Gamma-ray pulsars: A gold mine

Abstract

The most energetic neutron stars, powered by their rotation, are capable of producing pulsed radiation from the radio up to γ rays with nearly TeV energies. These pulsars are part of the universe of energetic and powerful particle accelerators, using their uniquely fast rotation and formidable magnetic fields to accelerate particles to ultra-relativistic speed. The extreme properties of these stars provide an excellent testing ground, beyond Earth experience, for nuclear, gravitational, and quantum-electrodynamical physics. A wealth of γ-ray pulsars has recently been discovered with the Fermi Gamma-Ray Space Telescope. The energetic γ rays enable us to probe the magnetospheres of neutron stars and particle acceleration in this exotic environment. We review the latest developments in this field, beginning with a brief overview of the properties and mysteries of rotation-powered pulsars, and then discussing γ-ray observations and magnetospheric models in more detail. RésuméLes pulsars γ : une mine d'or : Lesétoilesà neutrons les plus puissantes, qui tirent leurénergie de leur rotation, sont capables d'émettre des impulsions lumineuses des ondes radio jusqu'aux rayons γ d'énergies proches du TeV. Ces pulsars font partie des puissants accélérateurs de particules de l'Univers, profitant de leur rotation unique et de leur formidable champ magnétique pour accélérer des particules jusqu'à des vitesses ultra-relativistes. Les propriétés extrêmes de cesétoiles permettent de tester la physique nucléaire, la gravitation et l'électrodynamique quantique dans des conditions inaccessibles sur Terre. Le télescope gamma spatial Fermi vient de révéler un richeéchantillon de pulsars γ. Leur rayonnement γénergétique permet de sonder la magnétosphère desétoilesà neutrons et d'étudier l'accélération de particules dans cet environnement exotique. Nous présentons les derniers développements de ce domaine, en commençant par une rapide revue des propriétés et mystères soulevés par ces pulsars, puis en détaillant plus avant les observations γ et les modèles magnétosphériques.Keywords : pulsar ; neutron star ; magnetosphere ; gamma rays ; acceleration Mots-clés : pulsar ;étoileà neutrons ; magnétosphère ; rayons gamma ; accélération Neutron stars, pulsars, and their puzzlesA neutron star is an extreme object in many regards. It is a compact, rapidly spinning, highly magnetized star, formed from the core of a massive star which runs out of nuclear power and collapses under its own gravity, with 53 radio-loud and γ-loud young pulsars (orange upward triangles), 37 radio-faint and γ-loud young pulsars (red downward triangles), 71 radio-loud and γ-loud millisecond pulsars (green filled circles, circled in black and red when in black-widow and redback systems, respectively), and 2256 other radio pulsars (light blue). Recently discovered millisecond pulsars, with noṖ measurement yet, are plotted as squares atṖ near 10 −21 . Lines of constant spin-down power (brown) and polar magnetic field strength (green) are given for a magnetic dipole i...

The Search for Millisecond Pulsars – Implications from Fermi Observations and Future Prospects

“…This quickly confirmed that, despite the differences in the physical properties of MSPs and young pulsars (e.g. surface magnetic field strengths more than a thousand times lower), MSPs are also prolific gamma-ray emitters, and have pulse profiles remarkably similar to those of the young gamma-ray detected pulsars [9].…”

The Search for Millisecond Pulsars – Implications from Fermi Observations and Future Prospects

“…This quickly confirmed that, despite the differences in the physical properties of MSPs and young pulsars (e.g. surface magnetic field strengths more than a thousand times lower), MSPs are also prolific gamma-ray emitters, and have pulse profiles remarkably similar to those of the young gamma-ray detected pulsars [9].…”

Current closure in the pulsar magnetosphere

“…This simple relation tells us that for typical γ-ray pulsars with observed γ-ray luminosity efficiencies equal to 0.1% − 1% − 10%, the corresponding pair formation multiplicities are expected to lie in the range κ ≈ 500 − 50 − 5 respectively. Notice also that, if we assume that L γ /Ė is roughly proportional toĖ −1/2 as suggested by observations (Thompson 2008;Grenier & Harding 2015), then κ ∝Ė 1/2 . A final comment is in order here before we move on to the next section.…”

Influence of relativistic rotation on the confinement-deconfinement transition in gluodynamics

“…4(b)). 2 In order to assess systematic effects, in Fig. 4 we present the results for various lattice sizes.…”

The Search for Millisecond Pulsars – Implications from Fermi Observations and Future Prospects

“…This quickly confirmed that, despite the differences in the physical properties of MSPs and young pulsars (e.g. surface magnetic field strengths more than a thousand times lower), MSPs are also prolific gamma-ray emitters, and have pulse profiles remarkably similar to those of the young gamma-ray detected pulsars [9].…”

Current closure in the pulsar magnetosphere

“…This simple relation tells us that for typical γ-ray pulsars with observed γ-ray luminosity efficiencies equal to 0.1% − 1% − 10%, the corresponding pair formation multiplicities are expected to lie in the range κ ≈ 500 − 50 − 5 respectively. Notice also that, if we assume that L γ /Ė is roughly proportional toĖ −1/2 as suggested by observations (Thompson 2008;Grenier & Harding 2015), then κ ∝Ė 1/2 . A final comment is in order here before we move on to the next section.…”

Influence of relativistic rotation on the confinement-deconfinement transition in gluodynamics

“…4(b)). 2 In order to assess systematic effects, in Fig. 4 we present the results for various lattice sizes.…”

The Search for Millisecond Pulsars – Implications from Fermi Observations and Future Prospects

“…This quickly confirmed that, despite the differences in the physical properties of MSPs and young pulsars (e.g. surface magnetic field strengths more than a thousand times lower), MSPs are also prolific gamma-ray emitters, and have pulse profiles remarkably similar to those of the young gamma-ray detected pulsars [9].…”

Current closure in the pulsar magnetosphere

“…This simple relation tells us that for typical γ-ray pulsars with observed γ-ray luminosity efficiencies equal to 0.1% − 1% − 10%, the corresponding pair formation multiplicities are expected to lie in the range κ ≈ 500 − 50 − 5 respectively. Notice also that, if we assume that L γ /Ė is roughly proportional toĖ −1/2 as suggested by observations (Thompson 2008;Grenier & Harding 2015), then κ ∝Ė 1/2 . A final comment is in order here before we move on to the next section.…”

Influence of relativistic rotation on the confinement-deconfinement transition in gluodynamics

“…4(b)). 2 In order to assess systematic effects, in Fig. 4 we present the results for various lattice sizes.…”