SIMBAD references

Photometric CCD observations (V, R, and I) of Seyfert 1 galaxy Markarian 335 (Mrk 335) were carried out from 1994 to 2001. During this monitoring period, the source was generally quiescent, but possible microvariation was found for 1999 November 20. If a hot spot on the accretion disk was responsible for this microvariation, then there is probably a supermassive black hole of around 3x10⁷ M_☉at the center of the source. The historical light curve from 1974 to 2000 was also compiled, and a possible period of 6.3 yr was found using the Jurkevich method.