Supermassive black holes and their jets through cosmic time

• Applicant: Lea Marcotulli, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443220636

The question of supermassive black hole formation, growth and evolution in the early universe is an open issue in astrophysics. In particular, the existence of numerous, extremely massive, and active supermassive black holes which host powerful relativistic jets within the first billion years of the universe poses a challenge to our understanding of black hole seeding and growth, and its connection to jet launching and regulation. To address these open issues, we will focus our attention on the most extreme blazar jets. Although such blazars are rare objects (detected only when pointed directly along our line-of-sight), their powerful jets are tracers of the general population and their detection shows that supermassive black holes exist in large numbers within the Universe’s first billion years. With this proposal, we aim to tackle two fundamental questions that could lead a step closer in solving these open issues: (1) how many jets and supermassive black holes exist within the first billion years of the Universe?; and (2) can we build a successful subgrid blazar model that simultaneously matches the observed evolution of X-ray blazar jets and radio galaxies in cosmological simulations? From an observational standpoint, we aim to construct a comprehensive catalog of the most powerful and distant blazars (so-called "MeV blazars'") with complete black hole masses and jet properties measurements as well as trace their evolution with a variety of X-ray surveys to pinpoint their evolution (and that of their supermassive black hole hosts). From a simulation point of view, we will instead focus on developing a blazar sub-grid model prescription that aims at reproducing the observed evolution of blazar jets as manifested in the X-ray/gamma-ray blazar appearance and in form of radio galaxies. This will help us elucidating the conditions necessary to create these jets in the first place.

• DFG Programme: Research Units
• Subproject of: FOR 5195: Relativistic Jets in Active Galaxies
• Co-Investigators: Professor Dr. Christoph Pfrommer; Professor Dr. Jörn Wilms