[vsnet-grb-info 8683] GRB 091120: MAXI GSC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10188
SUBJECT: GRB 091120: MAXI GSC detection
DATE:    09/11/24 11:19:53 GMT
FROM:    Atsumasa Yoshida at Aoyama Gakuin U  <grbalert-ylab at phys.aoyama.ac.jp>

M.Nakajima (Nihon U.), S.Nakahira (AGU), M.Sugizaki, M.Kohama(RIKEN),
M.Suzuki (ISAS/JAXA), A.Yoshida, K.Yamaoka (AGU), 
N.Kawai, M.Morii(Tokyo Tech), H.Negoro (Nihon U.), M.Matsuoka, H.Tomida,
S.Ueno(ISAS/JAXA), Y.Ueda, S.Eguchi (Kyoto U.) and H.Tsunemi (Osaka Univ.)  
on behalf of the MAXI team report:

The Gas Slit Camera (GSC) of MAXI detected a bright hard X-ray
transient at 04:34:56 on 20 November 2009 (UT).  This event should
correspond to a GRB detected by Fermi-GBM, INTEGRAL SPI-ACS
andKonus-Wind.

The location of the source derived from the GSC data is 
(R.A.,Dec.)=(226.81 deg, -21.79 deg)=(15:07:14.40, -21:47:24.0)(J2000) 
with an uncertainty of about 0.5 degree.  This is consistent with that
reported by Gruber (GCNC10187) within an error.

The GSC FOV scanned over the source from 04:34:56 (UT) (16 seconds
after the GBM trigger) for about 40 seconds.  The average X-ray flux
over the observation is 4.9x10^-8 erg/cm2/s in 3-15 keV.  Significant
intensity variation was clearly seen in the light curve. 

MAXI is currently under the commissioning phase and the systematic
uncertainty in localization will be significantly improved with the
progress of the alignment calibration.
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