Revisiting a Quasar Microlensing Event Towards AGN~J1249+3449

TL;DR

This paper investigates whether a transient optical bump observed in an AGN can be explained by gravitational microlensing, analyzing light curve data with multiple models to identify the lensing event and its properties.

Contribution

It demonstrates that the observed optical bump in AGN J1249+3449 can be explained by a microlensing event caused by a stellar-mass lens within the host galaxy.

Findings

The optical bump is consistent with a microlensing event.

The lens mass is estimated to be around 0.1 solar masses.

The analysis supports microlensing as an explanation for the transient feature.

Abstract

The gravitational wave event GW190521 seems to be the only BH merger event possibly correlated with an electromagnetic counterpart, which appeared about 34 days after the GW event. This work aims to confirm that the electromagnetic bump towards the Active Galactic Nucleus (AGN) J1249+3449 can be explained within the framework of the gravitational microlensing phenomenon. In particular, considering the data of the Zwicky Transient Facility (ZTF), what emerges from a detailed analysis of the observed light curve using three fitting models (Point Source Point Lens, Finite Source Point Lens, Uniform Source Binary Lens) is that the optical bump can be explained as a microlensing event caused by a lens with mass {$\sim\,$0.1 $M_{\odot}$}, lying in the host galaxy of the AGN in question.}