The X-ray spectrum is essential for studying the central engines of Active Galactic Nuclei (AGN), as X-rays originate close to the black hole, are less affected by absorption, and are easier to isolate than optical or UV emissions. The primary X-ray emission is believed to result from Comptonization of optical/UV photons in a hot corona, and is further modified by absorption and reflection from nearby or distant material. A persistent feature called the soft X-ray excess, observed below 2 keV, has been observed for decades and is common in type 1 AGN, yet its origin remains uncertain. AGN also show strong X-ray variability, which helps in probing the physical processes involved.
This project aims to investigate the nature of the variable soft excess using data from Swift, XMM-Newton, and Chandra. Several models will be tested, ranging from simple blackbody fits to more advanced ones involving warm Comptonization and ionized reflection. The goal is to characterize source variability, compare nearby AGN, and assess data from X-ray catalogs for broader analysis in future projects.
