EUROPEAN SPACE AGENCY

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

DOI: 10.1103/PhysRevD.110.123029 Bibcode: 2024PhRvD.110l3029C

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

United States, Germany, United Kingdom

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 and supplemented by additional photometric and spectroscopic resources, we searched ∼70% of the sky area probability for transient phenomena and discovered six 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 gravitational wave BBH optical counterpart candidate in the disk of an AGN.

2024 • Physical Review D
Gaia 11
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