Every now and then, astronomers see an intense burst of radio waves coming from space; An explosion that lasts only a moment but releases in milliseconds as much energy as the sun radiates in several years. The origin of these “fast radio bursts” is one of the great mysteries of modern astronomy.

There is no shortage of ideas to explain the cause of epidemics: a catalog of current theories shows more than 50 potential scenarios. You can choose highly magnetized neutron stars, collisions of incredibly dense stars, or many other extreme or exotic events.

How can we tell which theory is correct? One way is to seek more information about the explosions through other channels: particularly through ripples in the fabric of the universe called gravitational waves. In a new study published Astrophysical JournalWe compared dozens of observations of fast radio bursts with data from gravitational wave telescopes to see if we could find connections.

Astronomy of gravitational waves

When you think of telescopes, you probably think of telescopes that look for electromagnetic signals such as light, radio waves, or X-rays. These signals produce many stars and other things in space. However, dust and gas, which are abundant in galaxies that host star systems, can block or block these signals.

Gravitational waves are different: They pass through matter, so nothing can get in their way. Astronomers have now detected gravitational waves from colliding systems of compact stars, such as black holes and neutron stars, and discovered the engines behind gamma-ray bursts.

What creates fast radio bursts?

Some repeating fast radio bursts have been observed, but most appear to be single events. As for repeated bursts, recent simultaneous observations of X-rays and a radio burst from a highly magnetized neutron star in our Milky Way galaxy prove that such stars can produce fast radio bursts. The source of the unique messages has not yet been determined.

But some theories concern astronomical objects and events that we know produce strong gravitational waves. So if we have an idea of ​​where and when a fast radio burst occurred in the sky, we can search for gravitational waves in the same region of the sky in a targeted and precise way.

CHIME radio telescope

To find new evidence of what causes fast radio bursts, I assisted in a targeted study using fast radio bursts detected by the CHIME radio telescope in Canada. Since the CHIME/FRB project has detected hundreds of fast radio bursts, there is a good chance of capturing a burst close enough to Earth to be observed with a gravitational wave telescope. This is important because fast radio bursts are so bright that they can be seen billions of light-years away, far beyond what modern gravitational wave observatories can see.

So what did we do and how did we do it? The project team provided us with data on hundreds of fast radio bursts. Since most of this data is still not publicly available, we have signed a private agreement not to share the details outside of search groups.

We then estimated the distance to each fast radio burst and searched for gravitational wave data around the 40 closest events (for which there was evidence of being within range of the gravitational wave detector).

Our search team consisted of a small group of scientists from the LIGO Gravitational Wave Observatory in the United States, the Virgo Observatory in Italy, and the CHIME/FRB team, which studies fast radio bursts.

We looked for gravitational wave signals around each unique fast radio burst’s location in the sky at the time it occurred. We performed two types of searches for these uniquely fast radio bursts: one looked for known gravitational wave signals, such as those from colliding black holes or neutrons, and the other looked essentially for any unusual bursts of energy.

As for the repeat bursts, knowing that at least one such source was associated with a magnetized neutron star, we looked for the type of gravitational wave signals we might expect from an isolated neutron star.

What did we learn?

Did we discover something? Not this time. This isn’t much of a surprise, as we believe fast radio bursts are much more common than detectable gravitational wave signals. In other words, gravitational wave sources will cause only a small fraction of fast radio bursts.

But the closest fast radio burst in our sample was close enough to rule out the possibility that it was caused by a collision between a neutron star and a black hole. The uncertainty in the distance to the burst means we cannot rule it out with certainty, but we are encouraged by the fact that the sensitive range of gravitational wave detectors is approaching the distance to fast radio bursts.

What’s next?

Although definitive results are not available this time, future research could be a vital step toward understanding fast radio bursts.

Gravitational wave detectors have become more sensitive than when we conducted this research and will continue to improve in the coming years. This means they will provide greater coverage in space, so we can test a much larger sample of fast radio bursts. We are also targeting fast radio bursts from the known repeating source in our own galaxy mentioned above.