Temporal variability in low-frequency radio interference: Insight from high-cadence monitoring at a candidate radio notification zone in Malaysia

TL;DR

This study compares urban and rural sites in Malaysia for radio astronomy, using high-cadence low-frequency RFI monitoring and spectral kurtosis detection to identify interference patterns and assess site suitability.

Contribution

It introduces a high-cadence RFI monitoring approach with spectral kurtosis for site assessment, highlighting the rural site’s lower interference levels for future radio telescopes in Malaysia.

Findings

Rural site shows significantly lower RFI contamination than urban sites.

Identified persistent and transient RFI sources and their temporal evolution.

Tested and discussed multiple RFI mitigation strategies.

Abstract

Extensive radio frequency interference (RFI) monitoring is essential in the site selection process before constructing radio astronomy observatories, followed by mitigation strategies to minimize its adverse effects. Malaysia has an enormous prospect for radio astronomy due to its prominent location in the centre of Southeast Asia, but is challenged by its relatively high population density. In this research article, we perform high-cadence, low-frequency RFI monitoring at two sites, each representing an urban and a rural environment. Using modified generalized spectral kurtosis (GSK) as an RFI detection method, we ascertain the suitability of Glami Lemi, a rural area in the centre of Peninsular Malaysia previously assigned as a candidate radio notification zone (RNZ), as a potential site for radio astronomy observations due to its lower RFI contamination in our high-cadence monitoring, especially when compared with urban areas. We identified a number of persistent and transient RFI in our dataset, associate each of them with their potential origins and, if present, characterize their temporal evolution. A few types of RFI mitigation strategies were also tested and discussed. This study lays the groundwork for Malaysia's endeavours in establishing its first research-grade radio telescope, emphasizing the importance of robust RFI detection and mitigation strategies in optimizing observational outcomes.