S. L. Gibson (U Leicester), A. Y. Lien (GSFC/UMBC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:
At 04:23:54 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160412A (trigger=682522). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 33.107, -67.645 which is
RA(J2000) = 02h 12m 26s
Dec(J2000) = -67d 38' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
peak structure with a duration of about 80 sec. The peak count rate
was ~1800 counts/sec (15-350 keV), at ~13 sec after the trigger.
The XRT began observing the field at 04:25:13.5 UT, 78.8 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 33.0482, -67.6266 which is equivalent to:
RA(J2000) = +02h 12m 11.57s
Dec(J2000) = -67d 37' 35.8"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 104 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 9.17e-09 erg cm^-2 s^-1 (0.2-10
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 90 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 S. L. Gibson (slg44 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.)