More than 15 years after the discovery of fast radio bursts (FRBs) -- millisecond-long, deep-space cosmic explosions of electromagnetic radiation -- astronomers worldwide have been combing the universe to uncover clues about how and why they form.
Nearly all FRBs identified have originated in deep space outside our Milky Way galaxy. That is until April 2020, when the first Galactic FRB, named FRB 20200428, was detected. This FRB was produced by a magnetar (SGR J1935+2154), a dense, city-sized neutron star with an incredibly powerful magnetic field.
This groundbreaking discovery led some to believe that FRBs identified at cosmological distances outside our galaxy may also be produced by magnetars. However, the smoking gun for such a scenario, a rotation period due to the spin of the magnetar, has so far escaped detection. New research into SGR J1935+2154 sheds light on this curious discrepancy.
In the July 28 issue of the journal Science Advances, an international team of scientists, including UNLV astrophysicist Bing Zhang, report on continued monitoring of SGR J1935+2154 following the April 2020 FRB, and the discovery of another cosmological phenomenon known as a radio pulsar phase five months later.
Unraveling a Cosmological Conundrum
To aid them in their quest for answers, astronomers rely in part on powerful radio telescopes like the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China to track FRBs and other deep-space activity. Using FAST, astronomers observed that FRB 20200428 and the later pulsar phase originated from different regions within the scope of the magnetar, which hints towards different origins.
"FAST detected 795 pulses in 16.5 hours over 13 days from the source," said Weiwei Zhu, lead author of the paper from National Astronomical Observatory of China (NAOC). "These pulses show different observational properties from the bursts observed from the source."
This dichotomy in emission modes from the region of a magnetosphere helps astronomers understand how -- and where -- FRBs and related phenomena occur within our galaxy and perhaps also those at further cosmological distances.
sources-science daily
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