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A sample of 18 long-lag (τlag > 1 s) gamma-ray bursts (GRBs) has been drawn from our catalog of all Swift long GRBs. Four different tests were done on this sample to test the prediction that a large fraction of long-lag GRBs are from our Local Supercluster. The results of these four tests reveal that: (1) the distribution of these GRBs shows no tendency toward the Supergalactic plane; (2) the distribution shows no tendency toward the Virgo or Coma Cluster; (3) no associated bright host galaxies (m ≤ 15) in the Local Supercluster are found for any of the 18 GRBs; (4) 17 of these 18 GRBs have redshifts of z > 0.5, which are too far to be in the Local Supercluster. All these results disproved the hypothesis that any significant fraction of long-lag GRBs are from Local Supercluster. Hence these long-lag GRBs cannot be counted in the calculation of LIGO detection rates. An explanation of why we can detect long-lag GRBs at high redshift is presented. © 2009. The American Astronomical Society. All rights reserved..

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Astrophysical Journal

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