A Molecular Line Survey around Orion at Low Frequencies with the MWA

TL;DR

This study conducted a low-frequency molecular line survey around Orion using the MWA, leading to tentative detections of molecules potentially involved in amino acid formation, expanding understanding of interstellar chemistry.

Contribution

First low-frequency survey of molecular lines around Orion, detecting molecules linked to amino acid precursors at frequencies below 200MHz.

Findings

Tentative detection of nitric oxide and isotopologues

Detection of deuterated formic acid

Identification of molecular oxygen and unknown transitions

Abstract

The low-frequency sky may reveal some of the secrets yet to be discovered and until recently, molecules had never been detected within interstellar clouds at frequencies below 700MHz (Lovas, 2003) . Following the pilot survey towards the Galactic Centre at 103--133MHz with the Murchison Widefield Array (Tremblay, 2017), we surveyed 400 degree squared centered on the Orion KL nebula from 99--170MHz. Orion is a nearby region of active star formation and known to be a chemically rich environment. In this paper, we present tentative detections of nitric oxide and its isotopologues, singularly deuterated formic acid, molecular oxygen, and several unidentified transitions. The three identified molecules are particularly interesting as laboratory experiments have suggested these molecules are precursors to the formation of amines.