GRB 980425

Abstract

J. S. Bloom, California Institute of Technology (CIT); D. Frail, National Radio Astronomy Observatory; and S. R. Kulkarni, CIT, report on behalf of the CIT gamma-ray burst team: ``Using the 2.54-m reflector at Las Campanas, S. Vogel and M. Regan obtained V, R, and I images of the field of GRB 980425 (IAUC 6884) near the presumed supernova discovered by Galama et al. (IAUC 6895, 6898). Using the secondary standards of Lidman et al. (IAUC 6895), we determine that the transient has continued to brighten, with the following derived magnitudes (+/- 0.05): May 8.311 UT, V = 13.87; 8.306, R = 13.84; 8.309, I = 13.98. The error comes predominately from the zero-point uncertainty. The contribution to the flux from a nearby star about 4’'.9 to the northwest and the host galaxy is negligible (< 0.02 mag). A composite light curve from published fluxes can be obtained at h ttp://astro.caltech.edu/åisebox-0.5ex jsb/ltcu rve_980425.ps. It is still unclear as to the connection between the presumed supernova and GRB 980425. In order to correlate the time of both, an accurate light curve must be obtained.’’

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