Photoionization models for extreme Ly$\alpha$ $\lambda$1216 and HeII $\lambda$1640 ratios in quasar halos, and PopIII vs AGN diagnostics

A. Humphrey, M. Villar-Martín, L. Binette +1

We explore mechanisms to produce extremely high Ly-alpha/HeII flux ratios, or to enhance the observed number of Ly-alpha photons per incident ionizing photon, in extended AGN-photo…