B.P. Gompertz (U Leicester), J. R. Cummings (NASA/UMBC),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Swift Team:
At 07:18:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 141031A (trigger=617110). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 128.599, -59.138 which is
RA(J2000) = 08h 34m 24s
Dec(J2000) = -59d 08' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed one peak with a
duration of about 20 sec. The peak count rate was ~1437 counts/sec
(15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 07:20:05.5 UT, 98.9 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 128.60808, -59.16815 which is
RA(J2000) = 08h 34m 25.94s
Dec(J2000) = -59d 10' 05.3"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 109 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 (2.17 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 2.4
(+2.45/-2.14) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 102 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 0.17.
Burst Advocate for this burst is B.P. Gompertz (bpg6 AT le.ac.uk).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)