ERC FUNDED PROJECTS

The detection of primordial gravity waves created during the Big Bang ranks among the greatest potential intellectual achievements in modern science. During the last few decades, the instrumental progress necessary to achieve this has been nothing short of breathtaking, and we today are able to measure the microwave sky with better than one-in-a-million precision. However, from the latest ultra-sensitive experiments such as BICEP2 and Planck, it is clear that instrumental sensitivity alone will not be sufficient to make a robust detection of gravitational waves. Contamination in the form of astrophysical radiation from the Milky Way, for instance thermal dust and synchrotron radiation, obscures the cosmological signal by orders of magnitude. Even more critically, though, are second-order interactions between this radiation and the instrument characterization itself that lead to a highly non-linear and complicated problem. I propose a ground-breaking solution to this problem that allows for joint estimation of cosmological parameters, astrophysical components, and instrument specifications. The engine of this method is called Gibbs sampling, which I have already applied extremely successfully to basic CMB component separation. The new and ciritical step is to apply this method to raw time-ordered observations observed directly by the instrument, as opposed to pre-processed frequency maps. While representing a ~100-fold increase in input data volume, this step is unavoidable in order to break through the current foreground-induced systematics floor. I will apply this method to the best currently available and future data sets (WMAP, Planck, SPIDER and LiteBIRD), and thereby derive the world's tightest constraint on the amplitude of inflationary gravitational waves. Additionally, the resulting ancillary science in the form of robust cosmological parameters and astrophysical component maps will represent the state-of-the-art in observational cosmology in years to come.

1 999 205 €

Start date: 2018-04-01, End date: 2023-03-31

Understanding how galaxies form in the early universe and how they evolve through cosmic time is a major goal of modern astrophysics. Panchromatic look-back sky surveys significantly advanced the field in the past decade, and we are now entering a 'golden age' of radio astronomy given an order of magnitude improved facilities like JVLA, ATCA and ALMA. I am leading two unique, state-of-the-art (JVLA/ATCA) radio surveys that will push to the next frontiers. The proposed ERC project will focus on the growth of stellar and black-hole mass in galaxies across cosmic time by: 1-probing various types of extremely faint radio sources over cosmic time, revealing the debated abundance of faint radio sources, 2-exploring star formation conditions at early cosmic times, allowing to access for the first time the dust-unbiased cosmic star formation history since the epoch of reionization, 3-performing the first census of high-redshift starbursting galaxies (SMGs), and their role in galaxy formation and evolution, and 4-performing a full census of galaxies hosting supermassive black holes (AGN), with different black-hole accretion modes, and their roles in galaxy evolution. The exploitation of these radio sky surveys is essential for the preparation and success of the future large facilities like ASKAP, and SKA as they will 1-provide best predictions of the to-date uncertain cosmic radio background seen with the SKA, and 2-optimize photometric redshift estimates, essential for the success of the first ASKAP sky survey (EMU, >2016). My radio surveys, expected to yield >100 refereed publications, carry an immense legacy value. The proposed ERC funding is essential for the success of these timely surveys, which I will conduct from Croatia. The ERC grant will allow me to lead my own research group working on this novel data, and to even more firmly establish myself as a leading survey scientist, and lead my group to internationally competitive levels, and enhance EU competitiveness.

1 500 000 €

Start date: 2014-02-01, End date: 2019-01-31

In the aftermath of the high-precision Planck and BICEP2 experiments, cosmology has undergone a critical transition. Before 2014, most breakthroughs came as direct results of improved detector technology and increased noise sensitivity. After 2014, the main source of uncertainty will be due to astrophysical foregrounds, typically in the form of dust or synchrotron emission from the Milky Way. Indeed, this holds as true for the study of reionization and the cosmic dawn as it does for the hunt for inflationary gravitational waves. To break through this obscuring veil, it is of utmost importance to optimally exploit every piece of available information, merging the world's best observational data with the world's most advanced theoretical models. A first step toward this ultimate goal was recently published as the Planck 2015 Astrophysical Baseline Model, an effort led and conducted by myself. Here I propose to build Cosmoglobe, a comprehensive model of the radio, microwave and sub-mm sky, covering 100 MHz to 10 THz in both intensity and polarization, extending existing models by three orders of magnitude in frequency and a factor of five in angular resolution. I will leverage a recent algorithmic breakthrough in multi-resolution component separation to jointly analyze some of the world's best data sets, including C-BASS, COMAP, PASIPHAE, Planck, SPIDER, WMAP and many more. This will result in the best cosmological (CMB, SZ, CIB etc.) and astrophysical (thermal and spinning dust, synchrotron and free-free emission etc.) component maps published to date. I will then use this model to derive the world's strongest limits on, and potentially detect, inflationary gravity waves using SPIDER observations; forecast, optimize and analyze observations from the leading next-generation CMB experiments, including LiteBIRD and S4; and derive the first 3D large-scale structure maps from CO intensity mapping from COMAP, potentially opening up a new window on the cosmic dawn.

1 999 382 €

Start date: 2019-06-01, End date: 2024-05-31

The detection of life beyond our Solar System is possible only via the remote sensing of the atmospheres of exoplanets. The recent discovery that small exoplanets are common around cool, red stars offers an exciting opportunity to study the atmospheres of Earth-like worlds. Motivated by this revelation, the EXOKLEIN project proposes to construct a holistic climate framework to understand astronomical observations in the context of the atmosphere, geochemistry and biosignatures of the exoplanet. The proposed research is divided into three major themes. Research Theme 1 aims to construct a virtual laboratory of an atmosphere that considers atmospheric dynamics, chemistry and radiation, as well as how they interact. This virtual laboratory enables us to understand the physical and chemical mechanisms involved, as well as predict the observed properties of an exoplanet. Research Theme 2 aims to generalize the carbonate-silicate cycle (also known as the long-term carbon cycle) by considering variations in rock composition, water acidity and atmospheric conditions. The carbonate-silicate cycle is important because it regulates the long-term presence of carbon dioxide (a vital greenhouse gas) in atmospheres. We also aim to investigate the role of the cycle in determining the fates of ocean-dominated exoplanets called “water worlds”. Research Theme 3 aims to investigate the long-term stability of biosignature gases in the context of the climate. Whether a gas uniquely indicates the presence of biology on an exoplanet depends on the atmospheric properties and ultraviolet radiation environment. We investigate three prime candidates for biosignature gases: methyl chloride, dimethylsulfide and ammonia. Overall, the EXOKLEIN project will significantly advance our understanding of whether the environments of rocky exoplanets around red stars are stable and conducive for life, and whether the tell-tale signatures of life may be detected by astronomers.

1 984 729 €

Start date: 2018-02-01, End date: 2023-01-31