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Rapid Centroids and the Refined Position Accuracy of the Swift Gamma-ray Burst CatalogueThe Swift X-ray Telescope autonomously refines the Burst Alert Telescope positions (approx.1-4' uncertainty) to better than 5 arcsec, within 5 seconds of target acquisition by the observatory for typical bursts. The results of the rapid positioning capability of the XRT are presented here for both known sources and newly discovered GRBs, demonstrating the ability to automatically utilize one of two integration times according to the burst brightness, and to correct the position for alignment offsets caused by the fast pointing performance and variable thermal environment of the satellite as measured by the Telescope Alignment Monitor. We present an evaluation of the position accuracy for both the onboard centroiding software and the ground software for the calibration targets and show that a significant improvement in position accuracy is obtained if the boresight detector position is optimized relative to the spacecraft pointing. Finally, we present an updated catalogue of Swift GRB X-ray positions obtained in Photon Counting Mode using the improved, calibrated boresight.
Document ID
20060012317
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Hill, J. E.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Angelini, L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Moretti, A.
(Osservatorio Astronomico di Brera Merate, Italy)
Morris, D. C.
(Pennsylvania State Univ. University Park, PA, United States)
Racusin, J.
(Pennsylvania State Univ. University Park, PA, United States)
Burrows, D. N.
(Pennsylvania State Univ. University Park, PA, United States)
Beardmore, A. P.
(Leicester Univ. United Kingdom)
Campana, S.
(Osservatorio Astronomico di Brera Merate, Italy)
Capalbi, M.
(Italian Space Agency Frascati, Italy)
Kennea, J. A.
(Pennsylvania State Univ. University Park, PA, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Astrophysics
Meeting Information
Meeting: SWIFT Maryland Conference
Location: Washington, DC
Country: United States
Start Date: November 29, 2005
End Date: December 2, 2005
Funding Number(s)
CONTRACT_GRANT: PPA/Z/S/2003/00507
CONTRACT_GRANT: NCC5-637
CONTRACT_GRANT: NAS5-00136
CONTRACT_GRANT: I/R/039/04
Distribution Limits
Public
Copyright
Public Use Permitted.
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