Some of the most energetic pulsars exhibit rotationmodulated
Magnetic reconnection is ubiquitous in astrophysical systems, and in many such systems the plasma suffers from significant cooling due to synchrotron radiation. We study relativistic magnetic reconnection in the presence of strong synchrotron cooling, where the ambient magnetization,
 NSFPAR ID:
 10398342
 Publisher / Repository:
 DOI PREFIX: 10.3847
 Date Published:
 Journal Name:
 The Astrophysical Journal
 Volume:
 944
 Issue:
 2
 ISSN:
 0004637X
 Page Range / eLocation ID:
 Article No. 173
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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Abstract γ ray emission in the 0.1–100 GeV band. The luminosity of this emission is typically 0.1%–10% of the pulsar spindown power (γ ray efficiency), implying that a significant fraction of the available electromagnetic energy is dissipated in the magnetosphere and reradiated as highenergy photons. To investigate this phenomenon we model a pulsar magnetosphere using 3D particleincell simulations with strong synchrotron cooling. We particularly focus on the dynamics of the equatorial current sheet where magnetic reconnection and energy dissipation take place. Our simulations demonstrate that a fraction of the spindown power dissipated in the magnetospheric current sheet is controlled by the rate of magnetic reconnection at microphysical plasma scales and only depends on the pulsar inclination angle. We demonstrate that the maximum energy and the distribution function of accelerated pairs is controlled by the available magnetic energy per particle near the current sheet, the magnetization parameter. The shape and the extent of the plasma distribution is imprinted in the observed synchrotron emission, in particular, in the peak and the cutoff of the observed spectrum. We study how the strength of synchrotron cooling affects the observed variety of spectral shapes. Our conclusions naturally explain why pulsars with higher spindown power have wider spectral shapes and, as a result, lowerγ ray efficiency. 
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Abstract Magnetic reconnection is often invoked as a source of highenergy particles, and in relativistic astrophysical systems it is regarded as a prime candidate for powering fast and bright flares. We present a novel analytical model—supported and benchmarked with largescale threedimensional kinetic particleincell simulations in electron–positron plasmas—that elucidates the physics governing the generation of powerlaw energy spectra in relativistic reconnection. Particles with Lorentz factor
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