News 2017

Mar 11, 2017
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 870 microns. Combining maps obtained at different wavelengths is essential to fully characterize the physical conditions (temperature, density ...) of the dense interstellar matter that forms the 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.).

Nov 28, 2017

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 Release Science). Parmi eux, deux programmes auxquels participe le CEA. Ces observations auront lieu au cours des cinq premiers mois des opérations scientifiques du JWST, après une période de mise en service de six mois.

 

Mar 13, 2017
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 simulations showed that, most likely, these stars had managed to retain the initial rotational motion of a cloud that gave rise to the cluster. This discovery, if confirmed in other clusters, could lead to reconsideration of the fundamental processes of star formation. These works make headlines in the journal Nature Astronomy of March 13, 2017

Watch the author's interview : The mysterious alignment of the rotation axis of stars 

Feb 16, 2017

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. Kepler's data were also compared with those of the  European satelite Soho (ESA/NASA).

Just as the vibrating note of a drum is directly related to its size, solar oscillation analysis makes it possible to calculate the mass, the radius and even the internal structure of the Sun. Curiously the data calculated from the light reflected by Neptune provided slightly different quantities of those obtained from direct sunlight. These deviations can be attributed to a particular state of activity of the Sun when the satellite observed Neptune.

Apr 16, 2017

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 Sabatier University) and the Institute of Space Astrophysics (CNRS / Université Paris-Sud) and the Institute of Research into the Fundamental Laws of the Universe (CEA-Irfu). Detectors capable of detecting infrared radiation from dust have been developed at the CEA and are the result of research done to realize the PACS camera that equiped the Herschel space observatory.

 

Sep 14, 2017

The Cassini probe will finish this September 15, 2017 its mission of more than 13 years around Saturn. On board, the smallest instrument, a detector only 5 millimetres long, was developed by the Department of Astrophysics of CEA-Irfu, which carried it out in collaboration with CEA/LETI (Electronics and Information Technology Laboratory). This detector, which is at the heart of the CIRS (Composite InfraRed Spectrometer), has made it possible to measure the temperature of Saturn's rings with an unequalled resolution and has also made it possible to discover many molecules in the atmosphere of Saturn and its Titan satellite.

Jul 31, 2017
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 days, about 4 times faster than its surface. This rapid rotation could have been inherited from the first moments of the sun formation. These results are published in the Astronomy & Astrophysics journal of June 2017.

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.
Thanks to the INTEGRAL satellite in orbit, the astrophysicists of the Department of Astrophysics-AIM Laboratory (CEA, CNRS, Univ Paris Diderot) were able to show that the wave GW170817 was accompanied by a gamma burst, a brief emission of gamma rays emitted just 2 seconds after the fusion of the two stars. By pointing in record time one of the giant telescopes of the VLT (Chile), they also participated in the study of the visible light emission that followed the fusion, showing in particular that this light was not polarized.
Physicists from the Department of Particle Physics of CEA-Irfu also analyzed the data obtained by the ANTARES experiments for neutrino and H.E.S.S. for the search for very high energy gamma rays, showing that the GW170817 wave did not provide detectable emission.

The study of this new phenomenon, never observed directly so far, offers many exciting perspectives for astrophysics as the possibility of better understanding the origin of the heavy elements of the Universe and even the ability to measure in a complete independent way the rate of expansion of the Universe.
All of these outstanding results are published in a series of articles presented in the journals Nature, Astrophysical Journal and Physical Review Letters on October 16, 2017.

For more information : see the French version

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.
Thanks to the INTEGRAL satellite in orbit, the astrophysicists of the Department of Astrophysics-AIM Laboratory (CEA, CNRS, Univ Paris Diderot) were able to show that the wave GW170817 was accompanied by a gamma burst, a brief emission of gamma rays emitted just 2 seconds after the fusion of the two stars. By pointing in record time one of the giant telescopes of the VLT (Chile), they also participated in the study of the visible light emission that followed the fusion, showing in particular that this light was not polarized.
Physicists from the Department of Particle Physics of CEA-Irfu also analyzed the data obtained by the ANTARES experiments for neutrino and H.E.S.S. for the search for very high energy gamma rays, showing that the GW170817 wave did not provide detectable emission.

The study of this new phenomenon, never observed directly so far, offers many exciting perspectives for astrophysics as the possibility of better understanding the origin of the heavy elements of the Universe and even the ability to measure in a complete independent way the rate of expansion of the Universe.
All of these outstanding results are published in a series of articles presented in the journals Nature, Astrophysical Journal and Physical Review Letters on October 16, 2017.

For more information : see the French version

 

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