and May 4, 2017. The 12m array was used for both datasets, using 43 antennas for H02 and 41-46 antennas for S05. The observations were carried out in configurations C40-5 and C40-4 for H02 and S05, respectively.

The data were pipeline-calibrated using CASA version 4.7.2. The H02 observations of HCN (1–0) have a final beamsize of 1.0$\times$0.73 and a sensitivity of 5.5 mJy/beam at a spectral resolution of 0.252 km/s. The H02 observations of HCO$^+$ (1–0) have a final beamsize of 1.1$\times$0.72 and a sensitivity of 2.7 mJy/beam at a spectral resolution of 1.004 km/s. Neither line is detected. The S05 observations of HCN (1–0) and HCO$^+$ (1–0) are also non-detections. The S05 observations of HCN (1–0) have a final beamsize of 1.4$\times$1.2 and a sensitivity of 570 $\mu$Jy/beam at a spectral resolution of 1.729 km/s. The S05 observations of HCO$^+$ (1–0) have a final beamsize of 1.3$\times$1.2 and a sensitivity of 570 $\mu$Jy/beam at a spectral resolution of 1.718 km/s. In order to calculate upper limits on the integrated intensities, we assume the same linewidths as the CO observations: 172 km/s for H02 and 350 km/s for S05.

We test the robustness of these upper limits in several ways. 