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arXiv · 0906.1268

Survival analysis of the Swift optical transient data

L. G. Balazs·I. Horvath·Zs. Bagoly·A. Meszaros
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Abstract

In a systematic search of the OTs at GRBs the Swift satellite determined only an upper limit of the apparent brightness in a significant fraction of cases. Combining these upper limits with the really measured OT brightness we obtained a sample well suited to survival analysis. Performing a Kaplan-Meier product limit estimation we obtained an unbiased cumulative distribution of the V visual brightness. The lg(N(V)) logarithmic cumulative distribution can be well fitted with a linear function of V in the form of lg(N(V))= 0.234 V + const. We studied the dependence of V on the gamma ray properties of the bursts. We tested the dependence on the fluence, T90 duration and peak flux. We found a dependence on the peak flux on the 99.7% significance level.

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L. G. Balazs, I. Horvath, Zs. Bagoly, A. Meszaros. 2009-06-06. Survival analysis of the Swift optical transient data. https://doi.org/10.1393/ncb%2Fi2007-10282-1

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