A Reverberation Lag for the High-Ionization Component of the Broad Line Region in the Narrow-Line Seyfert 1 Mrk 335

TL;DR

This study measures the time delay of high-ionization emission lines in Mrk 335, revealing the size of the broad line region and estimating the black hole mass, marking the first such measurement for a narrow-line Seyfert 1 galaxy.

Contribution

It provides the first robust lag measurement for a high-ionization line in a narrow-line Seyfert 1 galaxy, linking emission region size to ionization level.

Findings

He II lag is 2.7 days, Hβ lag is 13.9 days.

Black hole mass estimated at 2.6 x 10^7 solar masses.

He II emission originates closer to the black hole than Hβ.

Abstract

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 galaxy Mrk 335, collected over a 120-day span in the fall of 2010. From these data we measure the lag in the He II 4686 broad emission line relative to the optical continuum to be 2.7 \pm 0.6 days and the lag in the H\beta 4861 broad emission line to be 13.9 \pm 0.9 days. Combined with the line width, the He II lag yields a black hole mass, MBH = (2.6 \pm 0.8)\times 10^7 Msun. This measurement is consistent with measurements made using the H\beta 4861 line, suggesting that the He II emission originates in the same region as H\beta, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in a narrow-line Seyfert 1 galaxy.