S. R. Oates (UCL-MSSL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 03:36:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130211A (trigger=548276). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 147.523, -42.339 which is
RA(J2000) = 09h 50m 05s
Dec(J2000) = -42d 20' 18"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows several overlapping
peaks with a duration of about 20 sec. The peak count rate
was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 03:38:26.0 UT, 113.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 147.53605,
-42.34244 which is equivalent to:
RA(J2000) = 09h 50m 08.65s
Dec(J2000) = -42d 20' 32.8"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
location is 36 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 http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.16
x 10^21 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 7.98e-10 erg cm^-2 s^-1 (0.2-10
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 125 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 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
Results from the list of sources generated on-board are not available at this
time. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.54.
Burst Advocate for this burst is S. R. Oates (sro AT mssl.ucl.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.)