In a dwarf galaxy nearly 400 million light-years from ours, an object has recently caught the attention of astronomers. It could be one of the youngest and most powerful pulsars ever discovered. And researchers hope it will help them solve the mystery of fast radio bursts (FRBs).
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[EN VIDÉO] A “black widow” pulsar devours its companion When talking about spiders, black widow spiders are the ones that devour their mates after mating. And astronomers have observed similar behavior in the sky. When a pulsar and a low mass star form a binary system. Faced with the radiation emitted by the pulsar, the star has little chance of surviving for long. (in English) © NASA Goddard
Its nickname is VT 1137-0337. It nests in a dwarf galaxy containing about 100 million times the mass of our Sun and located some 395 millionlight years of our Earth. And according to what the researchers presented in Pasadena (USA) during the American Astronomical Union Congressit is one of the youngest neutron stars never discovered. A pulsar that would not be more than 60 to 80 years old!
But all this deserves some clarification. First, remember that a neutron star is what remains of a supermassive star that exploded in supernova. An extremely dense remnant since it maintains, within a diameter of only a few tens of kilometres, a mass comparable to that of our Sun. And one pulsar, this is the term used to designate a neutron star which rotates extremely quickly on its axis. Sometimes in just a few milliseconds.
What the astronomers think they have discovered in the data of the VLA Sky Surveythis is actually what they call a nebula of wind of pulsar. It forms from charged particles accelerated by a powerful magnetic field Has gears close to that of light after a supernova explosion gave birth to a pulsar. This pulsar wind nebula first appeared in an image recorded in 2018.
A key to the mystery of fast radio bursts?
Yet the neutron star that generated it is likely not quite so young. The researchers believe that VT 1137-0337 did not appear earlier because its emission radio was to be obscured by debris from the supermassive star’s initial supernova explosion. With the dilation from this shell, the radio waves were finally able to reach us.
Note that this is not the first time astronomers have observed a pulsar wind nebula. The famous crab nebula, in the constellation of Taurus, is one. She was born from a supernova that appeared in the year 1054. And remains visible with the help of a telescope amateur. The difference between the crab nebula and VT 1137-0337 is that the latter appears to be no less than 10,000 times more energetic. With a much stronger magnetic field. What earned him the nickname of “great crab” emerging.
And the fact that its magnetic field is so strong could even eject it from the category of pulsar wind nebulae. VT 1137-0337 could hide… a magnetar. The very people who are strongly suspected of being behind the fast radio bursts. The famous FRBs that intrigue astronomers so much. More than just a magnetar, VT 1137-0337 would then be neither more nor less than the whole first magnetar “caught in the act of appearing”.
Even more exciting, the intriguing features of some fast radio bursts — radio bursts associated with persistent radio signals — bear strong resemblances to the properties of this strange object. What also raises the following question finally: could not FRBs also find their source in pulsar wind nebulae? Astronomers now intend to monitor VT 1137-0337 closely to learn more about this strange object and its evolution over time.
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