2023/12/05 by Yun Wang, Wang, Yun, Yujia Wei +9 · 2 citations
Physics and Astronomy · #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2312.02848
There are two classes of gamma-ray transients with a duration shorter than 2 seconds. One consists of cosmic short Gamma-Ray Bursts (GRBs) taking place in the deep universe via the neutron star mergers, and the other is the magnetar giant flares (GFs) with energies of ∼ 1044-1046 erg from ``nearby" galaxies. Though the magnetar GFs and the short GRBs have rather similar temporal and spectral properties, their energies (E\rm γ,iso) are different by quite a few orders of magnitude and hence can be distinguished supposing the host galaxies have been robustly identified. The newly observed GRB 231115A has been widely discussed as a new GF event for its high probability of being associated with M82. Here we conduct a detailed analysis of its prompt emission observed by Fermi-GBM, and compare the parameters with existing observations. The prompt gamma-ray radiation properties of GRB 231115A, if associated with M82, nicely follow the E\rm p,z-Eγ,\rm iso relation of the GFs, where E\rm p,z is the peak energy of the gamma-ray spectrum after the redshift (z) correction. To be a short GRB, the reshift needs to be ∼ 1. Though such a chance is low, the available X-ray/GeV observation upper limits are not stringent enough to further rule out this possibility. We have also discussed the prospect of convincingly establishing the magnetar origin of GRB 231115A-like events in the future.