A First Look for Molecules between 103 and 133 MHz using the Murchison Widefield Array

TL;DR

This pilot study explores the potential of low-frequency radio observations with the Murchison Widefield Array to detect molecular lines, resulting in tentative detections of nitric oxide and SH linked to evolved stars.

Contribution

It demonstrates the feasibility of using low-frequency radio arrays for molecular line detection in the Galaxy, focusing on a specific frequency range and molecular species.

Findings

Tentative detection of nitric oxide (NO)

Tentative detection of mercapto radical (SH)

Associations with evolved stars

Abstract

We detail and present results from a pilot study to assess the feasibility of detecting molecular lines at low radio frequencies. We observed a 400 square degree region centred on the Galactic Centre with the Murchison Widefield Array (MWA) between 103 and 133\,MHz targeting 28 known molecular species that have significant transitions. The results of this survey yield tentative detections of nitric oxide (NO) and the mercapto radical (SH). Both of these molecules appear to be associated with evolved stars.