TITLE: GCN CIRCULAR NUMBER: 39145 SUBJECT: IPN triangulation of GRB 250204B (short/hard) DATE: 25/02/04 17:51:38 GMT FROM: Dmitry Svinkin at Ioffe Institute svinkin@mail.ioffe.ru

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,

G. Waratkar, J.Joshi, V. Bhalerao, D. Bhattacharya, and S. Vadawale, on behalf of the Astrosat-CZTI team, report:

The short-duration GRB 250204B (Fermi-GBM detection: The Fermi GBM team, GCN 39141; AstroSat-CZTI detection: Dasgupta et al., GCN 39142) was detected by Fermi (GBM trigger 760344078), AstroSat (CZTI), Swift (BAT), Konus-Wind, and INTEGRAL (SPI-ACS) at about 24074 s UT (06:41:14).

We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 1.945 (00h 07m 47s) +35.469 (+35d 28' 07") Corners: 4.715 (00h 18m 52s) +29.985 (+29d 59' 08") 6.110 (00h 24m 26s) +29.936 (+29d 56' 11") 358.613 (23h 54m 27s) +40.986 (+40d 59' 08") 356.896 (23h 47m 35s) +41.060 (+41d 03' 34") --------------------------------------------- The error box area is 13.4 sq. deg, and its maximum dimension is 13.4 deg (the minimum one is 1 deg). The Sun distance was 64 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of, the Fermi-GBM localization (GCN 39141).

A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250204_T24073/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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