Highly Variable Active Galactic Nuclei in the SRG/eROSITA Sky Survey: II. Spectroscopic Identification of Sources with Russian Telescopes

We present the results of our spectroscopic identification of nine highly variable X-ray sources detected by the eROSITA telescope of the SRG observatory during its all-sky survey and published in the first paper of this series (the complete sample consists of 49 objects; Medvedev et al. 2022). For our observations we used the BTA, SAI25, AZT-33IK, and RTT-150 telescopes. One of the objects has turned out to be a cataclysmic variable, and another one has already been known previously as a tidal disruption event. The remaining seven objects have turned out to be active galactic nuclei (AGNs) at redshifts from 0.035 to 0.523. For four objects we have estimated the mass of the central black hole from the width and luminosity of the broad H $$\alpha$$ line component. These black holes have turned out to be moderately massive: from $${\sim}8\times 10^{6}$$ to $${\sim}10^{8}$$ $$M_{\odot}$$ .