May 20, 2020
The fourth catalog of Fermi-LAT sources comes on line
The Fermi-LAT collaboration has published its fourth source catalog, named 4FGL. Based on eight years of data, it contains 5064 celestial objects emitting gamma rays at energies around 1 GeV, adding more than 2000 high-energy sources to the previous collection (published in 2015). More than one fourth of the objects are of unknown nature, calling for numerous follow-up studies.
Dec 21, 2019
The European Space Agency is shaping its science programme for the period 2035-2050
After the Horizon 2000 programme started in 1983, followed by its extension Horizon 2000 Plus, the European Space Agency (ESA) is committed until 2035 into the Cosmic Vision programme that includes the launches of Athena (2031) and LISA (2034). To plan its scientific priorities beyond this date, ESA has solicited the community through a call for ideas/projects.
Dec 04, 2019
The hot heart of the SN 1987A supernova
An international team, led by astronomers from Cardiff University, with the contribution of the Astrophysics Department of CEA-Irfu, may have spotted for the first time the compact remains of the last star explosion visible by eye that occurred on February 23, 1987 in a nearby galaxy, the Large Magellanic Cloud, only 160 000 light-years away.
Oct 06, 2019
Optical follow-up of gravitionnal waves
The first results of the space mission SVOM (for Space-based multi-band astronomical Variable Objects Monitor) have just fallen before the launch scheduled for the end of 2021. How is this possible? Quite simply because this ambitious Franco-Chinese mission, which aims at studying gamma-ray bursts of the Universe, is also developing a network of ground-based cameras able to detect the emission of visible light that follows the outbreak of these bursts, the most violent known explosions.
Jul 08, 2019
The LISA experiment will be able to detect planets throughout the Galaxy
The recent detections of gravitational waves, tiny vibrations of space-time, have opened a new window in the observation of the Universe. Two researchers, including Camilla Danielski from the Astrophysics Department of CEA-Irfu, have just demonstrated that, when these waves are emitted by two dense stars in orbit, they can be disturbed if a planet is in orbit around this pair of stars.
Mar 20, 2019
Two chimneys of hot gas found around the central back hole
Thanks to the X-ray satellites Chandra and XMM-Newton, an international team including the Department of Astrophysics of CEA-Irfu has just discovered the existence of two bubbles of hot gas escaping to distances of about 500 light-years, on both sides of the massive black hole environment, in the center of our galaxy.
Nov 08, 2018
Outstanding results from this Japanese X-rays observatory
Despite a short period of activity, the japanese space agency (Jaxa) Hitomi satellite has shown its full potential by delivering relevant information’s on several celestial objects.
May 10, 2018
THESEUS pre-selected for an ESA M5 mission
On May 7, 2018, the European Space Agency (ESA) announced the three selected space missions, out of the 25 proposed, for the fifth ESA middle class mission in its scientific program Cosmic Vision, whose launch date is planned in 2032. One of these three missions is the THESEUS project (Transient High-Energy Sky and Early Universe Surveyor), a project developed in recent years by a large European consortium in which the Astrophysics Department-AIM Laboratory of CEA-Irfu plays a major role.
Apr 09, 2018
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.
Feb 22, 2018
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.
Oct 16, 2017
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.
Oct 06, 2017
The Cherenkov Telescope Array (CTA) consortium brings together 1300 scientists from 32 countries. They have published their scientific aims in a document over 200 pages long. This is the result of several years of work, and includes contributions from approximately fifteen Irfu researchers involved in X-ray and gamma-ray observatories (Fermi, Integral, XMM-Newton, H.E.S.S., etc.).
Jun 13, 2016
A laboratory scale-model of accretion column onto a highly magnetized dense star
Scientists from a large international collaboration (Oxford, AWE, CEA, LULI, Observatoire de Paris, University of Michigan, University of York and STFC Rutherford Appleton Laboratory) have succeeded for the first time in generating a laboratory analogue of a strong shock that is produced when matter falls at very high speed on the surface of extremely dense stars called white dwarfs.
