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Fast Radio Bursts: First Distance Measurement

Have we finally traced a Fast Radio Burst to its place of origin? News from the CSIRO (Commonwealth Scientific and Industrial Research Organisation) radio telescopes in eastern Australia, along with confirming data from the Japanese Subaru instrument in Hawaii, suggests the answer is yes. Fast Radio Bursts (FRBs) are transient radio pulses that last scant milliseconds. In that amount of time, they have been known to emit as much energy as the Sun emits in 10,000 years. And exactly what causes FRBs is still a mystery.

Take the so-called ‘Lorimer Burst’ ( FRB 010724) which was discovered in archival data from 2001 at the Parkes radio telescope in New South Wales. Here we’re dealing with a 30-jansky dispersed burst that was less than 5 milliseconds in duration. Although the burst appeared roughly in the direction of the Small Magellanic Cloud, the FRB is not thought to be associated with our galaxy at all. A 2015 event, FRB 110523, was discovered in data from the Green Bank dish in West Virginia, with an origin thought to be as much as six billion light years away.

Sixteen FRBs have been detected, but according to this news release from the Max Planck Institute for Radio Astronomy, researchers believe they are a much more common phenomenon. A new paper in Nature now tells us that the Parkes telescope detected a new Fast Radio Burst (FRB 150418)) on April 18, 2015. But in this case, we have a twist. Evan Keane (Square Kilometre Array Organisation, Jodrell Bank UK) and an international team have been developing a system to detect FRBs within seconds, which makes it possible to alert other telescopes to pinpoint the source.


Image: The infrared image on the left shows the field of view of the Parkes radio telescope with the area where the signal came from marked in cyan. On the right are successive zoom-ins on that area. At the bottom right is the Subaru optical image of the FRB galaxy, with the superimposed elliptical regions showing the location of the fading 6-day afterglow seen with ATCA. Credit: © D. Kaplan (UWM), E. F. Keane (SKAO).

The system, part of the Survey for Pulsars and Extragalactic Radio Bursts (SUPERB), allows quick detection and transmission of the relevant information to other telescopes. Using it, within two hours of the Parkes detection the Australia Telescope Compact Array (ATCA) 400 kilometers to the north was able to trace the FRB to a radio source that lasted six days before finally fading out. What the Subaru telescope adds to the mix was that it found a galaxy at optical wavelengths that matches up with the radio source detected by the Compact Array. Unlike the previous sixteen detected bursts, we now have a far more precise fix on a location.

The culprit turns out to be an elliptical galaxy with a redshift consistent with a distance of six billion light years. This marks the first time a host galaxy has been determined for an FRB, and the first time an FRB’s distance has been measured. Simon Johnston (Head of Astrophysics at CSIRO) notes that the galaxy in question is well past its prime period for star formation, an unexpected result. Johnston speculates that the cause of the FRB may be two neutron stars colliding rather than any process associated with the birth of young stars.

Whatever causes them, Fast Radio Bursts turn out to be useful in interesting ways. They show a frequency-dependent dispersion, which means the radio signal is affected by the amount of material it has moved through. An FRB thus makes it possible to conduct a cosmological measurement. Says Johnston:

“Until now, the dispersion measure is all we had. By also having a distance we can now measure how dense the material is between the point of origin and Earth, and compare that with the current model of the distribution of matter in the universe. Essentially this lets us weigh the universe, or at least the normal matter it contains.”

The result: A universe made up of 70 percent dark energy, 25 percent dark matter and 5 percent ordinary matter is a good fit for the measurement conducted on the FRB pulse. What’s intriguing here is the prospect that we are moving into an era of FRB astronomy. As we detect more and more of these events, we may find new ways to investigate cosmological questions.

standard_sans_both (2)

Image: This image shows the increased delay in the arrival time of the Fast Radio Burst as a function of the frequency. The delay in the signal is caused by the material it goes through between its point of origin in a distance of 6 billion light years and Earth. Credit: © E. F. Keane (SKAO).

To be sure, we still don’t know what causes FRBs. But as Johnston points out, the Australian SKA Pathfinder (ASKAP) is going to be able to start looking for FRBs later this year. ASKAP is a next-generation radio telescope made up of 36 identical 12-meter antennas that will work together as an interferometer. The fully implemented Square Kilometre Array is likewise expected to detect numerous FRBs and pinpoint their locations. We should soon have abundant data to pursue questions of FRB origin and the cosmological issues the bursts can illuminate.

