Lyα Maps Expose Embedded Hosts in Little Red Dots, Forcing Revisions to Early Galaxy Assembly

The Ji et al. (2026) preprint delivers the first systematic Lyα probe of 110 spectroscopically confirmed Little Red Dots at z≥4 drawn from the de Graaff catalog using JWST/NIRSpec PRISM data. Lyα is detected at S/N≥3 in only 32 objects, with luminosities and equivalent widths resembling ordinary star-forming galaxies, yet Lyα/Hα ratios lie systematically below expectations and track [O III] luminosity rather than equivalent width. This pattern indicates Lyα originates primarily from an extended host component, not the compact red source driving broad Balmer lines. For 13 sources at z≳5.5, continuum-subtracted maps from HST/ACS and NIRCam show spatially extended, asymmetric, and offset emission consistent with resonant scattering in clumpy, anisotropic gas. The work is a preprint and therefore lacks peer review; its mapping subsample remains modest. Mainstream reporting has emphasized LRD compactness and possible AGN dominance while overlooking how these host-scale gas structures tighten constraints on rapid baryon assembly and feedback models. Cross-referencing with Labbé et al. (2023, Nature) on photometric LRD overabundance and Matthee et al. (2024, ApJ) on Lyα escape fractions at z>6 reveals that the observed offsets and low ratios disfavor isolated compact objects, instead favoring embedded growth within turbulent, gas-rich halos whose CGM regulates both Lyα escape and black-hole seeding timelines.