Flash of luck: Astronomers find cosmic radio burst source

A flash of luck helped astronomers solve a cosmic mystery: What causes powerful but fleeting radio bursts that zip and zigzag through the universe?

Scientists have known about these energetic pulses—called fast radio bursts—for about 13 years and have seen them coming from outside our galaxy, which makes it harder to trace them back to what’s causing them. Making it even harder is that they happen so fast, in a couple of milliseconds.

Then this April, a rare but considerably weaker burst coming from inside our own Milky Way galaxy was spotted by two dissimilar telescopes: one a California doctoral student’s set of handmade antennas, which included actual cake pans, the other a $20 million Canadian observatory.

Bochenek’s antennas cost about $15,000. Each is “the size of a large bucket. It’s a piece of 6-inch metal pipe with two literal cake pans around it,” the doctoral student said. They are crude instruments designed to look at a giant chunk of the sky—about a quarter of it—and see only the brightest of radio flashes.

Bochenek figured he had maybe a 1-in-10 chance of spotting a fast radio burst in a few years. But after one year, he hit pay dirt.

The Canadian observatory in British Columbia is more focused and refined but is aimed at a much smaller chunk of the sky. They tracked that fast radio burst to a weird type of star called a magnetar that’s 32,000 light-years from Earth in the constellation Vulpecula.

It was not only the first fast radio burst traced to a source, but the first emanating from our galaxy. Astronomers say there could be other sources for these bursts, but they are now sure about one guilty party: magnetars.

There are maybe a dozen or so of these magnetars in our galaxy, apparently because they are so young and part of the star birth process, and the Milky Way is not as flush with star births as other galaxies.

Source: “Flash of luck: Astronomers find cosmic radio burst source” PhysOrg, 4 November 2020

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