Nicholas Seymour
Curtin University, Australia

Abstract
While the existence of billion mass super-massive black holes (SMBHs) in the early Universe (z>6) has been known for a while, JWST is rapidly advancing our knowledge of SMBH growth in the early Universe. SMBHs are being found at ever greater redshifts and at lower masses, but their formation remains a mystery. As JWST only surveys relatively small areas, an alternate method must be found to discover the most extreme of these sources. I will present the latest results from an on-going programme using the low-frequency (70-230 MHz) GLEAM survey to find candidate, obscured, but heavily accreting SMBHs in the very early Universe. Our pilot survey found the second most distant powerful (L500>10^27 W/Hz) radio galaxy at z=5.55. This galaxy appears to have extended CO and have a black hole mass putting it well above the local m-sigma relation. I will report the latest status of our full survey which has deep K-band follow-up from the VLT as well as ALMA data. Our most extreme sources have 150MHz to K-band flux ratios >10^5 (similar to known powerful radio galaxies at 2<z<6), but with fainter K-band fluxes (K>24). Are these `regular’ powerful radio galaxies at z>6 or at lower redshift but with extremely massive SMBHs to power their jet? I will also discuss future prospects of using radio surveys to probe the early growth of SMBHs with Euclid.

2023 November 15, 10:30

IA
Online broadcast (Zoom)