TITLE: GCN GRB OBSERVATION REPORT NUMBER: 277 SUBJECT: GRB990316: simultaneous optical observation DATE: 99/03/18 03:27:59 GMT FROM: Hye-Sook Park at LLNL H.S. Park, L. Ott, R. Porrata (LLNL), G. Williams, D. Hartmann (Clemson Univ.) report on behalf of the LOTIS collaboration: LOTIS obtained realtime images of GRB990316 (BATSE Trigger 7475). LOTIS started recording the first image 13.6 sec after the burst (on the rising edge of the GRB light curve). The first image was taken with a 30 s integration time, thus this image completely overlapped the remainder of the GRB gamma-ray emission which lasted a total of ~40 sec. The first image from one of our 4 cameras (each with 8.8 x 8.8 deg field of view) covers > 98% of the BATSE 3 sigma (0.3 deg statistical + 1.6 deg systematic) error circle. The GRB location is further constrained by an annulus derived from IPN data (GCN/IPN notice) that passes through the BATSE error circle in the image. We searched for optical transients in this image by 1) comparing background images taken at later times and 2)comparing the stellar objects in the image with objects in the Guide Star Catalog and Digital Sky Survey images. We found one transient object at RA=147.54, DEC=-4.95 (J2000) near the edge of the IPN annulus with V~12.5 brightness. This object was seen only in the first image. No object is seen in the DSS image at this location. The second image was started after the gamma ray emission was over (at 55 sec after the start of the burst). We cannot rule out the possibility that this OT is a local effect rather than associated with the gamma ray burst. However, we encourage follow up observations at this location for possible afterglow observations. Further analysis is in progress and associated data will be placed on our web page.