Skip navigation tools.

• Home
• Quick Look
• Data Archive
• Data Analysis

• About Swift
• GCN
• Swift Results
• Links

---

XRT position for GRB 090515 enhanced by UVOT field astrometry

Related pages: Burst Analyser | Light curve | Spectrum | Download obs data | SPER analysis

RA (J2000):	10 56 36.11
Dec (J2000):	+14 26 30.3
90% Error radius:	2.6"
Number of overlaps included in position:	1
Exposure time in final position:	2254 s
Total number of overlaps considered:	18
Total overlap time:	8786 s
Number of overlaps where no X-ray source was found:	17
Number of low-X-ray-count fits rejected:	0
Number of spurious fits rejected:	0
Number of bad astrometric corrections:	0
Number of outliers removed:	0

For details of how these positions are produced, and why some positions are rejected, see the online documentation.

All enhanced positions

GCN E-mail

The following paragraphs should be used to announce this position in a GCN circular:

Using 2254 s of XRT Photon Counting mode data and 1 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching to the USNO-B1 catalogue): RA, Dec = 164.1505, 14.4417 which is equivalent to:

RA (J2000): 10 56 36.11
Dec (J2000): +14 26 30.3

with an uncertainty of 2.6 arcsec (90% confidence).

This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, arXiv:0812.3662).

Final Position

The image below shows the UVOT field with the final, astrometrically corrected XRT refined position. The image is 50" to a side, and contains 890 s of data in the WHITE filter.

---

Individual Frame Positions

The final position (magenta) is the weighted mean of 1 positions (green). A further 0 positions were rejected, either because they had too few photons to be secure (red) or because they are more than 3 sigma away from the mean position, more than 40" from the early mean, or had a problematic astrometric correction (yellow). The image is 50" to a side.