Two telescopes assembled in Toulouse to discover the first stars
How were galaxies formed? How did the universe ignite? How did it get rich in metals? How did black holes form? So many questions that astrophysicists have asked themselves and which could soon have the beginning of an answer. In any case, this is the ambition of the Franco-Chinese SVOM (Space-based multi-band astronomical Variable Objects Monitor) mission, which is due to take off in June 2023 from China for a minimum period of 3 years. Fruit of the collaboration of Cnes, CNSA (China National Space Administration), the CEA (Atomic Energy Commission) and several laboratories, its objective is to detect, locate and study gamma-ray bursts, the most energetic form of light. “The power is such that it illuminates all planes of the universe between us and the exploding star. This is the sign of the death of a massive star, which emits X and gamma rays, explains Bertrand Cordier, researcher at the CEA. With gamma-ray bursts, we may be seeing the very first generation of stars. »
The SVOM satellite, equipped with new generation telescopes, will be placed in low orbit, 625 km from the Earth, to detect and locate these events. A gauge because of their brevity. One of the two French instruments, the ECLAIRs telescope, will be able to measure the time and direction of arrival of X-rays and gamma rays in real time, thanks to the coded mask, before alerting telescopes on the ground. The rays illuminate this mask, a metal plate pierced with holes, and thus form a unique pattern allowing their direction to be reconstructed. “We expect, by covering a sixth of the sky, to observe a gamma-ray burst approximately every 3 days”, specifies Jean-Luc Atteia, from Irap (Institute for Research in Astrophysics and Planetology).
A cost of 175 million euros
The second French equipment, MXT, is a telescope “inspired by the vision of crustaceans”, explains Diego Götz, of the CEA. This optic of barely 2 kg, made up of a mosaic of glass microtubes of a few tens of microns on each side, is a jewel of technology which notably allows a large field of view. This is a first in the space industry.
Nearly 300 people worked on this mission in France, between Cnes, CEA and CNRS. The cost is estimated at 175 million euros. From Toulouse, Cnes will also be the payload control center for the SVOM satellite.