GRB 090528B

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 12:22:31.29 UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090528B (trigger 265206153 / 090528516).
The on-ground calculated location, using the GBM trigger 
data, is RA = 312.2, DEC = 32.7 (J2000 degrees, 
equivalent to 20h 49m, 32d 42'), with a statistical uncertainty 
of less than 1 degree (radius, 1-sigma containment) and an additional 
systematic error which is currently estimated to be 2 to 3 degrees.
The angle from the Fermi LAT boresight is 65 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve shows a strong multiple peak event follwed by 
a weaker structered tail with a duration (T90) of about 102 s (8-1000 keV). 
The time-averaged spectrum from T0-2.048 s to T0+57.345 s is 
best fit by a Band function with Epeak = 172 +/- 12  keV, 
alpha = -1.10 +/- 0.04, and beta = -2.3 +/- 0.1
(chi squared 516 for 477 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(4.65 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+9.216 s in the 8-1000 keV band 
is 14.7 +/- 1.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."

V.Krushinski, I.Zalognikh, A.Popov, T.Kopytova
Ural State University, Kourovka

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov
Sternberg Astronomical Institute, Moscow State University

K.Ivanov, S.Yazev
Irkutsk State University

A. Tlatov, A.V. Parhomenko,
Kislovodsk Solar Station of the Pulkovo Observatory




MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
2x500mm,2 x 4 square degrees, 2 x 16Mpx Apogee CCD) located
at Kourovka Observatory has  observed  FERMI error box

GRB_RA:          313.740d {+20h 54m 58s} (J2000)
GRB_DEC:         +32.350d {+32d 21' 00"} (J2000)

1.18 degres error box radius (Trigg Number 265206153)

starting after sunset (19:18:23.275, ~7 hours after GRB time) with 180s 
exposure in R and V filters simultaniuosly at ~60 degrees zenit distance.


Robot do not detect OT with limit:
  R>19.0 V>18.1

Our images cover 30% last 1 sigma error box (A. von Kienlin, GCN Circ 
9447
Loading...
 
 )


The R-image is available at


http://observ.pereplet.ru/images/GRB090528B/grb090528B.jpeg

The black circle is A. von Kienlin, GCN Circ 9447
Loading...
 
  error box.
The message may be cited.

mailto: lipunov@sai.msu.ru

Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090528B (Fermi-GBM trigger 265206153 / 090528516;
von Kienlin et al., GCN9447
Loading...
 
 ) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 12:22:29.849 UT (=T0).

The observed light curve shows a bright multi-peaked structure
starting at T0-5 s, ending at T0+60 s, and very weak emission is seen
up to T0+120 s. The total T90 duration is about 77 seconds.

The fluence in 100 - 1000 keV was 3.08 (-0.16, +0.14) x10^-5 erg/cm2.
The 1-s peak flux measured from T0+11s was 3.53 (-0.32, +0.27)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-5 s
to T0+120 s is fitted by a single power-law with a photon index of
2.00 (-0.10, +0.11) (chi^2/d.o.f = 32.1/20).

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html