TITLE: GCN CIRCULAR NUMBER: 20103 SUBJECT: GRB 161023A: A long GRB detected by INTEGRAL DATE: 16/10/23 23:45:13 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, S.Fotopoulou(ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: a gamma ray burst lasting about 45 s has been detected by IBAS in the IBIS/ISGRI data at 22:38:40 UT of 2016 October 23. The refined coordinates (J2000) are: R.A.= 311.0342 deg DEC.= -47.6614 deg with an uncertainty of 1 arcmin (90% c.l.). The burst had a peak flux greater than 5 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range greater than 5e-6 erg/cmq. These are lower limits because this bright burst caused ISGRI telemetry saturation. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html