TITLE:   GCN CIRCULAR
NUMBER:  29601
SUBJECT: GRB 210306B: Swift detection of a burst
DATE:    21/03/06 09:54:05 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), K. L. Page (U Leicester) and
T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 09:32:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210306B (trigger=1036024).  Swift did not slew to the burst
because of Sun constraint.  The BAT on-board calculated location is 
RA, Dec 331.848, +10.175 which is 
   RA(J2000)  = 22h 07m 23s
   Dec(J2000) = +10d 10' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a few peaks
structure with a duration of at least 15 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew to this target. 
There will be no XRT or UVOT data. 

Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT inaf.it). 
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/)