Gamma-Ray Burst Light Curves in the Relativistic Turbulence and Relativistic Subjet Models

Lazar, Ayah; Nakar, Ehud; Piran, Tsvi

doi:10.1088/0004-637x/695/1/l10

Cited by 85 publications

(117 citation statements)

References 20 publications

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“…Since magnetic reconnection can be the source of turbulence (e.g. Lazarian et al 2015), the emitting eddies have turbulent motions within the comoving frame of the outflow, as prescribed in the relativistic turbulence model (Lazar et al 2009;), At variance with the previous models, fast variability originates in the emission region (Lyutikov & Blandford 2003;Lyutikov 2006). The relative strength of the fast over the slow component reflects the filling factor of the eddies in the jet.…”

Section: Discussionmentioning

confidence: 96%

Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

Dichiara

Guidorzi

Amati

et al. 2016

A&A

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Context. The origin of the gamma-ray burst (GRB) prompt emission still defies explanation, in spite of recent progress made, for example, on the occasional presence of a thermal component in the spectrum along with the ubiquitous non-thermal component that is modelled with a Band function. The combination of finite duration and aperiodic modulations make GRBs hard to characterise temporally. Although correlations between GRB luminosity and spectral hardness on one side and time variability on the other side have long been known, the loose and often arbitrary definition of the latter makes the interpretation uncertain. Aims. We characterise the temporal variability in an objective way and search for a connection with rest-frame spectral properties for a number of well-observed GRBs. Methods. We studied the individual power density spectra (PDS) of 123 long GRBs with measured redshift, rest-frame peak energy E p,i of the time-averaged ν F ν spectrum, and well-constrained PDS slope α detected with Swift, Fermi and past spacecraft. The PDS were modelled with a power law either with or without a break adopting a Bayesian Markov chain Monte Carlo technique. Results. We find a highly significant E p,i -α anti-correlation. The null hypothesis probability is ∼10 −9 . Conclusions. In the framework of the internal shock synchrotron model, the E p,i -α anti-correlation can hardly be reconciled with the predicted E p,i ∝ Γ −2 , unless either variable microphysical parameters of the shocks or continual electron acceleration are assumed. Alternatively, in the context of models based on magnetic reconnection, the PDS slope and E p,i are linked to the ejecta magnetisation at the dissipation site, so that more magnetised outflows would produce more variable GRB light curves at short timescales ( 1 s), shallower PDS, and higher values of E p,i .

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Section: Discussionmentioning

confidence: 96%

Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

Dichiara

Guidorzi

Amati

et al. 2016

A&A

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“…It is a candidate for explaining (i) particle acceleration at pulsar wind termination shocks (Kirk & Skjaeraasen 2003;Pétri & Lyubarsky 2007;Sironi & Spitkovsky 2011a); (ii) the flat radio spectra from galactic nuclei and AGNs (Birk et al 2001) and from extragalactic jets (Romanova & Lovelace 1992); (iii) GeV flares from the Crab nebula (Bednarek & Idec 2011;Uzdensky et al 2011;Cerutti et al 2012aCerutti et al ,b, 2013; (iv) flares in active galactic nuclei (AGN) jets (Giannios et al 2009) or in gamma-ray bursts (Lyutikov 2006a;Lazar et al 2009); (v) the heating of AGN and microquasar coronae and the observed flares (Di Matteo 1998;Merloni & Fabian 2001;Goodman & Uzdensky 2008;Reis & Miller 2013;Romero et al 2014;Zdziarski et al 2014); (vi) the heating of the lobes of giant radio galaxies (Kronberg et al 2004); (vii) transient outflow production in microquasars and quasars (de Gouveia dal Pino & Lazarian 2005;de Gouveia Dal Pino et al 2010;Kowal et al 2011;Dexter et al 2014); (viii) gamma-ray burst outflows and non-thermal emissions (Drenkhahn & Spruit 2002;Giannios & Spruit 2007;McKinney & Uzdensky 2012); (ix) X-ray flashes (Drenkhahn & Spruit 2002); or (x) soft gamma-ray repeaters (Lyutikov 2006b;Uzdensky 2011).…”

