Press release Nucléaire et Particules CNRS, 14 february 2025

Type Ia supernovae are the dramatic explosions of white dwarf stars at the ends of their lives. Approximately 2 weeks later, each single event reaches a peak luminosity of 10 millions sun-like stars with a remarkable consistency between different events. We call these objects “standard candles”. Cosmologists have learned to use them to probe distances across the universe by comparing their fluxes, as further objects appear dimmer. The acceleration of the Universal expansion, awarded by the Nobel prize in 2011, has been discovered in the late 90s using ~100 of these Supernovae. Since then, cosmologists are investigating the reason for this acceleration caused by the dubbed dark energy that plays the role of an anti-gravity force across the Universe. Recent state-of-the-art Type Ia Supernovae datasets compile ~2000 objects gathered from many different telescopes and acquired for the last two decades. Interestingly, analyses of these samples suggest that dark energy may be more complicated than a simple mathematical constant in Einstein’s equation as assumed since its first discovery ; but then what ? Unfortunately, improvement of our understanding of the dark energy properties has been limited by our sparse knowledge of the exact physics responsible for the Type Ia Supernovae astrophysical phenomenon, which in turn affects our ability to derive precision distances to probe the fundamental physics of the Universe.

Press release: https://www.in2p3.cnrs.fr/en/cnrsinfo/zwicky-transient-facility-survey-publishes-its-long-awaited-sample-3628-type-ia-supernovae

CPPM Contacts:

Benjamin Racine, CNRS researcher, ZTF scientific manager, in Renoir team

William Gillard, teacher-researcher at Aix-Marseille University, head of the Renoir team

Press release Nucléaire et Particules CNRS 14 january 2025

After nine years of construction, the Vera C. Rubin Observatory (*) is just a few months away from the start of its ten-year mission: to make a film about the fine evolution of our night sky and the depths of the cosmos on the scale of an entire hemisphere. In preparation for this monumental production, the observatory has just successfully completed a series of comprehensive tests of the observing system using a technical test camera (ComCam), marking the green light for the final stage of Rubin's construction: the installation of the 3200-megapixel LSST camera (LSSTCam), the world's largest digital camera.

The test camera, or commissioning camera (ComCam), consists of a mosaic of nine CCD sensors totalling 144 megapixels and covering an area almost twice the size of the full moon. During the seven-week ComCam technical test campaign, from October 24 to December 11, 2024, around 16,000 images were taken to test the Rubin Observatory's hardware and software systems, as well as the image processing pipeline.

(*) The Vera C. Rubin Observatory, formerly known as the Large Synoptic Survey Telescope (LSST).

More informaiton:

Press release (only in french): https://www.in2p3.cnrs.fr/en/cnrsinfo/rubin-observatory-declared-fit-after-3-months-tests-test-camera

CPPM Contacts:

Dominique Fouchez, CNRS researcher, LSST scientific manager at CPPM, Renoir team

Aurélien Marini, CNRS engineer, LSST technical manager at CPPM.

William Gillard, teacher-researcher at Aix-Marseille University, head of the Renoir team

An extraordinary event consistent with a neutrino with an estimated energy of about 220 PeV (220 x 1015 electron volts or 220 million billion electron volts), was detected on February 13, 2023, by the ARCA detector of the kilometre cubic neutrino telescope (KM3NeT) in the deep sea. This event, named KM3-230213A, is the most energetic neutrino ever observed and provides the first evidence that neutrinos of such high energies are produced in the Universe. After long and meticulous work to analyse and interpret the experimental data, today, February 12, 2025, the international scientific collaboration of KM3NeT reports the details of this amazing discovery in an article published in Nature.

The detected event was identified as a single muon which crossed the entire detector, inducing signals in more than one third of the active sensors. The inclination of its trajectory combined with its enormous energy provides compelling evidence that the muon originated from a cosmic neutrino interacting in the vicinity of the detector.

“KM3NeT has begun to probe a range of energy and sensitivity where detected neutrinos may originate from extreme astrophysical phenomena. This first ever detection of a neutrino of hundreds of PeV opens a new chapter in neutrino astronomy and a new observational window on the Universe”, comments Paschal Coyle, KM3NeT Spokesperson at the time of the detection, and researcher at CNRS Centre National de la Recherche Scientifique – Centre de Physique des Particules de Marseille, France.

Contacts:

Paschal Coyle, CNRS researcher, previous spokesperson for the KM3NeT Collaboration, Manager for Laboratoire Sous-marin Provence Méditerranée

Damien Dornic, CNRS resarcher, deputy spokesperson for the KM3NeT Collaboration

More information:

• CNRS press release: https://www.cnrs.fr/en/press/first-detection-ultra-high-energy-neutrino

• Publication « Observation of an ultra-high-energy cosmic neutrino with KM3NeT » : https://doi.org/10.1038/s41586-024-08543-1

• Multimedia folder : https://images.cnrs.fr/en/node/102771

• Videos - Resources : https://www.cppm.in2p3.fr/web/en/research/astroparticles/index.html

CNRS press release, February 4, 2025

The ODISSEE project, funded by the European Union, aims to develop innovative technologies and methodologies for processing the unprecedented volume of scientific data produced by research infrastructures such as CERN's HL-LHC and SKAO. In particular, it plans to use AI to process data on the fly. On-the-fly data processing is a major challenge in research in the physical sciences, and SLICES RI's contribution will be crucial to the project's success. Coordinated by Damien Gratadour, a CNRS researcher at the Laboratoire d'instrumentation et de recherche en astrophysique (CNRS/Observatoire de Paris-PSL/Sorbonne Université/Université Paris Cité), ODISSEE draws on the European HPC ecosystem to open up a new era in science, helping to unravel fundamental mysteries such as the nature of dark matter

More information:

Press release (only in french): https://www.cnrs.fr/fr/presse/lancement-du-projet-europeen-odissee-lia-pour-traiter-le-deluge-de-donnees-du-skao-et-du-hl

CPPM Contact:

Dorothea vom Bruch, CNRS researcher, LHCb team.

Press release Nucléaire & Particules CNRS, January 8, 2025

The European Commission announced this Tuesday, January 7, that it has granted the Cherenkov Telescope Array Observatory (CTAO) the status of a European Research Infrastructure Consortium (ERIC), a specific legal form under European Union law that facilitates the creation and operation of research infrastructures of European interest. CTAO thus becomes the 29th ERIC created since 2009.

More information:

Press realease: https://www.in2p3.cnrs.fr/en/cnrsinfo/ctao-gamma-ray-observatory-promoted-european-research-infrastructure-consortium

CPPM Contact:

Heide Costantini, head of the astroparticles-photons team.