TITLE:   GCN CIRCULAR
NUMBER:  29529
SUBJECT: GRB 210218A: Swift detection of a burst
DATE:    21/02/18 13:45:55 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

B. Sbarufatti (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and
K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 13:35:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210218A (trigger=1033328).  Swift did not slew 
immediately due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 47.291, +35.287 which is 
   RA(J2000) = 03h 09m 10s
   Dec(J2000) = +35d 17' 14"
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 30 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Moon observing constraint, Swift cannot slew to the BAT
position until 11:37 UT on 2021 February 20. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is B. Sbarufatti (bxs60 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/)