock origin.