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GCN Circular 31024

Subject
IPN triangulation of GRB 211022A
Date
2021-10-30T12:36:29Z (3 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,

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, D. Palmer, and A. Tohuvavohu
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:

The long-duration GRB 211022A
(GECAM-B detection: Zhao et al., GCN Circ. 30955Loading...
 
 ;
AstroSat-CZTI detection: Prasad et al., GCN Circ. 30968Loading...
 
 )
was detected by BepiColombo (MGNS; see introductory GCN Circ. 30949Loading...
 
 ),
Mars-Odyssey (HEND), GECAM-B, AstroSat (CZTI), Konus-Wind,
INTEGRAL (SPI-ACS), and Swift (BAT), at about 2845 s UT (00:47:25).
The burst was outside the coded field of view of the BAT.

The burst light curves in the energy range 30 keV-1.5 MeV (HEND)
and 250-450 keV (MGNS) exhibit a multi-peaked pulse structure
with a total duration of ~150 s.

We have triangulated GRB 211022A to the following 3 sigma annuli:
------------------------------------------------------------
            R.A.(J2000)  Dec.(J2000)    R      +dR     -dR
                deg         deg        deg     deg     deg
------------------------------------------------------------
MGNS-HEND      30.161     12.392    125.005  +0.096  -0.214
SPI-ACS-HEND  202.386     -8.806     53.850  +0.093  -0.071
Konus-SPI-ACS 193.415    -14.239     44.866  +5.706  -5.232
------------------------------------------------------------
The MGNS-HEND and SPI-ACS-HEND annuli intersect to form two error
boxes one of which is inconsistent with the Konus-SPI-ACS annulus,
the KW ecliptic latitude response, and the GECAM position.

The correct preliminary, 3 sigma error box is:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   161.615 (10h 46m 27s) -51.006 (-51d 00' 21")
  Corners:
   160.852 (10h 43m 24s) -50.508 (-50d 30' 29")
   162.525 (10h 50m 06s) -51.893 (-51d 53' 33")
   161.845 (10h 47m 23s) -51.080 (-51d 04' 47")
   160.242 (10h 40m 58s) -49.672 (-49d 40' 19")
  ---------------------------------------------
The error box area is 1026 sq. arcmin, and its maximum
dimension is 2.6 deg (the minimum one is 9.8 arcmin).
The Sun distance was 54 deg.

This box may be improved.

A triangulation maps are posted at:
http://www.ioffe.ru/LEA/GRBs/GRB211022_T02845/IPN

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