ERC FUNDED PROJECTS

BEACON aims at performing an ambitious multi-disciplinary (optical, radio astronomy and theoretical physics) study to enable a fundamentally improved understanding of gravitation and space-time. For almost a century Einstein's general relativity has been the last word on gravity. However, superstring theory predicts new gravitational phenomena beyond relativity. In this proposal I will attempt to detect these new phenomena, with a sensitivity 20 times better than state-of-the-art attempts. A successful detection would take physics beyond its current understanding of the Universe. These new gravitational phenomena are emission of dipolar gravitational waves and the violation of the strong equivalence principle (SEP). I plan to look for them by timing newly discovered binary pulsars. I will improve upon the best current limits on dipolar gravitational wave emission by a factor of 20 within the time of this proposal. I also plan to develop a test of the Strong Equivalence Principle using a new pulsar/main-sequence star binary. The precision of this test is likely to surpass the current best limits within the time frame of this proposal and then keep improving indefinitely with time. This happens because this is the cleanest gravitational experiment ever carried out. In order to further these goals, I plan to build the ultimate pulsar observing system. By taking advantage of recent technological advances in microwave engineering (particularly sensitive ultra-wide band receivers) digital electronics (fast analogue-to-digital converters and digital spectrometers) and computing, my team and me will be able to greatly improve the sensitivity and precision for pulsar timing experiments and exploit the capabilities of modern radio telescopes to their limits. Pulsars are the beacons that will guide me in these new, uncharted seas.

1 892 376 €

Start date: 2011-09-01, End date: 2016-08-31

Studying quasars (actively accreting supermassive black holes) and galaxies at the earliest cosmic epochs is one of the prime objectives in modern astrophysics. How the first luminous sources formed and reionized the universe is one of the most fundamental open questions in cosmology. Likewise, a detailed characterization of the evolution of the cosmic molecular gas density, which lies at the heart of galaxy evolution, is a fundamental goal in observational astrophysics. The proposed program capitalizes on current and upcoming facilities and encompasses three aspects: The first (I) will use the recently started Pan-STARRS1 survey to identify a sizeable sample of z>7 quasars, i.e. when the universe was less than 0.8 Gyr old (<1/15th of today’s age), to statistically probe black hole growth in the Epoch of Reionization. The second project (II) will characterize the physical properties of z~6 and z~7 quasar hosts selected from project (I) and the SDSS / VISTA VIKING surveys using new observational NIR/(sub)millimeter capabilities, including ALMA (observations approved in cycle 0). The last project (III) will use the IRAM Plateau de Bure Interferometer, and ALMA, to embark on the first molecular deep field which will provide a complete ‘blind’ census of the molecular gas density through cosmic times (from z~1 to z~8, approved pilot program). The overarching goal of this ERC proposal is thus to greatly increase our understanding of the physical properties of the earliest massive objects in the universe, and to shed first light on the evolution of the cosmic molecular gas density in galaxies after the universe emerged from the cosmic ‘dark ages’. The PI is internationally recognized as a leader in molecular gas studies of high-redshift galaxies, and through his track record and access to the needed combination of research facilities, is uniquely positioned to successfully lead this program.

1 439 000 €

Start date: 2012-11-01, End date: 2017-10-31

Numerical simulations of galaxy formation provide a powerful technique for calculating the non-linear evolution of cosmic structure formation. In fact, they have played an instrumental role in establishing the current standard cosmological model known as LCDM. However, unlocking the predictive power of current petaflop and future exaflop computing platforms requires a targeted effort in developing new numerical methods that excel in accuracy, parallel scalability, and in physical fidelity to the processes relevant in galaxy formation. A new moving-mesh technique for hydrodynamics recently developed by us provides a significant opportunity for a paradigm shift in cosmological simulations of structure formation, replacing the established smoothed particle hydrodynamics technique with a much more accurate and flexible approach. Building on the first successes with this method, we here propose a comprehensive research program to apply this novel numerical framework in a new generation of hydrodynamical simulations of galaxy formation that aim to greatly expand the physical complexity and dynamic range of theoretical galaxy formation models. We will perform the first simulations of individual galaxies with several tens of billion hydrodynamical resolution elements and full adaptivity, allowing us to resolve the interstellar medium in global models of galaxies with an unprecedented combination of spatial resolution and volume. We will simultaneously and self-consistently follow the radiation field in galaxies down to very small scales, something that has never been attempted before. Through cosmological simulations of galaxy formation in representative regions of the Universe, we will shed light on the connection between galaxy formation and the large-scale distribution of gas in the Universe, and on the many facets of feedback processes that regulate galactic star formation, such as energy input from evolving and dying stars or from accreting supermassive black holes.

1 488 000 €

Start date: 2013-02-01, End date: 2018-07-31

In the arising era of gravitational-wave (GW) astronomy the demand for the next-generation of neutron-star (NS) merger models has never been so great. By developing the first relativistic moving-mesh simulations of NS mergers, we will be able to reliably link observables of these spectacular events to fundamental questions of physics. Our approach will allow us to maximize the information that can be obtained from different GW oscillations of the postmerger remnant. In this way we will demonstrate the scientific potential of future postmerger GW detections to unravel unknown properties of NSs and high-density matter. Based on our models we will work out the optimal GW data analysis strategy towards this goal. Employing a revolutionary numerical technique we will be able to achieve an unprecedented resolution of the merger outflow. High-resolution simulations of these ejecta are critical to uncover the detailed conditions for nucleosynthesis, specifically, for the rapid-neutron capture process (r-process). The r-process forges the heaviest elements such as gold and uranium, but its astrophysical production site still has to be clarified. Moreover, the nuclear decays in the expanding outflow power electromagnetic counterparts, which are targets of optical survey telescopes (iPTF, ZTF, BlackGEM, LSST). Our multi-disciplinary approach combines hydrodynamical models, nuclear network calculations and light-curve computations to facilitate the interpretation of future electromagnetic observations within a multi-messenger picture. Linking these observables to the underlying outflow properties is pivotal to unravel the still mysterious origin of heavy elements created by the r-process.

1 499 485 €

Start date: 2018-07-01, End date: 2023-06-30