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GCN Circular 40976

Subject

IPN triangulation of GRB 250703A

Event

GRB 250703A

Date

2025-07-05T14:48:05Z (19 hours 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 20250703A
(Fermi-GBM detection: Fermi GBM team, GCN Circ. 40909Loading...
 
 )
was detected by Fermi (GBM trigger 773226456), Konus-Wind,
and Mars-Odyssey (HEND) at about 32851 s UT (09:07:31).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:

 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  351.240 (23h 24m 58s) +28.375 (+28d 22' 31")
 Corners:
  352.362 (23h 29m 27s) +28.111 (+28d 06' 39")
  350.071 (23h 20m 17s) +28.695 (+28d 41' 42")
  350.131 (23h 20m 32s) +28.603 (+28d 36' 11")
  352.423 (23h 29m 41s) +28.013 (+28d 00' 47")
 ---------------------------------------------

The error box area is 0.16 sq. deg, and its maximum
dimension is 2.2 deg (the minimum one is 5 arcmin).
The Sun distance was 96 deg.

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

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250703_T32851/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.