[vsnet-grb-info 8341] GRB 090831A: IPN Triangulation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9864
SUBJECT: GRB 090831A: IPN Triangulation
DATE:    09/09/02 04:31:29 GMT
FROM:    Valerie Connaughton at MSFC  <valerie at nasa.gov>

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.