Broadband Imaging to Study the Spectral Distribution of Meteor Radio Afterglows

TL;DR

This study uses broadband imaging at LWA-SV to analyze the spectral distribution of 86 meteor radio afterglows, revealing spectral characteristics and correlations with physical properties of meteoroids.

Contribution

First broadband spectral analysis of meteor radio afterglows using the LWA-SV, providing insights into their spectral shapes and physical correlations.

Findings

Spectra fit better with a log-normal function showing turnovers at 30-40 MHz.

Spectral index distribution peaks at -1.73, indicating spectral steepness.

FWHM duration correlates with local time, incidence angle, luminosity, and kinetic energy.

Abstract

We present observations of 86 meteor radio afterglows (MRAs) using the new broadband imager at the Long Wavelength Array Sevilleta (LWA-SV) station. The MRAs were detected using the all-sky images with a bandwidth up to 20 MHz. We fit the spectra with both a power law and a log-normal function. When fit with a power law, the spectra varied from flat to steep and the derived spectral index distribution from the fit peaked at -1.73. When fit with a log-normal function, the spectra exhibits turnovers at frequencies between 30-40 MHz, and appear to be a better functional fit to the spectra. We compared the spectral parameters from the two fitting methods with the physical properties of MRAs. We observe a weak correlation between the log-normal turnover frequency and the altitude of MRAs. The spectral indices from the power law fit do not show any strong correlations with the physical properties of MRAs. However, the full width half maximum (FWHM) duration of MRAs is correlated with the local time, incidence angle, luminosity and optically derived kinetic energy of parent meteoroid. Also, the average luminosity of MRAs seems to be correlated with the kinetic energy of parent meteoroid and the altitude at which they occur.