Interpretation of infrared AGN populations in the optical Seyfert–LINER classification

Establish whether the AGN populations with different preferred values of alpha_ox identified in infrared studies correspond to the classical optical Seyfert and LINER populations.

Background

The paper notes that recent infrared analyses suggest multiple AGN populations characterised by different preferred values of the ionising-continuum parameter alpha_ox. However, the optical MaNGA analysis finds abundance differences between Seyfert and LINER regions whose physical interpretation remains unresolved.

Connecting the infrared populations to the optical Seyfert–LINER classification would help determine whether differences in the ionising spectral energy distribution explain the observed sulphur-to-oxygen trends and whether distinct ionising prescriptions are needed for the two optical classes.

References

In this context, recent infrared studies have suggested the existence of different preferred values of $\alpha_{\rm ox}$ among AGN populations, although the connection between those infrared populations and the classical optical Seyfert--LINER classification remains unclear.

— HII-CHI-mistry for active galactic nuclei: optical sulphur abundances without empirical ionisation correction factors  (2608.25919 - Pérez-Montero et al., 26 Aug 2026) in Section 5, “Summary and conclusions”