OzDES Reverberation Mapping Program: H$\beta$ lags from the 6-year survey

TL;DR

This paper reports six-year reverberation mapping measurements of Hβ in active galactic nuclei, extending the redshift range and refining the R-L relation, which is crucial for black hole mass estimation and cosmology.

Contribution

First multi-object reverberation mapping survey providing Hβ lag measurements at higher redshifts, improving the R-L relation accuracy and consistency with previous studies.

Findings

Recovered reverberation lags for 8 AGN at 0.12<z<0.71

Measured R-L relation slope of 0.41±0.03

Intrinsic scatter of 0.23±0.02 dex

Abstract

Reverberation mapping measurements have been used to constrain the relationship between the size of the broad-line region and luminosity of active galactic nuclei (AGN). This $R-L$ relation is used to estimate single-epoch virial black hole masses, and has been proposed for use to standardise AGN to determine cosmological distances. We present reverberation measurements made with H$\beta$ from the six-year Australian Dark Energy Survey (OzDES) Reverberation Mapping Program. We successfully recover reverberation lags for eight AGN at $0.12<z< 0.71$, probing higher redshifts than the bulk of H$\beta$ measurements made to date. Our fit to the $R-L$ relation has a slope of $\alpha=0.41\pm0.03$ and an intrinsic scatter of $\sigma=0.23\pm0.02$ dex. The results from our multi-object spectroscopic survey are consistent with previous measurements made by dedicated source-by-source campaigns, and with the observed dependence on accretion rate. Future surveys, including LSST, TiDES and SDSS-V, which will be revisiting some of our observed fields, will be able to build on the results of our first-generation multi-object reverberation mapping survey.