On Reverberation Mapping Lag Uncertainties

TL;DR

This paper investigates how systematic errors affect the uncertainty estimates of reverberation mapping lag measurements using JAVELIN and ICCF methods, highlighting their robustness and limitations under various error conditions.

Contribution

It provides a comparative analysis of systematic error impacts on two popular reverberation mapping methods, emphasizing JAVELIN's generally better error estimation and identifying conditions that cause significant issues.

Findings

JAVELIN generally yields more accurate error estimates than ICCF.

Both methods are robust against changes in the stochastic process and transfer function.

Significant problems arise if the line lightcurve contains additional variability sources.

Abstract

We broadly explore the effects of systematic errors on reverberation mapping lag uncertainty estimates from {\tt JAVELIN} and the interpolated cross-correlation function (ICCF) method. We focus on simulated lightcurves from random realizations of the lightcurves of five intensively monitored AGNs. Both methods generally work well even in the presence of systematic errors, although {\tt JAVELIN} generally provides better error estimates. Poorly estimated lightcurve uncertainties have less effect on the ICCF method because, unlike {\tt JAVELIN}, it does not explicitly assume Gaussian statistics. Neither method is sensitive to changes in the stochastic process driving the continuum or the transfer function relating the line lightcurve to the continuum. The only systematic error we considered that causes significant problems is if the line lightcurve is not a smoothed and shifted version of the continuum lightcurve but instead contains some additional sources of variability.