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| Paper: |
Signature of Kerr Black Holes in Time Profiles of GRBs |
| Volume: |
312, Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era |
| Page: |
106 |
| Authors: |
McBreen, S.; McBreen, B.; Hanlon, L.; Duggan, P. |
| Abstract: |
The cumulative light curves of gamma ray bursts (GRBs) were obtained by summing the BATSE counts. For most GRBs the slope of the cumulative light curve is approximately constant over a large fraction of the burst. However in 19 out of 398 GRBs with duration (T90) > 2 s, the cumulative light curve was found to increase with time as ~ t². The non-linear sections last for a substantial fraction of the GRB duration, have a large proportion of the cumulative count and many resolved pulses that usually end with the highest pulse in the burst. The reverse behaviour was found in 11 GRBs where the running light curve decreased with time and some bursts are good mirror images of the increases. These GRBs are among the spectrally hardest bursts observed by BATSE. The most likely interpretation is that these effects are signatures of black holes that are either being spun up or down in the accretion process. In the spin up case, the increasing Kerr parameter of the black hole allow additional rotational and gravitational energy to become available for extraction. The process is reversed if the black hole is spun down by magnetic field torques. The luminosity changes in GRBs are consistent with the spin up / spin down predictions of the BZ process and neutrino annihilation. GRBs provide a new window for studying the general relativistic effects of Kerr black holes. |
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