A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He lambda 4686 broad emission line relative to the optical continuum to be 2.7 +/- 0.6 days and the lag in the H beta lambda 4861 broad emission line to be 13.9 +/- 0.9 days. Combined with the line width, the He II lag yields a black hole mass M-BH = (2.6 +/- 0.8) x 10(7) M-circle dot. This measurement is consistent with measurements made using the H beta lambda 4861 line, suggesting that the He II emission originates in the same structure as H beta, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.