TITLE:   GCN CIRCULAR
NUMBER:  22619
SUBJECT: IPN Triangulation of GRB 180409A
DATE:    18/04/10 05:36:22 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D.Svinkin,
and T. Cline on behalf of the Konus-Wind team,

V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa,
and A. Goldstein, on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

A long-duration GRB 180409A was detected by Fermi (GBM), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT) at about 29899 s
UT (08:18:19).
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:
  175.842 (11h 43m 22s) +36.308 (+36d 18' 30")
 Corners:
  175.961 (11h 43m 51s) +35.973 (+35d 58' 21")
  176.118 (11h 44m 28s) +36.645 (+36d 38' 43")
  175.721 (11h 42m 53s) +36.644 (+36d 38' 37")
  175.567 (11h 42m 16s) +35.969 (+35d 58' 10")
 ---------------------------------------------
The error box area is 772 sq. arcmin, and its maximum
dimension is 49 arcmin (the minimum one is 19 arcmin).
The Sun distance was 131 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180409_T29904/IPN/

Swift ToO has been approved (Evans, GCN Circ. 22618).

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