Categories: Fast Radio Bursts

A Fast Radio Burst Has Been Detected From Inside The Milky Way

Now and then there are bright flashes of radio light in the sky, and they are bothering astronomers. They are called Fast Radio Bursts (FRBs), and they’re like the chirp of a smoke alarm that needs its battery changed. They last for such a short time that it’s difficult to track down the source. They have become a nagging mystery in astronomy.

Dynamic spectrum of the local FRB. Credit: The Astronomer’s Telegram

One of the reasons FRBs are difficult to study is because most radio telescopes only capture a small portion of the sky at any given time. So they have only been observed if they are in the telescope’s field of view. There’s no way to predict where one might occur, and their short bursts can sometimes be confused with radio interference from Earth.

This changed when the CHIME observatory came online. It has a wide field of view, so it can observe dozens of radio bursts every day. Recently CHIME detected an FRB much closer than ever detected. So close that it must have occurred within our own galaxy.

Astronomers determine the distance of a radio burst through what is known as its dispersion measure (DM). The more distant a radio source, the more interstellar gas it must travel through to reach us. As the radio burst travels through this interstellar medium, the signal spreads out in frequency. The greater this dispersion, the greater the distance.

FRBs could be cause by magnetic bursts of a neutron star. Credit: NASA’s Goddard Space Flight Center/S. Wiessinger

This latest FRB came from the direction of a highly magnetic neutron star (or magnetar) known as SGR 1935+2154. The neutron star emits strong pulses of gamma rays and x-rays from time to time, and from this we know it is about 30,000 light years away. This distance is consistent with the DM meaure of the FRB, which makes the neutron star the likely source.

It has long been suspected that FRBs are caused by electromagnetic bursts of magnetars, similar to the way the magnetic field of the Sun creates solar flares. But since previous FRBs occurred within other galaxies, there was no way to confirm this. This latest burst gives us the first opportunity to verify the idea. If SGR 1935+2154 also happens to be a repeating FRB, then we should soon be able to solve the mystery of these cosmic radio chirps.

Reference: Paul Scholz. “A bright millisecond-timescale radio burst from the direction of the Galactic magnetar SGR 1935+2154.” The Astronomer’s Telegram 14:19 UT, 7 May (2020)

Brian Koberlein

Brian Koberlein is an astrophysicist and science writer with the National Radio Astronomy Observatory. He writes about astronomy and astrophysics on his blog. You can follow him on YouTube, and on Twitter @BrianKoberlein.

Recent Posts

The Building Blocks for Supermassive Black Holes are Found in Dwarf Galaxies

Did this grow from the merger of little black holes to a giant supermassive object…

20 mins ago

“Wind-Ruffled Waves, Foam and Wave Shadows, Above Natural Blue Seawater.” This is how we’ll Spot Exoplanets With Oceans

Our planet's oceans generate tell-tale light signatures when sunlight reflects off them. Exoplanets with significant…

1 hour ago

Solar Orbiter’s Pictures of the Sun are Every Bit as Dramatic as You Were Hoping

On March 26th, the ESA's Solar Orbiter made its closest approach to the Sun so…

1 day ago

Update on the Potential May 31st tau Herculid Meteor Storm

If skies are clear, be sure to watch for a potential meteor outburst early next…

1 day ago

The Moon’s Ancient Volcanoes Could Have Created Ice Sheets Dozens of Meters Thick

Everyone loves looking at the Moon, especially through a telescope. To see those dark and…

2 days ago

Spacesuits are Leaking Water and NASA is Holding off any Spacewalks Until They can Solve the Problem

NASA's spacesuits are getting old. The extra-vehicular mobility units - EMUs for short - were…

2 days ago