Afterglows from Binary Neutron Star Postmerger Systems Embedded in Active Galactic Nuclei Disks

Journal Article · 27 August 2024 · The Astrophysical Journal

DOI: https://doi.org/10.3847/1538-4357/ad63a3 · OSTI ID:2438393

Kathirgamaraju, Adithan ; Li, Hui ; Ryan, Benjamin R. ; Tchekhovskoy, Alexander

Abstract The observability of afterglows from binary neutron star mergers occurring within active galactic nuclei (AGN) disks is investigated. We perform 3D GRMHD simulations of a postmerger system and follow the jet launched from the compact object. We use semianalytic techniques to study the propagation of the blast wave powered by the jet through an AGN disk-like external environment, extending to distances beyond the disk scale height. The synchrotron emission produced by the jet-driven forward shock is calculated to obtain the afterglow emission. The observability of this emission at different frequencies is assessed by comparing it to the quiescent AGN emission. In the scenarios where the afterglow could temporarily outshine the AGN, we find that detection will be more feasible at higher frequencies (≳10 ¹⁴ Hz) and the electromagnetic counterpart could manifest as a fast variability in the AGN emission, on timescales less than a day.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: 89233218CNA000001; AC02-05CH11231
• OSTI ID: 2438393
• Report Number(s): LA-UR--23-31757
• Journal Information: The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 1 Vol. 972; ISSN 0004-637X
• Publisher: American Astronomical SocietyCopyright Statement
• Country of Publication: United States
• Language: English