TITLE:   GCN CIRCULAR
NUMBER:  29748
SUBJECT: GRB 210403A: Swift detection of a burst
DATE:    21/04/03 08:40:22 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K. L. Page (U Leicester) and A. Y. Lien (GSFC/UMBC) report on behalf
of the Neil Gehrels Swift Observatory Team:

At 08:27:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210403A (trigger=1040345).  Swift did not slew immediately 
to the burst due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 2.767, -32.999 which is 
   RA(J2000) = 00h 11m 04s
   Dec(J2000) = -32d 59' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 140 sec.  The peak count rate
was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 21:34 UT on 2021 April 14. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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/)