New Constraints on Simultaneous Optical Emission from Gamma-Ray Bursts Measured by the Livermore Optical Transient Imaging System Experiment

LOTIS is a gamma-ray burst optical counterpart search experiment located near Lawrence Livermore National Laboratory in California. Since operations began in 1996 October, LOTIS has responded to five triggers as of 1997 July 30, which occurred during good weather conditions. GR-B 970223 (BATSE trigger 6100) was an exceptionally strong burst, lasting approx. 30 s with a peak at approx. 8 s. LOTIS began imaging the error box approx. 11 s after the burst began and achieved simultaneous optical coverage of 100% of the region enclosed by the BATSE 3 sigma error circle and the interplanetary network annulus. No optical transients were observed brighter than the m{}_{V} approx.11 completeness limit of the resulting images, providing a new upper limit on the ratio of simultaneous optical to gamma-ray fluence of R-{L) less than 1.1 x 10 logical and {-4} and on the ratio of simultaneous optical (at 700 mn) to gamma-ray (at 100 keV) flux density of R-{F} less than 305 for a B-type spectrum and R-{F} less than 475 for an M-type spectrum.