Unveiling Obscured Accretion in the Local Universe

Heavily obscured active galactic nuclei (AGNs), especially Compton-thick sources with line-of-sight column density (NH,los) > 1024 cm−2, are critical to understanding supermassive black hole growth and the origin of the cosmic X-ray background. However, their observed fraction remains significantly below model predictions, due to strong absorption bias, even in the hard X-ray (i.e., above 10 keV) band. We analyze a sample of 26 nearby (z < 0.1) AGNs from the Swift-BAT 150 month catalog, selected via mid-IR to X-ray diagnostics and observed with NuSTAR and soft X-ray telescopes (XMM-Newton, Chandra, or Swift-XRT). Using self-consistent torus models (MyTorus, Borus02, and UXCLUMPY), we aim to constrain NH,los, the average torus column density, and other geometrical parameters of the obscuring medium. A comparative analysis among the three torus models showed that while estimates of NH,los were generally in agreement, Borus02 tended to classify a slightly larger number of sources as Compton-thick AGNs. Building on this comparison, we benchmark two prediction schemes—a mid-IR/X-ray relation and a multivariate analysis model—against our broadband best-fit NH,los measurements to assess which approach more effectively bridges the gap between predicted and measured obscuration. We find that while the former works effectively in the heavily obscured region (logNH ≳ 23.5 cm−2), the latter provides improved accuracy, particularly for Compton-thin to moderately thick regimes (logNH ≲ 23.5 cm−2).