TY - JOUR
T1 - Hypernovae, collapsars, and gamma-ray bursts
AU - Hartmann, D. H.
AU - MacFadyen, A. I.
N1 - Funding Information:
Just as an accreting supermassive black hole can give rise to a variety of observational phenomena - blazars, BL-Lac objects, Seyferts, quasars, and radio galaxies - depending on the environ- ment in which the black hole finds itself and the viewing angle - a hyperaccret.ing stellar mass black hole can also be created in various ways and display various attributes. In a massive helimn star, the prompt formation of a black hole might make a classical GRB of typical duration 20 s. In a massive red supergiant star though, the result, might be an asymmetric supernova with anomalously large energy (SN 1997cy) and little or no accompanying GRB. In a helium star in which tile jet energy source is lost before the jet has had time to break through the surface one may get an intermediate case, a Type Ib supernova with a weak GRB. In a massive helium star in which the black hole forms over a longer period (owing to fallback in an otherwise successful supernova), a long GRB could be made. Hyperaccreting holes can also be set up by the merger of compact objects and give rise to short, GRBs - or they could be set up by the merger of white dwarfs or helium stars with black holes and give long GRBs. Indeed, what we have traditionally called G1RBs may just be the leading edge of a collection of high energy phenomena whose diversity has yet to be fully sampled. Acknowledgements: Part. of this work has been supported by NASA (NAG5-2843 and MIT SC A292701) and the NSF lAST-97-31569). We acknowledge many helpful conversations with Chris Fryer, Bob Popham, and Stan Woosley. We thank Andi Fruchter and the HST GRB Team for providing the afterglow image of GRB990123, and the BATSE Team for providing public access to up-to-date GRB data, such as the angular distribution shown in Figure 1. A portion of this work was carried out at the Max Pianck Institute (MPI) for Astrophysics and the MPI for Extraterrestrial Physics (Garching, FRG), and we gratefully acknowledge the support, and hospitality of these two institutions.
PY - 2000/1
Y1 - 2000/1
N2 - Cosmic gamma-ray bursts now appropriately hold the distinction of being the "largest explosions in the universe". Their afterglows are often brighter than supernovae, thus often referred to as "hypernovae". Their kinetic energies may also be greater, or at least highly collimated, and require a new source of energy. Recent photometric and spectroscopic observations of the afterglow emission have provided a major breakthrough in our understanding of these powerful explosions. The data place at least some bursts at large distances and in association with faint host galaxies. But what is (or are) the underlying cause(s) of these violent events? The answer to this question remains uncertain, but several theoretical arguments point towards the creation of hyperaccreting black holes with accretion rates from 10-4 to 10 solar masses per second, whose accretion disks produce narrow jets of relativistically expanding plasma. We review the basic concepts of one of these models, the "collapsar model".
AB - Cosmic gamma-ray bursts now appropriately hold the distinction of being the "largest explosions in the universe". Their afterglows are often brighter than supernovae, thus often referred to as "hypernovae". Their kinetic energies may also be greater, or at least highly collimated, and require a new source of energy. Recent photometric and spectroscopic observations of the afterglow emission have provided a major breakthrough in our understanding of these powerful explosions. The data place at least some bursts at large distances and in association with faint host galaxies. But what is (or are) the underlying cause(s) of these violent events? The answer to this question remains uncertain, but several theoretical arguments point towards the creation of hyperaccreting black holes with accretion rates from 10-4 to 10 solar masses per second, whose accretion disks produce narrow jets of relativistically expanding plasma. We review the basic concepts of one of these models, the "collapsar model".
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U2 - 10.1016/S0920-5632(99)00835-X
DO - 10.1016/S0920-5632(99)00835-X
M3 - Article
AN - SCOPUS:0033633692
SN - 0920-5632
VL - 80
SP - 135
EP - 142
JO - Nuclear Physics B - Proceedings Supplements
JF - Nuclear Physics B - Proceedings Supplements
IS - 1-3
ER -