  A thermal component is suggested to be the physical composition of the ejecta
of several bright gamma-ray bursts (GRBs). Such a thermal component is
discovered in the time-integrated spectra of several short GRBs as well as long
GRBs. In this work, we present a comprehensive analysis of ten very short GRBs
detected by Fermi Gamma-Ray Burst Monitor to search for the thermal component.
We found that both the resultant low-energy spectral index and the peak energy
in each GRB imply a common hard spectral feature, which is in favor of the main
classification of the short/hard versus long/soft dichotomy in the GRB
duration. We also found moderate evidence for the detection of thermal
component in eight GRBs. Although such a thermal component contributes a small
proportion of the global prompt gamma-ray emission, the modified
thermal-radiation mechanism could enhance the proportion significantly, such as
in subphotospheric dissipation.
