TITLE:   GCN CIRCULAR
NUMBER:  31512
SUBJECT: IPN triangulation of a bright burst from SGR 1935+2154
DATE:    22/01/21 16:19:14 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov,
and A.B. Sanin on behalf of the HEND/Mars Odyssey teams,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

A very bright, short-duration, soft burst has been detected by
Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND), so far,
at about 35470 s UT (09:51:10).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   293.659 (19h 34m 38s) +21.934 (+21d 56' 03")
  Corners:
   293.077 (19h 32m 18s) +22.236 (+22d 14' 11")
   293.139 (19h 32m 33s) +22.259 (+22d 15' 34")
   294.235 (19h 36m 56s) +21.626 (+21d 37' 33")
   294.173 (19h 36m 41s) +21.604 (+21d 36' 15")
  ---------------------------------------------
The error box area is 213 sq. arcmin, and its maximum
dimension is 74 arcmin (the minimum one is 5 arcmin).
The Sun distance was 44 deg.

This box may be improved.

The position of SGR 1935+2154 is inside the box
at 4.6 arcmin from the box center.

Given the positional coincidence of this burst with SGR 1935+2154, its
time history, and softness of its spectrum  (as observed by Konus-Wind),
we conclude this burst is likely originated from SGR 1935+2154.

A triangulation map is posted at
http://www.ioffe.ru/LEA/SGRs/220120_T35475/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.