Unveiling Obscured Accretion in the Local Universe

Abstract Heavily obscured active galactic nuclei (AGNs), especially Compton-thick sources with line-of-sight column density ( N H,los ) > 10 24 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 N H,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 N H,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 N H,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 (log N H ≳ 23.5 cm −2 ), the latter provides improved accuracy, particularly for Compton-thin to moderately thick regimes (log N H ≲ 23.5 cm −2 ).