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GCN Circular 39653

Subject
IPN triangulation of GRB 250308A (short)
Date
2025-03-10T16:02:51Z (3 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,

Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier
on behalf of the SVOM-GRM team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

E. Burns on behalf of the IPN,

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 short-duration GRB 250308A
(SVOM-GRM detection: Wang et al., GCN 39632Loading...
 
 , 39636Loading...
 
 )
was detected by SVOM (GRM), Konus-Wind, Swift (BAT), CALET (GBM),
and Mars-Odyssey (HEND) at about 65191 s UT (18:06:31).
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
  ---------------------------------------------
  Center:
   160.761 (10h 43m 03s) +23.741 (+23d 44' 26")
  Corners:
   160.858 (10h 43m 26s) +24.405 (+24d 24' 18")
   160.981 (10h 43m 55s) +24.338 (+24d 20' 15")
   160.655 (10h 42m 37s) +23.074 (+23d 04' 27")
   160.536 (10h 42m 09s) +23.145 (+23d 08' 43")
  ---------------------------------------------
The error box area is 578 sq. arcmin, and its maximum
dimension is 1.3 deg (the minimum one is 7.4 arcmin).
The Sun distance was 159 deg.

This localization may be improved.

The distance between the center of SVOM (GRM) localization (GCN 39636Loading...
 
 )
and the IPN box center is 9.4 deg.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250308_T65194/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.