Witnessing AGN outflows cooling and enriching CGM at Cosmic Noon

Understanding the physical properties and phase interactions within galactic outflows remains a major challenge. In this talk, I will present results from a detailed study of the multi-phase outflows in the z ~ 2.8 submillimeter galaxy-quasar system SMM J02399-0136, a uniquely rich environment for exploring large-scale feedback. Leveraging high-resolution observations from HST, JWST, and ALMA/ACA across a suite of emission lines—including Ly⍺, [O III], [C II], [N II], [C I], and CO—we map a complex structure of ionized, neutral, and molecular gas extending from the QSO out to 60 kpc. These observations reveal jet-ISM interactions, collimated outflows, filamentary and enriched CGM, with evidence for periodic feedback, turbulence, strong UV/optical line cooling. I will discuss how multi-line diagnostics constrain key physical conditions—such as density, ionization state, and chemical abundance, and highlight how deep imaging enables new insights into feedback processes at galactic scales.