A Q-band Line Survey toward Orion KL Using the Tianma Radio Telescope

Abstract We have conducted a line survey toward Orion KL using the Q -band receiver of Tianma 65 m radio telescope (TMRT), covering 34.8–50 GHz with velocity resolution between 0.79 and 0.55 km s −1 , respectively. The observations reach sensitivity level 1–8 mK, proving that TMRT is sensitive for conducting deep-line surveys. In total, 597 Gaussian features are extracted. Among them, 177 recombination lines (RRLs) identified, including 126, 40, 11 RRLs hydrogen, helium, carbon, maximum Δ n 16, 7, 3, carbon confirmed to originate from photodissociation regions V LSR ∼ 9 . addition, 371 molecular transitions 53 species identified. Twenty-one this were not firmly detected in band by Rizzo et al., such as H 2 CS, HCOOH, C 5 OH, H 2 13 CO, CCO, CH 3 CHO, OCH HCN υ = 1, OCHO t 1. particular, vibrationally excited states ethyl cyanide (C CN 13/ 21) first time band. NH (15,15) (16,16) they so far highest inversion KL. All identified can be reproduced radiative transfer model.