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 »
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 »
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 »
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 »
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 »
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. The XXL survey helped to locate and identify 450 ... More »
Cosmology with cosmic shear observations
In a review article in "Reports on Progress in Physics", Martin Kilbinger of Astrophysics Department - AIM Laboratory at CEA-IRFU presents a comprehensive assessment of the results obtained from observations of the cosmic shear in the last 15 years. The cosmic shear effect has been measured for the first time in 2000. This effect is a distortion of the images of galaxies under the effect of gravity of the intervening clumps of matter. It allows to map the dark matter but also to determine how dark ... More »
A key for unsderstanding galaxy evolution
As part of an observing program carried out with the Hubble Space Telescope, a group of researchers from the “Service d’Astrophysique-Laboratoire AIM” of CEA-IRFU led by Anita Zanella discovered the birth cry of a massive star-forming clump in the disk of a very distant galaxy. This giant clump is less than 10 million years old, and it is the very first time that such a young star-forming region is observed in the distant Universe. This discovery sheds new light on how stars were born within distant ... More »
A giant survey of weak gravitational lensing
An international collaboration of astrophysicists, led by Martin Kilbinger from the Astrophysics Division - AIM Laboratory AIM at CEA Saclay-Irfu and the Institute of Astrophysics Paris, has obtained the largest survey of galaxy images that are deformed by gravitation. More than 4.2 million galaxies have been observed during more than 500 nights at the Canada-France Hawaii Telescope (CFHT) with the camera MegaCam, built at the CEA. The fine analysis of these images is the goal of the CFHTLenS project [1]. The very ... More »
First detection of gravity-like waves in a red giant star
Waves traveling inside the core of a giant star have been discovered by a international team of researchers including Rafael A. Garcia, member of the Service d'Astrophysique of CEA-Irfu [1]. The results were obtained using 320-day observations  of the Kepler satellite by means of stellar seismology. These waves, known as gravity modes, produce very small changes in the brightness at the surface of the star. The vibrations of the star offer the possibility of measuring the density, chemical composition, and the ... More »
An international team of astronomers, including several French researchers, has just completed a precise measurement of the distance to five distant galaxies using the ESA Herschel Space Observatory together with ground-based data from the interferometer operated by the Institute for Millimetric Radioastronomy (IRAM)1 . The research team has shown that the light from these galaxies has travelled for around ten thousand million years before reaching Earth. In order to obtain these results, the team developed an entirely ... More »
The most famous collision of galaxies decoded using ‘high-resolution’ simulations
‘High-resolution’ numerical simulations carried out by scientists at the Astrophysics Department of the CEA-Irfu/AIM  have just revealed that the most famous galactic collision ever, the Antennae collision, produces far more stars than observations suggested. When two galaxies meet, the resulting gas compression causes the ignition of new stars. Until now, it seemed that these new stars appeared only in high-density regions, mainly near the core of the collision. A computer re-creation of the ... More »
The giant gas ring in Leo, formed when two galaxies collided
An international team led by astrophysicists from the Lyon Observatory (CRAL, CNRS/INSU, Université Lyon 1) and the AIM laboratory (CEA-Irfu, CNRS, Université Paris 7) has just shed some light on the origins of the giant gas ring in Leo.  The astrophysicists were able to detect an optical counterpart to this cloud, which corresponds to stars in formation, using the Canada-France-Hawaii telescope (INSU-CNRS, CNRC, U. Hawaii). The scientists then carried out numerical simulations on the supercomputers ... More »
First images of the farthest massive galaxies
An international team of astronomers led by Dr. Masato Onodera at the Astrophysical Department of the Commissariat a l'Energie Atomique in France [1] has used the Subaru Telescope [2] to take an infrared spectra of a very distant, extremely bright, massive elliptical galaxy. This galaxy is 10 billion light-years from Earth and is observed at time when the Universe was only about one-quarter of its current age. Paradoxically, and in contrast with some previous studies, this galaxy  appears to be a similar to its ... More »
High resolution mapping of the first light in the Universe
Following its launch on 14 May 2009, the Planck satellite [1] has been continually observing the celestial vault and has mapped the entire sky since 13 August to obtain the first very high resolution image of the dawn of the universe. The Planck satellite has just finished its first sky coverage. The preliminary images reveal undreamed of details of emissions of gas and dust in our own galaxy. Scientists from CEA-IRFU, as part of a broad international collaboration, are currently working on the extraction and ... More »
Do quasars give birth to galaxies?
Which came first - the black hole or the galaxy? Many large galaxies in the Universe have a supermassive black hole at their centre. But which came first? The black hole that is frantically consuming the matter around it or the vast galaxy that is its home? A European team led by David Elbaz from CEA-IRFU's  Astrophysics Department has just discovered a spectacular interaction between a quasar and a galaxy from observations made with the VISIR camera. The camera was built at CEA-IRFU and installed on ... More »
A new look at early star births (23 January 2008)
An international team of astronomers lead by scientists of the Astrophysics Division of CEA-IRFU has discovered large molecular gas reservoirs - the combustible for forming new stars - hosted in ordinary massive galaxies in the young, distant Universe. The discovery has been made with the IRAM Plateau de Bure Interferometer located in the French Alps, observing at millimeter wavelengths. This finding indicates that massive galaxies built major fractions of their stars in a nearly continuous way, and not on very rapid ... More »
First astronomical image at 450 µm on APEX with P-ArTéMiS (6 juillet 2007)
The first Astronomical image taken by a new generation of camera called "ArTeMiS-1" were obtained with the APEX telescope in March 2007, at Chajnantor in Chile. This bolometer camera operates in the "submillimetre" domain, between the infrared and the millimetre waves, where the cold objects of the Universe emit most of their energy. The camera is based on the technology developed at the Service d'Astrophysique of CEA/DAPNIA, and LETI/LIR at CEA/Grenoble for the Herschel Space Observatory. This ... More »
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