Changing-Look AGNs -- I. Tracking the transition on the main sequence of quasars

Understand

This paper is the first in a series of preparing and analyzing spectral and other properties for a database of already discovered Changing-Look active galactic nuclei (CL AGNs).

• Here, we focus on the spectral fitting and analysis of broad emission lines in a sample of 93 CL AGNs collected from the literature with existing SDSS/BOSS/eBOSS spectroscopy where the H$\beta$ emission line profile does not completely disappear in any epochs.
• Additionally, we have gathered older/newer spectral epochs from all the available SDSS data releases to make the database more complete.
• We use PyQSOFit and perform a homogeneous spectral decomposition of all of our SDSS spectra and tabulate the AGN continuum and emission line properties per epoch per source, chronologically.