DCO+ and DCN 1-0 survey in cold clumps

Large-sample surveys for deuterated molecules are needed to understand the enhancement of deuterated molecules from diffuse molecular gas to cold cores. A single-pointing survey toward the 559 Planck cold clumps of the Early Cold Core Catalogue (ECC) has been conducted using the Arizona Radio Observatory 12-meter telescope, focusing on the J=1-0 transitions of DCO+ and DCN.

The survey included observations of 309 cores for DCO+ and DCN 1-0 simultaneously, followed by 71 of these cores where DCO+ 1-0 was detected for H^13^CO+ and H^13^CN 1-0 simultaneously, aiming to determine the deuterated fraction (D_frac). Additionally, 250 cores were observed for DCO+, DCN, H^13^CO+ and H^13^CN 1-0 simultaneously. Among the 309 sources, DCO+ and DCN 1-0 were detected in 79 and 11 sources, with a detection rates of 25.6% and 3.6% respectively.