GCN Circular 44111

Subject
IPN triangulation of GRB 260316B
Event
GRB 260316B
Date
2026-03-25T13:33:31Z (10 days ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
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. Goyal, A. Arya, M. Tembhurnikar, G. Waratkar, V. Bhalerao, 
D. Bhattacharya, and S. Vadawale, on behalf of the Astrosat-CZTI team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi-GBM 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 260316B
(Ferm-GBM detection: The Fermi GBM team, GCN 44031Loading...
 
 ;
AstroSat-CZTI detection: Harsha et al., GCN 44035Loading...
 
 ;
SVOM-GRM detection: Zhang et al., GCN 44039Loading...
 
 ;
GECAM-B detection: Zhang et al., GCN 44040Loading...
 
 ;
CALET-GBM detection: Tamura et al., GCN 44100Loading...
 
 )
was detected by Fermi (GBM trigger 795373977),
Konus-Wind, Astrosat (CZTI), SVOM (GRM), GECAM-B, CALET (GBM),
and Mars-Odyssey (HEND) at about 61973 s UT (17:12:53).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  345.026 (23h 00m 06s) -80.127 (-80d 07' 37")
 Corners:
  292.551 (19h 30m 12s) -74.130 (-74d 07' 48")
  293.015 (19h 32m 04s) -74.416 (-74d 24' 57")
   32.817 (02h 11m 16s) -74.223 (-74d 13' 24")
   32.021 (02h 08m 05s) -74.386 (-74d 23' 10")
 ---------------------------------------------
The error box area is 1.7 sq. deg, and its maximum
dimension is 24.2 deg (the minimum one is 4.3 arcmin).
The Sun distance was 75 deg.

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB260316_T61972/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.

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