BVR_cI_c light curves of GRB970508 optical remnant and magnitudes of underlying host galaxy

Abstract

The observations with the SAO-RAS 6-m telescope in July-August 1998 show that the GRB970508 optical remnant has varied very little since November 1997. We can conclude that we observe a proper host galaxy without the GRB optical remnant. The fitting results of the light curve of the GRB remnant plus the host galaxy until about 400 days after the primary event are reported here. The best $χ^2$-fits with a power law, for most of the filters used, are not acceptable. Some intrinsic variability of the GRB optical remnant fading is possible, which demands a more complex law presenting the largest multiband homogeneous data set from a single telescope.