GRB 120512A

S.Mereghetti (IASF-Milano), C.Ferrigno, E.Bozzo (ISDC, Versoix), D.Gotz 
(CEA, Saclay), and J.Borkowski (CAMK, Torun) on behalf of the IBAS 
Localization Team report:

a gamma ray burst lasting about 40 s has been detected by IBAS in the 
IBIS/ISGRI data at 02:41:40 UT of May 12.

Due to the 7.3 sigma statistical significance of the detection, only an 
Alert Packet of WEAK type was distributed in real time (Packet n. 6550).

With an off-line analysis with the standard OSA software we obtained the 
following GRB coordinates (J2000):

RA:  325.558    [degrees]
DEC:  13.636    [degrees]

with an uncertainty of 1 arcmin (90% c.l.).

These coordinates differ from those derived automatically (Alert Packet 
n.6550) because the extreme off-axis angle of the GRB (15 degrees) caused 
a wrong identification of its position in the real time image.

The burst has a peak flux of 5 counts/cm2/s (20-200 keV, 1-s integration 
time) and a fluence in the same energy range of about 1e-5 erg/cm2,

A plot of the light curve has been posted at 
http://ibas.iasf-milano.inaf.it/IBAS_Results.html

A. Sakamoto, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda, K. Takahara,
M. Asahina, S. Kobayashi, H. Ueno (Saitama U.),
M. Akiyama, N. Ohmori,  M. Yamauchi (Univ. of Miyazaki),
K. Yamaoka, Y. E. Nakagawa (Waseda U.),
Y. Hanabata,  T. Kawano, K. Takaki, Y.Tanaka, R. Nakamura, M. Ohno,
Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), M. Kokubun,
T. Takahashi (ISAS/JAXA), Y. Urata, P. Tsai (NCU), K. Nakazawa,
K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report:

The long GRB 120512A (INTEGRAL/IBIS; Mereghetti et al., GCN 13300
Loading...
 
 )
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an 
energy range of 50 keV - 5 MeV at 02:41:43.783 UT (=T0).
The observed light curve shows  a multi-peaked structure starting at 
T0+4 s, ending at T0+24 s,  with a duration (T90) of about 20 seconds. 
The fluence in 100 - 1000 keV was 9.33(-1.13 +0.27) x 10^-6 erg/cm^2. 
The 1-s peak flux measured from T0+9.5s was 2.81(-0.56 +0.26) 
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from T0+4s to 
T0+24s is well fitted by a power-law with exponential cutoff model:
   dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
   alpha       1.05(-0.47 +0.39), and
   Epeak       508.5(-72.2 +114.3) keV (chi^2/d.o.f. = 13.74/24).
We also shows the results with the same spectrum fitted by a GRB Band
model fixing beta of 2.5,���the low-energy photon index alpha: 
-1.03(-0.47 +0.78),���and the peak energy Epeak: 470.5(-85.4 +136.2) keV 
(chi^2/d.o.f = 17.86/24).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves for this burst are available at:

http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html