The Epoch of Reionization marks the last major transition of the Universe: approximately 100-200 million years after the Big Bang, the neutral intergalactic medium, mainly composed of hydrogen atoms, started to be ionized by radiation from the first cosmic sources. The onset, timeline and topology of the Reionization process are all tightly linked to the nature of the sources of ionizing radiation: by studying them we can gain fundamental insights into what shaped the evolution of the Universe, from the smooth matter distribution of early times, as revealed by the cosmic microwave background, to the wealth of structures, like galaxies and clusters of galaxies, that formed at later epochs.

Our project exploits the critical synergies in expertise of the 4 PIs, ranging from the modeling of the intergalactic medium ionization and metal enrichment to the detailed observations of high-redshift galaxies and active galactic nuclei, with the aim of shedding light on the complex energy and baryon exchange between such ionizing sources and their environment. We will use superb proprietary and archival datasets from state-of-the-art facilities, such as the recently launched JWST, present and future VLT instrumentation and ALMA. To support and drive the interpretation of these new observations, we will produce novel large-scale and zoom-in simulations that can be readily compared to real data. RECAP is designed to capitalize on the massive investment in observing time and to maximize the scientific outcome expected from the concurrent use of multi-wavelength observations and specifically tailored numerical simulations, by creating a new, scientifically diverse and complementary team, which will combine, enlarge and enhance the expertise of each PI’s group.

Objectives of the project