Showing papers by "Chang-Hwan Lee published in 1999"
TL;DR: In this paper, the authors suggest that high-mass black holes can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common envelope evolution which begins only after the massive core has finished He core burning.
50 citations
TL;DR: In this paper, a black hole is orbited by a precessing accretion disk that is fed by a neutron star, and gamma rays are produced in a highly collimated beam via the Blandford-Znajek mechanism.
Abstract: We present a phenomenological model to explain the light curves of gamma-ray bursts. In the model, a black hole is orbited by a precessing accretion disk that is fed by a neutron star. Gamma rays are produced in a highly collimated beam via the Blandford-Znajek mechanism. The gamma-ray beam sweeps through space because of the precession of the slaved accretion disk. The light curve expected from such a precessing luminosity cone can explain the complex temporal behavior of observed bright gamma-ray bursts.
44 citations
TL;DR: In this paper, the 2.11-and 5.15-MeV states were assigned tentatively by angular distribution measurements, as 2{sup +} and 3{sup {minus}, respectively.
Abstract: The {sup 20}Ne(p,t)h{sup 18}Ne reaction has been studied in order to investigate the properties of {sup 18}Ne excited states. A missing 3{sup +} state of {sup 18}Ne, which could have a great influence on the {sup 17}F(p,{gamma})h{sup 18}Ne reaction rate, was searched for, but the existence of this state was not clearly verified. The spins and parities of the 5.11- and 5.15-MeV states were assigned tentatively by angular distribution measurements, as 2{sup +} and 3{sup {minus}}, respectively. We were able to resolve the doublets at 4.5, 5.1, and 6.3 MeV clearly for the first time due to our high precision system, which allowed us to determine the widths of some critical states above the proton threshold of {sup 18}Ne more precisely. {copyright} {ital 1999} {ital The American Physical Society}
15 citations
TL;DR: In this paper, a model for the dilepton yield from a quark gluon plasma was developed, which explains the observed considerable enhancement of the yield in the low mass region.
15 citations
TL;DR: In this article, a transport model study of kaon production and flow in heavy-ion collisions at SIS energies is presented, and the effects of the kaon in-medium properties extracted from heavy ion data on neutron star properties are discussed.
5 citations
TL;DR: In this article, a phenomenological model is presented to explain the light curves of gamma-ray bursts, where gamma-rays are produced in a narrow beam which sweeps through space due to the precession of a slaved accretion disc.
Abstract: A phenomenological model is presented to explain the light curves of gamma-ray bursts. Gamma-rays are produced in a narrow beam which sweeps through space due to the precession of a slaved accretion disc. The light curve expected from such a precessing luminosity cone can explain the complex temporal behavior of bright gamma-ray bursts.
5 citations
TL;DR: In this article, the authors analyzed the γγ → ππ, KK, ηη, πη reactions through S = 2 GeV, using the master formula approach to QCD with three flavors.
5 citations
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TL;DR: In this article, the authors suggest that high-mass black holes can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common envelope evolution which begins only after the massive core has finished He core burning.
Abstract: We suggest that high-mass black holes; i.e., black holes of several solar masses, can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common envelope evolution which begins only after the massive star has finished He core burning. Our evolution scenario naturally explains the gap (low probability region) in the observed black hole masses.
4 citations
Posted Content•
TL;DR: In this article, the authors used binary stellar evolution to argue that binaries with at least one black hole dominate the rate of compact-object mergers and two phenomena generally attributable to such mergers, gamma-ray bursts and gravity-wave bursts, are therefore likely to originate from near the event horizon of a black hole.
Abstract: We use recent results in binary stellar evolution to argue that binaries with at least one black hole dominate the rate of compact-object mergers. Two phenomena generally attributable to such mergers, gamma-ray bursts and gravity-wave bursts, are therefore likely to originate from near the event horizon of a black hole. In addition to sheer numbers, black holes have an added advantage over neutron stars in both phenomena. For gamma-ray bursts, the presence of an event horizon eases the baryon pollution problem, because energy can be stored into rotation until most baryons have been swallowed, and then released into a cleaner environment via the Blandford-Znajek process. For gravity-wave bursts, black holes offer higher luminosities due to their higher masses, thus enabling detection out to larger distances, which leads to a 30-fold increase in the predicted LIGO event rate.
2 citations
TL;DR: In this article, a gamma ray burst was used to power a Type Ib supernova (SN) and showed that there is evidence both that the black hole was spun up by accretion and that there was a supernova explosion.
Abstract: We suggest Nova Sco 1994 (GRO 1655-40) as a possible relic of a Gamma Ray Burster (GRB) and Type Ib supernova (SN) explosion, showing that there is evidence both that the black hole was spun up by accretion and that there was a supernova explosion. We use the disc energy delivered from the rotational energy of the black hole to power the SN, and give arguments that roughly equal energy goes into the GRB and into the accretion disc to power the supernova.