Related papers: Long GRBs from binary stars: runaway, Wolf-Rayet p…
The origin of Gamma-Ray Bursts is one of the most interesting puzzles in recent astronomy. During the last decade a consensus formed that long GRBs (LGRBs) arise from the collapse of massive stars and that short GRBs (SGRBs) have a…
We model the late evolution and mass loss history of rapidly rotating Wolf-Rayet stars in the mass range $5\,\rm{M}_{\odot}\dots 100\,\rm{M}_{\odot}$. We find that quasi-chemically homogeneously evolving single stars computed with enhanced…
There is strong evidence that long duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the Collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN)…
It is now accepted that long duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. The standard "collapsar" model predicts that a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies every…
There is mounting evidence for the binary nature of the progenitors of gamma-ray bursts (GRBs). For a long GRB, the induced gravitational collapse (IGC) paradigm proposes as progenitor, or "in-state", a tight binary system composed of a…
Within the framework of star formation in starburst galaxies undergoing interactions, connections among the red quasars, the BL Lacs, and the Blazars with the gamma-ray bursts are discussed in the light of the "hypernovae" scenario. It is…
Gamma-ray bursts (GRBs) are luminous and violent phenomena in the universe. Traditionally, long GRBs are expected to be produced by the collapse of massive stars and associated with supernovae. However, some low-redshift long GRBs have no…
Over the past decade our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (T < 2 s) GRBs are associated with the explosive…
Recent comparative observations of long duration gamma-ray bursts (LGRBs) and core collapse supernovae (cc SN) host galaxies demonstrate that these two, highly energetic transient events are distributed very differently upon their hosts.…
In the collapsar model for common gamma-ray bursts, the formation of a centrifugally supported disk occurs during the first $\sim$10 seconds following the collapse of the iron core in a massive star. This only occurs in a small fraction of…
Recently much work in Gamma-Ray Burst (GRB) studies was devoted to revealing the nature of outburst mechanism and to looking for GRB progenitors. Several types of progenitors were proposed for GRBs. Most promising objects are collapsars,…
A diverse range of phenomena is possible when a black hole experiences very rapid accretion from a disk due to the incomplete explosion of a massive presupernova star endowed with rotation. In the most extreme case, the outgoing shock fails…
After presenting a short history of gamma-ray burst (GRB) studies, we discuss the current constraints on GRB models which follows from astronomical observations. We concentrate on the energetics of the GRBs with known redshifts and the…
We study the scenario where the gamma-ray bursts (GRBs) arise from core-collapse of very massive stars in star-forming regions in the starburst galaxies at high redshift. The bimodial structure of the gamma-ray bursts point to their…
We consider a scenario for the longest duration gamma ray bursts, resulting from the collapse of a massive rotating star in a close binary system with a companion black hole. The primary black hole born during the core collapse is first…
The observational diversity of ``gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic…
Recent stellar evolutionary calculations of low-metallicity massive fast-rotating main-sequence stars yield iron cores at collapse endowed with high angular momentum. It is thought that high angular momentum and black hole formation are…
We study gravitational radiation from various proposed gamma-ray burst (GRB) progenitor models, in particular compact mergers and massive stellar collapses. These models have in common a high angular rotation rate, and the final stage…
It is now generally accepted that long-duration gamma ray bursts (GRBs) are due to the collapse of massive rotating stars. The precise collapse process itself, however, is not yet fully understood. Strong winds, outbursts, and intense…
Growing observational evidence supports the proposition that gamma-ray bursts (GRBs) are powered by relativistic jets from massive helium stars whose cores have collapsed to black holes and an accretion disk (collapsars). We model the…