  Thanks to the rapid position notice and response by HETE-2 and Swift, the
X-ray afterglow emissions have been found for four recent short gamma-ray
bursts (GRBs; GRB 050509b, GRB 050709, GRB 050724, and GRB 050813). The
positions of three out of four short GRBs are coincident with galaxies with no
current or recent star formation. This discovery tightens the case for a
different origin for short and long GRBs. On the other hand, from the prompt
emission point of view, a short GRB shows a harder spectrum comparing to that
of the long duration GRBs according to the BATSE observations. We investigate
the prompt emission properties of four short GRBs observed by Swift/BAT. We
found that the hardness of all four BAT short GRBs is in between the BATSE
range for short and long GRBs. We will discuss the spectral properties of short
GRBs including the short GRB sample of Konus-Wind and HETE-2 to understand the
hard nature of the BATSE short GRBs.
