Shock acceleration in gamma-ray bursts

Lemoine, Martin; Pelletier, G.

doi:10.1016/j.crhy.2011.01.011

Cited by 5 publications

(2 citation statements)

References 82 publications

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“…The fluid description erases all information of the particle momentum distribution. The usual assumption is that the wind particles will be accelerated to a powerlaw distribution in energy, an assumption that is required by observations but remains challenging to prove theoretically (Lemoine & Pelletier 2011). Numerical simulations find this occurs in unmagnetised pair plasmas (Spitkovsky 2008) or for nearly parallel magnetised shocks (Sironi & Spitkovsky 2009).…”

Section: The Transition To High-mass X-ray Binaries: Propellersmentioning

confidence: 99%

Gamma-ray binaries and related systems

Dubus

2013

Astron Astrophys Rev

290

274

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After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary (eta Car) have also been detected - 'related systems' that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common ? What drives their high-energy emission ? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants ? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as the components revolve on their orbit. I explain the basic ingredients that models of gamma-ray binaries use, the challenges that they currently face, and how they can bring insights into the physics of pulsars. I discuss how gamma-ray emission from microquasars provides a window into the connection between accretion--ejection and acceleration, while eta Car and novae raise new questions on the physics of these objects - or on the theory of diffusive shock acceleration. Indeed, explaining the gamma-ray emission from binaries strains our theories of high-energy astrophysical processes, by testing them on scales and in environments that were generally not foreseen, and this is how these detections are most valuable.Comment: 71 pages, 23 figures, minor updates to text, references, figures to reflect published versio

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Section: The Transition To High-mass X-ray Binaries: Propellersmentioning

confidence: 99%

Gamma-ray binaries and related systems

Dubus

2013

Astron Astrophys Rev

290

274

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“…The instantaneous synchrotron spectrum at a given shock location depends on three physical quantities: the slope p and minimum Lorentz factor γm of the initial distribution of electrons, and the magnetic field strength B. The last two are estimated by assuming that respective fractions ǫe and ǫB of the dissipated energy (in the local fluid frame) are used to accelerate electrons and amplify the magnetic field [9]. Comparing the hydrodynamical expansion time to the synchrotron cooling time then leads to define the Lorentz factor γc: electrons with Lorentz factors γ > γc can radiate efficiently while those with γ < γc mostly loose their energy by adiabatic expansion.…”

Section: Standard Model Of the Afterglowmentioning

confidence: 99%

Afterglows after Swift

Godet,

Mochkovitch

2012

Preprint

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Since their discovery by the Beppo-SAX satellite in 1997, gamma-ray burst afterglows have attracted an evergrowing interest. They have allowed redshift measurements that have confirmed that gamma-ray bursts are located at cosmological distances. Their study covers a huge range both in time (from one minute to several months after the trigger) and energy (from the GeV to radio domains). The purpose of this review is first to give a short historical account of afterglow research and describe the main observational results with a special attention to the early afterglow revealed by Swift. We then present the standard afterglow model as it has been developed in the pre-Swift era and show how it is challenged by the recent Swift and Fermi results. We finally discuss different options (within the standard framework or implying a change of paradigm) that have been proposed to solve the current problems.

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Observing the prompt emission of GRBs

Atteia¹,

Boër²

2011

Comptes Rendus. Physique

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Gamma-ray bursts (GRBs) were first detected thanks to their prompt emission, which was the only information available for decades. In 2010, while the high-energy prompt emission remains the main tool for the detection and the first localization of GRB sources, our understanding of this crucial phase of GRBs has made great progress. We discuss some recent advances in this field, like the occasional detection of the prompt emission at all wavelengths, from optical to GeV; the existence of sub-luminous GRBs; the attempts to standardize GRBs; and the possible detection of polarization in two very bright GRBs. Despite these advances, tantalizing observational and theoretical challenges still exist, concerning the detection of the faintest GRBs, the panchromatic observation of GRBs from their very beginning, the origin of the prompt emission, or the understanding of the physics at work during this phase.Significant progress on this last topic is expected with SVOM thanks to the observation of dozens of GRBs from optical to MeV during the burst itself, and the measure of the redshift for the majority of them. SVOM will also change our view of the prompt GRB phase in another way. Within a few years, the sensitivity of sky surveys at optical and radio frequencies, and outside the electromagnetic domain in gravitational waves or neutrinos, will allow them to detect several new types of transient signals, and SVOM will be uniquely suited to identify which of these transients are associated with GRBs. This radically novel look at GRBs may elucidate the complex physics producing these bright flashes.

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Shock acceleration in gamma-ray bursts

Cited by 5 publications

References 82 publications

Gamma-ray binaries and related systems

Gamma-ray binaries and related systems

Afterglows after Swift

Observing the prompt emission of GRBs

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