TITLE:   GCN CIRCULAR
NUMBER:  9839
SUBJECT: GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey
DATE:    09/08/25 19:12:25 GMT
FROM:    Antonio Copete at Harvard U  <acopete@head.cfa.harvard.edu>

A. Copete, J. Grindlay (Harvard)
S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC)

We hereby report confirmation of the Swift-BAT position of GRB 090823  
reported by Cummings et al. (GCN 9835, 9838), from an independent  
analysis of the BAT event-mode data done by the BAT Slew Survey  
(BATSS), in the slew that started at 16:10:02 UT and lasted 178 sec.  
The BATSS-calculated position is RA, Dec = 128.671, +60.641 deg, which  
is:

RA (J2000) =  08h 34m 41s
Dec(J2000) = +60d 38' 29"

with an uncertainty of 4.51 arcmin (90% confidence, including  
systematics). The burst was detected with a significance of 6.2 sigma  
and 6.7 sigma from imaging in the 15-50 keV and 15-150 keV energy  
bands, respectively. Consistent with the report in GCN 9835, the  
lightcurve in the slew data only spans a 15-sec trailing edge of the  
prompt emission of the burst before it fades into the background.