The mass distribution of the different stars formed from a collapsing gas cloud has just been successfully reproduced by two researchers from the Astrophysics Department/AIM Laboratory of CEA-Irfu. The collapse of a gas cloud of 1000 solar mass has been reconstructed thanks to numerical simulations, varying the density and the influence of turbulence. The results of these simulations show the emergence of a characteristic mass that corresponds well to that observed and this largely independently of the initial ... More »
The HESS international collaboration, to which CNRS and CEA contribute, has published the results of fifteen years of gamma ray observations of the Milky Way. Its telescopes installed in Namibia have studied populations of pulsar wind nebulae and supernova remnants, as well as microquasars, never before detected in gamma rays. These studies are supplemented by precise measurements such as those of the diffuse emission at the center of our Galaxy. The entire set of data will henceforth serve as a reference for the ... More »
Detection by ALMA of polarized dust emission in the protostar B335
An international team led by the Department of Astrophysics/AIM Laboratory of CEA-Irfu has just shown for the first time that the magnetic field plays a fundamental role in the collapse of proto-stars. Based on observations from the Atacama Large Millimeter Array (ALMA) in Chile, researchers measured the polarization of dust in the B335 protostar. This polarization, emission of light in a preferred direction, results from the alignment of the dust grains under the influence of the magnetic field. In B335, this ... More »
The very first moments of a star explosion
An unprecedented observation of a supernova, an explosion of a massive star, was captured in its early days by an amateur astronomer, at the exact moment when the supernova became visible in the sky. These early data and additional observations obtained by a battery of telescopes enabled a team of researchers from several institutes of CONICET [1], in Argentina, and the Astrophysics Department-AIM Laboratory (CEA-CNRS-University Paris Diderot) in France, to test for the first time theoretical predictions about the ... More »
A theoretical breakthrough paves the way for anticipation of solar storms
A single phenomenon could control all solar flares. This is what researchers from the Ecole Polytechnique, CNRS, CEA-Irfu and Inria have just proposed in an article in the front page of the journal Nature on February 8, 2018. They highlighted the presence of a reinforced "cage" in which a "magnetic cord" develops, an entanglement of twisted magnetic lines of force at the origin of the solar flares. It is the resistance of this cage to the onslaught of the rope that determines the power and type of ... More »
A galactic cohabitation more hectic than expected
The MegaCam camera developed at CEA-Irfu has revealed previously unsuspected structures within the famous Stephan Quintet, a spectacular combination of five galaxies. The discovery of a very large red halo, consisting of old stars, centered on one of the elliptical galaxies, NGC 7317, shows that the group of galaxies is still in very strong interaction, an aspect totally ignored in previous studies. This interaction shows that Stephan's Quintet is still the scene of generalized galactic cannibalism, in ... More »
Giant galaxies that no longer form stars have 100 times more gas than expected.
By succeeding for the first time to analyze the light of nearly 1000 very distant elliptical galaxies, more than 10 billions light-years away, a team of researchers including three astrophysicists from the Astrophysics Department of CEA-Irfu has just revealed that these galaxies of the beginning of the universe contain a lot of gas but do not form stars. A real enigma that challenges our understanding of the evolution of these giant galaxies. These results are published in the journal Nature Astronomy of January 16, ... More »
TO BE TRANSLATED Après une sélection sévère, les premières cibles d'observation du télescope spatial James Web (JWST) qui doit être lancé au printemps 2019, viennent d'être dévoilées.  Sur les 200 déclarations d’intention initialement envoyées par des chercheurs du monde entier, seulement 13 programmes ont été retenus au titre des "Premières publications scientifiques (ERS pour Early ... More »
The James Webb Space Telescope (JWST) has reached a key milestone with the completion of cryogenic tests on its telescope and instruments. Working within an international consortium, France, in particular the CEA, the CNRS and the CNES, has played a key role in the development, for the scientific successor to the Hubble and Spitzer space telescopes, of the Mid-InfraRed Imager (MIRIM) that will enable it to see wavelengths of 5 to 28 microns.  
Planetary migration: magnetic or tidal effects ?
