The second repetitive radio transmitter was detected by the Chime radio telescope


The rapid explosions of the radio, these short bursts of very energetic radio waves, are already mysterious in themselves. They are even more confused when they are repeated. Astronomers have just announced the discovery of FRB 180814.J0422 + 73, a recurring recurring radio blast, the second in history. 12 point signals were also detected. Not bad for starters: the Chime radio telescope, which recorded these explosions, is undoubtedly worthy of all expectations!

The hunt for rapid bursts of the radio, cosmic flashes whose origin is still mysterious, is bearing fruit. Astronomers have announced that they have detected 13 new signals, one of which is repeated, using the radio telescope Chime (Experiment to map the intensity of Canadian hydrogen). This is only the second ever recurring rapid radio ever recorded since the discovery of FRB 121102 from the Arecibo radio telescope a few years ago.

the fast radio bursts o FRB (Fast burst of the radio) are short pulses of radio waves, very energetic but also very short: they last only a few milliseconds. Since their existence was highlighted in 2007, around sixty bursts were recorded, all on time. These phenomena seem to originate far from Milky Way and in a millisecond they emit the same energy of the Sun in 10,000 years. Their nature, meanwhile, remains an enigma.

Illustration of fast radio gusts detected in the sky. © NRAO

Origins still unknown

Most of the theories about their origin evoke cataclysmic events that lead to the destruction of their source as the explosion of a star that gives supernova, a fusion ofneutron stars… – it has also been suggested that these signals be emitted from extraterrestrial civilizations advanced, but this is another story. These theories began to falter when, in 2015, a succession of fast radio bursts having the same origin (FRB 121102) was registered by the powerful Arecibo radio telescope, located on the island of Puerto Rico – note that FRB 121102 was first observed in 2012 and that other events were detected a few years later.

Astronomers are driving the nail today by announcing the detection of a new signal that repeats itself. Called FRB 180814.J0422 + 73, the bursting of the fast radio seems to originate about 1.5 billion light years from land. The source could be "A dense mass, like a remnant of a supernova, or a point near the central black hole of a galaxy"says Cherry Ng of the University of Toronto, one of the astronomers involved in this discovery.

1,000 other radio explosions at the end of the year?

Survey of FRB 180814.J0422 + 73 and of the other twelve specific FRBs, which is the subject of two studies published in the prestigious journal nature (here is here), is one of the first results of the Chime radio telescope, located in British Columbia, Canada, and inaugurated at the end of 2017 (see also the article below). The signals were detected in only three weeks of observation between July and August 2018, while the telescope was still not working at full capacity. In all, six repetitions were recorded from source FRB 180814.J0422 + 73, which was studied a little longer than the sporadic FRB, until October.

For the fifty scientists of the Canadian collaboration behind this discovery, this second series of fast radio bursts suggests that there might be others. "With the daily mapping of the northern hemisphere by Chime, surely we will find other successes of gusts over time", rejoices in a declaration Ingrid Stairs, of the University of British Columbia.

"At the end of the year we may have found another 1,000 bursts"added Deborah Good from the same university. After all, astronomers estimate that up to 10,000 FRB could occur daily and expect Chime to be able to detect 2 to 50 days a day (see article below).

Multiplying the observations of these signals will put their finger on the nature of their source. "It is still unclear whether the sources that generate repetitive FRBs are different from those that seem to generate only one.It is possible that what we think is nowadays, FRBs are repeated only very rarely, but that they come from the same kind of sources"says Shriharsh Tendulkar of McGill University in Montreal, co-author of the study.

If the origin of these flashes radio waves are still little known, for the researcher that is "Extremely unlikely" that are issued by extraterrestrial civilizations. Although he recognizes it, "As a scientist, he can not exclude him 100%".

What to remember

  • Fast radio bursts (Fast burst of the radio or FRB in English) are short explosions of milliseconds that take place outside the Milky Way and whose power and characteristics challenge simple explanations in terms of known astrophysical phenomena.
  • The Canadian radio telescope Chime has detected 13 new rapid radio bursts, 12 of which are punctual and repetitive. FRB 180814.J0422 + 73 is only the second repetitive radio burst ever recorded.

