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Non-Isotropic Angular Distribution for Very Short-Time Gamma-Ray Bursts

David B. Cline·C. Matthey·S. Otwinowski
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Abstract

While most gamma-ray bursts (GRBs) are now believed to be from cosmological distances, the origin of very short-time GRBs is still not known. In the past, we have shown that GRBs with time duration (T90) less than 100 ms may form a separate class of GRBs based on the hardness and time distribution of these events. We have also shown that the ln N ln S distribution is consistent with the expectation of quasi-Euclidean distribution of sources. In this paper, we report the study of the angular location of these GRBs showing a strong deviation from isotropy within the Galactic coordinates of plus 180 degrees < longitude < 90 degrees and -30 degrees < latitude < 30 degrees. We have studied the rest of the GRBs and do not find a similar deviation. This further indicates that the very-short GRBs likely form a separate class of GRBs, most probably from sources of Galactic or near solar origin.

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David B. Cline, C. Matthey, S. Otwinowski. 2001-05-03. Non-Isotropic Angular Distribution for Very Short-Time Gamma-Ray Bursts. https://doi.org/10.1007/10853853_14

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