DEEP OPTICAL COUNTERPART SEARCHES OF GAMMA-RAY BURST LOCALIZATIONS

We report the results of a 5 year CCD imaging program of small gamma-r ay burst (GRB) error boxes from the First Interplanetary Network and a n optical transient held The fields include GBS 0010-16, GBS 0552-08, GBS 1028 + 46, GBS 1205 + 23, GBS 1412 + 79, OTS 1809 + 31, GBS 2006-2 2, and GBS 2252-03. A total of 274 hours of open shutter time was used to obtain multiple UBVI-filtered frames covering an area approximatel y twice that of the 99% confidence localizations. For 2070 objects in these fields above the survey detection limit of V approximate to 24, 79,000 calibrated photometric measurements were made. The objectives o f the survey were to search for objects of unusual colors, variability , or proper motions. The final census of objects in these fields is co nsistent with the expected numbers of normal stars, galaxies, and prop er motion objects based on statistics of large-scale surveys. While no obvious GRB optical counterparts were found, several potentially inte resting objects were discovered, along with marginal evidence for a QS O excess at the rate of one per high Galactic latitude localization. T he results and implications are discussed in detail along with suggest ions for future work.