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Exploring Origins of a Fast Radio Burst

Fast Radio Bursts (FRBs) continue to intrigue us given their energy levels. You may recall FRB 121102, which was revealed at a press conference almost exactly one year ago to be located in a radio galaxy some 3 billion light years away. This is a repeating FRB (the only repeating source yet found), making its study an imperative as we try to characterize the phenomenon.

With data from Arecibo, the Very Large Array and the European VLBI network, astronomers determined its position to within a fraction of an arcsecond, where a source of weak radio emission is also traced. Today, drawing on new observations from Arecibo and the Green Bank instrument in West Virginia, we learn something about the source of these bursts.

The energies we are talking about are obviously titanic. Given the distance between the source and us, researchers have calculated that each burst throws as much energy in a single millisecond as our Sun releases in an entire day. And as we learn in the latest issue of Nature, an international team has been able to show that the bursts from FRB 121102 are highly polarized, allowing insights into the environment from which it sprang. The analysis was revealed at a meeting of the American Astronomical Society in Washington, D.C.

In play here is a phenomenon known as Faraday rotation, which is the ‘twisting’ that happens to polarized radio waves as they pass through a magnetic field. And what stands out in these findings is the apparent strength of the magnetic field involved, for the Faraday rotation is extreme, among the largest ever measured in a radio source. The implication: The bursts are evidently moving through an exceedingly powerful magnetic field in a dense plasma.

Image: The 305-metre Arecibo telescope, in Puerto Rico, and its suspended support platform of radio receivers is shown amid a starry night. A flash from the Fast Radio Burst source FRB 121102 is seen: originating beyond the Milky Way, from deep in extragalactic space. Credit: Image design: Danielle Futselaar – Photo usage: Brian P. Irwin / Dennis van de Water / Shutterstock.com.

We now move into the realm of speculation. Is FRB 121102 situated close to a massive black hole at the center of its host galaxy? That would correspond to some degree with the magnetized plasmas that have been observed in the Milky Way, associated with its own supermassive black hole. But there are other possibilities, as Arecibo staff astronomer Andrew Seymour comments, referring to the FRB observations at higher radio frequencies than before:

“We developed a new observing setup at the Arecibo Observatory to do this, and our colleagues from Breakthrough Listen at the Green Bank Telescope confirmed the results with observations at even higher radio frequencies. What’s more, the polarization properties and shapes of these bursts are similar to radio emission from young, energetic neutron stars in our galaxy. This provides support to the models that the radio bursts are produced by a neutron star.”

But given that it is the only repeating FRB, is FRB 121102 somehow different from all other, non-repeating FRBs? Bursts from the former have been observed with as many as seven peaks, a more complicated structure in time and radio frequency than observed in other FRBs, which show one or occasionally two peaks in time.

“We’ve observed bursts from FRB121102 with as many as seven peaks, and the bursts peak in radio frequency as well as time,” says Laura Spitler, an astronomer at the Max-Planck-Institut für Radioastronomie, Bonn. “We are now trying to understand whether the bursts’ structure is an intrinsic feature of the process that generates the radio emission or the result of the propagation through the dense plasma local to the source.”

Image: One of FRB121102’s radio bursts, as detected with the Arecibo telescope. This 3D print shows how bright the burst is as a function of observed radio frequency and time. Credit: Anne Archibald (University of Amsterdam).

We may get some help in the next phase of the investigation from CHIME (Canadian Hydrogen Intensity Mapping Experiment), an interferometric radio telescope under construction in British Columbia, which should be coming online later this year. The researchers believe the instrument will be well-tuned for the detection of FRBs and for studying their degrees of polarization. McGill University’s Shriharsh Tendulkar believes CHIME will be capable of detecting “…between a few and a few dozen FRBs every day.”

Also in the cards is future observation at Green Bank, where Breakthrough Listen has allotted more time to study not just the emissions of FRB 121102, but also other FRB sources. The plan is to observe at higher frequencies, up to 12 GHz — the current Green Bank work has taken place from 4-8 GHz. Whether or not the energy of FRB 121102 drops off at higher frequency may provide additional insights into its source.

The paper is Michilli et al., “An Extreme Magneto-Ionic Environment Associated with Fast Radio Burst Source FRB121102,” Nature 11 January 2018 (abstract).

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{ 21 comments… add one }
  • DJ Kaplan January 10, 2018, 14:59

    Could data have been encoded into this Faraday “twisting”?

    • Paul Gilster January 10, 2018, 16:05

      On that, let me quote from a UC-Berkeley news release:

      Another possibility, though remote, is that the FRB is a high-powered signal from an advanced civilization. Hence the interest of Breakthrough Listen, which looks for signs of intelligent life in the universe, funded by $100 million over 10 years from internet investor Yuri Milner.

      “We can not rule out completely the ET hypothesis for the FRBs in general,” Gajjar said.

