GCN Circular 39588
Subject
IPN triangulation of GRB 250222A
Event
Date
2025-03-04T12:59:51Z (2 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
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,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:
The long-duration GRB 250222A
(SVOM-GRM detection: Wang et al., GCN 39454)
was detected by SVOM (GRM), Konus-Wind, and INTEGRAL (SPI-ACS)
at about 51859 s UT (14:24:19).
Fermi (GBM) and Swift (BAT) were taking data, but shows
no rate increase at the burst time.
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
359.336 (23h 57m 21s) +0.946 ( +0d 56' 47")
Corners:
335.308 (22h 21m 14s) +25.783 (+25d 47' 00")
352.637 (23h 30m 33s) +12.776 (+12d 46' 35")
6.156 (00h 24m 37s) -19.368 (-19d 22' 04")
2.915 (00h 11m 40s) -9.794 ( -9d 47' 40")
---------------------------------------------
The error box area is 38.5 sq. deg, and its maximum
dimension is 54 deg (the minimum one is 3 deg).
The Sun distance was 25 deg.
This localization may be improved.
The SVOM (GRM) localization (GCN 39454) is inconsistent with
the IPN localization and also with burst non-detection by Fermi (GBM) and Swift (BAT).
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250222_T51862/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.