Duration Versus Brightness of Gamma-Ray Bursts: Comparisons Between SIGNE and BATSE

Kargatis, V. E., Li, H., Liang, E. P., Smith, I. A., Hurley, K., Barat, C., & Niel, M.

We analyze duration and brightness distributions of both the SIGNE Venera 13 and 14 and Burst and Transient Source Experiment (BATSE) gamma-ray burst databases. Choosing T_50 as a measure of the burst duration and using both 64 and 1024 ms peak count rates, we search for correlations between duration, peak brightness, and the ratio V = C_64/C_1024, proposed as a measure of variability by Lamb, Graziani, & Smith. The duration histogram for SIGNE shows a long-duration peak that is consistent with BATSE, but does not exhibit the short population, instead appearing flat below 0.6 s; the difference is presumably caused by the failure of SIGNE to detect the short, faint bursts that were observed by BATSE. Estimating the instantaneous brightness by C_64, we find that SIGNE confirms the BATSE result that the long and short bursts have similar maximum instantaneous brightnesses. Scatter-plots between duration, brightness, and V are consistent for both databases; we show that SIGNE confirms the BATSE observation that there is a lack of bursts that are both bright over 1024 ms and contain a short, bright spike.

Status: 1994, ApJ, 421, L83.

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