GCN Circular 5030

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, and D. Frederiks
on behalf of the Konus-Wind team,

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

I. Mitrofanov, A. Kozyrev, M. Litvak, A. Sanin, V. Tret'yakov and
A. Parshukov, 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,

S. Barthelmy, J. Cummings, N. Gehrels, and H. Krimm, on behalf of
the Swift-BAT team, and

A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti,
on behalf of the INTEGRAL GRB team,  report:

A short duration hard spectrum GRB, 060427B, occurred at about 23:51:55
UT.  It was observed by Konus-Wind, Mars Odyssey (GRS and HEND),
INTEGRAL-SPI-ACS, and Swift-BAT.  The burst was outside of the field of
view of Swift-BAT, so it was not imaged.  As the burst arrived almost
along the Odyssey-Earth vector, the resulting annulus was unusually
wide.

The burst light curve shows a single pulse with a duration of ~0.2 sec.
A weak emission is seen in the K-W G2 band (83-360 keV) starting
at ~0.3 sec before the main pulse.

The burst has been triangulated to RA, Dec = 98.472, +21.348 deg (J2000).
The corners of the 3 sigma error box are:
-----------------------
RA, deg   Dec, deg
-----------------------
98.8479  22.7146
98.7014  19.9202
98.0629  19.9948
98.1954  22.8568
--------------------

The area of this error box is 1.7 sq. deg.

Konus-Wind spectral analysis is in progress.  Preliminary analysis
indicates that Epeak was >1 MeV.