TITLE: GCN CIRCULAR NUMBER: 9864 SUBJECT: GRB 090831A: IPN Triangulation DATE: 09/09/02 04:31:29 GMT FROM: Valerie Connaughton at MSFC S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM team, K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, K. Makishima, and Y. Hanabata on behalf of the Suzaku-WAM team, M. Suzuki, A. Yoshida, N. Kawai, S. Nakahira, Y.E. Nakagawa, M. Kohama and M. Matsuoka on behalf of the MAXI team and A. von Kienlin, G. Lichti, A. Rau, and K. Hurley on behalf of the INTEGRAL SPI-ACS GRB team, report: GRB 090831A, reported in GCN 9850 (Rau) as Fermi/GBM trigger 273396998 / 090831317, and as a MAXI event in GCN 9852 (Matsuoka et al.), and as a Konus event in GCN 9861 (Golenetskii et al.), was also detected by Suzaku-WAM and INTEGRAL (SPI-ACS). We have triangulated this burst to a Konus-GBM annulus centered at RA(2000)=155.584 (10h 22m 20s) Dec(2000)=+3.772 (+3d 46' 21"), with a radius of 49.244 ± 0.177 deg (3 sigma). The Konus-WAM annulus is centered at RA(2000)=155.807 (10h 23m 14s) Dec=+3.771 (+3d 46' 16"), with a radius of 49.210 ± 0.249 deg (3 sigma). The Konus-SPI-ACS annulus is centered at RA(2000)=156.539 (10h 26m 09s) Dec(2000)=-3.361 (-3d 21' 41"), with radius of 56.520 ± 0.412 deg (3 sigma). A map is posted at http://www.ioffe.ru/LEA/GRBs/GRB090831_T27393/IPN/ showing the GBM best-fit position (blue star), the MAXI localization circle and best-fit position (pink star), and the IPN annuli (solid lines with centers dot-dashed). The shaded area shows the intersection of the Konus-GBM annulus with the 1-deg MAXI localization circle. The maximum distance between points on this overlapping region is 1.47 deg, at coordinates RA, Dec = 143.985 (09h 35m 56s) +51.878 (+51d 52' 40") and 146.304 (09h 45m 13s) +52.229 (+52d 13' 46"). The area of this region is 0.160 sq. deg. This map will also be posted at http://ssl.berkeley.edu/ipn3/090831A. The IPN localization may be improved.