Feb 29, 2016
An exceptional flaring activity from a galactic black hole revealed by the INTEGRAL satellite
Analysis of the high-energy emission from the microquasar V404 Cygni has lead to the discovery of gusts of electron and positron (the electron anti-particle) plasma. This amazing discovery was possible thanks to the exquisite sensitivity of the INTEGRAL/SPI spectrometer during a strong outburst of the source in June 2015. These findings show that microquasars can be very efficient to provide significant pairs electron-positron and thus can be considered somehow as  “antimatter factories”.
Feb 17, 2016
Launch of the Japanese X-ray Astronomy satellite Astro-H
The X-ray astronomy satellite Astro-H was successfully launched on 17 February 2016  at 17H 45 (UT 8H45) from the JAXA Tanegashima Space Center in Japan. The satellite was put into orbit 14 min later and the first tests started. ASTRO-H is a JAXA / NASA mission under the Japanese leadership and with an ESA participation. This new observatory aims to observe and study the hot and energetic Universe. Astro-H embeds several instruments that when combined cover the spectral band 0.3-600 keV.
Jan 07, 2016
Recent change in the optical and gamma-ray polarization observed in the center of the Crab Nebula
The Crab Nebula, thought for decades to be a "standard candle", has recently seen this status challenged by the observation of intense high-energy gamma rays flares. An Irish and French team (centre for Astronomy of the Université of Galway and Service d’Astrophysique from CEA–Irfu ) has stressed this finding by observing for the first time a change of polarization in visible and gamma-ray light in the central region of the nebula from 2005 to 2012.
Jun 22, 2015
The enigma of the quasi-periodic oscillations
A team of researchers from CEA (Astrophysical Department and CEA-DAM) and the LUTH Laboratory (Paris Observatory) has just published a comprehensive study of an enigmatic phenomenon of quasi-periodic oscillations at the surface of strongly magnetic white dwarfs also called "Polars ". These dense stars are orbiting a companion and capture its material that falls freely toward the white dwarf poles. Strongly heated to millions of degrees, the hot gas or plasma then emits mainly in X-rays.
Sep 30, 2014
Progress and involvement of the CEA into this chinese and french space mission
2014 has been a fruitful year for SVOM (Space-based multiband astronomical Variable Objects Monitor), a chinese and french space mission dedicated to the study of gamma-ray bursts. The decisions taken at the highest level, the governments in March and the respective space agencies in August, restart the project after a frozen period. As a direct result, two important meetings of the consortium (kick-off meeting) took place in September, one at CNES in Toulouse and the other at Shanghai.
Aug 15, 2013
Detection by XMM-Newton of a periodic absorption line close to the surface of a Magnetar
The intense and sporadic activity of Magnetars, rotating neutron stars, has its origin in the current model from their extreme magnetic field. At odds to the large majority of the sources of this kind, an exceptionally low value for the magnetic field of SGR 0418+5729 had been recently reported.
Nov 05, 2012
Computation of the X-ray emission of a supernova remnant
An international team of astrophysicists, including Samar Safi-Harb and Gilles Ferrand at the University of Manitoba (Canada) and Anne Decourchelle from the Astrophysical Department-AIM Laboratory (CEA Saclay - France), has produced the first 3D simulations of supernova remnants (SNRs) showing the effect of particle acceleration at the wave fronts generated by these powerful X-ray sources in our galaxy. The research is published in the last issue of the Astrophysical Journal.  
Oct 09, 2012
New type of cosmic ray discovered after 100 years
Using the European X-ray astronomy satellite XMM-Newton [1], researchers from CNRS [2] and CEA [3] have discovered a new source of cosmic rays. In the vicinity of the remarkable Arches cluster, near the center of the Milky Way, these particles are accelerated in the shock wave generated by tens of thousands of young stars moving at a speed of around 700,000 km/h. These cosmic rays produce a characteristic X-ray emission by interacting with the atoms in the surrounding gas.
