The Temporal and Spectral Characteristics of “Fast Rise and Exponential Decay” Gamma-Ray Burst Pulses

Peng, Zhao-Yang; Yin, Yue; Bi, X. W.; Zhao, Xiaoxia; Fang, Lu; Bao, Y. Y.

doi:10.1088/0004-637x/718/2/894

Cited by 14 publications

(11 citation statements)

References 19 publications

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“…In total, 26% of the events in our sample contain a clear exponentially decaying part. A similar behavior (Fast Rise Exponential Decay-FRED) was observed in the past in γ-rays with the BATSE instrument aboard the CGRO satellite (e.g., Peng et al [27]). We are well aware that, in the highly dynamical environment of a collapsing stellar core, the accumulated magnetic flux threading the black hole will not always be time independent, and this is why we only observe a clear exponential decay in a fraction of GRB events.…”

Section: Discussionsupporting

confidence: 72%

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

2017

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In 1977, Blandford and Znajek showed how the spin energy of a rotating black hole may be extracted electromagnetically through a magnetic field that threads the black hole horizon. A characteristic feature of this mechanism is that, under certain fairly general conditions, the energy loss rate decays exponentially. We looked precisely for such behavior in the X-ray light curves of Long and Ultra Long duration Gamma-Ray Bursts (GRBs) observed with the XRT instrument on board the Swift satellite, and found that almost 30% of XRT light curves show an exponential decay before they reach the afterglow plateau. A similar behavior (Fast Rise Exponential Decay-FRED) was observed in γ-rays with the BATSE instrument aboard the CGRO satellite. We consider both of these findings as the signature of the Blandford-Znajek mechanism in action in the central engine of GRBs.

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Section: Discussionsupporting

confidence: 72%

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

2017

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“…In the case where A < 0 the decay time is larger than the rise time. Such "fast rise -exponential decay" flare shapes can be seen in gamma-ray bursts (e.g., Peng et al 2010). In the case where A > 0, the rise time is larger than the decay time.…”

Section: Time Asymmetry Of Flux Variationsmentioning

confidence: 95%

Ornstein-Uhlenbeck parameter extraction from light curves of Fermi-LAT observed blazars

Burd

Kohlhepp

Wagner

et al. 2021

A&A

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Context. Monthly binned γ-ray light curves of 236 bright γ-ray sources, particularly blazars, selected from a sample of 2278 highgalactic latitude objects observed with Fermi-LAT show flux variability characterized by power spectral densities consisting of a single power-law component, ranging from Brownian to white noise. Aims. The main goal here is to assess the Ornstein-Uhlenbeck (OU) model by studying the range of its three parameters that reproduces these statistical properties. Methods. We develop procedures for extracting values of the three OU model parameters (mean flux, correlation length, and random amplitude) from time series data and apply them to compare numerical integrations of the OU process with the Fermi-LAT data. Results. The OU process fully describes the statistical properties of the flux variations of the 236 blazars. The distributions of the extracted OU parameters are narrowly peaked around well-defined values (σ, µ, θ) = (0.2, −8.4, 0.5) with variances (0.004, 0.07, 0.13). The distributions of rise and the decay time scales of flares in the numerical simulations, meaning major flux variations fulfilling predefined criteria, are in agreement with the observed ones. The power spectral densities of the synthetic light curves are statistically indistinguishable from those of the measured light curves. Conclusions. The long-term γ-ray flux variability of blazars on monthly time scales is well described by a stochastic model that involves only three parameters. The methods described here are powerful tools for studying randomness in light curves and thereby for constraining the physical mechanisms responsible for the observed flux variations.

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“…Two evolution patterns of E p have been seen in GRBs, i.e., hard-to-soft evolution and intensity tracking (Liang & Kargatis 1996;Ford et al 1995;Kaneko et al 2006;Peng et al 2010). Two-thirds of the smooth GRB pulses in the BATSE sample have E p showing a hard-to-soft evolution, while in the others, strong intensity tracking was observed .…”

Section: Introductionmentioning

confidence: 97%

A COMPREHENSIVE ANALYSIS OFFERMIGAMMA-RAY BURST DATA. II.E_pEVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS

Lü

Wei

Liang

et al. 2012

ApJ

151

145

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We present a time-resolved spectral analysis of 51 long and 11 short bright gamma-ray bursts (GRBs) observed with the Fermi/Gamma-Ray Burst Monitor, paying special attention to E p evolution within each burst. Among eight single-pulse long GRBs, five show an evolution from hard to soft, while three show intensity tracking. The multi-pulse long GRBs have more complicated patterns. Statistically, the hard-to-soft evolution pulses tend to be more asymmetric than the intensity-tracking ones, with a steeper rising wing than the falling wing. Short GRBs have E p tracking intensity exclusively with the 16 ms time-resolution analysis. We performed a simulation analysis and suggest that for at least some bursts, the late intensity-tracking pulses could be a consequence of overlapping hard-to-soft pulses. However, the fact that the intensity-tracking pattern exists in the first pulse of the multi-pulse long GRBs and some single-pulse GRBs, suggests that intensity tracking is an independent component, which may operate in some late pulses as well. For the GRBs with measured redshifts, we present a time-resolved E p −L γ,iso correlation analysis and show that the scatter of the correlation is comparable to that of the global Amati/Yonetoku relation. We discuss the predictions of various radiation models regarding E p evolution, as well as the possibility of a precessing jet in GRBs. The data pose a great challenge to each of these models, and hold the key to unveiling the physics behind GRB prompt emission.

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The Temporal and Spectral Characteristics of “Fast Rise and Exponential Decay” Gamma-Ray Burst Pulses

Cited by 14 publications

References 19 publications

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

Ornstein-Uhlenbeck parameter extraction from light curves of Fermi-LAT observed blazars

A COMPREHENSIVE ANALYSIS OFFERMIGAMMA-RAY BURST DATA. II.E_pEVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS

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The Temporal and Spectral Characteristics of “Fast Rise and Exponential Decay” Gamma-Ray Burst Pulses

Cited by 14 publications

References 19 publications

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

The Signature of the Blandford-Znajek Mechanism in GRB Light Curves

Ornstein-Uhlenbeck parameter extraction from light curves of Fermi-LAT observed blazars

A COMPREHENSIVE ANALYSIS OFFERMIGAMMA-RAY BURST DATA. II.EpEVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS

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A COMPREHENSIVE ANALYSIS OFFERMIGAMMA-RAY BURST DATA. II.E_pEVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS