PI: Ricarda Beckmann

Almost every massive galaxy in the local Universe contains a supermassive black hole (SMBH) at its centre. These present-day SMBHs evolved from smaller seed black holes (BHs) through processes such as gas accretion and mergers between black holes. Understanding the origins of these SMBHs and validating the role of black hole feedback, such as active galactic nuclei, are crucial for our understanding of galaxy evolution. To achieve this, we must explore when and how massive galaxies acquired their seed black holes by studying the evolution of these seeds during the first billion years of the Universe in relation to their host galaxies.

In this project, we conducted cosmological simulations using the DIRAC dial3 facility, which centred on an over-dense region. Within this environment, we meticulously recorded details such as mass evolution, luminosity, spin evolution, and trajectory of over 400 BH within their host galaxies.

Using this unique dataset, we investigated how seed black holes evolved in the early Universe, focusing on how their location affected their ability to mature into the precursors of the SMBHs observed today. Recent studies suggest that Super-Eddington accretion could provide an early mass boost for some seed black holes. A considerable early increase in mass could potentially shorten their dynamic times, offering a significant advantage for settling into the centres of their highly disturbed host galaxies in the early Universe.

To explore this possibility, we extended our fiducial simulation with a companion simulation that allowed black holes to accrete beyond the Eddington limit. By comparing the two simulations, we isolated the impact of super-Eddington accretion on the evolution and dynamics of seed black holes. This comparative analysis enabled us to infer whether super-Eddington accretion could indeed facilitate quicker growth and central positioning within galaxies, potentially altering their evolutionary paths.