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

作者：Tomás Cabrera, A. Palmese, Lei Hu, Brendan O’Connor, K. E. Saavik Ford, Barry McKernan, Igor Andreoni, Tomás Ahumada, Ariel Amsellem, Malte Busmann, P. Clark, M. W. Coughlin, Ekaterine Dadiani, Verónica Marín Díaz, M. J. Graham, D. Gruen, Keerthi Kunnumkai, Jake Postiglione, A. Riffeser, Julian S. Sommer, F. Valdés · 发表于：Physical review. D/Physical review. D. · 年份：2024 · DOI：10.1103/physrevd.110.123029 · 被引用次数：24 · 研究领域：Pulsars and Gravitational Waves Research、Gamma-ray bursts and supernovae、Astrophysical Phenomena and Observations

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 $\ensuremath{\sim}70%$ 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.