In recent weeks, astronomers have spotted a bright, millisecond-duration radio burst emitted by a galactic magnetar called SGR 1935+2154. The object is a soft gamma repeater (SGR) that is an old stellar remnant.
The finding, which was registered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope, could be significant for enhancing the understanding of the source of fast radio bursts (FRBs).
SGR 1935+2154 Registered Extreme Values
Magnetars are neutron stars with incredibly powerful magnetic fields, more than a quadrillion times stronger than Earth‘s magnetic field. Degeneration of magnetic fields in magnetars fuels the discharge of high-energy electromagnetic radiation in particular ways, such as X-rays or radio waves. FRBs are powerful bursts of radio emission that last for milliseconds and depict the usual spread sweep of radio pulsars.
SGR 1935+2154 is located about 30,000 light-years away in the Vulpecula constellation, which has recently entered a period of incredibly powerful X-ray burst activity. As soon as the period started, a team of scientists led by Paul Scholz of the University of Toronto, Canada, started to analyze the pulsar with CHIME.
The observations resulted in the finding of a two-part bright millisecond radio burst from SGR 1935+2154 on April 28th of 2020, similar to FRBs seen at extragalactic distances.
“The burst was detected simultaneously in 93 of the 1,024 CHIME/FRB formed beams, indicating an extremely bright event,” the astronomers wrote in their paper.
Filling the Gap
The event consisted of two sub-bursts that lasted for 0.585 and 0.355 milliseconds, respectively, with the second taking place about 0.03 seconds after the first one. The team mentioned that the emission’s incredible values suggest a 400 to 800 MHz burst energy at a level of 30 decillion ergs, which is brighter than those of any radio-emitting magnetar registered so far.
Researchers do not know whether the recently discovered radio burst from SGR 1935+2154 is an FRB or not, but their finding may help to answer the energy questions of most bright galactic sources and extragalactic FRBs.
“This event thus bridges a large fraction of the radio energy gap between the population of galactic magnetars and FRBs, strongly supporting the notion that magnetars are the origin of at least some FRBs,” the authors of the paper concluded.