A large part of the exoplanets known today are in very close orbit around their star, allowing very intense interactions between the planets and the host star. An international collaboration, led by researchers from Department of Astrophysics-AIM Laboratory at CEA-Irfu, has shown that these planets in close orbits migrate rapidly, due to the combined effect of tidal forces and magnetic forces. This study provides essential elements for understanding the formation and evolution of star-planet systems. These migration ... More »
The discovery of a new type of gravitational wave
Using a range of detectors developed with the participation of the CEA, physicists at CEA-Irfu have scrutinized the region from which the gravitational wave was detected on August 17, 2017 by LIGO-VIRGO facilities. Unlike the four previous detections of waves of the same type discovered since 2015, this new vibration of space, called GW170817, is of different origin. It does not result from the fusion of two black holes but of two densest known stars, the neutron stars. Thanks to the INTEGRAL satellite in orbit, the ... More »
An international team including two researchers from the Department of Astrophysics-Laboratory AIM of CEA-Irfu detected for the first time the presence of the CH+ molecule in distant galaxies of the young universe, thanks to the large ALMA interferometer. The presence of this particular molecule demonstrates the existence around the young galaxies of large turbulent reservoirs of low-density cold gas. Their presence could explain how galaxies succeed in prolonging their phase of intense stellar formation despite the ... More »
The study of solar vibrations reveals the astonishing behavior of the thermonuclear center of the Sun
By analyzing more than 16 years of data collected by the GOLF instrument onboard the SOHO satellite, an international collaboration involving two researchers from the Department of Astrophysics-Laboratory AIM of CEA-IRFU has demonstrated a rapid rotation of heart of the sun. For the first time, researchers were able to indirectly determine the properties of solar gravity waves, oscillations affecting the innermost layers of the star. They were able to show that the Sun centre turns on average in a little more than 7 ... More »
The secret of the star magnetic cycles
Thanks to new numerical simulations, a scientific team led by researchers from the Astrophysics Department-Laboratory AIM of CEA-Irfu has succeeded in explaining why the magnetic field of the Sun reverses every 11 years. Scientists have highlighted the existence of a strong feedback between the star magnetic field and its internal rotation profile, with temporal modulations that ultimately determine the period of the cycle. This major discovery in the understanding of the origin of the star magnetic fields is published ... More »
A new link between the dynamics of galaxies and the activity of their central black hole
Using images obtained with the Hubble Space Telescope, an international team of researchers led by Yu-Yen Chang from the Service d’Astrophysique-Laboratoire AIM at CEA–IRFU showed that some galaxies hosting an active nucleus are much more compact than those without nuclear activity. This discovery sheds new light on the physical processes driving the evolution of super-massive black holes at the center of distant galaxies. It suggests that the huge amount of gas needed for their growth could be funneled to ... More »
New study simulates how tornado-shaped flow in a dynamo strengthens the magnetic field
An international team, including researchers from the Department of Astrophysics (CEA-Irfu) and Department of Solid State Physics (CEA-Iramis), conducted an unprecedented simulation based on the Von-Kármán-Sodium (VKS) dynamo experiment (CEA-CRS-ENS) [1], to examine more closely how the liquid vortex created in liquid sodium by the propellers of VKS device can generate a magnetic field. The researchers studied the effects of electrical resistivity and fluid turbulence on the generation and collimation of ... More »
An old galaxy with unexpected features
An international team including a researcher from the AIM Laboratory-Astrophysics Department of CEA-Irfu has just discovered an elliptical galaxy of completely unexpected shape within the galaxy cluster Abell 2670. Deep observations made by the new MUSE multi-spectrograph recently put into operation at the European Observatory VLT in Chile revealed a highly deformed elliptical galaxy, showing in particular long gas tails and star formation regions normally absent in this type of galaxy. Astronomers now assume that ... More »
The PILOT astrophysics experiment has been launched the 17th April under a stratospheric balloon from Alice Springs in central Australia. The aim is to observe the polarization of the emission of dust particles present in the interstellar medium of our Galaxy and the nearby galaxies. With a mass of nearly one ton, PILOT [1] uses the biggest balloons launched by the National Center for Space Studies (CNES). It was developed by the Institute for Research in Astrophysics and Planetology (CNRS / CNES / Paul ... More »
Key role of the gaseous phase underlined by numerical simulations and analytical approach
The proto-clusters, which are the birth sites of stars, are formed non-uniformly inside molecular clouds of the interstellar medium. Studying the steps leading to the collapse of pre-stellar dense cores is essential to understanding the star formation. Using both numerical simulations carried out on massively parallel computers and an analytical approach, two researchers from the Astrophysics Department / AIM Laboratory of CEA-Irfu, Y.-N. Lee and P. Hennebelle, have shown that certain properties of a stellar cluster ... More »
Mysterious alignment of the rotation axis of stars in two clusters
The stars do not play dice! It is the extraordinary discovery that the researchers of the Department of Astrophysics-Laboratoire AIM of the CEA-Irfu made by succeeding in determining the orientation in the space of the axis of rotation of stars belonging to two clusters of stars, thanks to asteroseismology. About 70% of the observed stars have perfectly aligned axes of rotation, in formal contradiction with the star formation models which predict that these axes of rotation should be randomly distributed. Numerical ... More »
