2024/07/20 by Meng-Hua Chen, Li‐Xin Li, Chen, Meng-Hua +3
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2407.14762
openalex publication_date 2024/07/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The observation of a kilonova AT2017gfo associated with the gravitational wave event GW170817 provides the first strong evidence that neutron star mergers are dominant contributors to the production of heavy r-process elements. Radioactive gamma-ray lines emitted from neutron star merger remnants provide a unique probe for investigating the nuclide composition and tracking its evolution. In this work, we studied the gamma-ray line features arising from the radioactive decay of heavy nuclei in the merger remnants based on the r-process nuclear reaction network and the astrophysical inputs derived from numerical relativity simulations. The decay chain of 12650Sn (T1/2=230 kyr) → 12651Sb (T1/2=12.35 days) → 12652Te (stable) produces several bright gamma-ray lines with energies of 415, 667, and 695 keV, making it the most promising decay chain during the remnant phase. The photon fluxes of these bright gamma-ray lines reach ∼10-5 γ cm-2 s-1 for Galactic merger remnants with ages less than 100~kyr, which can be detected by the high energy resolution MeV gamma-ray detectors like the MASS mission.