The Swift observatory was placed into low-Earth orbit on November 20, 2004 to detect gamma ray bursts. Gamma ray bursts (GRBs) are the most powerful explosions taking place in the Universe. Everyday a gamma-ray bursts occurs somewhere in the Universe, lasting between a few milliseconds and a few hundred seconds. Scientists are still unsure what causes these massive explosions. Swift was designed with three instruments to help answer questions about the origin of gamma-ray bursts by observing in the gamma ray, x-ray, ultraviolet, and optical wavebands. It is the first of multi-wavelength observatory devoted to gamma-ray burst science. With the aid of Swift, scientists hope to determine the origin of GRBs, classify GRBs, determine the evolution of the blastwave, study the early universe, and perform the first sensitive hard X-ray survey of the sky.
Named after the agile bird, the Swift observatory was designed to quickly maneuver its three instruments so that it can relay the location of gamma-ray bursts within seconds of an explosion. Ground-based and space-based telescopes can use this information to observe the bursts’ afterglows. The development of the hardware on the observatory was the result of an international collaboration between the United States, the United Kingdom, Italy, France, Japan, Germany, Denmark, Spain and South Africa.
When a gamma-ray burst occurs, Swifts Burst Alert Telescope (BAT) determines its location within 10 seconds. This location is fed to both ground observers and the other two instruments on Swift, the X-Ray Telescope (XRT) and the Ultra Violet/Optical Telescope (UVOT). Within 60 seconds the XRT is able to refine the location of the burst and within 200 seconds the UVOT refines the location with even more accuracy. While the XRT and UVOT are refining the position of the burst the BAT obtains a picture of how the gamma-ray burst evolves over time. Within 20 minutes the XRT obtains a picture of the gamma-ray burst in the x-ray wavelength. Within 2 hours the UVOT obtains a picture of the burst in the ultraviolet wavelength. These three observations provide scientists with a clear picture of the evolution of gamma-ray bursts in three wavelengths.
Swift not only disseminates gamma-ray bursts’ positions, it also can upload burst locations detected by other telescopes. The observatory’s agility allows it to perform rapid observations of bursts found by other telescopes. Over its two year life span, Swift is expected to perform the most comprehensive study to date of GRBs, by observing more than 200 GRBs.