Related papers: On the Progenitors of Collapsars
We present the evolution of rotation in models of massive single stars covering a wide range of masses and metallicities. These models reproduce very well observations during the early stages of the evolution (in particular WR populations…
The Collapsar model provides a theoretical framework for the well known association between long gamma-ray bursts (GRBs) and collapsing massive stars. A bipolar relativistic jet, launched at the core of a collapsing star, drills its way…
Millisecond magnetars produced in the center of dying massive stars are one prominent model to power gamma-ray bursts (GRBs). However, their detailed nature remains a mystery. To explore the effects of the initial mass, rotation rate, wind…
Most gamma-ray bursts are made during the deaths of massive stars. Here the environmental circumstances, stellar evolutionary paths, and explosion physics that might produce the bursts are reviewed. Neither of the two leading models -…
As a massive star evolves through multiple stages of nuclear burning on its way to becoming a supernova, a complex, differentially rotating structure is set up. Angular momentum is transported by a variety of classic instabilities, and also…
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,…
We discuss how rotation and binary interactions may be related to the diversity of type Ibc supernovae and long gamma-ray bursts. After presenting recent evolutionary models of massive single and binary stars including rotation, the…
Hypermassive neutron stars (HMNSs) -- equilibrium configurations supported against collapse by rapid differential rotation -- are possible transient remnants of binary neutron star mergers. Using newly developed codes for…
We present the results from a series of two-dimensional core-collapse simulations using a rotating progenitor star. We find that the convection in these simulations is less vigorous because a) rotation weakens the core bounce which seeds…
We investigate the structure and evolution of blue stragglers stars which were formed from direct stellar collisions between main sequence stars in globular clusters. In particular, we look at the rotational evolution of the products of…
The current generation of millimeter interferometers have revealed a population of compact (r <~ 0.1 pc), massive (M ~ 100 Msun) gas cores that are the likely progenitors of massive stars. I review models for the evolution of these objects…
We investigate the collapsar scenario for the long gamma ray bursts. The energetics % of explosions in the $\gamma$-ray band are consistent with the binding energy of a progenitor star. The events duration times, lightcurve profiles,…
It has been suggested that magnetic fields play a dynamically-important role in core-collapse explosions of massive stars. In particular, they may be important in the collapsar scenario for gamma-ray bursts (GRB), where the central engine…
It is now recognized that long-duration Gamma-Ray Bursts (GRBs) are linked to the collapse of massive stars, based on the association between (low-redshift) GRBs and (type Ic) core-collapse supernovae (SNe). The census of massive stars and…
The collapsar model explains the association of long duration gamma-Ray Bursts (GRBs) with stellar collapse. It involves a relativistic jet that forms at the core of a collapsing massive star. The jet penetrates the stellar envelope and the…
The rotation rate in pre-supernova cores is an important ingredient which can profoundly affect the post-collapse evolution and associated energy release in supernovae and long gamma ray bursts (LGRBs). Previous work has focused on whether…
We present self-similar solutions that describe the gravitational collapse of rotating, isothermal, magnetic molecular-cloud cores, relevant to the formation of rotationally supported protostellar disks. This work focuses on the evolution…
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…
The origin of ultra-intense magnetic fields on magnetars is a mystery in modern astrophysics. We model the core collapse dynamics of massive progenitor stars with high surface magnetic fields in the theoretical framework of a self-similar…
While there is mounting evidence that long Gamma-Ray Bursts (GRBs) are associated with the collapse of massive stars, the detailed structure of their pre-supernova stage is still debatable. Particularly uncertain is the degree of mixing…