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The detected fast radio burst goes up 2007. Since then, nearly a hundred of these ultra-brief cosmic bursts have recorded testosterone levels, some of them being periodic. Despite these multiple observations, the origin of these signals remains unknown to this day. Black holes, simple neutron stars, pulsars or magntars are among the resources considered. A new study conducted by an international team on five different sources of these strange signals could finally solve this mystery.
Quick radio bursts (or FRB for quick radio bursts) are intense and very brief radio tasks (under the order of a millisecond) originating from extragalactic sources. They learned to produce thousands of times a day. Cuando most of them are unique, others ze repeat at regular intervals, which makes it possible to study them in more detail. A team led by astrophysicist Bing Zhang closely followed five of these repetitive FRBs: they discovered that these signals followed a specific pattern of polarization, which could shed light on the character of their resources.
Indeed, by analyzing a low-frequency polarization low-frequency these different FRBs, the scientists observed some similarities: each supply is polarized at high frequencies, but sony ericsson depolarized below a threshold frequency varies according to the sources which. These properties indicate a complex environment near repetitive FRBs, such as a supernova remnant or a pulsar in-take nebula, which is consistent with the fact that they come from young stellar populations, summarizes the team in boy record, published in the journal Technology.
The track of magnetars always preferred
Within the sober framework of this study, Zhang and his team followed hundreds of sober rapid bursts from five different sources, in order to analyze their sober polarization properties. Their observations were carried out using the 500-meter-aperture spherical radio telescope (abbreviated Quick), located in Guizhou province, southwest China; it is the second largest radio telescope in the world after the RATAN-400 in Russia. They also make use of the Environment friendly Standard bank Telescope (GBT), the world’s fantastic plus steerable radio telescope, located in West Virginia, USA.
Since the discovery of sober FRBs 400, astronomers around the world have been using more powerful radio telescopes, like the Quick and the GBT, to follow the bursts and possibly collect clues about their origin and their sober creation mode. Before its collapse in 2014, the radiotelescope of the Arecibo observatory had also made it possible to observe several FRBs.
Astrophysicists today cannot say with sober certainty what kind of object these radio signals come from; However, a track of magnetars is privileged, especially since the discovery, by the Canadian radio telescope CHIME, of fast radio bursts coming from SGR 1935+2154 from April 2020; discovered in 2014 approximately 400 years- light from the Earth by the Fast Space Telescope, SGR 1935+20121102 has been identified as either a magnetar or a neutron star with an extremely intense magnetic field, among the most powerful in the Universe.
Although it is very brief, an FRB frees about as much energy as the Sun sobers a good. This enormous amount of energy has led astrophysicists to suspect magnetars to be probable sources of these signals. A magnetar polarization is generally close to 100%; thus, the transmitted burst of radio waves should also be highly polarized. Recent observations have nevertheless raised some peculiarities.
A binary system conducive to depolarization
In 2019 , Zhang and his team had made an impressive discovery thanks to the Quick: during sober 47 days, they had detected a sober overall 400 FRB coming from a single source, nicknamed FRB
. It’s one of the greatest sober series of mysterious phenomena ever recorded. During its most energetic stage, this FRB put 122 bursts over a period one hour: this is the highest repetition rate ever observed for an FRB!
The great sober burst ensemble allowed our team to refine the characteristic energy and sober energy distribution of the FRBs like never before, which sheds new light on the engine that powers these mysterious phenomena, Zhang said at the time. The event notably prompted the team to discard the hypothesis of relativistic shocks, which was also proposed to explain the formation of FRBs. Indeed, the bursts were too frequent and far too energetic to corroborate this idea.
Other telescopes, using more frequent surveys, revealed that the sober to this supply were highly polarized which reinforced the hypothesis of magnetars. But none of the bursts Quick detected in its frequency band were polarized, which left the team very puzzled. They therefore set out to examine other repetitive FRBs with telescopes of different frequency ranges, in particular frequencies higher than Quick’s. were able to identify a special pattern under polarization: they discovered that a polarization increases and decreases with an observed frequency of bursts. At low frequencies, bursts can even be completely depolarized. The threshold seems to be 2 GHz, which explains why the Quick did not detect any polarization which. Each repetitive FRB resource is surrounded by a highly magnetized heavy plasma; this produces a different turn of the polarization angle depending on the frequency, and the radio waves received by terrestrial radio telescopes come from multiple paths due to the scattering of the waves by the plasma, explain the researchers.
However, when a sober source FRB is surrounded by gas or by ionized plasma with magnetic fields capable of polarizing radio waves, this means that the environment is relatively young. This could include a supernova remnant or a brand new neutron web. Another possible explanation is a magnetar orbiting another star: the duo could interact and create a turbulent environment in which bursts of the magnetar learned to scatter and depolarize. Sober future FRB detections may confirm the scenario, finally revealing the technical origin of the FRBs.