TITLE:   GCN CIRCULAR
NUMBER:  31878
SUBJECT: IPN triangulation of GRB 220408B
DATE:    22/04/11 21:15:27 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo team,

J. Benkhoff on behalf of the BepiColombo team,

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
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, report:

The bright, long-duration GRB 220408B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31854;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 31863)
was detected by Fermi (GBM trigger 671095689), Konus-Wind,
BepiColombo (MGNS), and AstroSat (CZTI) at about 26884 s UT (07:28:04).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    92.538 (06h 10m 09s) -49.610 (-49d 36' 36")
  Corners:
    93.180 (06h 12m 43s) -49.644 (-49d 38' 40")
    93.133 (06h 12m 32s) -47.629 (-47d 37' 43")
    91.896 (06h 07m 35s) -49.572 (-49d 34' 20")
    91.889 (06h 07m 33s) -51.597 (-51d 35' 50")
  ---------------------------------------------
The error box area is 1.7 sq. deg, and its maximum
dimension is 4.0 deg (the minimum one is 48 arcmin).
The Sun distance was 86 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi GBM final position (GCN 31854).

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB220408_T26885/IPN/

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