Section: Introductionmentioning

confidence: 99%

The energetics of relativistic magnetic reconnection: ion-electron repartition and particle distribution hardness

Melzani

Walder

Folini

et al. 2014

A&A

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Collisionless magnetic reconnection is a prime candidate to account for flare-like or steady emission, outflow launching, or plasma heating, in a variety of high-energy astrophysical objects, including ones with relativistic ion-electron plasmas. But the fate of the initial magnetic energy in a reconnection event remains poorly known. What are the amounts assigned to kinetic energy, the ion and electron distribution, and the hardness of the particle distributions? We explored these questions with 2D particle-in-cell simulations of ion-electron plasmas. We find that 45 to 75% of the total initial magnetic energy ends up in kinetic energy, this fraction increasing with the inflow magnetization. Depending on the guide field strength, ions get from 30% to 60% of the total kinetic energy. Particles can be separated into two populations that mix only weakly: (i) particles initially in the current sheet heated by its initial tearing and subsequent contraction of the islands, and (ii) particles from the background plasma that primarily gain energy via the reconnection electric field when passing near the X-point. Particles of (ii) tend to form a power law with an index p = −dlog n(γ)/dlog γ that depends mostly on the inflow Alfvén speed V A and magnetization σ s of species s. For electrons p = 5 to 1.2 for increasing σ e . The highest particle Lorentz factor for ions or electrons increases roughly linearly with time for all the relativistic simulations. This is faster, and the spectra can be harder, than for collisionless shock acceleration. We discuss applications to microquasar and AGN coronae, to extragalactic jets, and to radio lobes. We point out situations where effects, such as Compton drag or pair creation, are important.

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“…This turbulent process, plus the inverse Compton mechanism, was applied to the study of radiation in GRB 080319B ). In the turbulent fluid, the random and small emitters can produce short-time variabilities, indicating many pulses shown in the GRB prompt light curve (Lyutikov 2006;Lazar et al 2009). It is worth noting the key point of this "jetin-jet" model: these microemitters within the bulk jet of GRB explosion also have a jet structure.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, the multiwavelength spectral result of GRB 100728A is especially precious to constrain our theoretical model of jitter/JSC radiation. Furthermore, from the clues of Lyutikov (2006) and Lazar et al (2009), we expect that the observed gross emission from a bulk jet launched by GRB explosion might be related to the emissions from the small-scale emitters with the minijet structure. Therefore, in this paper, we stress the following issues.…”

Section: Introductionmentioning

confidence: 99%

JITTER SELF-COMPTON PROCESS: GeV EMISSION OF GRB 100728A

Mao

Wang

2012

ApJ

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Jitter radiation, the emission of relativistic electrons in a random and small-scale magnetic field, has been applied to explain the gamma-ray burst (GRB) prompt emission. The seed photons produced from jitter radiation can be scattered by thermal/nonthermal electrons to the high-energy bands. This mechanism is called jitter self-Compton (JSC) radiation. GRB 100728A, which was simultaneously observed by Swift and Fermi, is a great example to constrain the physical processes of jitter and JSC. In our work, we utilize jitter/JSC radiation to reproduce the multiwavelength spectrum of GRB 100728A. In particular, due to JSC radiation, the powerful emission above the GeV band is the result of those jitter photons in the X-ray band scattered by the relativistic electrons with a mixed thermal-nonthermal energy distribution. We also combine the geometric effect of microemitters to the radiation mechanism, such that the "jet-in-jet" scenario is considered. The observed GRB duration is the result of summing up all of the contributions from those microemitters in the bulk jet.

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Gamma-Ray Burst Light Curves in the Relativistic Turbulence and Relativistic Subjet Models

Cited by 85 publications

References 20 publications

Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

The energetics of relativistic magnetic reconnection: ion-electron repartition and particle distribution hardness

JITTER SELF-COMPTON PROCESS: GeV EMISSION OF GRB 100728A

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