To be or not to be: Are JWST-discovered AGN real black holes?

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• Dr. Xihan Ji, Kavli Institute for Cosmology, Cambridge
• Tuesday 29 October 2024, 11:15-12:00
• Coffee area, Battcock Centre.

If you have a question about this talk, please contact Charles Walker.

Recent JWST observations have revealed a large population of low-luminosity broad-line AGN in the early Universe, showing a clear broad-line component in their H-alpha and/or H-beta emission. However, these AGN exhibit peculiar properties clearly different from the local AGN as well as high-luminosity QSOs at high redshift. The low-luminosity AGN uncovered by JWST are weak in the hard X-ray, frequently show significant nuclear dust obscuration, and sometimes show narrow absorption in permitted transitions. More recently, based on the non-variability of several JWST -identified AGN through multi-epoch photometry, it was suspected that a considerable number of JWST -identified AGN are not accreting black holes, but are star-formation (SF) driven processes in disguise. In this talk, I will briefly review some recent ideas on the explanations for the peculiarities of JWST -identified broad-line AGN , including galactic outflows, inelastic Raman scattering, obscuration by broad-line regions, or an alternative accretion disk model. In general, we find that current non-AGN explanations require exotic physical conditions unlikely to be found in the general population of JWST -identified broad-line sources. The AGN explanations, on the other hand, require future investigations based on deep and multi-band follow-up to verify.

This talk is part of the Hills Coffee Talks series.

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