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arXiv · 1411.6940

Broad band turbulent spectra in gamma-ray burst light curves

Maurice H. P. M. van Putten·Cristiano Guidorzi·Filippo Frontera
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Abstract

Broad band power density spectra offer a window to understanding turbulent behavior in the emission mechanism and, at the highest frequencies, in the putative inner engines powering long GRBs. We describe a chirp search method which steps aside Fourier analysis for signal detection in the Poisson noise-dominated 2 kHz sampled BeppoSAX light curves. An efficient numerical implementation is described in $O(Nn\log n)$ operations, where $N$ is the number of chirp templates and $n$ is the length of the light curve time series, suited for embarrassingly parallel processing. For detection of individual chirps of duration $\tau=1$ s, the method is one order of magnitude more sensitive in SNR than Fourier analysis. The Fourier-chirp spectra of GRB 010408 and GRB 970816 show a continuation of the spectral slope up to 1 kHz of turbulence identified in low frequency Fourier analysis. The same continuation is observed in an ensemble averaged spectrum of 40 bright long GRBs. An outlook on a similar analysis of upcoming gravitational wave data is included.

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Maurice H. P. M. van Putten, Cristiano Guidorzi, Filippo Frontera. 2014-11-11. Broad band turbulent spectra in gamma-ray burst light curves. https://doi.org/10.1088/0004-637x/786/2/146

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