GCN Circular 31129

Subject
IPN triangulation of GRB 211120A
Event
Date
2021-11-26T13:51:12Z (4 years ago)
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 MGNS/BepiColombo and HEND/Mars Odyssey teams,

J. Benkhoff on behalf of the BepiColombo team,

K. Hurley on behalf of the IPN,

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

and

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

The long-duration GRB 211120A
(GECAM-B detection: Li et al., GCN Circ. 31100Loading...
 
 ;
AstroSat-CZTI detection: Prasad et al., GCN Circ. 31104Loading...
 
 ;
AGILE-MCAL detection: Ursi et al., GCN Circ. 31105Loading...
 
 )
was detected by GECAM-B (GRD), AstroSat (CZTI), AGILE (MCAL),
Konus-Wind, Mars-Odyssey (HEND),
and BepiColombo (MGNS; see introductory GCN Circ. 30949Loading...
 
 )
at about 83120 s UT (23:05:20).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   315.138 (21h 00m 33s) +42.856 (+42d 51' 20")
  Corners:
   315.108 (21h 00m 26s) +43.024 (+43d 01' 25")
   315.128 (21h 00m 31s) +42.774 (+42d 46' 28")
   315.185 (21h 00m 44s) +42.640 (+42d 38' 25")
   315.164 (21h 00m 39s) +42.890 (+42d 53' 23")
  ---------------------------------------------
The error box area is 30 sq. arcmin, and its maximum
dimension is 23 arcmin (the minimum one is 0.7 arcmin).
The Sun distance was 95 deg.

This box may be improved.

The distance between the box and the GECAM position
(RA, Dec, Err = 304.99, 41.42, 1.34; GCN 31100Loading...
 
 ) is
7.6 deg, thus it is inconsistent with the box.

The box Galactic latitude is -2.2 deg (noticed by Shaolin XIONG),
so the Galactic origin can not be ruled out
using the burst localization only.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB211120_T83120/IPN/

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