Probing properties of nearly two-hundred new active galactic nuclei

We present a comprehensive analysis of the X-ray spectral properties of 198 newly identified active galactic nuclei (AGNs), leveraging archival data from the Chandra X-ray Observatory. All these AGNs exhibit a power-law spectral signature spanning a broad energy range of 0.5\!-\!7.0 keV, characterized by the photon index (Γ) values ranging from 0.3+0.16-0.14 to 2.54+0.14-0.13. Particularly, 76 of these AGNs display discernible levels of intrinsic absorption, after considering the Galactic absorption. The column densities associated with this local absorption (nHˡᵒᶜᵃˡ) are within a range of ~ 10¹⁹\!-\!10²²\ cm⁻². We study the cosmological evolution of AGNs using the variation of nHˡᵒᶜᵃˡ and Γ with their estimated redshift. The intrinsic spectral signature did not reveal any significant cosmological evolution; however, a deficit of hard sources at high redshift is possibly intrinsic. Our sample covers several orders of broad-band intrinsic luminosity (LBⁱⁿᵗʳ) ranging from 4.59+0.41-0.41 × 10⁴² to 2.4+0.12-0.12 × 10⁴⁶\, erg~s⁻¹ with peak at 1.84 redshift. We also investigate the hardness–luminosity diagram to further probe the AGNs. We conduct a sanity check by applying our findings to known AGNs, and the results are consistent with our observations.