On Detecting Interstellar Scintillation in Narrowband Radio SETI

TL;DR

This paper explores detecting interstellar scintillation as a new method to identify extraterrestrial technosignatures in narrowband radio signals, supplementing traditional sky location-based searches.

Contribution

It introduces a novel approach using interstellar scintillation analysis to distinguish technosignatures from RFI in radio SETI searches.

Findings

Scintillation timescales can be estimated using the NE2001 model.

Strong intensity scintillations can be practically detected in signals.

Scintillation can serve as an effective filter for technosignature candidates.

Abstract

To date, the search for radio technosignatures has focused on sky location as a primary discriminant between technosignature candidates and anthropogenic radio frequency interference (RFI). In this work, we investigate the possibility of searching for technosignatures by identifying the presence and nature of intensity scintillations arising from the turbulent, ionized plasma of the interstellar medium (ISM). Past works have detailed how interstellar scattering can both enhance and diminish the detectability of narrowband radio signals. We use the NE2001 Galactic free electron density model to estimate scintillation timescales to which narrowband signal searches would be sensitive, and discuss ways in which we might practically detect strong intensity scintillations in detected signals. We further analyze the RFI environment of the Robert C. Byrd Green Bank Telescope (GBT) with the proposed methodology and comment on the feasibility of using scintillation as a filter for technosignature candidates.