TITLE:   GCN CIRCULAR
NUMBER:  37696
SUBJECT: IPN triangulation of GRB 240930B / EP 240930a
DATE:    24/10/03 15:44:56 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@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 team,

A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
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,

and

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

The long-duration GRB 240930B
(Fermi-GBM detection: Fermi GBM team, GCN 37640;
Smith & Meegan, GCN 37660;
Swift/BAT-GUANO detection: DeLaunay et al., GCN 37654;
GRBAlpha detection: Dafcikova et al., GCN 37658;
CALET/GBM detection: Shimizu et al., GCN 37691)
was detected by Fermi (GBM trigger 749409487),
Konus-Wind, INTEGRAL (SPI-ACS), Swift (BAT),
GRBAlpha, CALET (CGBM), and Mars-Odyssey (HEND)
at about 62282 s UT (17:18:02).
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:
  319.774 (21h 19m 06s) +41.359 (+41d 21' 33")
 Corners:
  314.492 (20h 57m 58s) +43.551 (+43d 33' 05")
  314.622 (20h 58m 29s) +43.741 (+43d 44' 27")
  324.617 (21h 38m 28s) +38.847 (+38d 50' 49")
  324.470 (21h 37m 53s) +38.668 (+38d 40' 06")
 ---------------------------------------------
The error box area is 1.9 sq. deg, and its maximum
dimension is 9.0 deg (the minimum one is 13 arcmin).
The Sun distance was 118 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM localization. The position of EP240930a (Tian et al., GCN 37648;
Peng et al., GCN 37653) is inside the IPN localization,
strengthening the association of GRB 240930B with the EP240930a.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240930_T62287/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.

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