Investigation the connection between the intermediate gamma-ray bursts   and X-ray flashes
  Gamma-ray bursts can be divided into three groups: short-, intermediate and long-duration bursts. While the progenitors of the short and long ones are relatively known, the progenitor objects of the intermediate-duration bursts are generally unknown, however, recent statistical studies suggest, that they should be related to the long-duration bursts. In this work we investigate whether there is a differ- ence between the global parameters of the X-ray flashes and intermediate-duration group of gamma-ray bursts. The statistical tests do not show any significant discrepancy regarding most of the parameters, except the BAT photon index, which is only a consequence of the defintion of the X-ray flashes. 
J\'ozsef K\'obori, Zsolt Bagoly, Lajos G. Bal\'azs, Istv\'an Horv\'ath
astro-ph.HE