GCN Circular 3430
D. Gotz, S. Mereghetti (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC, Versoix) and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A 80 s long GRB has been detected by IBAS in IBIS/ISGRI data at 00:05:53 on May 20 2005. Its refined coordinates (J2000) are: RA: 192.5087 [degrees] DEC: +30.4506 [degrees] with an uncertainty of 1.5 arcmin (90% c.l. radius). Its preliminary peak flux (20-200 keV, 1s integration time) is about 0.7 ph (5E-08 erg)/cmsq/s. Its fluence (20-200 keV, 80 s integration time) is 28.6 ph (2.4E-06 erg)/cmsq. A plot of the multi peaked light curve will be posted at http://ibas.mi.iasf.cnr.it/IBAS_Results.html Note that this burst is located at high galactic latitude (b=+86 deg) and not affected by Galactic absorption. It is therefore a good target for optical follow-up searches. This message can be cited.