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Last year, we observed a monumental observation of the cosmos: the simultaneous light and gravitational waves of a pair of neutron stars colliding over 130 million light-years from the Earth. But the mysteries of this event remained the same: as the radiation emitted in the form of X-rays and radio waves progressively lightened for six months. This mystery may have been solved by matter that seems to go faster than light.
Scientists have observed the source of gravitational waves repeatedly using a network of 10 telescopes around the world, called High Sensitivity Array (HSA). The observations implied that these neutron star fusions produce jets of collimated particles that emerge from a larger cocoon of matter. They also relate these collisions to mysterious gamma-ray flashes called "short gamma rays".
Last August, observatories from around the world observed space-time waves called gravitational waves and a flash of light from the same place. It was a foolproof signature of colliding bodies called neutron stars, objects slightly more massive than the sun but smaller than a typical city. It was a moment of transformation in astronomy.
But the gamma rays of the collision were weaker than expected and those who continued to monitor the position of "GW170817" noticed that radio waves and X-rays continued to illuminate for months after the big event. the jet of particles moving at a speed almost equal to the light and oriented in a direction opposite to the Earth, the jet was actually smothered by the debris and then became a large cocoon of slower material, gamma rays You can read all about this mystery here:
The radio that illuminates the monumental stars The collision with a neutron star tells a confusing story
The August sighting of two colliding neutron stars was incredible …
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Thus, scientists have observed the destruction of GW170817 using the HSA's facilities: the Very Large Array, the Green Bank Telescope and the dishes of the Very Long Baseline Array. They watched for four periods between September 2017 and April 2018, each period consisting of two to four observations lasting up to ten days. The observation is based on the principle of very long base interferometry, where observers combine data from distant radio telescopes.
According to the article published in Nature, observations revealed that radio emissions seemed to move four times faster than the speed of light. This is not a mistake – it is an illusion when jets of particles moving at almost equal speed travel indirectly to Earth. Think of it this way: the jet takes time to travel a distance. But since the jet, which approaches the Earth but does not point directly towards us, moves slightly slower than the radiation it emits, the light from the back of the jet will reach the Earth slightly before the light from the front of the jet. Thus, the jet seems to move perpendicularly faster than light.
According to a press release from the National Radio Astronomy Observatory, the new analysis suggests the existence of a thin stream tilted at 20 degrees from the Earth and moving at 97% of the speed of light . He also argued that the source emitting the jet was "compact", probably a black hole.
This makes it possible to answer the mystery of radio waves and X-rays, the source (probably a black hole) continuing to emit the particle stream within six months of the collision of neutron stars. "The VLBI data shows that the jet did not get smothered but that it managed to get out of the cocoon," Gizmodo Mansi Kasliwal, an assistant professor of astronomy at Caltech, told Gizmodo. The radio waves would first come from the cocoon, then from the jet two months later.
According to the article, it also provides evidence linking neutron stars to phenomena called "short gamma ray bursts".
The newspaper does not fully answer all the questions, Kasliwal explained. The jet still differed significantly from what physicists were waiting for. This means, of course, that there are more observations to make and more work to do.
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