ERC FUNDED PROJECTS

The discoveries that the expansion of the universe is accelerating due to an unknown “dark energy” and that most of the matter is invisible, highlight our lack of understanding of the major constituents of the universe. These surprising findings set the stage for research in cosmology at the start of the 21st century. The objective of this proposal is to advance observational constraints to a level where we can distinguish between physical mechanisms that aim to explain the properties of dark energy and the observed distribution of dark matter throughout the universe. We use a relatively new technique called weak gravitational lensing: the accurate measurement of correlations in the orientations of distant galaxies enables us to map the dark matter distribution directly and to extract the cosmological information that is encoded by the large-scale structure. To study the dark universe we will analyse data from a new state-of-the-art imaging survey: the Kilo- Degree Survey (KiDS) will cover 1500 square degrees in 9 filters. The combination of its large survey area and the availability of exquisite photometric redshifts for the sources makes KiDS the first project that can place interesting constraints on the dark energy equation-of-state using lensing data alone. Combined with complementary results from Planck, our measurements will provide one of the best views of the dark side of the universe before much larger space-based projects commence. To reach the desired accuracy we need to carefully measure the shapes of distant background galaxies. We also need to account for any intrinsic alignments that arise due to tidal interactions, rather than through lensing. Reducing these observational and physical biases to negligible levels is a necessarystep to ensure the success of KiDS and an important part of our preparation for more challenging projects such as the European-led space mission Euclid.

1 316 880 €

Start date: 2012-01-01, End date: 2016-12-31

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

When interstellar clouds collapse to form new stars and planets, the surrounding gas and dust become part of the infalling envelopes and rotating disks, thus providing the basic material from which new solar systems are made. Instrumentation to probe the physics and chemistry in low-mass star-forming regions has so far lacked spatial resolution. I propose here an integrated observational-modeling-laboratory program to survey protostars and disks on the relevant scales of 1-50 AU where planet formation takes place. The observations are centered on new data coming from the Atacama Large Millimeter / submillimeter Array (ALMA), and the analysis includes unique new data from key programs on Herschel, Spitzer and VLT that I am (co-)leading. The combination of millimeter and infrared data allows the full range of temperatures from 10-2000 K in star- and planet- forming regions to be probed, for both gas and solids. The molecular line data are used as diagnostics of physical parameters (such as UV field, cosmic ray ionization rate, kinematics, mixing, shock strength, grain growth, gas/dust ratios) as well as to follow the chemistry of water and complex organic molecules from cores to disks, which ultimately may be delivered to terrestrial planets. The implications for the history of volatile material in our own solar systen and exo-planetary atmospheres will be assessed by comparing models and data with cometary taxonomy and, ultimately, feeding them into planet population synthesis models. Altogether, this program will bring the link between interstellar chemistry and solar system and exo-planetary research to a new level. The project will train four PhD students in a truly interdisciplinary environment in which they are exposed to all aspects of molecular astrophysics and have access to ample ALMA expertise, and it will prepare two postdocs for future faculty positions.

2 499 150 €

Start date: 2012-07-01, End date: 2018-06-30

Timing is everything in ecology, and because plants provide the foundation for most land-based food webs, the timing of their activities profoundly orchestrates the majority of ecological interactions. Most photosynthetic and growth processes are under circadian control, but many additional processes--approximately 30-40% of all genes—are under circadian control, and yet the Darwinian fitness impact of being “in synch” with the environment has not been systematically studied for any organism. We have developed a toolbox for a native tobacco plant, Nicotiana attenuata, that allows us to “ask the plant” which genes, proteins or metabolites are regulated in particular plant-mediated ecological interactions; identify “the genes that matter” for a given interaction; silence or ectopically express these genes, and conduct field releases with the transformed plants at a nature preserve in the Great Basin Desert to rigorously test hypotheses of gene function. By taking advantage of both our understanding of what it takes for this plant to survive in nature, and the procedures established to disentangle the skein of subtle interactions that determine its performance, we will systematically examine the importance of synchronous entrained endogenous rhythms at all life stages: longevity in the seed bank, germination, rosette growth, elongation, flowering and senescence. Specifically, we propose to silence a key components (starting with NaTOC1) of the plant’s endogenous clock to shorten the plant’s circadian rhythm, both constitutively and with strong dexamethasone-inducible promoters, at all life stages. With a combination of real-time phenotype imaging, metabolite and transcriptome analysis, and ecological know-how, the research will reveal how plants adjust their physiologies to the ever-changing panoply of environmental stresses with which they must cope; by creating arrhythmic plants, we will understand why so many processes are under circadian control.

2 496 002 €

Start date: 2012-04-01, End date: 2017-03-31