      “Breakthrough Listen has to date recorded data from a dozen FRBs, including FRB 121102, and plans eventually to sample all 30-some known sources of fast radio bursts.

      “We want a complete sample so that we can conduct our standard SETI analysis in search of modulation patterns or narrow-band signals — any kind of information-bearing signal emitted from their direction that we don’t expect from nature,” he said.”

    • Ron S. January 11, 2018, 9:59

      EM can be modulated in any of its overt parameters, be it amplitude, frequency, phase or polarity. Polarity is a little different in that the modulation must happen in the antenna system rather than the electronics behind it. However, there are far easier methods to perform polarity modulation than by manipulating an intervening plasma! I’ll have to leave it to someone else to say whether polarity modulation in general has any advantages or disadvantages versus others over inter-stellar distances (ISM distortion, etc.); IMO there are no significant advantages.

      On a further note, modulation techniques can and routinely do extend far beyond these fundamental parameters. There is quite a lot of flexibility these days to design sophisticated modulation systems to the needs of a particular application by use of DSP.

      • DJ Kaplan January 11, 2018, 13:33

        Considerable room for speculation.
        “However, there are far easier methods to perform polarity modulation than by manipulating an intervening plasma!”
        Of course, if there is a life-form creating this as a signal, we can only guess as to what is easy or difficult for it.

        • Ron S. January 11, 2018, 17:15

          You can visit your neighbor to the east by walking east for a few seconds, or you can travel 40,000 km in the other direction. You can speculate that some life form would find the latter easier.

  • ljk January 10, 2018, 15:24

    Across the universe, fast radio bursts ‘shout and twist’

    http://news.cornell.edu/stories/2018/01/across-universe-fast-radio-bursts-shout-and-twist

    SETI project homes in on strange ‘fast radio bursts’

    http://news.berkeley.edu/2018/01/10/seti-project-homes-in-on-strange-fast-radio-bursts/

    To quote:

    “This result is an excellent demonstration of the capabilities of the Breakthrough Listen instrumentation and the synergies between SETI and other types of astronomy,” said Andrew Siemion, director of the Berkeley SETI Research Center and of the Breakthrough Listen program. “We look forward to working with the international scientific community to learn more about these enigmatic and dynamic sources.”

    Are FRBs signals from advanced civilizations?

    Another possibility, though remote, is that the FRB is a high-powered signal from an advanced civilization. Hence the interest of Breakthrough Listen, which looks for signs of intelligent life in the universe, funded by $100 million over 10 years from internet investor Yuri Milner.

    “Although it’s extremely unlikely that pulses we have detected from FRB 121102 were transmitted by ETs, we would like to test various ET hypotheses for the FRB type transient signals in general,” Gajjar said.

    Breakthrough Listen has to date recorded data from a dozen FRBs, including FRB 121102, and plans eventually to sample all 30-some known sources of fast radio bursts.

    “We want a complete sample so that we can conduct our standard SETI analysis in search of modulation patterns or narrow-band signals – any kind of information-bearing signal emitted from their direction that we don’t expect from nature,” he said.

  • Andrew Palfreyman January 10, 2018, 17:52

    An instantaneous power output of 10^34 Watts is not too shabby!

  • Alex Tolley January 10, 2018, 18:38

    Naive questions. Does this data require that the burst is either omnidirectional or a “widish” beam and not a very narrow, directed beam that could possibly be artificial? If very narrow, would this reduce the total energy requirement for this burst to a tiny fraction of the assumed energy value?

    • Mark Zambelli January 17, 2018, 13:24

      That’s my question too… just like when GRBs were thought to break physics.

  • ljk January 11, 2018, 10:49

    Black hole breakthrough: new insight into mysterious jets

    Supercomputer power enables advanced simulations of relativistic jets’ behavior

    January 09, 2018 | By Kayla Stoner

    https://news.northwestern.edu/stories/2018/january/black-hole-breakthrough-new-insight-into-mysterious-jets/

  • ljk January 11, 2018, 10:53

    Mysterious space signal could be neutron star near black hole

    Dutch-led team suggests a new explanation to account for a transient astronomical phenomenon. Andrew Masterson reports.

    https://cosmosmagazine.com/space/mysterious-space-signal-could-be-neutron-star-near-black-hole

    • Harry R Ray January 18, 2018, 10:37

      Not just any old black hole. It MUST be the host galaxy’s central super-massive black hole. “FRB 121102: A repeatedly and marginally combed neutron star by a nearby low-luminosity accreting super-massive black hole.” by Bing Zhang.

      • ljk January 18, 2018, 11:03

        https://arxiv.org/abs/1801.05436

        FRB 121102: A repeatedly and marginally combed neutron star by a nearby low-luminosity accreting super-massive black hole

        Bing Zhang (UNLV)

        (Submitted on 16 Jan 2018)

        The origin of fast radio bursts (FRBs) remains mysterious. Recently, the only repeating FRB source, FRB 121102, was reported to possess an extremely large and variable rotation measure (RM). The inferred magnetic field strength in the burst environment is comparable to that in the vicinity of the super-massive black hole Sagittarius A* of our Galaxy.

