TITLE:   GCN CIRCULAR
NUMBER:  26612
SUBJECT: IPN triangulation of GRB 191227B (short)
DATE:    19/12/30 12:40:46 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

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

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

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

S. Barthelmy, J. Cummings, 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 very bright, short-duration GRB 191227B was detected by
Fermi (GBM trigger 599160109), Mars-Odyssey (HEND), Konus-Wind,
and Swift (BAT) at about 62504 s UT (17:21:44).
The burst was outside the coded field of view of the BAT.

We have triangulated it to two preliminary, 3 sigma error boxes
whose coordinates are:
Box 1:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   256.466 (17h 05m 52s) -26.739 (-26d 44' 19")
  Corners:
   256.590 (17h 06m 22s) -26.856 (-26d 51' 20")
   256.273 (17h 05m 05s) -27.785 (-27d 47' 06")
   256.342 (17h 05m 22s) -26.619 (-26d 37' 09")
   256.724 (17h 06m 54s) -25.195 (-25d 11' 40")
  ---------------------------------------------

  Box 2:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   257.405 (17h 09m 37s) -19.765 (-19d 45' 52")
  Corners:
   257.550 (17h 10m 12s) -19.678 (-19d 40' 41")
   257.500 (17h 10m 00s) -18.708 (-18d 42' 29")
   257.260 (17h 09m 02s) -19.853 (-19d 51' 12")
   257.244 (17h 08m 59s) -21.319 (-21d 19' 08")
  ---------------------------------------------
The area of each error box is 1162 sq. arcmin,
and their maximum dimension is 2.62 deg
(the minimum one is 14.16 arcmin).
The Sun distance for each box was ~18 deg.

These error boxes are both consistent with the GBM localization.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB191227_T62500/IPN

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