The spectral energy distribution (SED) of low-luminosity active galactic nuclei (LLAGN) presents unique challenges as the emission
from these objects is comparable to the radiation from their host galaxy and the accretion physics involved is particularly complex. This
study introduces a novel CIGALE module specifically designed to address these challenges. The module combines the empirical LX–
L12 m relationship with physically motivated accretion models, such as advection-dominated accretion flows (ADAFs) and truncated
accretion disks, providing a more accurate depiction of LLAGN central engine emission. A mock analysis of the module revealed
good recovery of true parameters, with only a slight bias toward higher input values, further validating its reliability. We tested
the module on a sample of 50 X-ray-detected local galaxies, including low-ionization nuclear emission-line regions (LINERs) and
Seyferts, and demonstrated its capacity to accurately estimate bolometric luminosities, even in the presence of significant galaxy
contamination. Notably, the previous X-ray module failed to provide AGN solutions for this sample, stressing the need for a novel
approach. Comparisons with mid-luminosity AGN datasets confirm the module’s robustness and applicability up to LX < 1045 erg/s.
We also expanded the X-ray-to-bolometric correction formula, making it applicable to AGN spanning ten orders of magnitude in
luminosity, and revealing lower kX values for LLAGN than typically assumed. Additionally, our analysis of the ox index, which
represents the slope between UV and X-ray emissions, uncovered trends that dier from those observed in high-luminosity AGN.
Unlike quasars, where ox correlates with Edd, LLAGN exhibit nearly constant or weakly correlated ox values, suggesting a shift
in accretion physics and photon production mechanisms in low-luminosity regimes. These results underscore the importance of a
multiwavelength approach in AGN studies and reveal distinct behaviors in LLAGN compared to quasars. Our findings significantly
advance our understanding of LLAGN and oer a comprehensive framework for future research to complete the AGN population
census.
