TITLE:   GCN CIRCULAR
NUMBER:  15127
SUBJECT: IPN triangulation of GRB130821A
DATE:    13/08/28 17:00:07 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@ssl.berkeley.edu>

K. Hurley on behalf of the Mars Odyssey GRB team,

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, 
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

D. M. Smith, J. McTiernan, R. Schwartz, and W.
Hajdas, on behalf of the RHESSI GRB team, 

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of the Fermi
GBM team, report:

GRB 130821A, observed by the Fermi GBM (GCN 15113) and LAT (GCN 15115),
was also observed by Konus-Wind (GCN 15125), RHESSI, INTEGRAL SPI-ACS,
and Mars Odyssey-HEND.  We have triangulated it to an annulus centered
at RA(2000)=297.840 deg (19h 51m 22s)  Dec(2000)=-21.890 deg (-21d 53'
24"), whose radius is 18.673 +/- 0.049 deg (3 sigma).  The minimum
distance between the center of the LAT one sigma error circle (GCN
15115) and the IPN annulus center line is 0.266 degrees; the circle lies
entirely outside the annulus. The two Swift XRT sources reported by
Page et al. (GCN 15123) also lie outside the IPN annulus, and are
therefore unlikely to be associated with the GRB.  A map has been posted at
ssl.berkeley.edu/ipn3/130821.  

Only minor improvement in the IPN localization is possible.