Simulations of the OzDES AGN Reverberation Mapping Project

TL;DR

This paper simulates the OzDES reverberation mapping project to evaluate its efficiency in measuring black hole masses and the radius-luminosity relationship for quasars up to redshift 4, highlighting potential improvements.

Contribution

It provides a detailed simulation of the OzDES AGN reverberation mapping campaign, assessing its expected success rate and proposing enhancements to improve parameter constraints.

Findings

Expected lag recovery rate of 35-45%.

Shorter lags and higher variability increase detection likelihood.

Survey extensions can significantly improve $R-L$ relationship constraints.

Abstract

As part of the OzDES spectroscopic survey we are carrying out a large scale reverberation mapping study of $\sim$500 quasars over five years in the 30 deg$^2$ area of the Dark Energy Survey (DES) supernova fields. These quasars have redshifts ranging up to 4 and have apparent AB magnitudes between $16.8<r<22.5$ mag. The aim of the survey is to measure time lags between fluctuations in the quasar continuum and broad emission line fluxes of individual objects in order to measure black hole masses for a broad range of AGN and constrain the radius-luminosity ($R-L$) relationship. Here we investigate the expected efficiency of the OzDES reverberation mapping campaign and its possible extensions. We expect to recover lags for $\sim$35-45\% of the quasars. AGN with shorter lags and greater variability are more likely to yield a lag, and objects with lags $\lesssim$6 months or $\sim$1 year are expected be recovered the most accurately. The baseline OzDES reverberation mapping campaign is predicted to produce an unbiased measurement of the $R-L$ relationship parameters for H$\beta$, Mg II $\lambda$2798, and C IV $\lambda$1549. However, extending the baseline survey by either increasing the spectroscopic cadence, extending the survey season, or improving the emission line flux measurement accuracy will significantly improve the $R-L$ parameter constraints for all broad emission lines.