Jul 05, 2012
Discovery of a transient radio jet from an intermediate-mass black hole
Sporadic ejections of matter are observed in the form of radio jets from supermassive black holes in active galaxies as well as from galactic binary systems hosting a black hole of several solar masses.
Feb 03, 2012
First experimental approach of the asymmetric explosion of a star
The explosive death of massive stars begins with the collapse of their iron core which gives birth to a neutron star. Despite spherical initial conditions, this explosion can kick the neutron star several hundred kilometers per second. Exclusively studied by numerical simulations so far, the hydrodynamic instability responsible for this asymmetry is revealed here in a simple experiment.
Mar 24, 2011
First gamma-ray polarisation measure around a galactic black hole
Prototype of the X-ray binary systems harboring a black hole, Cygnus X-1 is the subject of many studies since its discovery in the 1960s. By studying its behavior at high energy, an international team led by Philippe Laurent, astrophysicist at the Service d'Astrophysique of the CEA-Irfu and laboratory APC discovered a surprising property of the light emitted by the system, a high degree of polarization.
Oct 14, 2010
Discovery of a magnetar with a magnetic field similar to the one of common pulsars
Magnetars form a class of neutron stars with a much higher (100-1000 times) magnetic field with respect to common rotation powered pulsars. This extreme magnetic field is currently believed to be the cause of their unpredictable and intense activity. But the observation by an international team, which includes a researcher from AIM/Service d’Astrophysique of CEA-Irfu, of the magnetar dubbed SGR 0418+5729 casts some doubts about this classification.
Sep 02, 2010
News observations with the refurbished Hubble Space Telescope
An international team of astronomers/astrophysicists that includes a member of the Service d'Astrophysique  (CEA-Irfu,  Saclay) has obtained new data of the spectacular surroundings of the famous supernova SN 1987A using the recently refurbished Hubble Space Telescope. New spectroscopic data, long awaited since the failure of the STIS instrument in 2004, allow pursuing the study of the inner equatorial ring, of its hot spots, and of the shocks induced by the explosion.
May 27, 2010
Molecular clouds reveal a giant outburst of the supermassive black hole at the centre of the Galaxy
The central black hole of the Galaxy, today surprisingly quiet, has undergone, several hundred years ago, a violent phase of activity. This is the conclusion reached by an international team led by astrophysicists of the APC laboratory and including scientists of the Service d'Astrophysique of CEA-Irfu, by studying the high energy emission of molecular clouds located in the central regions of the Galaxy.
Feb 26, 2010
The influence of particle acceleration
For the first time, the events following the explosion of a star have now been simulated in three dimensions by a team from the Astrophysics Division of CEA-IRFU. The simulation includes the significant contribution of particles accelerated by the shock that is produced in the expansion. Until now, these complex simulations have concentrated either on calculating movement of the expanding ejected material, or on calculating particle acceleration.
Dec 08, 2009
Microquaser gamma emission observed for the first time
For the first time, the high-energy gamma rays emitted by a microquasar have been spotted with certainty, thanks to NASA's Fermi telescope. The observation of the microquasar Cygnus X-3 by a French team (CEA-IRFU, CNRS-INSU and IN2P3, University of Paris Diderot, Joseph Fourier University) teaches us more about how these particular sources function and how a compact object orbiting a star can hurl a mass equivalent to the Moon's through the interstellar medium at almost the speed of light.
Feb 18, 2009
The FERMI observatory has discovered the most energetic gamma-ray burst ever detected
The Fermi gamma-ray space telescope  [1] has detected the most violent gamma-ray burst ever recorded; a gigantic explosion marking the death of a massive star. Light from this explosion, captured by the Fermi observatory on September 16th 2008, had taken 12.2 billion years to reach Earth. Hence, it must have been produced at a time when the Universe was just 1.5 billion years old.  The total amount of energy released makes this the most violent explosion observed in the Universe since the Big Bang.


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