Overmassive black holes at cosmic noon: linking the local and the high-redshift Universe

Understand

We report for the first time a sample of 12 supermassive black holes (SMBHs) hosted by low-mass galaxies at cosmic noon, i.e., in a redshift range consistent with the peak of star formation history: $z \sim 1-3$.

• These black holes are two orders of magnitude too massive for the stellar content of their hosts when compared with the local relation for active galaxies.
• These overmassive systems at cosmic noon share similar properties with the high-$z$ sources found ubiquitously in recent \textit{James Webb Space Telescope} (\textit{JWST}) surveys (same range of black hole-to-stellar mass ratio, bolometric luminosity, and Eddington ratio).
• We argue that black hole feedback processes, for which there is possible evidence in five of the sources, and the differing environments in galactic nuclei at these respective epochs play a key role in these overmassive systems.