R. Caputo (GSFC), M. G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB),
P. D'Avanzo (INAF-OAB), S. Dichiara (PSU),
R. A. J. Eyles-Ferris (U Leicester), M. Ferro (INAF-OAB),
J.D. Gropp (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII),
H. A. Krimm (NSF), A. Y. Lien (U Tampa), K. L. Page (U Leicester),
D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII),
C. Salvaggio (INAF-OAB), A. Tohuvavohu (U Toronto) and
M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift
At 20:06:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 221202A (trigger=1142997). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 77.095, -59.806 which is
RA(J2000) = 05h 08m 23s
Dec(J2000) = -59d 48' 21"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single peak
structure with a duration of about 20 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 20:07:48.2 UT, 97.6 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 77.08221,
-59.83213 which is equivalent to:
RA(J2000) = 05h 08m 19.73s
Dec(J2000) = -59d 49' 55.7"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 96 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 https://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 2.11
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 101 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.
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
Burst Advocate for this burst is R. Caputo (regina.caputo AT nasa.gov).
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/)