Rms-flux relation in the optical fast variability data of BL Lacertae object S5 0716+714

TL;DR

This study investigates the presence of a linear rms-flux relation in the optical variability data of BL Lac S5 0716+714, finding it occurs infrequently and that the flux distribution is not log-normal, informing models of AGN variability.

Contribution

It provides the first systematic analysis of rms-flux relation in optical IDV data of BL Lac objects, challenging assumptions about flux distribution and variability mechanisms.

Findings

Less than 8% of cases show a significant rms-flux relation.

Flux distribution is not log-normal with high confidence.

Results inform the debate on the origin of optical IDV in AGNs.

Abstract

The possibility that BL Lac S5 0716+714 exhibits a linear root mean square (rms)-flux relation in its IntraDay Variability (IDV) is analysed. The results may be used as an argument in the existing debate regarding the source of optical IDV in Active Galactic Nuclei. 63 time series in different optical bands were used. A linear rms-flux relation at a confidence level higher than 65% was recovered for less than 8% of the cases. We were able to check if the magnitude is log-normally distributed for eight timeseries and found, with a confidence > 95%, that this is not the case.