Intensity Mapping Could Expose the Obscured AGN Population Driving Galaxy-Black Hole Co-Evolution at Cosmic Noon

This arXiv preprint (v1, June 2026) by Eli Visbal and colleagues proposes [Ne V] line-intensity mapping (LIM) to detect the cumulative emission from faint, dust-obscured active galactic nuclei at z=2-3, where direct surveys miss much of the population. Using a Fisher matrix formalism on two hypothetical instruments (CDIM-like for optical [Ne V] λ3426 and PRIMA-like for mid-IR 14.3 μm), the analysis forecasts strong constraints on mean intensity times bias (S_NeV b_NeV), with redshift-space distortions separating the two parameters. Roughly 10% of the predicted signal arises below the 5σ detection threshold (L_bol ~5e43 erg/s at z=3), recoverable at S/N=4-9. As a preprint, results remain unpeer-reviewed forecasts without observational data. The 97.1 eV ionization potential cleanly isolates AGN narrow-line regions even in heavily obscured systems, addressing a gap in co-evolution models where faint-end luminosity functions and black-hole seeding mechanisms are poorly constrained. Complementary work such as the 2023 COMAP [CII] LIM forecasts (arXiv:2302.05480) and the 2024 obscured-AGN demographics study in ApJ (doi:10.3847/1538-4357/ad2c0e) shows similar cross-correlation gains, yet both overlook [Ne V]'s dust-insensitivity advantage highlighted here.