Opening new windows on Early Universe with multi-messenger astronomy – MMUniverse

The goal of the proposed project is to explore the possibility of opening new observational windows on the Early Universe via modelling and observations of cosmological magnetic fields, gravitational waves and primordial black holes.

Magnetic fields might be present in their initial form in the intergalactic medium. Measurements of the intergalactic magnetic field (IGMF) is possible using techniques of gamma-ray, radio and ultra-high-energy cosmic ray astronomies. Our goal is to explore what kind of information on the early universe could be extracted from IGMF measurements. We will scrutinize previously proposed models of magnetic field generation at Inflation, Electroweak and QCD phase transition and work out the details of evolution of those fields up to the present-day Universe, using constrained numerical simulations of the large scale structure. We will use these numerical models to work out IGMF model dependent Imaging and spectral templates of gamma-ray, radio and ultra-high-energy signals will allow us to achieve crucial improvement of sensitivity of IGMF searches. This approach will be directly useful for the IGMF related analysis of the next generation gamma-ray telescope CTA, of radio observation facility SKA, of upgraded ultra-high-energy cosmic ray experiments at Pierre Auger Observatory, Telescope array and of the next-generation space-based observatory EUSO. We will explore the power of “multi-messenger” combination of different cosmological magnetic field probes (combined analysis of gamma-ray, radio and ultra-high-energy cosmic ray data).

The origin of magnetic fields may be related to gravitational wave signal from the early universe. A stochastic gravitational wave background (SGWB) can be generated by the same processes that might have magnetized the universe. These are for instance first order phase transitions, bulk fluid motions, a network of topological defects, or particle production during inflation. The SGWB signal from these processes falls in the frequency range of present and future detectors: pulsar timing arrays, the space-based interferometer LISA, or the network of ground-based detectors. We will model both the gravitational wave signal and the characteristics of the magnetic field produced by these processes, and forecast the possibility of a combined detection of the IGMF by gamma-ray telescopes and of the SGWB by space or Earth-based detectors.

The same cosmological phase transition which might have generated IGMF and SGWB also might have produced primordial black holes (PBH). We will study observational signatures of such black holes in particular in relation to the binaries which are sources of the presently observed gravitational wave bursts, as well as to the intermediate mass and supermassive black holes in different astronomical objects. We will also investigate impact of PBH on the cosmic microwave background and cosmic structure formation. We will also explore further model-specific observational signatures of PBH which include e.g. existence of peculiar compact stars consisting of antimatter and observable via characteristic annihilation emission detectable with gamma-ray telescopes.

For each of the three phenomena: IGMF, SGWB and PBH, we will investigate two questions: which characteristics of observational signals can ascertain their common origin? How much we gain in constraining the generation process if signals in multiple channels are detected? What constraints on the early universe physics could we extract from observational signals? If indications of the cosmological nature of large scale cosmic magnetic fields, or of existence of cosmological SGWB or of PBH will be found in the data, they will be extremely important in the context of cosmology, providing a cosmological probe of the state of the Universe between Inflation and Big Bang Nucleosynthesis.