2006/04/21 by F. Hammer, H. Flores, D. Schaerer +5 · 4 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astronomy #Astrophysics #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Mitochondrial Function and Pathology #Physics #Star cluster #Star formation #Stars #Supernova #Wolf–Rayet star #astro-ph
paper · pdf · doi:10.1051/0004-6361:20064823
(1) GEPI, Observatoire de Paris-Meudon, France, (2) Observatoire de Geneve, Switzerland, (3) Laboratoire d'Astrophysique Toulouse-Tarbes, France,(4) Steward Observatory, University of Arizona, USA
arxiv created 2006/04/21 · openalex publication_date 2006/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We have obtained deep spectroscopic observations of several nearby gamma-ray burst (GRB) host galaxies revealing for the first time the presence of Wolf-Rayet (WR) stars and numerous O stars located in rich and compact clusters or star forming regions. Surprisingly, high spatial resolution imaging shows that the GRBs and the associated supernovae did not occur in these regions, but several hundreds of parsec away. Considering various scenarios for GRB progenitors, we do not find any simple explanation of why they should be preferentially born in regions with low stellar densities. All the examined GRBs and associated SNe have occurred 400 to 800 pc from very high density stellar environments including large numbers of WR stars. Such distances can be travelled through at velocities of 100 km s-1 or larger, assuming the travel time to be the typical life time of WR stars. It leads us to suggest that GRB progenitors may be runaway massive stars ejected from compact massive star clusters. The ejection from such super star clusters may lead to a spin-up of these stars, producing the loss of the hydrogen and/or helium envelopes leading to the origin of the type Ibc supernovae associated with GRBs. If this scenario applies to all GRBs, it provides a natural explanation of the very small fraction of massive stars that emit a GRB at the end of their life. An alternative to this scenario could be a binary origin for GRBs, but this still requires an explanation of why it would preferentially occur in low stellar density regions.