Shen, RF (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China.
We have studied the averaged power density spectra (PDSs) of two classes of long-duration gamma-ray bursts in the recent classification by Balastegui et al. (2001) based on neural network analysis. Both PDSs follow a power law over a wide frequency range with approximately the same slope, which indicates that a process with a self-similar temporal property may underlie the emission mechanisms of both. The two classes of bursts are divided into groups according to their brightness and spectral hardness respectively and each group's PDS was calculated. For both classes, the PDS is found.