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.).
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 the central region following the violent gravitational instabilities that occur within the galaxy gaseous disk. These instabilities may trigger a phase a dynamical contraction, hence explaining the ultra-compact morphology of the galaxies studied here. These results are published in the Monthly Notices of the Royal Astronomical Society.
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 this galaxy has undergone a recent fusion with another gas-rich galaxy. Much of this gas was then driven to the center of the elliptical galaxy during the collision. These results are published in the Astrophysical Journal Letters of May 2017
At the center of a small galaxy located about 1.8 billion light-years from Earth, a giant black hole swallowed a star for about a decade, which is exceptionally longer than any observed episode of this kind. This discovery was made by an international collaboration involving an astrophysicist from IRFU, thanks to a trio of orbiting X-ray telescopes.
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 , 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 clusters of galaxies, responsible for the most energetic events in the Universe after the Big Bang. This work is being published in the journal Astronomy & Astrophysics..
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 ejection of matter induced during the explosions of stars. These results are published in the journal Nature of 30 August 2017.
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.