TITLE:   GCN CIRCULAR
NUMBER:  39365
SUBJECT: IPN triangulation of GRB 250217C (short)
DATE:    25/02/18 16:19:04 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. 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, 

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 bright, short-duration GRB 250217C
(Fermi-GBM detection: The Fermi GBM team, GCN 39357;
AstroSat-CZTI detection: Tembhurnikar et al., GCN 39359)
was detected by Fermi (GBM trigger 761529286), AstroSat (CZTI),
Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND)
at about 86082 s UT (23:54:42).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  122.164 (08h 08m 39s) +45.257 (+45d 15' 24")
 Corners:
  121.397 (08h 05m 35s) +45.429 (+45d 25' 44")
  122.008 (08h 08m 02s) +45.505 (+45d 30' 17")
  122.915 (08h 11m 40s) +45.069 (+45d 04' 08")
  122.314 (08h 09m 15s) +45.007 (+45d 00' 27")
 ---------------------------------------------
The error box area is 818 sq. arcmin, and its maximum
dimension is 1.13 deg (the minimum one is 17.6 arcmin).
The Sun distance was 137 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM (GCN 39357) localization.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250217_T86086/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.

Swift-XRT ToO has been submitted.

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