LSST AGN SC Cadence Note: Two metrics on AGN variability observable

TL;DR

This paper introduces two metrics to evaluate LSST's ability to measure AGN variability, demonstrating that denser cadences improve measurement reliability with minimal performance differences across cadences.

Contribution

The paper develops new metrics for AGN variability observables and assesses LSST OpSim cadences, extending previous work to include AGN variability analysis.

Findings

Denser cadences yield more reliable AGN variability measurements.

Differences between cadences are minor according to Kullback-Leibler divergence.

Metrics extend previous DCR and SF analyses to AGN variability.

Abstract

We have developed two metrics related to AGN variability observables (time-lags, periodicity, and Structure Function (SF)) to evaluate LSST OpSim FBS 1.5, 1.6, 1.7 performance in AGN time-domain analysis. For this purpose, we generate an ensemble of AGN light curves based on AGN empirical relations and LSST OpSim cadences. Although our metrics show that denser LSST cadences produce more reliable time-lag, periodicity, and SF measurements, the discrepancies in the performance between different LSST OpSim cadences are not drastic based on Kullback-Leibler divergence. This is complementary to Yu and Richards results on DCR and SF metrics, extending them to include the point of view of AGN variability.