TITLE:   GCN CIRCULAR
NUMBER:  26087
SUBJECT: IPN triangulation of GRB 191027A
DATE:    19/10/29 07:12:56 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,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia,
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,

S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT 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 191027A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26078;
BALROG localization: Biltzinger et al., GCN Circ. 26079)
was detected by Fermi (GBM trigger 593882352), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND),
and Swift (BAT), at about 55148 s UT (15:19:08).
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:
    186.657 (12h 26m 38s) +30.957 (+30d 57' 25")
   Corners:
    166.009 (11h 04m 02s) +19.308 (+19d 18' 27")
    202.558 (13h 30m 14s) +30.844 (+30d 50' 39")
    206.169 (13h 44m 40s) +29.642 (+29d 38' 31")
    170.349 (11h 21m 24s) +23.297 (+23d 17' 48")
   ---------------------------------------------
The error box area is about 7.5 sq. deg, and its maximum
dimension is 37.7 deg (the minimum one is 13.0 arcmin).
The Sun distance was about 42 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi-GBM one.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB191027_T55143/IPN

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