[vsnet-grb-info 3170] GRB 060425: IPN localization and KW spectrum of a short, hard burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5005
SUBJECT: GRB 060425: IPN localization and KW spectrum of a short, hard burst
DATE:    06/04/27 01:41:41 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc at milkyway.gsfc.nasa.gov>

J. Cummings, S. Barthelmy, N. Gehrels, and H. Krimm, on behalf of
the Swift-BAT team,
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
and T. Cline on behalf of the Konus-Wind team,
A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti,
on behalf of the INTEGRAL GRB team,
K. Hurley, 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 K.Yamaoka, M.Ohno, Y.Fukazawa, T.Takahashi, M.Tashiro, Y. Terada,
T.Murakami, and K.Makishima on behalf of the Suzaku WAM team
report:
 
A short, hard GRB was observed at 2006-04-25 16:57:40 by Swift-BAT,
Konus-Wind, Suzaku-WAM, RHESSI, and INTEGRAL-SPI-ACS.  The T90 was 
0.13 +- 0.01 sec.  This burst was Mars-occulted to Odyssey.  The burst 
had 2 main peaks of roughly similar intensity and hardness, the second 
slightly shorter than the first.

The IPN triangulated error box is as follows:
 
 ----------------------
 RA, deg     Dec, deg          (J2000)
 ----------------------
 Center:
 212.3007   -5.0667
 
 Corners:
   214.5693  -1.7277
   210.9652  -7.0326
   210.7765  -8.4092
   213.8848  -3.1685
 -----------------------
 
The area of the box is 2.53 sq. deg
 
Preliminary analysis of the Konus-Wind data yields a burst fluence of 
2.57 (-1.85, +0.47) x 10^-6 erg/cm2.  The peak flux measured from 
T0(K-W)-0.036 s on a 16-ms time scale was 
3.64 (-2.74, +1.06) x 10^-5 erg/cm2/sec. Both are quoted in the 
20 keV - 10 MeV energy range.  The K-W spectrum accumulated from 
T0(K-W) to T0(K-W)+0.128 s is well fitted (in the 20 keV - 10 MeV range) 
by a power law with exponential cutoff model:
     dN/dE ~ E^(-alpha) * exp(-(2-alpha)*E/Ep)
with alpha = 0.92 (-0.37, + 0.28) and Ep = 1403 (-594, 1273) keV 
(chi^2 = 16.7/18 dof). T0(K-W) = 61063.000 s UT (16:57:43.000).
 
We note that the X-ray source 1RXS J140902.5-050430, and nearby galaxies 
LEDA 1048719 and LEDA 1047950 are within this error box close to the 
center.