TITLE:   GCN CIRCULAR
NUMBER:  18855
SUBJECT: IPN Triangulation of GRB 151231A
DATE:    16/01/12 20:45:20 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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,

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

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

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT 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 GRB 151231A was detected by Fermi (GBM: Veres, et al., 
GCN Circ. 18787), Konus-Wind, Swift (BAT), and Mars-Odyssey (HEND), at 
about 38267 s UT (10:37:47). 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
  ---------------------------------------------
  Center:
    69.528 (04h 38m 07s) -61.010 (-61d 00' 36")
  Corners:
    70.843 (04h 43m 22s) -60.244 (-60d 14' 37")
    71.191 (04h 44m 46s) -60.345 (-60d 20' 41")
    68.143 (04h 32m 34s) -61.761 (-61d 45' 40")
    67.789 (04h 31m 09s) -61.652 (-61d 39' 07")
  ---------------------------------------------
The error box area is 1425 sq. arcmin, and its maximum
dimension is 2.1 deg (the minimum one is 11.6 arcmin).
The Sun distance was 91 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB151231_T38267/IPN/

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