GCN Circular 2461

K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey,
and KONUS GRB teams,

E. Mazets, S. Golenetskii, and V. Palshin, on behalf of the Konus-Wind 
and Helicon GRB teams,

I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and
A. Sanin, on behalf of the HEND-Odyssey GRB team,

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

D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W.
Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, and

A. von Kienlin, G. Lichti, and A. Rau, on behalf of the
INTEGRAL SPI-ACS GRB team, report:

These two events were detected quasi-simultaneously, in such a way that
their time histories overlapped, making the analysis very difficult,
and the results subject to large uncertainties.

GRB031127A was about 10 s long and arrived at 68338 s.  It was detected
by Konus-Wind, RHESSI, and INTEGRAL SPI-ACS.  This event can only be
localized very coarsely.  Triangulation gives an annulus centered at
RA, Decl(2000)=21.275, -60.447 degrees, whose outer radius is
approximately 70 degrees and whose inner radius is zero degrees.  The
Konus ecliptic latitude determination limits the arrival direction to
ecliptic latitudes between -60 degrees and -20 degrees.

GRB031127B was over 70 s long and arrived at 68356 s.  This event was
detected by Konus-Wind, INTEGRAL SPI-ACS, Mars Odyssey - HEND, and
Helicon.  We have triangulated it to an annulus centered at RA,
Decl(2000)=350.166, -5.279 degrees, whose radius is 73.555 +/- 1.271
degrees (3 sigma).  In addition, the Konus ecliptic latitude response
limits the arrival direction to ecliptic latitudes between +30 and +70
degrees, that is, to those portions of the annulus between RA,
Decl=276, +6 and 291, +50 degrees, and between 316, +62 and 49, +49
degrees.

These two localizations are definitely mutually exclusive.  They may be
improved slightly, but a small error box cannot be derived for either
event.