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GRB 090305C

GCN Circular 8941

Subject

IPN localization of short GRB 090305C

Date

2009-03-06T18:09:18Z (16 years ago)

From

Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind 
and Konus-RF teams,

K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
  Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku-WAM team,

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

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

Suzaku-WAM, Konus-Wind, Konus-RF, Swift-BAT, and INTEGRAL-SPI-ACS 
observed the short GRB 090305C at about 62379 s UT (17:19:39). The burst 
was outside the coded field of view of the BAT.

The burst light curve shows a multipeaked structure with a duration of 
~1 sec.

We have triangulated it to the following 3-sigma
error box:
-----------------------------------------------
       RA(2000), deg            Dec(2000), deg
-----------------------------------------------
Center:
   34.187 (02h 16m 45s)   -22.840 (-22d 50' 23")
Corners:
   34.482 (02h 17m 56s)   -17.203 (-17d 12' 09")
   34.645 (02h 18m 35s)   -19.974 (-19d 58' 28")
   33.140 (02h 12m 34s)   -28.787 (-28d 47' 14")
   33.533 (02h 14m 08s)   -25.759 (-25d 45' 32")
-----------------------------------------------

The error box area is 2.524 sq. deg.

This error box may be improved.

The Konus-Wind light curve of this GRB and the IPN triangulation map is
available at http://www.ioffe.ru/LEA/GRBs/GRB090305_T62376/

GCN Circular 8957

Subject

GRB 090305C: Suzaku WAM observation of the prompt emission

Date

2009-03-09T09:36:28Z (16 years ago)

From

Makoto Tashiro at Saitama U/Swift <tashiro@phy.saitama-u.ac.jp>

GRB 090305C: Suzaku WAM observation of the prompt emission

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

The IPN localized short GRB 090305C (Golenetskii et al., GCN 8941Loading...
 
 )
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 17:19:38.326 UT (=T0).

The observed light curve shows a multi-peaked structure starting at T0
+0.2s, ending at T0+1.3s with a duration (T90) of about 0.9 seconds.
The fluence in 100 - 1000 keV was 1.85(-0.58, +0.13)x 10^-06 erg/cm2.
The 0.5-s scaled peak flux measured from T0+0s was 4.13(-0.97, +0.19)
photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0+0s
to T0+1.5s is fitted by a power-law with exponential cutoff model:

dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha	1.05(-0.49, 0.38), and
Epeak	835 ( -237, 618) keV (chi^2/d.o.f. = 5.20/13).

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