2012/05/30 by L. Izzo, Izzo, L., R. Ruffini +16 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Solar and Stellar Astrophysics (astro-ph.SR) #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.1205.6651
7 pages, 10 figures, submitted to ApJ
arxiv created 2012/05/30 · openalex publication_date 2012/05/30 · arxiv updated 2012/05/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Following the recent theoretical interpretation of GRB 090618 and GRB 101023, we here interpret GRB 970828 in terms of a double episode emission: the first episode, observed in the first 40 s of the emission, is interpreted as the proto-black-hole emission; the second episode, observed after t0+50 s, as a canonical gamma ray burst. The transition between the two episodes marks the black hole formation. The characteristics of the real GRB, in the second episode, are an energy of Etote+e- = 1.60 × 1053 erg, a baryon load of B = 7 × 10-3 and a bulk Lorentz factor at transparency of Γ= 142.5. The clear analogy with GRB 090618 would require also in GRB 970828 the presence of a possible supernova. We also infer that the GRB exploded in an environment with a large average particle density <n> ≈ 103 part/cm3 and dense clouds characterized by typical dimensions of (4 - 8) × 1014 cm and δn/n ∝ 10. Such an environment is in line with the observed large column density absorption, which might have darkened both the supernova emission and the GRB optical afterglow.