GCN Circular 37602
Subject
IPN triangulation of GRB 240918B
Event
Date
2024-09-24T19:25:27Z (a year ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
Via
Web form
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,
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,
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 240918B
(Fermi-GBM detection: The Fermi GBM team, GCN 37558;
INTEGRAL SPI-ACS detection: Pawar, GCN 37560;
AstroSat CZTI detection: Joshi et al., GCN 37588)
was detected by Fermi (GBM), Konus-Wind, INTEGRAL (SPI-ACS),
AstroSat (CZTI), and Mars-Odyssey (HEND)
at about 75416 s UT (20:56:56).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
143.280 (09h 33m 07s) -17.435 (-17d 26' 07")
Corners:
141.159 (09h 24m 38s) -19.395 (-19d 23' 40")
141.379 (09h 25m 31s) -19.587 (-19d 35' 15")
145.293 (09h 41m 10s) -15.401 (-15d 24' 02")
145.075 (09h 40m 18s) -15.211 (-15d 12' 41")
---------------------------------------------
The error box area is 1.6 sq. deg, and its maximum
dimension is 5.6 deg (the minimum one is 17 arcmin).
The Sun distance was 35 deg.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM localization (GCN 37558).
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240918_T75415/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.