TITLE:   GCN CIRCULAR
NUMBER:  31138
SUBJECT: IPN triangulation of GRB 211118A
DATE:    21/11/29 13:54:51 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>

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

K. Hurley, on behalf of the IPN,

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

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

and

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

The long-duration GRB 211118A
(Swift/BAT-GUANO detection: Raman et al., GCN 31096;
AstroSat CZTI detection: Prasad et al., GCN 31099;
Fermi GBM detection: Mangan et al., GCN 31125)
was detected by Fermi (GBM trigger 658971499),
Konus-Wind, INTEGRAL (SPI-ACS), Swift-BAT, and
AstroSat (CZTI) at about 85093 s UT (23:38:13).
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:
   26.464 (01h 45m 51s) +73.778 (+73d 46' 40")
 Corners:
   20.795 (01h 23m 11s) +68.534 (+68d 32' 02")
   13.882 (00h 55m 32s) +68.354 (+68d 21' 14")
   39.770 (02h 39m 05s) +78.696 (+78d 41' 47")
   54.289 (03h 37m 09s) +77.757 (+77d 45' 24")
 ---------------------------------------------
The error box area is 28.9 sq. deg, and its maximum
dimension is 14.5 deg (the minimum one is 2.3 deg).
The Sun distance was 120 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi GBM on-ground calculated localization (GCN Circ. 31125).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB211118_T85093/IPN

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