Quasar Microlensing Models with Constraints on the Quasar Light Curves

TL;DR

This paper evaluates the realism of quasar variability models in microlensing analyses by applying the damped random walk model to assess source variability likelihood, finding minimal impact on physical parameter estimates.

Contribution

It introduces the use of the DRW model to evaluate source variability likelihood in quasar microlensing analysis, demonstrating its limited effect on parameter estimation.

Findings

Applying the DRW likelihoods does not significantly change parameter estimates.

Unrealistic source light curve models are linked to poor microlensing fits.

The method helps assess the realism of quasar variability models.

Abstract

Quasar microlensing analyses implicitly generate a model of the variability of the source quasar. The implied source variability may be unrealistic yet its likelihood is generally not evaluated. We used the damped random walk (DRW) model for quasar variability to evaluate the likelihood of the source variability and applied the revised algorithm to a microlensing analysis of the lensed quasar RX J1131-1231. We compared the estimates of the source quasar disk and average lens galaxy stellar mass with and without applying the DRW likelihoods for the source variability model and found no significant effect on the estimated physical parameters. The most likely explanation is that unreliastic source light curve models are generally associated with poor microlensing fits that already make a negligible contribution to the probability distributions of the derived parameters.