First light of the ArTéMiS camera at two wavelengths and first results on interstellar filaments
The new ArTéMiS submillimetric camera was successfully re-installed in June 2016 on the APEX telescope in the Atacama desert in Chile. In its new configuration, with an increased number of detectors, this camera can simultaneously obtain images at 350 and 450 microns. ArTéMiS produces data with angular resolution more than three times better than that of Herschel satellite at the same wavelengths, and a factor 2 to 3 times better than the LABOCA instrument, also installed on APEX, and which observes at ... More »
An exceptional parade of exoplanets
Seven planets of terrestrial size and moderate temperature gravitate around the star Trappist-1, a small cool red star located at 40 light years from Earth. Better: at least three of them are in conditions compatible with the presence of liquid water on their surface. This was discovered by an international team involving CNRS, CEA and UPMC researchers at the Astrophysical Laboratory of Bordeaux (CNRS / University of Bordeaux), the Laboratoire de Météorologie Dynamique (CNRS / UPMC / École ... More »
In an article published in the Astrophysical Journal, an international team including two researchers from the Astrophysics Department- AIM Laboratory at CEA-Irfu, successfully detected the trace of solar oscillations in the light reflected by the planet. These very Low luminosity variations originate from the vibrations of the solar surface. The data were obtained from the Kepler/K2 (NASA) satellite which observed for 49 days continuously the planet located at an average distance of 4.5 billion kilometers from Earth. ... More »
The most energetic events of the Universe
A team of researchers led by Rémi Adam (Laboratoire Lagrange - OCA, UCA, LPSC Grenoble, CNES), Iacopo Bartalucci and Gabriel Pratt (Astrophysics Department- AIM Laboratory at CEA-Irfu) obtained for the first time an image of the gas velocity in colliding clusters of galaxies with NIKA [1], a new generation millimeter camera, at the focus of the 30 m diameter IRAM telescope of Pico Veleta (Spain). NIKA observations, which give accurate mapping of hot gas velocity in clusters, provide a new way to study the collision of ... More »
First evidence of the deformation of Saturn by tidal effects
Using several thousand images of Saturn's moons produced by the Cassini probe (NASA/ESA), an international team led by an astronomer from the Observatoire de Paris in the Institute of Celestial Mechanics and Calculation of Ephemerides ( Observatoire de Paris / CNRS / UPMC / Université Lille 1), in collaboration with CEA researchers, has succeeded in bringing to light small fluctuations in the gravitational field of the planet. These extremely fine results are the outcome of a series of works carried out by ... More »
The evolution of the structure and the rotation of the central star drastically modify the orbits of the planets
In a special issue of the international journal Celestial Mechanics and Dynamical Astronomy of November 2016, devoted to the study of the tidal interactions, two researchers from the University of Namur and the Astrophysics Division- AIM Laboratory of CEA-Irfu have computed the dynamics of short-period planets of different types orbiting low-mass mass stars. Their model is the first to simultaneously take into account the evolution over time of the structure and the rotation of the central star and its impact on the ... More »
New light on the formation of giant galaxies
Observations of Malin 1, a nearby galaxy and a perfect prototype of the "giant galaxies with low surface brightness," have allowed scientists from an international team including a researcher from the Astrophysics Laboratory-Service AIM CEA-IRFU to make an unexpected discovery that challenges the assumptions about galaxy formation process of this type. It suggests that the giant disk in Malin-1, the largest known in the universe, is not the consequence of a collision but is in place for several billion years, ... More »
The deepest millimetric observations of the young Universe
An international team of astronomers used the Atacama Large  (Sub) Millimeter Array (ALMA) to explore the farthest part of the universe revealed by the Ultra Deep Field of the Hubble satellite (HUDF). These new observations from ALMA are significantly deeper and more resolved than previous surveys in the millimeter range. They clearly demonstrate the existence of a close relationship between the star formation rate in young galaxies and their total stellar mass. They also reveal the abundance and spatial ... More »
A group of galaxies in turmoil
Through a unique combination of observations made by the largest telescopes in the world, an international collaboration led by researchers from the Astrophysics Department- AIM Laboratory of CEA-IRFU has detected the most distant galaxy cluster ever discovered in the Universe . Back 11.5 billion years in the past of the Universe, the snapshot of this cluster shows 17 galaxies in a strong starburst activity, a period of intense star formation. This is the first time such a structure, captured at the time of its ... More »
Discovery of a giant blob of ionized hydrogen in a galaxy cluster of the distant Universe
An international team led by researchers from the “Service d'Astrophysique / Laboratoire AIM” of CEA-IRFU has discovered a giant nebula of ionized gas in the central region of the distant galaxy cluster CL J1449+0856. Extending over 300,000 light-years, this nebula was detected from an emission line of hydrogen, arising from a gigantic reservoir of warm gas probably ionized by two luminous quasars of the cluster. It is the first time that astronomers find in a distant galaxy cluster such a giant ... More »
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