Discovery of two new fast X-ray transients with INTEGRAL: IGR J03346+4414 and IGR J20344+3913

We report on the discovery of two fast X-ray transients (FXTs) from analysis of archival INTEGRAL data. Both are characterized by a remarkable hard X-ray activity above 20?keV, in terms of duration (?15 and 30 min, respectively), peak flux (?10?9?erg?cm?2 s?1) and dynamic range (?2400 and 1360, respectively). Swift/X-ray telescope follow-up observations failed to detect any quiescent or low-level soft X-ray emission from either of the two FXTs, providing an upper limit of the order of a few times 10?12?erg?cm?2 s?1. The main spectral and temporal Imager on Board INTEGRAL Satellite (IBIS)/INTEGRAL Soft Gamma-Ray Imager (ISGRI) characteristics are presented and discussed with the aim of inferring possible hints on their nature