Jul 12, 2022

The dawn of a new era in astronomy has begun as the world discovers for the first time the full capabilities of the NASA/ESA/CSA James Webb Space Telescope. The telescope's first color images and spectroscopic data, which reveal a spectacular array of previously elusive cosmic features, were released on July 12, 2022.

 

Apr 14, 2022
The Eclairs and MXT instruments of the SVOM mission delivered to CNES-Toulouse

The French teams of the ECLAIRs and MXT telescopes, instruments at the heart of the SVOM mission, experienced an important moment during March 2022. First, a general review of the two projects took place at CNES in Toulouse in front of a group of experts. This review allowed to verify that the two instruments meet the technical specifications and will be able to carry out the scientific mission. Then a series of team visits took place in the two CNES clean rooms housing the flight models of the two instruments, ECLAIRs and MXT.

May 03, 2022

The KATRIN collaboration has just recently reported a new upper limit of 0.8 eV/c2 on the mass of neutrinos. The KATRIN spectrometer also has a strong potential to search for new, so-called "sterile" neutrinos, based on a fine analysis of the tritium beta decay spectrum. The collaboration has just published its new results in Physical Review D based on the first two data campaigns acquired in 2019. This work reveals no evidence of a fourth neutrino, and KATRIN may well be a key player in clarifying the anomalies observed by some neutrino oscillation experiments over the past 20 years or so.

Feb 14, 2022
KATRIN has just crossed a symbolic threshold and reveals a new upper limit!

The KATRIN (KArlsruhe TRItium Neutrino Experiment) located at the Karlsruhe Institute of Technology (KIT) has just crossed a symbolic threshold. In a paper published in the prestigious journal Nature Physics, the collaboration reveals a new upper limit of 0.8 eV/c^2 for the mass of neutrinos. This result is of fundamental interest for both particle physics and cosmology.

Apr 11, 2022

On February 12, 2022, the ANTARES neutrino telescope (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) put an end to its data taking started in 2007. During 15 years, thousands of neutrinos, precious elusive particles witnesses of the cataclysmic phenomena of the Universe, were detected at 2500 m in the Mediterranean abyss. The objective: find abnormal accumulations in the neutrino sky map revealing sources at the still mysterious origin of the cosmic rays, a rain of particles discovered more than a century ago. The CEA team played a leading role in the success of this project, a pioneer in multi-messenger astronomy.

 

May 06, 2022
New numerical simulations probe the origin of type Ia supernovae

While type Ia supernovae are considered as highly symmetric supernovae, the explosion in a tight binary system composed of two white dwarfs revises this paradigm. An international team (Japan, Canada, France), including a researcher from the Department of Astrophysics/AIM Laboratory of CEA Paris-Saclay, publishes a study in the Astrophysical Journal that reveals that the distinctive asymmetric structures of such a supernova leave post-mortem imprints on the morphology of the ejected matter. These morphological signatures persist and are observable in the late phase of supernova remnants. These results open the possibility to identify and characterize the explosion scenario of this type of supernova.

Apr 14, 2022
The Eclairs and MXT instruments of the SVOM mission delivered to CNES-Toulouse

The French teams of the ECLAIRs and MXT telescopes, instruments at the heart of the SVOM mission, experienced an important moment during March 2022. First, a general review of the two projects took place at CNES in Toulouse in front of a group of experts. This review allowed to verify that the two instruments meet the technical specifications and will be able to carry out the scientific mission. Then a series of team visits took place in the two CNES clean rooms housing the flight models of the two instruments, ECLAIRs and MXT.

Feb 17, 2022
The Fermi-LAT space telescope reveals the nature of particles accelerated in this historic supernova remnant.

The explosion of a star produces a shock wave that propagates at more than 5000 km/s for centuries and it is thought that these shocks are the main source of highly energetic particles called cosmic-rays. Studying the high-energy photon emission of supernova remnants allows us to probe the nature of the accelerated particles, their energy and their composition. A French team led by researchers from the Astrophysics division/AIM laboratory of CEA-Irfu at Paris-Saclay has confirmed the detection of gamma-ray emission above an energy of 100 MeV in the direction of the historic Kepler supernova remnant. Twelve years of observation from the LAT instrument onboard the NASA Fermi space telescope were needed to confirm the existence of an efficient particle acceleration in this remnant, one of the youngest in our Galaxy. The researchers have found that the gamma-ray emission most likely results from the interaction of accelerated ions with the surrounding medium but depending on the amplitude of the magnetic field, several scenario are plausible. This study has been accepted for publication in the journal Astronomy and Astrophysics.

Mar 10, 2022

IRFU scientists and the H.E.S.S. collaboration observe time-dependent particle acceleration in our Galaxy for the first time. Novae are powerful eruptions on the surface of a white dwarf in a binary star system, in which a larger star and a smaller star orbit each other. A nova creates a shock wave that tears through the surrounding medium, pulling particles with it and accelerating them to extreme energies. The H.E.S.S. high-energy gamma-ray observatory in Namibia has now been able to observe this acceleration process for the first time. Surprisingly, the detected nova seems to cause particles to accelerate at energies reaching the theoretical limit.

These results were published in Science: https://www.science.org/doi/10.1126/science.abn0567

Jun 17, 2022

Scientists from the CosmoStat laboratory at CEA have produced within the international science collaboration UNIONS (Ultraviolet Near Infrared Optical Northern Survey) a reference catalogue of 100 million gravitationally lensed distant galaxies, one of the largest datasets ever created. This new collection is based on thousands of deep images of the northern sky captured by MegaCam, a large digital camera built at CEA, mounted on the Canada-France-Hawaii Telescope (CFHT). Three new publications present dark-matter mass maps of the cosmic web, showing how the high-density regions in these maps help measure the still poorly known properties of dark matter. In the near future these observations will provide essential support to the European space telescope Euclid. This ESA satellite mission will map the cosmic web over the entire accessible sky at an unprecedented resolution to measure the properties of the mysterious dark energy.

Jun 17, 2022

The DPhN, in collaboration with the Department of Reactor Studies of Cadarache (DES) and the Institute of Particle and Nuclear Physics of Charles University in Prague (Czech Republic), studied the properties of gamma rays emitted by uranium isotopes during neutron capture reactions. Gamma-ray spectra measured at CERN's n_TOF facility were used as a test bed for nuclear reaction models and their ingredients, including the photon strength function that characterises the ability of a nucleus to emit or absorb photons. This work has enabled consistent modelling of the photon strength functions of the uranium isotopic chain (234U, 236U, 238U) and confirmed the presence of a particular oscillation mode of the nucleus shape at low excitation energy. This study was carried out as part of the PhD thesis of Javier Moreno-Soto [1] and the full results are published in Physical Review C [2].

 

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