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GCN Circular 19686

GRB 160712A: Swift-XRT observations
2016-07-12T21:28:03Z (8 years ago)
Phil Evans at U of Leicester <>
J.A. Kennea (PSU), G. Cusumano (INAF-IASF PA), M. Perri (ASDC), P.A.
Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows
(PSU) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 160712A at 20:47:52.7 UT,
3256.7 seconds after the BAT trigger. The position determined from
promptly downlinked data differs significantly from the on-board
position, suggesting that the XRT may have centroided on a cosmic ray;
the initial XRT position notice should be treated with caution. Using
promptly downlinked data we find an uncatalogued X-ray source with an
enhanced position: RA, Dec 304.1600, -26.9582 which is equivalent to:
   RA(J2000)  = 20h 16m 38.40s
   Dec(J2000) = -26d 57' 29.4"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 89 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (8.30 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.7
(+2.97/-2.55) x 10^21 cm^-2 (90% confidence).
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