TITLE: GCN CIRCULAR NUMBER: 15601 SUBJECT: GRB 131218A: a long GRB detected with INTEGRAL DATE: 13/12/18 22:15:53 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay), S. Mereghetti (IASF-Milano), E. Bozzo, C. Ferrigno, R. Farinelli, (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: a gamma ray burst lasting about 6 s has been detected by IBAS in the IBIS/ISGRI data at 21:05:32 U.T. on December 18. Its refined coordinates (J2000) are: R.A.: 113.7807 deg DEC.: -64.7373 deg with an uncertainty of 1.8 arc min (90% c.l.). A preliminary estimation of the burst fluence is 5x10^-7 erg/cmsq in the 20-200 keV energy band. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html