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GCN Circular 32971

Subject
IPN triangulation of GRB 221121A (long)
Date
2022-11-22T21:00:17Z (a year ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo team,

J. Benkhoff on behalf of the BepiColombo team,

A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The long-duration GRB 221121A
(Fermi-GBM detection: Fermi GBM Team, GCN Circ. 32960Not found
 
 
;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 32969Not found
 
 
)
has been detected by Fermi (GBM trigger 690705294), Konus-Wind,
INTEGRAL (SPI-ACS), AstroSat (CZTI), CALET (CGBM), GECAM-B
(trigger tn221121_063449_fb), Swift (BAT), and BepiColombo (MGNS),
so far, at about 23690 s UT (06:34:50).
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:
  163.104 (10h 52m 25s) +69.356 (+69d 21' 22")
 Corners:
  164.660 (10h 58m 38s) +69.887 (+69d 53' 12")
  164.681 (10h 58m 43s) +70.133 (+70d 08' 00")
  161.617 (10h 46m 28s) +68.809 (+68d 48' 31")
  161.623 (10h 46m 30s) +68.558 (+68d 33' 29")
 ---------------------------------------------
The error box area is 952 sq. arcmin, and its maximum
dimension is 1.9 deg (the minimum one is 9 arcmin).
The Sun distance was about 103 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN Circ. 32960Not found
 
 
).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB221121_T23691/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.