At last! Launched on 1 July 2023, the Euclid satellite delivered its very first images of the sky at the beginning of November, confirming its extraordinary capabilities. After so many years of preparation, 2024 marks the start of a fruitful period. The Paris Institute of Astrophysics (IAP) is at the heart of this scientific adventure, hosting the management of the Euclid International Consortium which is responsible for designing the mission, building the scientific instruments and producing, analyzing and exploiting the scientific data. The IAP is also responsible for the production and analysis of images obtained with the visible camera, from raw data to images that can be used by scientists, including characterization using extremely precise instrumental simulations.
Over the next six years, this space observatory will use its two visible and infrared instruments to observe a third of the sky, in order to build up a catalogue of around ten billion astronomical sources. Among these, the detailed morphology of a billion galaxies will be established with exquisite precision, in order to measure the minute deformations induced by the gravitational lensing effects of large-scale dark matter structures on foreground galaxies. At the same time, the near-infrared spectra of the galaxies in the foreground will be measured.
Thanks to this information, scientists will be able to reconstruct the history of the organisation of matter in the Universe over the last 10 billion years, under the opposing influences of gravity and dark energy. Euclid will then be able to determine the properties of this mysterious repulsive force or test the theory of gravitation on a very large scale. The harvest of data will enable many other studies to be carried out on the properties of our Universe, as well as on galaxy clusters, quasars and distant galaxies, stellar populations in nearby galaxies and the Milky Way, and even on objects in the Solar System.
The James Webb Space Telescope (JWST), launched earlier in December 2021, is now in the middle of its scientific production phase. The Institut d'Astrophysique de Paris is the French representative on the ESA scientific team that has accompanied the development of the European NIRSpec near-infrared spectrograph on board JWST. In 2024, the continuation of several large-scale observation programmes involving members of the Institute of Astrophysics promises to provide fascinating clues about the crucial moment when the first stars and galaxies pierced the cosmic darkness, a key event in the early evolution of our Universe. The nature of these first sources of light, composed almost entirely of hydrogen and helium, and the way in which their intense radiation shattered the hydrogen atoms that filled the early Universe, are discoveries eagerly awaited by the scientific community, and we have never been so close
The Franco-Chinese SVOM space mission SVOM will be launched in June 2024. The Paris Institute of Astrophysics has been involved in this project since it was launched in the early 2000s. In particular, it is contributing to the development of chains for analysing high-energy data following a detection and triggering alerts, and hosts the French scientific leader of the main programme for studying gamma-ray bursts. The mission is devoted to the detection and multi-wavelength monitoring of gamma-ray bursts and other high-energy transient phenomena, and to the observation of multi-messenger transient sources.
Using four instruments on board the satellite and follow-up telescopes on the ground, the aim is to explore the most extreme phenomena in the Universe, associated for example with the formation of a new black hole when a massive star collapses, or the merger of a binary system of two neutron stars, accompanied by the ejection of matter at near-light speeds. These phenomena emit light at all wavelengths, including the most energetic gamma photons. They are also sources of gravitational waves and probably neutrinos: if detected, these messengers provide physical information that complements that of light. The alerts issued by SVOM after a detection will be transmitted in real time to the scientific community for rapid monitoring of the phenomena observed
There's no doubt that 2024 promises a veritable firework display of scientific advances thanks to these three satellites, and that's without counting the progress made by the many other research projects we are pursuing, from the development of theories of fundamental interactions to the three-dimensional recording of the aurora borealis, not to mention the mapping of the polarisation of the cosmological background thanks to the 10-metre telescope at the South Pole and the quest for exoplanets, which is continuing at a frenetic pace.
Project manager and layout: Jean Mouette
Writing: François Bouchet
December 2023