Optical Variability Studies of the Galaxy Mrk 6 (IC 450)

In this work, the light curve of the Seyfert galaxy Mrk 6 constructed from photometric observations in the B, V, and Rc filters over the period from 5 April 2016 to 1 February 2026 is presented and analyzed. Over the entire monitoring interval (2016–2026), the variability amplitude of the light curve reaches ΔB=1.9 mag, ΔV=1.5 mag, and ΔRc=1.4 mag. During 2024–2026, the galaxy exhibits synchronous photometric variability in the B, V, and Rc filters with an amplitude of ∼0.3 mag. The study also uses spectroscopic observations obtained on 15 and 22 November 2025 and 16 February 2026 at the Shamakhy Astrophysical Observatory (Azerbaijan), as well as on 9 January 2026 at the Fesenkov Astrophysical Institute (Kazakhstan). The fluxes of the Hβ emission line were calibrated using the [O III] λ5007 Å line, ensuring consistent relative calibration of the spectral data. The radius of the broad-line region RBLR was taken to be equal to the average time delays (lags), amounting to ≈20 light-days for the Hβ line and ≈28 light-days for the Hα line.