The Existence of Self-Similar Ripple Structures in GRB Pulse Light Curves

Author: Jon Hakkila

Abstract: GRB pulses exhibit many correlative behaviors, suggesting that the pulse emission mechanism has few free parameters. Both for this reason and because of the paucity of photons in GRB observations, GRB pulse light curves have been modeled using relatively simple functional forms. Using data from BATSE, GBM, Suzaku, and Swift, we demonstrate that GRB pulse light curves contain organized faint ripples overriding the general pulse shape. The self-similar distribution of these ripples scales with pulse duration and appears as a ``wave'' with a decreasing amplitude and increasing wavelength. This wave feature provides additional evidence that a pulse's peak intensity is merely part of a spectral decay process, rather than its climax. The wave may be a signature of relativistic shocks, or of other direct aspects of pulse physics.