An Off-Axis Jet Model For GRB 980425 and Low-Energy Gamma-Ray Bursts

2003/06/30 by Ryo Yamazaki, Daisuke Yonetoku, Takashi Nakamura · 5 citations
Physics and Astronomy · #Astronomical and nuclear sciences #Astronomy and Astrophysical Research #Gamma-ray bursts and supernovae #astro-ph

paper · pdf · doi:10.1086/378736

published as Astrophys.J.594:L79-L82,2003 · 12 pages, 3 eps figures

openalex publication_date 2003/08/11 · arxiv created 2003/08/21 · arxiv updated 2009/12/01 · openalex created_date 2017/04/07 · openalex updated_date 2026/08/01

Abstract

Using a simple off-axis jet model of gamma-ray bursts (GRBs), we can reproduce the observed unusual properties of the prompt emission of GRB 980425, such as the extremely low isotropic equivalent γ-ray energy, the low peak energy, the high fluence ratio, and the long spectral lag when the jet with the standard energy of ~10 51 ergs and the opening half-angle of 10° ≲ Δθ ≲ 30° is seen from the off-axis viewing angle θ v ~ Δθ + 10γ -1 , where γ is a Lorentz factor of the jet. For our adopted fiducial parameters, if the jet that caused GRB 980425 is viewed from the on-axis direction, the intrinsic peak energy E p (1 + z ) is ~2.0-4.0 MeV, which corresponds to those of GRB 990123 and GRB 021004. We also discuss the connection of GRB 980425 in our model with the X-ray flash, and the origin of a class of GRBs with small E γ .

Citations

• X-Ray Flashes from Off-Axis Gamma-Ray Bursts
• Peak Luminosity–Spectral Lag Relation Caused by the Viewing Angle of the Collimated Gamma-Ray Bursts

Cited by

• A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X‐Ray Flashes
• Peak Energy-Isotropic Energy Relation in the Off-Axis Gamma-Ray Burst Model
• The Ep,i-Eiso correlation in gamma-ray bursts: updated observational status, re-analysis and main implications
• Does the Detection of X-Ray Emission from SN 1998bw Support Its Association with GRB 980425?
• Hypernova Signatures in the Late Rebrightening of GRB 050525A