On the Association of Gamma-Ray Bursts with Supernovae

The recent discovery of a supernova (SN 1998bw) seemingly associated withGRB~980425 adds a new twist to the decades-old debate over the origin ofgamma-ray bursts. To investigate the possibility that some (or all) bursts areassociated with supernovae, we performed a systematic search fortemporal/angular correlations using catalogs of BATSE and BATSE/{\it Ulysses}burst locations. We find no associations with any of the precise BATSE/{\itUlysses} locations, which allows us to conclude that the fraction ofhigh-fluence gamma-ray bursts from known supernovae is small ($<$0.2%). For themore numerous weaker bursts, the corresponding limiting fraction of 1.5% isless constraining due to the imprecise locations of these events. This limit($1.5% \simeq 18$ bursts) allows that a large fraction of the recent supernovaeused as a comparison data set (18 supernovae $\simeq 20%$) could haveassociated gamma-ray bursts. Thus, although we find no significant evidence tosupport a burst/supernova association, the possibility cannot be excluded forweak bursts.Comment: Re-Submitted to Astrophysical Journal Letters, 1998 Jul. 24, 10 pages, 1 figure, 2 tables; (3) marc.kippen@msfc.nasa.go