Searching for electromagnetic emission in an AGN from the gravitational wave binary black hole merger candidate S230922g

Tomás Cabrera; Antonella Palmese; Lei Hu; Brendan O'Connor; K. E. Saavik Ford; Barry McKernan; Igor Andreoni; Tomás Ahumada; Ariel Amsellem; Malte Busmann; Peter Clark; Michael W. Coughlin; Ekaterine Dadiani; Veronica Diaz; Matthew J. Graham; Daniel Gruen; Keerthi Kunnumkai; Jake Postiglione; Julian S. Sommer; Francisco Valdes

arXiv · 2407.10698

Searching for electromagnetic emission in an AGN from the gravitational wave binary black hole merger candidate S230922g

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Abstract

We carried out long-term monitoring of the LIGO/Virgo/KAGRA binary black hole (BBH) merger candidate S230922g in search of electromagnetic emission from the interaction of the merger remnant with an embedding active galactic nuclei (AGN) accretion disk. Using a dataset primarily composed of wide-field imaging from the Dark Energy Camera (DECam) and supplemented by additional photometric and spectroscopic resources, we searched ~ 70% of the sky area probability for transient phenomena, and discovered 6 counterpart candidates. One especially promising candidate - AT 2023aagj - exhibited temporally varying asymmetric components in spectral broad line regions, a feature potentially indicative of an off-center event such as a BBH merger. This represents the first live search and multiwavelength, photometric, and spectroscopic monitoring of a GW BBH optical counterpart candidate in the disk of an AGN.

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Tomás Cabrera, Antonella Palmese, Lei Hu, Brendan O'Connor, K. E. Saavik Ford, Barry McKernan, Igor Andreoni, Tomás Ahumada, Ariel Amsellem, Malte Busmann, Peter Clark, Michael W. Coughlin, Ekaterine Dadiani, Veronica Diaz, Matthew J. Graham, Daniel Gruen, Keerthi Kunnumkai, Jake Postiglione, Julian S. Sommer, Francisco Valdes. 2024-07-15. Searching for electromagnetic emission in an AGN from the gravitational wave binary black hole merger candidate S230922g. https://arxiv.org/abs/2407.10698

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