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GCN Circular 27625

Subject
IPN Triangulation of a bright burst from SGR 1935+2154
Date
2020-04-22T20:16:05Z (5 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak,
and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,

A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
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,

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

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

A bright, short-duration, soft burst
(CALET-GRBM detection: Cherry et al., GCN Circ. 27623Loading...
 
 )
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
Mars-Odyssey (HEND), CALET(GBM), and Swift (BAT)
at about 31997 s UT (08:53:17) on April 22.
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:
  293.773 (19h 35m 05s) +21.942 (+21d 56' 31")
 Corners:
  293.559 (19h 34m 14s) +21.634 (+21d 38' 02")
  293.555 (19h 34m 13s) +21.991 (+21d 59' 27")
  293.988 (19h 35m 57s) +22.248 (+22d 14' 52")
  293.990 (19h 35m 58s) +21.893 (+21d 53' 33")
 ---------------------------------------------
The error box area is 517 sq. arcmin, and its maximum
dimension is 44 arcmin (the minimum one is 18 arcmin).
The Sun distance was 91 deg.

This box may be improved.

The position of SGR 1935+2154 is inside the box
at 3.5 arcmin from its center.

Given the positional coincidence of this burst with
SGR 1935+2154 (initially suggested in GCN Circ. 27623Loading...
 
 ),
its time history, and softness of its spectrum (as observed
by Konus-Wind), we conclude that this burst is likely originated
from SGR 1935+2154.
we conclude THAT this burst
A triangulation map is posted at
http://www.ioffe.ru/LEA/SGRs/200422_T31996/IPN/

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