TITLE:   GCN CIRCULAR
NUMBER:  34917
SUBJECT: IPN triangulation of GRB 231020A
DATE:    23/10/30 20:36:49 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 and HEND/Mars Odyssey teams,

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, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

The long-duration GRB 231020A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 34856;
Bala et al., GCN Circ. 34869;
BALROG localization: Preis et al., GCN Circ. 34861;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 34880;
GRID detection: Wang and Yang, GCN Circ. 34903)
was detected by Fermi (GBM trigger 719521023), INTEGRAL (SPI-ACS),
Konus-Wind, Swift (BAT), Mars-Odyssey (HEND), BepiColombo (MGNS),
AstroSat (CZTI), and GRID, at about 68218 s UT (18:56:58).
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:
  314.493 (20h 57m 58s) -29.254 (-29d 15' 15")
 Corners:
  314.061 (20h 56m 15s) -28.067 (-28d 04' 02")
  314.696 (20h 58m 47s) -29.893 (-29d 53' 33")
  314.881 (20h 59m 31s) -30.286 (-30d 17' 09")
  314.275 (20h 57m 06s) -28.562 (-28d 33' 43")
 ---------------------------------------------
The error box area is 247 sq. arcmin, and its maximum
dimension is 2.3 deg (the minimum one is 2.2 arcmin).
The Sun distance was 101 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB231020_T68224/IPN

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