Fast Radio Bursts: The Chime Radio Telescope could decrypt them

Article by Laurent Sacco, published 10/08/2018

The gusts of fast radios are mysterious. They could also have an explanation as part of theastrophysics known as opening a new era in physical theoretical, or even exobiology. It is expected that a new Canadian radio telescope, called Chime, will detect many of these rapid radios and have started doing so. Will he be able to decipher them?

Every time a new one window The observation opened in astronomy, led to great leaps in our knowledge of the observable cosmos. We have two recent examples:

  • one with the birth of thegravitational astronomyThanks to Ligo is Virgin ;
  • the other with another avatar of multi-media astronomy, as shown by the IceCube neutrino detector.

The last year was marked by the inauguration of a new large radio telescope called "The Canadian Experience in Mapping the Intensity of the Earth".hydrogen Or, in English, Experiment to map the intensity of Canadian hydrogenand therefore, in short, Chime. It is very precisely a radio telescope interferometer located at the Dominion Radio Astrophysical Observatory in British Columbia, Canada.

Chime has several goals. The first, and most important, is to map the masses from neutral hydrogen to the least intergalactic scale Street the famous line at 21 cm, one spectral line released from this atom and that he had already revealed the structure of our Milky Way. The radio telescope should allow us to obtain a map of the distribution of this hydrogen throughout the celestial sphere, but also in the past of theuniversewhile this was between 2.5 and 7 billion years.

It is precisely towards the end of this period that the effects ofblack energyor, more prosaically, that the effects of the acceleration of the expansion of the observable cosmos began to be felt. Finally, the hydrogen masses must also retain the traces of the famous baryonic acoustic oscillations (BAO), already observed with the distributions of galaxies. Studies with Chime could therefore provide us with valuable information on the nature of dark energy and on the cosmology of primary importance.

A video presentation of the Chime radio telescope. For a fairly faithful French translation, click on the white rectangle at the bottom right. English subtitles appear. Then click on the gear on the right side of the rectangle, then on "Subtitles" and then on "Translate automatically". Choose "French". © McGill University

The ringtone should detect from 2 to 50 FRB per day

The 21 cm line is also a line to one frequency at 1,420 megahertz (MHz), but while it has moved red from the expansion of the universe, it falls, for us, on Earth today, in a band from 400 to 800 MHz. It turns out that this band allows also to study another enigma of the cosmos: rapid bursts of the radio (Fast Radio Burstsor FRB in English).

Recall that the fast radio bursts are short bursts of radio waves (a few milliseconds) discovered in 2007 thanks to the new analysis of the data archives collected by the Parkes radio telescope in Australia. At the beginning the FRBs were not taken seriously and their distance was unknown. We now know that these are not signs parasites and that they are extragalactic. This implies that the power released by such a short phenomenon must be enormous to be identifiable from so far. We know a few dozen, currently scattered in the sky, and one that is repeated, observed for the first time in 2012, hence the name "FRB 121102".

Statistically, there should be about a thousand every day all over the sky for an observer on Earth. This is positive because we do not yet know what the origin of this phenomenon is, although explanations have been made, such as the explosions ofPlanck's stars (neutron stars close to a supermassive black hole), or even completely real extraterrestrial civilizations.

With its large collecting surface, its huge field of vision and its broad the bandwidthThe chime should allow, according to the estimates of the radio astronomers, to record from 2 to 50 FRB per day. It should also give immediate notice in case of possible correlation with another major astrophysical phenomenon, for example a supernova.

The researchers have just announced in The Astronomer & # 39; s Telegram Chime detection of the FRB with the lowest known frequency so far, ie 580 megahertz. But FRB 180725A, its name, is not the first one observed by Chime since its commissioning last year. Progress towards a resolution of the FRB puzzle could be rapid and the consequences spectacular: imagine, for example, that it is wellPlanck's stars !

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