[vsnet-grb-info 23217] IPN triangulation of GRB 190805B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25316
SUBJECT: IPN triangulation of GRB 190805B
DATE:    19/08/13 08:09:10 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova at 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,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
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:

The long-duration GRB 190805B
(MAXI/GSC detection: Sato et al., GCN Circ. 25271;
Fermi/GBM detection: Hamburg & Meegan, GCN Circ. 25277)
was detected by Fermi (GBM trigger 586673165), INTEGRAL (SPI-ACS),
Mars-Odyssey (HEND), Konus-Wind and MAXI (GSC) at about 17159 s UT
(04:45:59).

We have triangulated it to a Konus-HEND annulus centered at
RA(2000)=321.552 deg (21h 26m 13s)  Dec(2000)=-16.302 deg (-16d 18' 
08"),
whose radius is 61.012 +/- 0.062 deg (3 sigma).

Only a rectangular error box of the MAXI/GSC position reported
by Sato et al. (GCN Circ. 25271) is consistent with the annulus.
The annulus combined with the MAXI (90 % containment, statistical-only)
localization gives the following error box:
---------------------------------------------
    RA(2000), deg                 Dec(2000), deg
   ---------------------------------------------
   Center:
    212.376 (14h 09m 30s) +19.776 (+19d 46' 32")
   Corners:
    212.356 (14h 09m 25s) +20.078 (+20d 04' 39")
    212.487 (14h 09m 57s) +20.071 (+20d 04' 15")
    212.395 (14h 09m 35s) +19.474 (+19d 28' 25")
    212.265 (14h 09m 03s) +19.480 (+19d 28' 49")
   ---------------------------------------------
The error box area is 267 sq. arcmin (a factor of 16
smaller than that of the MAXI error box), and its maximum
dimension is 38 arcmin (the minimum one is 7 arcmin).
The Sun distance was ~73 deg.

The box is partially covered with the Swift XRT observations
reported by Perri et al. (GCN Circ. 25279).

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190805_T17159/IPN/