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[Music throughout] In April 2020, astronomers 

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detected an unusually bright and powerful radio signal never before

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recorded in our home galaxy. The source is a magnetar,

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a type of compact object with the strongest magnetic fields in the cosmos.

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Like pulsars and neutron stars, magnetars are the

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crushed cores left behind when a massive star explodes, but

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their superstrong magnetic fields put them in a class by themselves.

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The fields are up to a thousand times stronger than typical neutron stars

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and over 10 trillion times stronger than a refrigerator magnet.

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They can rip molecules apart from thousands of miles away, distort

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the shapes of atoms and store enormous amounts of energy.

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On April 27th, the magnetar, named SGR 1935,

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produced a rapid-fire storm of short, powerful X-ray

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bursts that lasted hours. The activity, first spotted

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by Swift, was also monitored by NASA’s Fermi Gamma-ray Space Telescope

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and the NICER X-ray telescope on the International Space Station,

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along with other space missions. As the

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storm wound down early on April 28th, NICER recorded some

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200 X-ray bursts in just 20 minutes.

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Later that day, SGR 1935 fired off another X-burst.

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This time, though, it was accompanied by something new: 

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a powerful pulse of radio waves lasting a thousandth of a second.

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CHIME, a radio telescope in British Columbia

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led by several Canadian universities, discovered the signal and

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determined it came from the vicinity of SGR 1935.

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Another experiment, called STARE2 and operated by Caltech

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and NASA’s Jet Propulsion Laboratory, saw an even brighter signal at

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different radio wavelengths. Since 2007,

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astronomers have been trying to understand the sources of powerful, millisecond

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radio signals called fast radio bursts seen from other galaxies.

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Magnetars have been prominent suspects.

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The duration and energy release of SGR 1935’s radio 

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signal is closer to fast radio bursts than any other source.

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For the first time, astronomers saw a magnetar in our own backyard

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produce a signal only previously seen in other galaxies.

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The discovery strengthens the case that magnetars are responsible

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for at least some fast radio bursts. Data from

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NICER and Fermi on X-ray bursts at the end of the storm show that they differed 

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from the one that coincided with the radio signal. This event’s 

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characteristics set it apart from the other eruptions and further study

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may provide clues about how it also powered the radio burst.

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Radio waves from normal pulsars originate high above their surfaces —

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exactly where and how, we don’t know. A big

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eruption could launch a cloud of plasma to high enough that a radio burst

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could form. Never before have astronomers seen a

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fast radio burst so close to home. It’s just one more reason

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to watch the skies — and to keep tabs on the strongest

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magnets in the universe.

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[Music]

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Drone Footage: R. Shaw/UBC/CHIME Collective All-sky image: Axel Mellinger (Central Michigan University)