Broad Emission‐Line Variability in Markarian 335

Abstract

We present the results of 6 years of spectroscopic monitoring of the Seyfert 1 galaxy Mrk 335. Each year, the observations span 5¨7 months at a nominal sampling rate of one observation per week. Analysis of the spectroscopic observations shows clear coordinated variability in the continuum and in the broad Hb and He II j4686 emission lines. The principal goal of this monitoring program is to measure the time delay between the continuum variations and the corresponding responses of the broad Hb and He II emission lines. We derive time delays of D17 days for Hb and D2 days for He II. From the spectral time series we construct average, root mean square, and diUerence spectra, which show that the broad Hb variations are con—ned to the core of the broad emission lines, whereas the He II varia- tions take place across the full width of the pro—le. The He II emission line is about twice as broad as the Hb line. Comparison of the He II and Hb lags and line widths indicates that the BLR has a radially strati—ed ionization structure and that the highest velocity gas is closest to the continuum source. We also —nd no evidence for correlation between the line pro—le variations and the continuum and emission- line —ux variations, as has been found in other cases. Rather, the line pro—le variations seem to imply dynamical changes in the BLR. Subject headings: galaxies: activegalaxies: individual (Markarian 335) ¨ galaxies: Seyfert