Fourier Analysis of Gamma-Ray Burst Light Curves: Searching for Direct Signature of Cosmological Time Dilation

Abstract

We study the power density spectrum (PDS) of light curves of the observed gamma-ray bursts (GRBs) to search for a direct signature for cosmological time dilation in the PDS statistics with the GRBs whose redshifts $z$'s are known. The anticorrelation of a timescale measure and a brightness measure is indirect evidence of its effect. On the other hand, we directly demonstrate that a time dilation effect can be seen in GRB light curves. We find that timescales tend to be shorter in bursts with small redshift, as expected from cosmological time-dilation effects, and we also find that there may be non-cosmological effects constituting to this correlation. We discuss its implication on interpretations of the PDS analysis results. We put forward another caution to this kind of analysis when we statistically exercise with GRBs whose $z$ is unknown.

12 pages, 2 figures, 2 tables, accepted to ApJL

References in corpus (6)

• Power Density Spectra of Gamma-Ray Bursts in the Internal Shock Model
• Time Dilation and Quasar Variability
• Intrinsic and Cosmological Signatures in Gamma-Ray Burst Time Profiles: Time Dilation
• Power Density Spectra of Gamma-Ray Burst Light Curves: Implications on Theory and Observation
• Relativistic Conic Beams and Spatial Distribution of Gamma-Ray Bursts
• Effects of Luminosity Functions Induced by Relativistic Beaming on Statistics of Cosmological Gamma-Ray Bursts

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• A viable varying speed of light model in the RW metric
• Review on the minimally extended varying speed of light model
• Cosmography of the minimally extended Varying Speed of Light Model
• The significance of measuring cosmological time dilation in the Dark Energy Survey Supernova Program
• Constraints on the minimally extended varying speed of light model using the Pantheon+ dataset
• Revisiting Varying Speed of Light in Cosmology: Insights from the Friedmann-Lemaître-Robertson-Walker Metric
• 3+1 formalism of the minimally extended varying speed of light model
• Search for Cosmological time dilation from Gamma-Ray Bursts -- A 2021 status update
• Average Power-Density Spectrum of short and long Fermi-GBM Gamma-Ray Bursts