TITLE:   GCN CIRCULAR
NUMBER:  8120
SUBJECT: Swift Trigger 321481: A Large Flare from SGR 0501+4516
DATE:    08/08/23 05:16:41 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

H. A. Krimm (CRESST/GSFC/USRA), D. M. Palmer (LANL), M. Perri (ASDC),
B. Preger (ASDC), M. Stamatikos (NASA/ORAU) and L. Vetere (PSU)
report on behalf of the Swift Team:

At 04:47:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a large flare from the newly-discovered SGR 0501+4516 
(GCN 8113, Barthelmy et al.; trigger=321481).  Swift was pointed 
at the source at the time of the outburst. 
The BAT on-board calculated location is 
RA, Dec 75.270, +45.278 which is 
   RA(J2000) = 05h 01m 05s
   Dec(J2000) = +45d 16' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single spike
of duration < 0.128 sec with a second smaller spike 0.5 sec later.  
The peak count rate was ~175000 counts/sec (15-350 keV), 
at ~0 sec after the trigger.  There is no obvious 'ringing'
at the SGR's rotation frequency following the burst, but this
may be found in further analysis. 

Because this was identified onboard as a known source,
it did not result in a GRB response with XRT and UVOT data
immediately available through TDRSS.  However, both instruments
were observing the source at the time of the flare, and will return
data through Malindi.