Author: Yuji Urata
Abstract: We present the planned program for orphan GRB optical afterglow survey using the newly developed ultra-wide field-of-view camera Hyper-Suprime-Cam on the Subaru 8m telescope. Orphan GRB afterglow is thought to arise as a natural consequence of GRB jet. Hence the detection in optical and/or radio will be the direct evidence of the GRB jet. However, because of the limited sensitivity of current optical equipment, fewer than expected numbers of orphan GRBs have been detected. Two deep surveys (SDF and SXDS) were conducted using the current camera Suprime-Cam with Subaru. These data are powerful enough to search for the events. We summarize the results and introduce a planned survey using the newly developed Hyper-Suprime-Cam whose field-of view is 1.5 deg in diameter (10 times wider than that of Suprime-Cam) diameter on the Subaru telescope.