Rapid centroids and the refined position accuracy of the Swift gamma-ray burst catalogue

J. E. Hill, L. Angelini, A. Moretti, D. C. Morris, J. Racusin, D. N. Burrows, A. P. Beardmore, S. Campana, M. Capalbi, J. A. Kennea, J. P. Osborne, C. Pagani, G. Tagliaferri, G. Chincarini, N. Gehrels, A. Wells, J. A. Nousek

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Swift X-ray Telescope autonomously refines the Burst Alert Telescope positions (∼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 utilise 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 optimised 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.

Original languageEnglish (US)
Title of host publicationGAMMA-RAY BURSTS IN THE SWIFT ERA
Subtitle of host publicationSixteenth Maryland Astrophysics Conference
Pages297-300
Number of pages4
DOIs
StatePublished - May 19 2006
EventGAMMA-RAY BURSTS IN THE SWIFT ERA: 16th Maryland Astrophysics Conference - Washington, D.C., United States
Duration: Nov 29 2005Dec 2 2005

Publication series

NameAIP Conference Proceedings
Volume836
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherGAMMA-RAY BURSTS IN THE SWIFT ERA: 16th Maryland Astrophysics Conference
CountryUnited States
CityWashington, D.C.
Period11/29/0512/2/05

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Hill, J. E., Angelini, L., Moretti, A., Morris, D. C., Racusin, J., Burrows, D. N., Beardmore, A. P., Campana, S., Capalbi, M., Kennea, J. A., Osborne, J. P., Pagani, C., Tagliaferri, G., Chincarini, G., Gehrels, N., Wells, A., & Nousek, J. A. (2006). Rapid centroids and the refined position accuracy of the Swift gamma-ray burst catalogue. In GAMMA-RAY BURSTS IN THE SWIFT ERA: Sixteenth Maryland Astrophysics Conference (pp. 297-300). (AIP Conference Proceedings; Vol. 836). https://doi.org/10.1063/1.2207906