2019/05/31 by Vikas Chand, Partha Sarathi Pal, Ankush Banerjee +4
Physics and Astronomy · #Afterglow #Astronomy and Astrophysical Research #Astrophysics #Cutoff #Fermi Gamma-ray Space Telescope #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Lorentz factor #Lorentz transformation #MAGIC (telescope) #Optics #Photon #Physics #Redshift #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/abb5fc
published as ApJ 903 9 (2020) · Revised and accepted for publication in the ApJ
arxiv created 2020/10/15 · openalex publication_date 2020/10/26 · arxiv updated 2020/11/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract GRB 190114C is an unusual gamma-ray burst (GRB) due to its detection at sub-TeV energies by MAGIC, seen at redshift z = 0.42. This burst is one of the brightest GRB detected by Fermi. A joint GBM-LAT analysis of the prompt emission reveals the presence of sub-GeV spectral cutoff when the LAT low-energy event (LLE) data is also examined. A similar high-energy cutoff was likewise reported in GRB 160509A and GRB 100724B earlier, as well as a handful of other sources. The cutoff can be explained by the intrinsic opacity due to pair production within the emitting region. GRB 190114C shows a transition from nonthermal to a quasi-thermal-like spectrum and a radiation component that can be attributed to afterglow. Based on spectral analysis, we constrain the site of the prompt emission and Lorentz factor. Knowing that sub-TeV photons are detected in MAGIC, we perceive that the observed spectrum is indeed an overlap from two emission sites, where the emission observed in Fermi is more consistent with prompt emission produced via photospheric dissipation along with a concurrent component from the external shock.