Detectability of GRB Optical Afterglows with Gaia Satellite

With the launch of the Gaia satellite, detection of many different types of transient sources will be possible, with one of them being optical afterglows of gamma-ray bursts (GRBs). Using the knowledge of the satellite's dynamics and properties of GRB optical afterglows, we performed a simulation in order to estimate an average GRB detection rate with Gaia. Here, we present the simulation results for two types of GRB optical afterglows, differing in the observer's line of sight compared with a GRB jet axis: regular (on-axis) and orphan afterglows. Results show that for on-axis GRBs, less than 10 detections in 5 yr of foreseen Gaia operational time are expected. The orphan afterglow simulation results are more promising, giving a more optimistic number of several tens of detections in 5 yr.