A Systematic Search for Active Galactic Nuclei Obscuration Variability in the Chandra Archive
Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Vittoria Elvezia Gianolli et autres
Abstract The nature of the obscuring material in active galactic nuclei (AGN) can be studied by measuring changes in the line-of-sight column density, N H,LOS , over time. This can be accomplished by monitoring AGN over long periods of time and at …