TITLE:   GCN CIRCULAR
NUMBER:  9173
SUBJECT: GRB 090417B Correction to the BAT refined analysis position
DATE:    09/04/20 17:04:26 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy, H. A. Krimm (GSFC/USRA),
B. Sbarufatti(INAF-IASFPA), P.A. Evans (U. Leicester)
on behalf of the Swift team

We wish to make a correction to the reported analysis of the
extremely long-duration burst GRB 090417B (GCN circ #9135,
Sbarufatti et al.).

The position in the BAT refined-analysis circular (GCN circ #9139,
Cummings et al.) was based on the results of an automated script, 
which was unable to find the optimum imaging interval due to the 
unusual length of this burst.  Thus the reported position was not 
the best BAT ground-calculated position. The best position is 
RA, Dec 209.687 +47.015, which is:

RA (J2000)    13h 58m 44.8s
Dec (J2000)   47d 00m 55s

with an error radius of ~1 arcmin. This position is 0.35 arcmin 
from the XRT refined position (GCN circ #9155, Sbarufatti et al.).

We are grateful to those who noticed the discrepancy, and regret 
any confusion resulting from this error. Any corrections to other 
BAT refined-analysis items (which are expected to be slight), such 
as to the spectral index, will appear in the final Swift Team 
report on this burst.