TITLE:   GCN CIRCULAR
NUMBER:  31996
SUBJECT: IPN triangulation of GRB 220423A
DATE:    22/05/04 20:35:15 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,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB 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 220423A
(AGILE detection: Ursi et al., GCN Circ. 31938;
Swift/BAT-GUANO detection: Raman et al., GCN Circ. 31943;
VZLUSAT-2 detection: Ripa et al., GCN Circ. 31965)
was detected by CALET (CGBM), INTEGRAL (SPI-ACS), Konus-Wind,
Swift (BAT), AGILE (MCAL, SA, AC), BepiColombo (MGNS), and VZLUSAT-2
at about 51251 s UT (14:14:11).
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:
    20.784 (01h 23m 08s) +22.205 (+22d 12' 18")
  Corners:
    19.674 (01h 18m 42s) +21.578 (+21d 34' 40")
    21.136 (01h 24m 33s) +22.784 (+22d 47' 02")
    21.890 (01h 27m 34s) +22.712 (+22d 42' 43")
    20.459 (01h 21m 50s) +21.615 (+21d 36' 56")
  ---------------------------------------------
The error box area is 3047 sq. arcmin, and its maximum
dimension is 2.3 deg (the minimum one is 29 arcmin).
The Sun distance was 13 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220423_T51247/IPN

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