ERC FUNDED PROJECTS

One of the major outcomes of recent studies on the formation of the Solar System is the reconnaissance of the fundamental importance of processes which took place during the first 10 thousands to 2 or 3 millions years of the lifetime of the Sun and its accretion disk. Astrophysical observations in the optical to infrared wavelengths of circumstellar disks around young stars have shown the existence in the inner disk of high-temperature processing of the dust. X-ray observations of T-Tauri stars revealed that they exhibit X-ray flare enhancements by several orders of magnitude. The work we have performed over the last years on the isotopic analysis of either solar wind trapped in lunar soils or of Ca-, Al-rich inclusions and chondrules from primitive chondrites, has allowed us to link some of these astrophysical observations around young stars with processes, such as irradiation by energetic particles and UV light, which took place around the T-Tauri Sun. The aim of this project is to make decisive progress in our understanding of the early solar system though the development of in situ high-precision isotopic measurements by ion microprobe in extra-terrestrial matter. The project will be focused on the exploration of the variations in the isotopic composition of O and Mg and in the concentration of short-lived radioactive nuclides, such as 26Al and 10Be, with half-lives shorter than 1.5 millions years. A special emphasis will be put on the search for nuclides with very short half-lives such as 32Si (650 years) and 14C (5730 years), nuclides which have never been discovered yet in meteorites. These new data will bring critical information on, for instance, the astrophysical context for the formation of the Sun and the first solids in the accretion disk, or the timing and the processes by which protoplanets were formed and destroyed close to the Sun during the first 2 million years of the lifetime of the Solar System.

1 270 419 €

Start date: 2009-01-01, End date: 2013-12-31

Gamma-Ray Bursts (GRBs), short and intense bursts of gamma-rays originating from random directions in the sky, are the brightest explosions in our Universe. They involve ultra-relativistic motion, huge magnetic fields, the strongest gravitational fields, acceleration of photons, neutrinos and cosmic rays to ultra high energies, the collapse of massive stars, mergers of neutron star binaries and formation of newborn black holes. They are at the focal point of relativistic high energy astrophysics and they serve as the best laboratory for extreme physics. The internal-external shocks model was formulated to explain their inner working. This model had impressive successes in interpreting and predicting GRB properties. Still it had left many fundamental questions unanswered. Furthermore, recently it has been confronted with puzzling Swift observations of the early afterglow and it is not clear if it needs minor revisions or a drastic overhaul. I describe here an extensive research program that deals with practically all aspects of GRB. From a technical point of view this program involves sophisticated state of the art computations on one hand, fundamental theory and phenomenological analysis of observations and data analysis on the other one. My goal is to address both old and new open question, considering, among other options the possibility that the current model has to be drastically revised. My long term goal, beyond understanding the inner working of GRBs, is to create a unified theory of accretion acceleration and collimation and of emission of high energy gamma-rays and relativistic particles that will synergize our understanding of GRBs, AGNs, Microquasars, galactic binary black holes SNRs and other high energy astrophysics phenomena. A second hope is to find ways to utilize GRBs to reveal new physics that cannot be explored otherwise.

1 933 460 €

Start date: 2009-01-01, End date: 2014-12-31

In general relativity and other relativistic theories of gravity, space and time are combined to form ``space-time'' which is curved in the presence of mass. As masses move, for instance like the two components in a binary system, ripples in space-time are created that propagate through the Universe, very much like waves caused by a stone falling into a pond. These ``gravitational waves'' (GWs) are known to exist from the effect that they have on a system of two orbiting stars. After inferring their existence indirectly, the next great challenge is the {\em direct} detection of GWs. While this is the aim of a number of gravitational wave detectors around the world, a detection has not been made. Fortunately, a method exists that allows us today to detect GWs directly, in a frequency range that is much lower but complementary to those covered by ground-based detectors. This method utilises the radio astronomical observations of a special type of star known as radio pulsars. We propose an experiment to achieve the ground-breaking goal of GW detection with the help of an innovative approach. At the heart of this approach, named LEAP, lies the goal to combine the collective power of Europe's biggest radio-telescopes to form the biggest fully-steerable telescope on Earth, providing a ``leap'' in our sensitivity to go beyond the threshold that delivers the first direct detection of GWs. While the rewards for a successful detection of GWs are immense, we demonstrate that this is possible by harvesting the experience and resources uniquely available in Europe.

2 455 285 €

Start date: 2009-01-01, End date: 2014-09-30

Black holes (BHs) and ultra-high energy cosmic rays (UHECRs) are two extremes of the universe that link particle physics and astrophysics. BHs are the most efficient power generators in the universe while UHECRs are the most energetic particles ever detected. As we showed previously, a major fraction of the power of BHs is channeled into radio-emitting plasma jets, which are also efficient particle accelerators. Are BHs also responsible for UHECRs? This long-standing question could be answered soon, through the dawn of cosmic ray astronomy. The giant Auger observatory has now shown for the first time that the arrival directions of UHECRs are non-isotropic, potentially pointing back to their sources of origin. BHs turned out to be major suspects, but other sources could still also be responsible. To address this conclusively and to establish cosmic ray astronomy as a productive new field in the coming years, we need to increase statistics, expand current observatories, and have complementary all-sky radio surveys available to identify sources, since radio emission traces particle acceleration sites. Here, techniques pioneered by the Low-Frequency Array (LOFAR) promise major advances. First of all, working on LOFAR we uncovered a new technique to detect UHECRs with radio antennas and verified it experimentally. The technique promises to increase the number of high-quality events by almost an order of magnitude and provides much improved energy and direction resolution. We now want to implement this technique in Auger, combining LOFAR and AUGER know-how. Secondly, LOFAR and soon other SKA pathfinders will significantly improve all-sky radio surveys with high sensitivity, resolution, and image quality. Hence, we will use LOFAR to understand the astrophysics of UHECR source candidates and compile a radio-based catalog thereof. We start with jets from BHs and move later to other sources. Together this will allow us to identify UHECR sources and study them in detail.

3 460 000 €

Start date: 2009-01-01, End date: 2013-12-31