GCN Circular 44329
Subject
IPN triangulation of GRB 260411B
Event
Date
2026-04-17T15:16:20Z (23 days ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@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,
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
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,
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 260411B
(Fermi-GBM detection: The Fermi GBM team, GCN 44262,
Pathak & Sonawane, GCN 44266;
BALROG localization: Preis & Greiner, GCN 44263;
SVOM-GRM detection: Wang et al., GCN 44268;
Fermi-LAT detection: Longo et al., GCN 44277;
GECAM-B detection: Zao et al., GCN 44285;
Glowbug detection: Woolf et al., GCN 44312)
was detected by Fermi (GBM, LAT), Konus-Wind,
SVOM (GRM), GECAM-B, Glowbug,
and Mars-Odyssey (HEND) at about 29075 s UT (08:04:35).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
85.558 (05h 42m 14s) +2.297 ( +2d 17' 50")
Corners:
85.572 (05h 42m 17s) -0.527 ( +0d 31' 39")
85.610 (05h 42m 26s) -0.425 ( +0d 25' 29")
85.523 (05h 42m 05s) +5.509 ( +5d 30' 32")
85.486 (05h 41m 57s) +5.372 ( +5d 22' 20")
---------------------------------------------
The error box area is 844 sq. arcmin, and its maximum
dimension is 6.0 deg (the minimum one is 2.4 arcmin).
The Sun distance was 65 deg.
This localization may be improved.
The OT reported by GOTO (GOTO26dam, GCN 44265)
is inside the IPN box, strengthening the association of the OT and GRB 260411B.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB260411_T29079/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.