TITLE: GCN CIRCULAR NUMBER: 37639 SUBJECT: IPN triangulation of GRB 240926A DATE: 24/09/30 15:36:50 GMT 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 HEND/Mars Odyssey team,

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

E. Burns, on behalf of the IPN,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB 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 240926A (SVOM-GRM detection: Zhang et al., GCN 37616) was detected by SVOM (GRM), Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND) at about 42164 s UT (11:42:44).

We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 240.361 (16h 01m 27s) +45.364 (+45d 21' 52") Corners: 241.263 (16h 05m 03s) +45.816 (+45d 48' 59") 241.214 (16h 04m 51s) +45.898 (+45d 53' 53") 239.475 (15h 57m 54s) +44.903 (+44d 54' 12") 239.526 (15h 58m 06s) +44.822 (+44d 49' 21") --------------------------------------------- The error box area is 483 sq. arcmin, and its maximum dimension is 1.6 deg (the minimum one is 5.1 arcmin). The Sun distance was 68 deg.

The IPN localization is consistent with, but reduces the area of, the SVOM-GRM localization (GCN 37616).

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB240926_T42164/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.

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