A Tentative Size-Luminosity Relation for the Iron Emission-Line Region in Quasars

TL;DR

This paper presents new reverberation mapping data for the iron emission-line region in quasars, proposing a tentative size-luminosity relation that suggests similar physics to other broad emission lines.

Contribution

It provides the first measurements of the size of the iron emission-line region and proposes a size-luminosity relation based on new data.

Findings

The iron emission-line region size is comparable to the Hβ line.

The size-luminosity relation for iron lines is similar to other broad lines.

The formation physics of iron blends may be similar to other emission lines.

Abstract

New reverberation mapping measurements of the size of the optical iron emission-line region in quasars are provided, and a tentative size-luminosity relation for this component is reported. Combined with lag measurements in low-luminosity sources, the results imply an emission-region size that is comparable to and at most twice that of the H$\beta$ line, and is characterized by a similar luminosity dependence. This suggests that the physics underlying the formation of the optical iron blends in quasars may be similar to that of other broad emission lines.