Follow up ability for GRB observations on Swift

Swift is the first satellite to autonomously select its own targets and slew to them. To test the ability of the narrow field of view instruments (NFIs) to follow up gamma ray burst (GRB) triggers, we simulate a series of randomly positioned bursts. This allows us to explore how the follow up observations of the NFIs will proceed. Each located burst in the simulation is followed by four hours without bursts, to allow for the NFIs to follow up the GRB triggers. We simulated 50 bursts that were triggered and located by the Burst Alert Telescope (BAT) and observed by the NFIs to probe the follow up parameter space. The discovery orbit (when the burst is first observed after the trigger) has NFI observation durations that are random in duration, while the average observation per full-orbit (the orbits after the discovery orbit) is approximately 2500 seconds, which would then take four full orbits to fulfill the autonomous observation requirement. The NFI observations can only begin after Swift has settled on the GRB's location, which takes about a hundred seconds. This average hundred seconds limits to rapid follow up observations by the NFIs, leaving the earliest optical observations to ground-based robotic telescopes.