The paper is Keane et al., “The Host Galaxy of a Fast Radio Burst,” Nature 530 (25 February 2016), 453–456 (abstract).


Comments on this entry are closed.

  • Andrew Palfreyman February 24, 2016, 16:37

    Hopefully we can look forward to fully triangulated LIGO detections in parallel with the usual detection modes. The gravitational signature would provide additional valuable insight. Naively, an FRB is the signature of black hole creation from the merger of an inspiralling neutron star binary.

    • Michael February 25, 2016, 3:19

      A big issue here is firstly the distance ‘sqr rule’ and the low masses, neutron stars have limited masses. So these two neutron stars spiralling in to form a BH would be much smaller than the recent LIGO detection event by a factor of about 200! I think a LIGO on the moons other side would have enormous sensitivity to detect even these events.

  • Harry R Ray February 25, 2016, 10:17

    Not so fast. There now appears to be TWO DISTINCT CLASSES OF FRB’S! The cause of the two “double bursts” STILL REMAINS A MYSTERY! The RATIO of single bursts to double bursts is probably somewhere around ten to one, so it may be a while before this new technique can be used to track down the location of one of these less common events, so we will STILL probably have a mystery to ponder for at least a couple of years.

  • Michael February 26, 2016, 2:57

    The doubles blips could be due to favourability facing neutron star quake emissions which can be quite intense and very narrow via the poles.

  • Harry R Ray March 1, 2016, 10:25

    Aparrently the CONNECTION between the FRB and the radio afterglow is now seriously in question. A new paper argues that an actibe galactic nucleus(AGN)is likely responsible for the “afterglow”. It may be a few months before this issue is resolved by the signal FADING, like a true afterglow should, or remaining CONSTANT, like an AGN should.

  • Harry R Ray March 1, 2016, 11:42

    Paul Gilster(OR ANYONE ELSE): Can you VERIFY that the following quote: “[if] they know which planets are life-bearing in the galaxy, they could perhaps decide to eliminate these inhabited planets one after another,sequentially, which would provide a signal that showed up once or maybe twice, and then didn’t show up again for some unknown period.” IS a quote from Jill Tarter? If it is, and she’s right, we could just as well have detedced the Death Star blowing Alderaan to pieces! For the FULL CONTEXT of this quote vis-à-vis FRB’s, log on to http://www.hngn.com, click “science” and scroll down to the FRB atricle

    • Paul Gilster March 1, 2016, 13:05

      I’m seeing it quoted widely and attributed to Jill Tarter.

      • Harry R Ray March 2, 2016, 10:39

        Thanks,Paul. Even though THIS “discovery” is still in doubt, the fairly recent discovery that the Arecibo FRB IS ascociated with a nebula, and therefore ALMOST CERTAINLY is EXTRAGALACTIC in nature, I thought that the “aliens” conjecture had been put to rest FOR GOOD! I wonder why she STILL holds out for the non-natural solution. The scenario she puts out in the QUOTE is SO SCARY, that despite my ALMOST INFINITELY STRONG desire for CONCRETE PROOF that we are not alone in the universe, I have an EQUALLY STRONG DESIRE that THIS is NOT that concrete proof!

  • Mike Fidler March 2, 2016, 18:14

    Could Fast Radio Bursts or Gamma-Ray Bursts be Alien Communication Systems ?

    Non-random structures in universal compression and the Fermi paradox.

    Interesting article: http://arxiv.org/pdf/1603.00048v1.pdf

    We study the hypothesis of information panspermia assigned recently among possible solutions of the Fermi paradox (“where are the aliens?”). It suggests that the expenses of alien signaling can be significantly reduced, if their messages contain compressed information. To this end we consider universal compression and decoding mechanisms (e.g. the Lempel-Ziv-Welch algorithm) that can reveal non-random structures in compressed bit strings. The efficiency of Kolmogorov stochasticity parameter for detection of non-randomness is illustrated, along with the Zipf’s law. The universality of these methods, i.e. independence on data details, can be principal in searching for intelligent messages.

  • stephen March 11, 2016, 17:41

    “A universe made up of 70 percent dark energy, 25 percent dark matter and 5 percent ordinary matter is a good fit…”

    You give a percentage of dark energy but not a percentage of ordinary energy?

    And I wonder if that famous E=mc squared applies to dark matter and dark energy? Is it possible it doesn’t apply?

    Maybe it’s a silly question, but I shan’t assume.