TITLE:   GCN CIRCULAR
NUMBER:  17342
SUBJECT: IPN Triangulation of GRB 150118B (long/intense)
DATE:    15/01/21 21:12:38 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,

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

S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,

V. Connaughton, M. S. Briggs, C. Meegan, and 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,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB 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, bright GRB 150118B (Kocevski et al., GCN Circ. 17307) 
has been observed by Fermi (GBM trigger 443267300; Stanbro GCN Circ. 
17308), Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), MESSENGER 
(GRNS), and Swift (BAT), so far, at about 35298 s UT (09:48:18). 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:
    242.008 (16h 08m 02s) -36.020 (-36d 01' 12")
   Corners:
    242.375 (16h 09m 30s) -34.181 (-34d 10' 51")
    241.798 (16h 07m 12s) -36.507 (-36d 30' 24")
    241.669 (16h 06m 40s) -37.699 (-37d 41' 55")
    242.219 (16h 08m 53s) -35.520 (-35d 31' 13")
   ---------------------------------------------
The error box area is 1139 sq. arcmin, and its maximum
dimension is 3.56 deg (the minimum one is 8.3 arcmin).
The Sun distance was 52 deg.

The box is long because all annuli intersect at grazing incidence due to 
conjunction of the spacecraft involved in the triangulation.

The Fermi (LAT) position (Kocevski et al., GCN Circ. 17307) is outside 
of the box at 1.5 deg from its center.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB150118_T35302/IPN/

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