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GCN Circular 35862

IPN triangulation of GRB 240303B
2024-03-04T18:38:51Z (a month ago)
Dmitry Svinkin at Ioffe Institute <>
legacy email
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,

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


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

The long-duration GRB 240303B
(Fermi-GBM detection: The Fermi GBM team, GCN 35850;
Hamburg and Meegan, GCN 35860;
BALROG localization: Preiset al., GCN 35851;
CALET-GBM detection: Nakahira et al., GCN 35857)
has been detected by Fermi (GBM trigger 731161136),
and Mars-Odyssey (HEND), so far, at about 44331 s UT (12:18:51).

We have triangulated this GRB to the following annuli:
annulus           R.A.     Dec.     R     dR (3sigma)
                 (deg)    (deg)   (deg)     (deg)
Konus-GBM       320.846  -16.019  24.529  2.743
GBM-SPI-ACS     194.036   78.908  88.157  8.554
GBM-HEND        317.319  -17.507  23.796  0.133
The annuli intersect to form a long 8.1 sq.deg (3 sigma)
localization region.

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

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at

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

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