Limits on radio emission from meteors using the MWA

Abstract

Recently, low frequency, broadband radio emission has been observed\naccompanying bright meteors by the Long Wavelength Array (LWA). The broadband\nspectra between 20 and 60 MHz were captured for several events, while the\nspectral index (dependence of flux density on frequency, with $S_\\nu \\propto\n\\nu^\\alpha$) was estimated to be $-4\\pm1$ during the peak of meteor afterglows.\nHere we present a survey of meteor emission and other transient events using\nthe Murchison Widefield Array (MWA) at 72-103 MHz. In our 322-hour survey, down\nto a $5\\sigma$ detection threshold of 3.5 Jy/beam, no transient candidates were\nidentified as intrinsic emission from meteors. We derived an upper limit of\n-3.7 (95% confidence limit) on the spectral index in our frequency range. We\nalso report detections of other transient events, like reflected FM broadcast\nsignals from small satellites, conclusively demonstrating the ability of the\nMWA to detect and track space debris on scales as small as 0.1 m in low Earth\norbits.\n