GCN Circular 5665
D.Gotz (CEA, Saclay), S.Mereghetti, A.Paizis (IASF-Milano), M.Lazos, N.Mowlavi, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: An X-ray rich GRB lasting about 20 s has been detected by IBAS in IBIS/ISGRI data at 09:04:09 UT on September 30, 2006. The coordinates (J2000) are: RA: 304.5363 [degrees], DEC: -23.6253 with an uncertainty of 2.5 arcmin (90% c.l.). The peak flux in the 20-200 keV is 0.3 ph/cmq/s (2.2x10e-8 erg/cmq/s) over 1 s integration time and the fluence in the same energy range is 2.5x10e-7 erg/cmq We note that the faint ROSAT X-ray source 1RXS J201811.2-233536 is contained in the error region. Its RASS count rate of 0.03 counts/s corresponds to about 2x10e-13 erg/cmq/s A plot of the light curve will be posted at http://ibas.mi.iasf.cnr.it/IBAS_Results.html This message can be cited.