Sep 09, 2022
The origin of Galactic cosmic rays, their energy source and their acceleration process raise many questions more than 100 years after their discovery by Victor Hess in 1912. What are their sources of acceleration and energy? What are the acceleration mechanisms and their properties? If these are not the only sources considered, strong shocks in supernova remnants constitute one of the privileged places of acceleration which allows the acceleration of particles by the mechanism of diffusive acceleration.
Oct 01, 2018
Impressing results from a large X-ray catalog of galaxy clusters
Using the ESA's XMM-Newton observatory, an international team, led by Marguerite Pierre of the Astrophysics Department of CEA-Irfu, has revealed the latest results of the XXL survey, the largest observation program X-ray produced to date by the XMM satellite. The second batch of data just published in a special issue of the journal Astronomy & Astrophysics, includes information on 365 galaxy clusters and 26,000 active galactic nuclei (AGN).
Dec 15, 2015
3D-maps of galaxy clusters
A new 3D map of galaxy clusters has just been published by a research team led by Maguerite Pierre from the Astrophysics Department-AIM Laboratory of CEA-IRFU through a survey of two regions of the sky, each covering about 25 square degrees (about 100 times the area of ​​the full moon). The survey, called XXL, was conducted from 2011 to 2013 resulting from 543 observations of the X-ray satellite XMM-Newton and requiring over 6 million seconds exposure.
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.
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.
Nov 17, 2008
Dense electron clouds around neutron stars.
Neutron stars are the most magnetized objects in our Universe. Some of them, dubbed "Magnetars" have a record magnetic field of 1011 Tesla (T), which corresponds to one million of billions times that of the Sun during a quiescent phase. It's around this class of objects that an over-density of electrons has been discovered.

 

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