Interferometric Observations of Cyanopolyynes toward the G28.28-0.36 High-Mass Star-Forming Region (1808.08435v1)

Abstract: We have carried out interferometric observations of cyanopolyynes, HC${3}$N, HC${5}$N, and HC${7}$N, in the 36 GHz band toward the G28.28$-$0.36 high-mass star-forming region using the Karl G. Jansky Very Large Array (VLA) Ka-band receiver. The spatial distributions of HC${3}$N and HC${5}$N are obtained. HC${5}$N emission is coincident with a 450 $\mu$m dust continuum emission and this clump with a diameter of $\sim 0.2$ pc is located at the east position from the 6.7 GHz methanol maser by $\sim 0.15$ pc. HC${7}$N is tentatively detected toward the clump. The HC${3}$N : HC${5}$N : HC${7}$N column density ratios are estimated at 1.0 : $\sim 0.3$ : $\sim 0.2$ at an HC${7}$N peak position. We discuss possible natures of the 450 $\mu$m continuum clump associated with the cyanopolyynes. The 450 $\mu$m continuum clump seems to contain deeply embedded low- or intermediate-mass protostellar cores, and the most possible formation mechanism of the cyanopolyynes is the warm carbon chain chemistry (WCCC) mechanism. In addition, HC${3}$N and compact HC$_{5}$N emission is detected at the edge of the 4.5 $\mu$m emission, which possibly implies that such emission is the shock origin.