Goad 2007 用UVOT精确定位暴的位置

主要内容:
提出了一中方法，在早期用UVOT精确定位暴的位置。

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文章信息:
Accurate early positions for Swift GRBS: enhancing X-ray positions with UVOT astrometry

Authors: M.R. Goad (1) et al

Abstract: Here we describe an autonomous way of producing more accurate prompt XRT positions for Swift-detected GRBs and their afterglows, based on UVOT astrometry and a detailed mapping between the XRT and UVOT detectors. The latter significantly reduces the dominant systematic error -- the star-tracker solution to the World Coordinate System. This technique, which is limited to times when there is significant overlap between UVOT and XRT PC-mode data, provides a factor of 2 improvement in the localisation of XRT refined positions on timescales of less than a few hours. Furthermore, the accuracy achieved is superior to astrometrically corrected XRT PC mode images at early times (for up to 24 hours), for the majority of bursts, and is comparable to the accuracy achieved by astrometrically corrected X-ray positions based on deep XRT PC-mode imaging at later times (abridged).

Comments:	12 pages, 8 figures, 1 table, submitted to Astronomy and Astrophysics, August 7th 2007
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0708.0986v1 [astro-ph]