TITLE:   GCN CIRCULAR
NUMBER:  34669
SUBJECT: IPN triangulation of GRB 230911D (long)
DATE:    23/09/11 22:32:48 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,

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 bright, short-duration GRB 230911D
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 34656;
BALROG localization: Biltzinger et al., GCN Circ. 34657;
Konus-Wind detection: Frederiks et al., GCN Circ. 34659;
Fermi-LAT detection: Longo et al., GCN Circ. 34668)
was detected by Fermi (GBM trigger 716111594), INTEGRAL (SPI-ACS),
Konus-Wind, Swift (BAT), and Mars-Odyssey (HEND)
at about 28389 s UT (07:53:09).
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:
  151.360 (10h 05m 26s) -25.633 (-25d 38' 00")
 Corners:
  151.696 (10h 06m 47s) -26.192 (-26d 11' 31")
  151.638 (10h 06m 33s) -26.200 (-26d 12' 01")
  151.036 (10h 04m 09s) -25.072 (-25d 04' 18")
  151.093 (10h 04m 22s) -25.064 (-25d 03' 51")
 ---------------------------------------------
The error box area is 226 sq. arcmin, and its maximum
dimension is 1.3 deg (the minimum one is 3 arcmin).
The Sun distance was 35 deg.

The IPN localization is consistent with, but reduces the area of,
the Fermi-LAT localization (GCN 34668).

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230911_T28387/IPN