eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
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Έχει επεξεργασθεί από τον/την 2012 στις 05.03.10 10:41, 4 φορές συνολικά | |
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
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eleheart
Αριθμός μηνυμάτων : 235
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eleheart
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Έχει επεξεργασθεί από τον/την 2012 στις 14.05.10 11:55, 2 φορές συνολικά | |
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
| | Θέμα: Απ: .:. 2012 .:. 14.05.10 11:41 | |
| Black Holes Eating Stars May Form Gamma Ray Bursts An artistic illustration of a gamma ray burst. Source: NASA/Swift/Mary Pat Hrybyk-Keith and John Jones They are some of the most massive explosions of energy in our universe, gamma ray bursts are powerful jets of energy that scientists are still trying to adequately explain. Their energy is in the form of high energy x-rays and gamma rays (thus the name). In recent years, many astrophysicists have come to believe that they were the powerful energy rays unleashed when a massive star collapses into a black hole, although the mechanism is still not fully understood. Still other possibilities, though. One alternative explanation, presented originally back in the 1990's, has resurfaced in a new paper by Maxim Barkov at the University of Leeds, UK, and Serguei Komissarov of the Space Research Institute in Moscow. This explanation involves a black hole falling into the star and devouring it from the inside out. In the words of the papers' authors, from the abstract: In this paper, we re-examine the close binary scenario allowing for the possibility of late development of accretion disks in the collapsar model and investigate the available range of mass accretion rates, black hole masses, and spins. A particularly interesting version of the binary progenitor involves merger of a WR star with an ultra-compact companion, neutron star or black hole. In this case we expect the formation of very long-lived accretion disks, that may explain the phase of shallow decay and X-ray flares observed by Swift. Similarly long-lived magnetic central engines are expected in the current single star models of LGRB progenitors due to their assumed exceptionally fast rotation. The paper explains how this model can explain the X-ray flares observed shortly after gamma ray bursts begin, which are not explained by many of the other models. It remains to be seen if this model can also explain the other features of gamma ray burst behavior.  | |
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
| | Θέμα: Απ: .:. 2012 .:. 14.05.10 11:54 | |
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eleheart
Αριθμός μηνυμάτων : 235
Registration date : 03/03/2010
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