2003/11/30 by Bing Zhang, Xinyu Dai, Nicole Lloyd-Ronning +3 · 3 citations
Physics and Astronomy · #Afterglow #Astrophysics #Astrophysics and Cosmic Phenomena #Detector #Gamma-ray burst #Gamma-ray bursts and supernovae #Jet (fluid) #Mechanics #Optics #Physics #Population #Pulsars and Gravitational Waves Research #Solid angle #astro-ph
paper · pdf · doi:10.1086/382132
published as Astrophys.J. 601 (2004) L119-L122 · emulateapj style, 6 pages, 2 figures, accepted for publication in ApJ Letters
arxiv created 2003/12/16 · openalex publication_date 2004/01/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
An observed correlation E p ∝ ( E iso ) 1/2 extending from gamma-ray bursts (GRBs) to X-ray flashes (XRFs) poses problems both for a power-law universal jet model, in which the energy per solid angle decreases as the inverse square of the angle with respect to the jet axis, and for a conical jet model with a uniform energy density within the jet beam and a sharp energy cutoff at the jet edge. Here we show that the current GRB-XRF prompt emission/afterglow data can be understood in terms of a picture in which the GRB-XRF jets are quasi-universal and structured, with a Gaussian-like or similar structure, i.e., one where the jet has a characteristic angle, with a mild variation of energy inside and a rapid (e.g., exponential) decrease of energy outside of it. A Monte Carlo simulation shows that the current data is compatible with such a quasi-universal Gaussian jet with a typical opening angle of 5.7 deg and with a standard jet energy of about log( E j /1 erg) = 51.1 ± 0.3. According to this model, the true-to-observed number ratio of the whole GRB-XRF population is about 14 with the current instrumental sensitivity.