The exceptional event was discovered on February 11, at exactly 11 hours 42 minutes and 40 seconds, but required the collaboration of twenty -one telescopes in the world to be interpreted.
by Pierre Barthélémy
It all started on February 11, 2022, at exactly 11 hours 42 minutes and 40 seconds (Paris time). It was still dark in California on Mount Palomar, where several telescopes are installed. One of them is equipped with a camera that scrutinizes the sky with a fairly wide field of aim, in search of what astronomers call transitional events (comets, asteroids but also stars explosions, etc. ). And, on this winter day, this equipment called “Zwicky Transient Facility” (ZTF) sees a light that was not before. As announcing, Wednesday, November 30, two international studies – one published in nature and the other in Nature Astronomy -, this light is the index of an event as distant as rare: the heartbreak of a star Through a giant black hole near which she had the imprudence to pass.
Write so, all that seems simple, but, before arriving at this conclusion, the astrophysicists have had to follow a long journey that Susanna Vergani, CNRS research director at the Paris Observatory and Cosignate of Nature Study details us: “When the ZTF does a SCAN from the sky, he compares it with the previous one to detect sources transient. We find a lot of them every night and the whole game consists in understanding the cause of each variation. As we have developed automatic tools for this, this preliminary analysis is done very quickly and the information is then disseminated in an international network of researchers . “
When the behavior of a light source seems particularly interesting, the astronomical community is mobilizing to make a palette of additional observations at different wavelengths. In the case of the February 11 event, baptized at 2022CMC, in total, in total, twenty -one telescopes that have been robbed towards the source. “The idea is to then put all observations together and try to understand what it is,” said Susanna Vergani. The first hypothesis featured a gamma start, which betrays the transformation of a dying star into a black hole or into a neutron star, a cataclysmic event which sends a considerable amount of energy into space. But this scenario did not stick with observations.
Accretion disk
“The best interpretation involves a phenomenon known as the tidal effect breaking event, Tidal Disruption Event (TDE) in English, explains Susanna Vergani. A star is torn by the gravity of a black hole giant from which she approached. “The force of attraction of the black hole literally tears from the material to the star, just like the sleeve of a shirt tears when you pull too hard on it. This material then begins to turn around the black hole in what specialists call an accretion disk.
You have 37.47% of this article to read. The continuation is reserved for subscribers.