A simple theory of lags in gamma-ray bursts: Comparison to observations

Mochkovitch, R.; Heussaff, V.; Atteia, J. L.; Boçi, Sonila; Hafizi, M.

doi:10.1051/0004-6361/201527604

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…Short GRBs (S-GRBs) are consistent with negligible spectral lag (Norris et al 2001;Norris & Bonnell 2006;Bernardini et al 2015), while L-GRBs have positive, null or negative lag (Ukwatta et al 2012;Bernardini et al 2015). No clear physical motivation helps one in accounting for the spectral lag contribution in each single case (for possible interpretations of the spectral lag see Dermer 1998;Kocevski & Liang 2003;Ryde 2005;Peng et al 2011;Salmonson 2000;Ioka & Nakamura 2001;Dermer 2004;Shen et al 2005;Lu et al 2006;Guiriec et al 2010Guiriec et al , 2013Mochkovitch et al 2016). Thus, when deriving the limits for quantum gravity effects in specific GRBs, either long or short, we cannot properly model the contribution of the intrinsic spectral lag to estimate the possible delay induced by quantum gravity effects alone (see however Vasileiou et al 2013, who accounted for the intrinsic spectral lag in a statistical sense in single sources).…”

Section: Introductionmentioning

confidence: 99%

Limits on quantum gravity effects from Swift short gamma-ray bursts

Bernardini

Ghirlanda

Campana

et al. 2017

A&A

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The delay in arrival times between high and low energy photons from cosmic sources can be used to test the violation of the Lorentz invariance (LIV), predicted by some quantum gravity theories, and to constrain its characteristic energy scale E QG that is of the order of the Planck energy. Gamma-ray bursts (GRBs) and blazars are ideal for this purpose thanks to their broad spectral energy distribution and cosmological distances: at first order approximation, the constraints on E QG are proportional to the photon energy separation and the distance of the source. However, the LIV tiny contribution to the total time delay can be dominated by intrinsic delays related to the physics of the sources: long GRBs typically show a delay between high and low energy photons related to their spectral evolution (spectral lag). Short GRBs have null intrinsic spectral lags and are therefore an ideal tool to measure any LIV effect. We considered a sample of 15 short GRBs with known redshift observed by Swift and we estimate a limit on E QG 1.5 × 10 16 GeV. Our estimate represents an improvement with respect to the limit obtained with a larger (double) sample of long GRBs and is more robust than the estimates on single events because it accounts for the intrinsic delay in a statistical sense.

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Section: Introductionmentioning

confidence: 99%

Limits on quantum gravity effects from Swift short gamma-ray bursts

Bernardini

Ghirlanda

Campana

et al. 2017

A&A

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“…Moreover, the case of GRB 130427A is an exception, and its LAT emission was detected earlier than the GBM emission (Preece et al 2014). The decay time can be also related to the acceleration and cooling of the electrons as presented in the former discussion, and the cooling may induce the GRB spectral evolution (Mochkovitch et al 2016). We may further consider the time evolution of the turbulent cascade in the future.…”

Section: Discussionmentioning

confidence: 89%

Spectral Diversities of Gamma-ray Bursts in High Energy Bands: Hints from Turbulent Cascade

Mao,

Li,

Wang

2020

Preprint

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We statistically examine the gamma-ray burst (GRB) photon indices obtained by the Fermi-GBM and Fermi-LAT observations and compare the LAT GRB photon indices to the GBM GRB photon indices. We apply the jitter radiation to explain the GRB spectral diversities in the high-energy bands. In our model, the jitter radiative spectral index is determined by the spectral index of the turbulence. We classify GRBs into three classes depending on the shape of the GRB high-energy spectrum when we compare the GBM and LAT detections: the GRB spectrum is concave (GRBs turn out to be softer and are labeled as S-GRBs), the GRB spectrum is convex (GRBs turn out to be harder and are labeled as H-GRBs), and the GRBs have no strong spectral changes (labeled as N-GRBs). A universal Kolmogorov index 7/3 in the turbulent cascade is consistent with the photon index of the N-GRBs. The S-GRB spectra can be explained by the turbulent cascade due to the kinetic magnetic reconnection with the spectral index range of the turbulence from 8/3 to 3.0. The H-GRB spectra originate from the inverse turbulent cascade with the spectral index range of the turbulence from 2.0 to 3.5 that occurred during the large lengthscale magnetic reconnection. Thus, the GRB radiative spectra are diversified because the turbulent cascade modifies the turbulent energy spectrum. More observational samples are expected in the future to further identify our suggestions.

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“…Detailed analysis of the spectral lag would utilize both the temporal and spectral information and help to reveal the radiation mechanisms of GRBs. The existence of the spectral lag can be considered as a consequence of the spectral evolution in the radiation processes (e.g., Dermer 1998;Daigne & Mochkovitch 2003;Ryde 2005;Uhm & Zhang 2016;Mochkovitch et al 2016). For synchrotron and synchrotron self-Compton (SSC) processes in relativistic plasma outflows, the pulse width should be correlated with the photon energy E as E −1/2 and E −1/4 , respectively (Kazanas et al 1998;Chiang 1998;Dermer 1998).…”

Section: Introductionmentioning

confidence: 99%

A New Measurement of the Spectral Lag of Gamma-Ray Bursts and its Implications for Spectral Evolution Behaviors

Shao

Zhang

Wang

et al. 2017

ApJ

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We carry out a systematical study of the spectral lag properties of 50 single-pulsed Gamma-Ray Bursts (GRBs) detected by Fermi/GBM. By dividing the light curves into multiple consecutive energy channels we provide a new measurement of the spectral lag which is independent on energy channel selections. We perform a detailed statistical study of our new measurements. We find two similar power-law energy dependencies of both the pulse arrival time and pulse width. Our new results on the power-law indices would favor the relativistic geometric effects for the origin of spectral lag. However, a complete theoretical framework that can fully account for the diverse energy dependencies of both arrival time and pulse width revealed in this work is still missing. We also study the spectral evolution behaviors of the GRB pulses. We find that the GRB pulse with negligible spectral lag would usually have a shorter pulse duration and would appear to have a "hardness-intensity tracking" (HIT) behavior and the GRB pulse with a significant spectral lag would usually have a longer pulse duration and would appear to have a "hard-to-soft" (HTS) behavior.

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A simple theory of lags in gamma-ray bursts: Comparison to observations

Cited by 6 publications

References 26 publications

Limits on quantum gravity effects from Swift short gamma-ray bursts

Limits on quantum gravity effects from Swift short gamma-ray bursts

Spectral Diversities of Gamma-ray Bursts in High Energy Bands: Hints from Turbulent Cascade

A New Measurement of the Spectral Lag of Gamma-Ray Bursts and its Implications for Spectral Evolution Behaviors

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