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S. D. Hunsberger, P. W. A. Roming, P. F. Altimore, T. S. Koch, J. A. Nousek (Swift Explorer Project / PSU), K. O. Mason (MSSL / UCL)
The Swift Explorer mission, scheduled for launch in 2003, will be the first-of-its-kind observatory for multi-wavelength studies of gamma-ray bursts (GRBs) and other transient phenomena. The observatory consists of three co-aligned telescopes which operate at 10-150keV, 0.2-10keV, and 170-650nm. The primary goal of the mission is to determine the nature of GRBs: what kinds of objects are GRB progenitors and what can we learn about the astrophysical processes involved? Crucial to achieving this goal is the study of x-ray and optical afterglows which is why the Swift mission has been designed to perform multi-wavelength observations of GRBs rapidly and without intervention by ground operations.
The autonomous nature of the mission not only provides unique opportunities, but also presents some interesting challenges. Within 50 seconds of a GRB detection by the Burst Alert Telescope (BAT), the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) will begin their collection of data for afterglow studies. As part of the UVOT flight software, we will include a wide selection of automated observing sequences. However, during initial operations, we plan to execute a ``standard'' GRB observing sequence. So ... is there a single observing sequence which optimally utilizes the capabilities of UVOT and achieves our science goals? Using observational data on GRBs and their optical afterglows, as well as predictions of theoretical models, we simulate the observational characteristics of possible GRB populations which might be detected during Swift's three-year mission. These simulated populations are then input into the UVOT science simulator which will run through various observing sequences and produce the expected science data (e.g. finding chart, images, light curves, spectra). Here we present the results-to-date of simulations based on different observing strategies.
Funding for this project is provided by NASA grant NAS5-00136.