GCN Circular 43564

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,

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

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

G. Waratkar, J.Joshi, V. Bhalerao, D. Bhattacharya, A. Arya,
and S. Vadawale, on behalf of the Astrosat-CZTI team,

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

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

and

D. Kapshtan, M. Orlov, V. Bazunova, E. Shchepin, E. Meltsov,
K. Starikov, A. Khogoev, on behalf of the 239Alferov team,
report:

The long-duration GRB 260121A
was detected by Fermi (GBM; in continuous TTE data),
Konus-Wind, Astrosat (CZTI), INTEGRAL (SPI-ACS),
239Alferov CubeSat, and BepiColombo-MGNS
at about 8552 s UT (02:22:32).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  213.591 (14h 14m 22s) -62.629 (-62d 37' 45")
 Corners:
  212.178 (14h 08m 43s) -65.088 (-65d 05' 17")
  212.129 (14h 08m 31s) -64.984 (-64d 59' 01")
  214.879 (14h 19m 31s) -60.111 (-60d 06' 38")
  214.922 (14h 19m 41s) -60.220 (-60d 13' 11")
 ---------------------------------------------
The error box area is 855 sq. arcmin, and its maximum
dimension is 5.13 deg (the minimum one is 3 arcmin).
The Sun distance was 72 deg.

The localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB260121_T08549/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.