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GCN Circular 34845

Subject
IPN triangulation of GRB 231018A
Date
2023-10-19T18:41:19Z (7 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
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,
and E. Burns on behalf of the Fermi GBM team,

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,
report:

The bright, long-duration GRB 231018A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 34826Not found
 
 
;
BALROG localization: Preis et al., GCN Circ. 34827Not found
 
 
)
has been detected by Fermi (GBM trigger 719325015), CALET (GBM),
GECAM-B, INTEGRAL (SPI-ACS), Konus-Wind, and Swift (BAT),
so far, at about 45010 s UT (12:30:10).
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:
    1.122 (00h 04m 29s) +47.410 (+47d 24' 36")
 Corners:
    6.422 (00h 25m 41s) +50.650 (+50d 39' 01")
  356.061 (23h 44m 15s) +43.842 (+43d 50' 31")
  357.865 (23h 51m 28s) +44.479 (+44d 28' 43")
   10.820 (00h 43m 17s) +51.565 (+51d 33' 55")
 ---------------------------------------------
The error box area is 6.6 sq. deg, and its maximum
dimension is 12.54 deg (the minimum one is 38 arcmin).
The Sun distance was 137 deg.

The IPN localization is consistent with, but reduces the area of,
the final Fermi-GBM and the BALROG localizations.

This localization may be improved.

A triangulation map and HEALPix FITS files are posted at
http://www.ioffe.ru/LEA/GRBs/GRB231018_T45043/IPN

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