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GCN Circular 15588

IPN Triangulation of GRB 131209A
2013-12-10T13:01:52Z (10 years ago)
Dmitry Svinkin at Ioffe Institute <>
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,

S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, 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, N. Gehrels, H. Krimm, and D. Palmer, on 
behalf of the Swift-BAT team, and

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

The long-duration GRB 131209A (Vianello et al., GCN Circ. 15587) has 
been observed by Fermi (GBM: trigger 408287279), Konus-Wind, INTEGRAL 
(SPI-ACS), Swift (BAT), and MESSENGER (GRNS), so far, at about 47277 s 
UT (13:07:57). The burst was outside the coded field of view of the BAT.

We have triangulated this GRB to a Konus-MESSENGER annulus centered at 
RA(2000)=64.917 deg (04h 19m 40s)  Dec(2000)=+21.195 deg (+21d 11' 41"), 
whose radius is 87.724 +/- 0.105 deg (3 sigma).

This annulus intersects the Fermi-LAT 1 sigma error circle (Vianello et 
al., GCN Circ. 15587) to form an error box whose area is about 16 times 
smaller than that of the LAT error circle (2.5 sq. deg.), and whose 
corners are:
   RA(2000), deg                 Dec(2000), deg
    137.365 (09h 09m 28s) -32.668 (-32d 40' 06")
    137.509 (09h 10m 02s) -32.892 (-32d 53' 32")
    136.780 (09h 07m 07s) -34.069 (-34d 04' 09")
    136.475 (09h 05m 54s) -34.100 (-34d 05' 59")
The error box area is 559 sq. arcmin, and its maximum dimension is
1.48 deg (the minimum one is 12.6 arcmin).

This box may be improved.

The distance between the annulus center line and the center of Fermi-LAT 
location is 0.5 deg.

A triangulation map is posted at

The time history and spectrum will be given in forthcoming GCN Circulars.
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