The LWA keeps its eyes to the sky day and night, probing a poorly explored region of the electromagnetic spectrum. It’s one of only a handful of blind searches carried out below 100 MHz.
Over the course of 11,000 hours, graduate student Kenneth Obenberger from the University of New Mexico and colleagues found 49 radio bursts, 10 of which came from fireballs.
Most of the bursts appear as large point sources, limited to four degrees, roughly eight times the size of the full Moon. Some, however, extend several degrees across the sky. On January 21, 2014, a source left a trail covering 92 degrees in less than 10 seconds (see above). The end point continued to glow for another 90 seconds.
The only known astrophysical object with this ability is a fireball. So Obenberger and colleagues set out to see if NASA’s All Sky Fireball Network had detected anything at the same location and time as the bursts.
While the network shares only a portion of the sky with the LWA, the fireballs seen in this direction matched fireballs caught by NASA. Additionally, most bursts did occur directly after the peak of a bright meteor shower.
Image: a series of All-Sky (fish eye) images showing the plasma trail left by a fireball, which extends 92 degrees across the northern half of the sky. These images are 5 second snapshots captured at 37.8 MHz with the LWA1 radio telescope. The bright steady sources (Cygnus A, Cassiopeia A, the galactic plane, etc) have been removed using image subtraction. Image credit: Gregory Taylor (University of New Mexico)