Real-Time Optical Flux Limits From Gamma-Ray Bursts Measured By The GROCSE Experiment

The Gamma-Ray Optical Counterpart Search Experiment presents new experimental upper limits on the optical flux from gamma-ray bursts (GRBs). Our experiment consisted of a fully automated very wide-held opto-electronic detection system that imaged locations of GRBs within a few seconds of receiving trigger signals provided by BATSE's real-time burst coordinate distribution network. The experiment acquired 3800 observing hours, recording 22 gamma-ray burst triggers within similar to 30 s of the start of the burst event. Some of these bursts were imaged while gamma-ray radiation was being detected by BATSE. We identified no optical counterparts associated with gamma-ray bursts among these events at the m(V) similar to 7.0-8.3 sensitivity level. We find the ratio of the upper limit to the V-band optical flux, F-nu, to the gamma-ray fluence, Phi(gamma), from these data to be 1 x 10(-18) < F-nu/Phi(gamma) < 2 x 10(-16).