A reverberation lag for the high-ionization component of the broad-line region in the narrow-line seyfert 1Mrk 335

Abstract

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 IIλ4686 broad emission line relative to the optical continuum to be 2.7 ± 0.6days and the lag in the Hβλ4861 broad emission line to be 13.9 ± 0.9days. Combined with the line width, the He II lag yields a black hole mass M BH = (2.6 ± 0.8) × 107 M ⊙. This measurement is consistent with measurements made using the Hβλ4861 line, suggesting that the He II emission originates in the same structure as Hβ, 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. © 2012. The American Astronomical Society. All rights reserved.