[vsnet-grb-info 13732] GRB 130727A: Swift-XRT and Swift-UVOT prompt observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15047
SUBJECT: GRB 130727A: Swift-XRT and Swift-UVOT prompt observations
DATE:    13/07/27 18:25:06 GMT
FROM:    Michael Stroh at PSU/Swift  <stroh at astroh.org>

M. C. Stroh and M. M. Chester (PSU) report on behalf of the Swift team:

Swift-XRT observed the field of GRB 130727A (Stroh et al., GCN Circ. 15046) starting 3484.5 s after the BAT trigger, due to an observing constraint. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA,Dec = 330.7994, -65.5387 (degrees) which is equivalent to:

RA  (J2000.0) = 22 03 11.85
DEC (J2000.0) = -65 32 19.5

with an uncertainty of 2.5 arcsec (radius, 90% containment). This location is 130.7 arcseconds from the BAT onboard position, inside the BAT error circle.

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, MNRAS, 397, 1177).

UVOT took a finding chart exposure of 150 seconds with the White filter starting 3494 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03.