TITLE:   GCN CIRCULAR
NUMBER:  29886
SUBJECT: GRB 210422A: Swift detection of a burst
DATE:    21/04/22 23:07:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

E. Troja (NASA/GSFC/UMCP), C. Gronwall (PSU), A. Y. Lien (GSFC/UMBC)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:

At 17:47:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210422A (trigger=1044678). Due to an observing constraint,
Swift did not slew immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 21.139, +42.110 which is 
   RA(J2000) = 01h 24m 33s
   Dec(J2000) = +42d 06' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, 
including systematic uncertainty). The BAT light curve showed a 
single pulse structure with a duration of about 5 sec.  
The peak count rate was ~1000 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 2021 June 4. There will thus be no XRT or UVOT data
for this trigger before this time. 

Burst Advocate for this burst is E. Troja (eleonora.troja 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/)