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GCN Circular 33413

IPN triangulation of GRB 230307A (long/very bright)
2023-03-07T23:33:26Z (a year ago)
Dmitry Svinkin at Ioffe Institute <>
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, A. Lysenko, A. Ridnaia on behalf of the IPN,

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,


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

The very bright, long-duration GRB 230307A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33405;
Dalessi, GCN Circ. 33407; Dalessi and Roberts, GCN Circ. 33411;
GECAM detection: Xiong et al., GCN Circ. 33406;
Solar Orbiter STIX detection: Xiao and Krucker, GCN Circ. 33410;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33412)
has been detected by Fermi(GBM trigger 699896651), GECAM,
INTEGRAL (SPI-ACS), Swift (BAT), Solar Orbiter (STIX), AGILE (MCAL),
and Mars-Odyssey (HEND), so far, at about 56647 s UT (15:44:07).
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
   59.233       -75.226
   70.905       -76.077
   38.996       -71.948
   38.440       -72.064
   73.041       -76.146
The error box area is 1.948 sq. deg, and its maximum
dimension is 9.6 deg (the minimum one is 11.6 arcmin).
The Sun distance was 100 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN 33407).

A triangulation map and HEALPix FITS file are posted at
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