MEOW MIRI Survey Detects 16 AGN at z=4.5-7.2, Revealing Obscured Growth Missed by Optical and NIR Searches

MEOW targeted dust-obscured AGN by combining 0.5-3.6 μJy MIRI depths with HST, NIRCam, and SCUBA-2 photometry for SED modeling. This approach isolates hot-dust emission that optical and rest-UV selections overlook, recovering both broad-line and narrow-line populations at epochs when standard surveys report lower space densities. Twelve new detections include systems whose mid-IR colors indicate circumnuclear tori or host-galaxy dust lanes, directly addressing the incompleteness of broad-line spectroscopic censuses.

Number densities from the derived luminosity function at z=4.5-6 match those of broad-line AGN and little red dots, implying obscured objects contribute at least 50% of the total AGN population. This elevates the integrated black-hole accretion rate density during reionization, requiring revisions to models that assume predominantly unobscured growth. The diversity of host environments points to multiple obscuration channels rather than a single torus geometry.

Future multi-wavelength follow-up must quantify the exact contribution of these AGN to the ionizing photon budget. ALMA [C II] and NIRSpec IFS observations scheduled within 18 months will test whether host-scale dust or nuclear tori dominate, tightening constraints on early SMBH seeding and feedback efficiency.