The emergence of supermassive black holes in early galaxies

by Dr Matthew Hayes (Stockholm University)

Thursday 13 Mar 2025, 15:15 → 16:15 Europe/Stockholm

Cosmological simulations have been triumphant in predicting the observed properties of the galaxy population, in which fundamental components are connected to the supermassive black holes (SMBHs) that occupy the centers of (all?) massive galaxies. Unfortunately, however, we have no coherent, observationally-verified picture of how these black holes could have formed, which raises serious questions about how to realistically model the Universe. Estimates of the abundance of active galactic nuclei, when the Universe was ~10% its current age, allow us to place the strongest constraints on SMBH seeding scenarios and also provide the main focus of this talk. I will present several new observational approaches to identifying SMBHs at early times combining deep  observations with the Hubble & James Webb Space Telescopes (HST+JWST) and bespoke modeling of galaxy spectra. Our analysis suggests that formation scenarios must produce large numbers of massive seeds (or, less likely, extremely rapid growth of black holes), and that signatures of massive black hole activity are actually abundantly present already at redshifts of z∼6 (when the Universe was about 1 Gyr). I will discuss these results in the context of SMBH formation and their connection to early star formation episodes.

About the Speaker:

Matthew Hayes is a faculty member at the Department of Astronomy at Stockholm University. He received his Master’s degree in Physics from Leeds University, UK, in 1999 and his PhD in 2007 from the Department of Astronomy. He then spent 3 years as a postdoc at University of Geneva and 3 more years in Toulouse. Hayes works on various aspects of galaxy evolution, and has most recently been concerned with the first objects to form in the Universe: early galaxy and black hole formation, as well as the growth of these with time.