São Paulo School of Advanced Science

Recent detections of astrophysical events through non-electromagnetic channels have opened up new areas of research involving the exploration of the cosmos using Multiple Messengers (MM). Astronomers have always used different wavelengths, from radio to gamma rays, to study physical phenomena on small and large scales, as well as low and high energy regimes. However, in recent years we have begun to have access to a variety of new channels that can be traced to the same objects or events: high-energy cosmic rays, neutrinos, and gravitational waves. Each messenger brings a distinct window on black holes, neutron stars, quasars, blazares, supernovae and other sources, and the complementarity of these observations begins to profoundly impact physics and astronomy.

What are the physical mechanisms behind the acceleration of particles to energies as high as 10²⁰ eV? What happens as black holes and neutron stars collide? Is Einstein's General Relativity an accurate description of gravitational phenomena in these cataclysmic events? Can we detect supernovae by measuring the bursts of neutrinos that are produced when their core finally collapses, seconds before the supernova explodes? Is it possible to solve the long-standing dichotomy about the expansion rate of the Universe (the “Hubble tension”) using binary neutron stars mergers as standard sirens to measure cosmological parameters? Can we detect the cosmic background of neutrinos, which is believed to be a thermal relic with a temperature of approximately 2K today, and which should have decoupled from the remaining matter and radiation before the first minute after the Big Bang? Can we combine the cosmic microwave background with observations of primordial gravitational waves to show whether or not there was in fact an inflationary phase at the very beginning of the Universe?

This São Paulo Advanced School of Multi-Messenger Astrophysics will provide students with the knowledge and tooling to start working in these areas, detailing the physics behind these new discoveries and observations. This School will present the science behind these MM astrophysical phenomena, in addition to giving a review of the new experiments and instruments that will be relevant in the next decade.