TITLE:   GCN CIRCULAR
NUMBER:  20583
SUBJECT: GRB 170203A: Swift detection of a burst
DATE:    17/02/03 00:13:29 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. L. Racusin (NASA/GSFC), A. Cholden-Brown (PSU),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:

At 00:03:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170203A (trigger=736432).  Swift could not slew to the burst
due to the Sun observing constraint. 
The BAT on-board calculated location is 
RA, Dec 332.860, +25.173 which is 
   RA(J2000) = 22h 11m 26s
   Dec(J2000) = +25d 10' 24"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 40 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~4 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 01:25 UT on 2017 April 10. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is J. L. Racusin (judith.racusin 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/too.html.)