TITLE:   GCN CIRCULAR
NUMBER:  23688
SUBJECT: GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart
DATE:    19/01/14 21:17:08 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),
H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC),
M. J. Moss (George Washington University), D. M. Palmer (LANL),
B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 20:57:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190114C (trigger=883832).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 54.510, -26.939 which is 
   RA(J2000) = 03h 38m 02s
   Dec(J2000) = -26d 56' 18"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a very bright
multi-peaked structure with a total duration of about 25 sec.  The
peak count rate was ~200000 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 20:58:07.1 UT, 64.0 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 54.5068, -26.9467 which is equivalent to:
   RA(J2000)  = 03h 38m 1.63s
   Dec(J2000) = -26d 56' 48.1"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 29 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 0.1 s image was 7.39e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 73 seconds after the BAT trigger. There is a
candidate afterglow in  the rapidly available 2.7'x2.7' sub-image. We
can not provide a refined position due to a failed aspect correction. 
The estimated magnitude is 15.60 with a 1-sigma error of about  0.02. 
No correction has been made for the expected extinction corresponding
to E(B-V) of 0.01. 

Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 
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.)