Speaker
Description
Dual and multiple AGN provide a unique window into black-hole growth, galaxy interactions, and feedback in dense environments, yet they remain poorly constrained at high redshift. I will present JWST/NIRSpec IFU observations of GS10578, a massive quenched galaxy at z=3.06 hosting an X-ray AGN that drives multiphase outflows, with a close secondary AGN at a projected separation of 5 kpc. Exploiting rest-frame optical diagnostics enabled by new JWST observations, we investigate the nature of two Lyα emitters located in the environment of GS10578 and previously discovered with VLT/MUSE data. One of them, LAE2, lies at a projected distance of 28 kpc from GS10578, and had been proposed as a third AGN based on UV line diagnostics. Our NIRSpec observations reveal rest-frame optical line ratios fully consistent with AGN photoionisation, confirming that LAE2 hosts an accreting SMBH. In contrast, a second Lyα source (LAE1) remains undetected in all rest-frame optical lines and continuum emission, even in deep JWST/NIRCam and MIRI imaging. Its broad and asymmetric Lyα profile suggests resonantly scattered emission powered by LAE2 rather than in-situ star formation. Together, these results reveal a complex, multi-scale AGN environment around a quenched massive galaxy at z∼3, hosting three accreting SMBHs across separations ranging from a few to ~30 kpc. In addition, I will present recent results from the GA-NIFS collaboration on dual and multiple AGN systems uncovered with JWST, highlighting how NIRSpec IFU is transforming our view of black-hole growth and galaxy interactions in the early Universe.