A New Radio Window on the Growth of the First Supermassive Black Holes

Abstract:

From reionizing the Universe to quenching star formation in massive galaxies, accreting supermassive black holes (SMBHs), or active galactic nuclei (AGN), are thought to play a pivotal role in early galaxy evolution. Growing observational evidence, including recent results from JWST, suggests that accreting black holes are both more abundant and more massive at than predicted by current theoretical models. In this talk I will present recent observational results on accreting black holes in the early Universe, with a particular focus on radio-powerful AGN. I will show how relativistic jets can play an important role in both the rapid assembly of very massive black holes and the regulation of star formation in their host galaxies in the early Universe. 

While exciting, current studies focus on optically luminous AGN, which likely represent only the tip of the iceberg of the SMBH population at early cosmic times. Heavily obscured AGN, whose accretion signatures are hidden at optical and near-infrared wavelengths, are predicted to dominate the high-z AGN population, yet these sources remain largely unconstrained from an observational point of view. The synergy between next-generation radio and near-infrared wide-area surveys will soon open a new window on this elusive population. In particular, radio observations can reveal the presence of relativistic jets, and therefore ongoing black hole accretion, even in systems that are obscured at optical wavelengths. The combination of ASKAP/EMU and EUCLID-wide surveys will provide the deepest multi-wavelength view of the extra-Galactic southern sky, enabling the construction of the first large, unbiased census of accreting black holes at z>6. As an example of the power of this synergy, I will present a preliminary cross-match of EMU and Euclid over the EUCLID deep field South (∼25 deg²).

Please note that the event timezone is AWST (UTC+8 hrs)

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