GCN Circular 40129
Subject
IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
Date
2025-04-09T14:22:43Z (2 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
E. Burns on behalf of the IPN,
and
E. Bozzo, C. Ferrigno, and S. Mereghetti
on behalf of the INTEGRAL SPI-ACS GRB team,
report:
The long-duration GRB 250321D
was detected by Konus-Wind in the waiting mode and INTEGRAL (SPI-ACS)
at about 22405 s UT (06:13:25), ~200 s after EP triggered on
the fast X-ray transient EP250321a (Hu et al., GCNs 39800, 39833).
We have triangulated it to a Konus-SPI-ACS annulus centered at
RA(2000)=176.654 deg (11h 46m 37s) Dec(2000)=+10.352 deg (+10d 21' 08"),
whose radius is 11.845 +/- 11.845 deg (3 sigma).
This localization may be improved.
EP250321a is inside the annulus and is consistent with the Konus-Wind ecliptic latitude response,
lending support to the association of GRB 250321D and the transient.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB250321_T22405/IPN/
The burst time history and spectrum will be given in forthcoming
GCN circulars.