        Here we show that all the observational properties of FRB 121102 (including the high RM and its evolution, the high linear polarization degree, an invariant polarization angle across each burst and other properties previously known) can be interpreted within the cosmic comb model invoking a regular neutron star whose magnetosphere is sporadically and marginally combed by a variable outflow from a nearby low-luminosity accreting super-massive black hole in the host galaxy.

        We propose three falsifiable predictions of the model and discuss other FRBs within the context of the cosmic comb model as well as the challenges encountered by other repeating FRB models in light of the new observations.

        Comments: 5 pages, submitted to ApJL

        Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

        Cite as: arXiv:1801.05436 [astro-ph.HE]
        (or arXiv:1801.05436v1 [astro-ph.HE] for this version)

        Submission history

        From: Bing Zhang [view email]

        [v1] Tue, 16 Jan 2018 19:00:05 GMT (133kb,D)

        https://arxiv.org/pdf/1801.05436.pdf

  • ljk January 11, 2018, 17:33

    I have to wonder if there is any remaining life in the galaxy housing FRB 121102 after reading the following of its intensity:

    https://www.cnet.com/news/aliens-fast-radio-bursts-frb-121102-magnetar/

    Whatever it is, it’s a good thing we’re about 3 billion light-years away from it. In a flash lasting less than a millisecond, the source of the bursts radiates the same amount of energy as the total output of our sun for a whole day.

    “If we had one of these on the other side of our own galaxy — the Milky Way — it would disrupt radio here on Earth, and we’d notice, as it would saturate the signal levels on our smartphones,” said Shami Chatterjee, senior research associate in astronomy at Cornell University. “Whatever is happening there is scary. We would not want to be there.”

    Of course, there’s also the very remote possibility that the fast alien signals are from actual advanced aliens.

    “We can not rule out completely the E.T. hypothesis for the FRBs in general,” Gajjar said.

    • DJ Kaplan January 12, 2018, 13:31

      They obviously don’t have smartphones over there.

      • ljk January 15, 2018, 12:13

        Not anymore, in any event.

        Going on the FRB as a sign of a really advanced ETI, these bursts would be really good at both wiping out galactic competition and, if they wanted to be “humane”, merely disabling their technology so the competition could not emerge into their galaxy and compete for galactic resources and systems.

        If intelligent minds operate in certain ways the same as ours does literally universally, then the first use for certain technologies that would be funded by those in power are for military applications.

        Rockets were first (and still) used by humanity not for exploring space but for bombing the enemy into either submission or non-existence. Some of the first and most powerful signs of technological intelligence coming from Earth are military radars watching for incoming nuclear missiles.

        One of the criticisms against anyone building a Dyson Shell/Sphere/Swarm is the actual need by an ETI for them as originally envisioned. However, what is seldom brought up is what powerful and deadly megaweapons they would make: Capable of sending powerful energy beams clear across the galaxy to wipe out entire worlds in a single shot. A species with long terms ambitions for the galaxy that wants no competition from the neighbors and no sense of ethics as we recognize them – and who doesn’t want to spend the funds and resources on a vast armada of battlecruisers and troops – may find a weaponized Dyson Shell to be a bargain in achieving their goals.

        I know traditional SETI looks (and hopes) for benign transmissions from altruistic beings who have somehow evolved past all their evolutionary and cultural growing pains and now wish to share their wisdom and knowledge with the rest of the galaxy. Perhaps that is the actual case, it is just too bad we only have a few intelligent species to study and they happen to be, to quote the ETI in the 1997 film version of Contact: “…capable of such beautiful dreams, and such terrible nightmares.”

  • Stephen January 14, 2018, 13:48

    Are we totally certain this source is not actually a lot closer?

    • Ron S. January 15, 2018, 9:17

      Do you have a reason to suspect that the distance estimate is wrong? Red shift, source association with a known object and other techniques are pretty routine these days for locating events such as these. I have not read the paper for the particulars in this case. Have you?

  • Derek January 15, 2018, 13:06

    Other recent articles about FRBs, like at pjmedia.com, mention that these are not coming from within our galaxy; if they were, they would interfere with and jam our radio comma like even perhaps WiFi and Bluetooth. Is that true? If so, it would have been a neat fact to include in your original post.

  • ljk January 18, 2018, 11:00

    Alien or Natural: Strangest Sounds & Signals Detected from Space

    https://futurism.com/images/alien-or-natural-strangest-sounds-signals-detected-from-space/

    This infographic says the Wow! Signal of 1977 came from 200 light years away. I have not read that before. How did they determine this, or is it an error on the author’s part?

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