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GCN Circular 21820

IPN Triangulation of GRB 170904A (long/very bright)
2017-09-05T20:59:35Z (7 years ago)
Dmitry Svinkin at Ioffe Institute <>
K. Hurley, on behalf of the IPN,

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

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

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

S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team,

X. B. Li, Y. Huang, Z. W. Li, and S. L. Xiong,
on behalf of the Insight-HXMT team, and

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

The long-duration, very bright GRB 170904A (Li et al., GCN Circ. 21817)
was detected by Konus-Wind, INTEGRAL (SPI-ACS), Insight-HXMT (HE),
Mars-Odyssey (HEND), and Swift (BAT) at about 35161 s UT (09:46:01).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
   RA(2000), deg                 Dec(2000), deg
    35.374 (02h 21m 30s) -32.498 (-32d 29' 51")
    35.139 (02h 20m 33s) -34.082 (-34d 04' 56")
    35.438 (02h 21m 45s) -33.461 (-33d 27' 38")
    35.574 (02h 22m 18s) -30.892 (-30d 53' 32")
    35.302 (02h 21m 12s) -31.531 (-31d 31' 51")
The error box area is 1934 sq. arcmin, and its maximum
dimension is 3.2 deg (the minimum one is 12.6 arcmin).
The Sun distance was 125 deg.

This box may be improved.

A triangulation map is posted at

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
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