It is shown with a particle simulation that the outer gap can be reproduced under a few simple assumptions. The simulation includes just the first principles, namely Maxwell's equations, a relativistic equation of motion with radiation drag, and electron-positron pair creation. We also suggest that the Y-point (the open-close boundary in the equator) is likely to be a place of heating and acceleration of plasma, and therefore it would cause high-energy emission. The dead zone along the separatrix of the oppositely directed current is found in the middle latitude region, which separates the outer gap and the polar cap accelerators.

The inductive electric field is unjustifiably neglected in most models for pulsar electrodynamics; it cannot be screened by the magnetospheric plasma, and it is not small in comparison with the corotation electric field. The perpendicular component of the inductive electric field implies a drift motion that is inconsistent with corotation at any angular velocity. Some implications of the inductive electric field and the associated drift motion are discussed.

Current models of pulsar magnetospheres typically assume either a complete absence of plasma or abundant ideal plasma filling the magnetosphere in order to compute the field structure. The latter condition is thought to be closer to reality, but we know of a number of pulsars in which the ideal conditions break down, resulting in dissipation and high-energy emission. In this work we formulate a resistive force-free scheme that allows us to consider the effects of resistive plasma and accelerating fields on the magnetospheric structure. We run numerical simulations to construct a family of resistive solutions that smoothly bridges the gap between the vacuum and the force-free magnetosphere solutions. We further provide a self-consistent model for the spin-down of intermittent pulsars, pulsars which appear to transition between radio-loud and radio-quiet states with different spin-down rates. Finally, we present models for high-energy emission from reconnecting current sheets in Gamma-ray pulsars.

The inner workings of pulsar magnetospheres have fascinated and confused researchers since the discovery of pulsars. I will review the status of magnetospheric models, including vacuum, space-charge-limited and resistive force-free MHD. I will highlight model predictions for the integrated pulsar quantities (such as spin down and torques) and the observational consequences of calculated magnetic field structure. Particularly, high-energy emission from pulsars allows putting new constraints on the geometry of the emission region and the physics of particle acceleration in the magnetosphere.

Pulsars are potentially the most remarkable physical laboratories we will ever use. Although in many senses they are extremely clean systems there are a large number of instabilities and variabilities seen in the emission and rotation of pulsars. These need to be recognised in order to both fully understand the nature of pulsars, and to enable their use as precision tools for astrophysical investigations. Here I describe these effects, discuss the wide range of timescales involved, and consider the implications for precision pulsar timing.

Highly symmetric double features observed in averaged pulsar profiles can be interpreted as the imprint of microscopic radiation beam characteristic of radiative mechanism operating in pulsar magnetosphere. The data put strong constraints on the possible radiation patterns, excluding entire classes of mechanisms, such as those based on parallel acceleration, or those that have complicated beams. Instead, several properties of double features (such as their symmetry, depth, shape, merging rate, large polarisation degree, and the association with bifurcated emission components) are consistent with the extraordinary-mode part of the curvature radiation beam. This shows that double notches are a clear signature of the curvature radiation process. We show that even with the emission process fixed, detailed modelling of double features remains a rather sophisticated and demanding task.

The 2nd Fermi-LAT pulsar catalog includes 117 γ-ray pulsars, of which roughly one third are millisecond pulsars (MSPs) while the remaining two thirds split evenly into young radio-loud and radio-quiet pulsars. Although this large population will enable future, detailed studies of emission mechanisms and the evolution of the underlying neutron star population, some nearly-universal properties are already clear and unequivocal. We discuss some of these aspects below, including the altitude of the γ-ray emission site, the shape of the γ-ray spectrum, and the implications of the latter for the radiation mechanism.

We studied the radio spectrum of PSR B1259-63 in an unique binary with Be star LS 2883 and showed that the shape of the spectrum depends on the orbital phase. We proposed a qualitative model which explains this evolution. We considered two mechanisms that might influence the observed radio emission: free-free absorption and cyclotron resonance. Recently published results have revealed a new aspect in pulsar radio spectra. There were found objects with turnover at high frequencies in spectra, called gigahertz-peaked spectra (GPS) pulsars. Most of them adjoin such interesting environments as HII regions or compact pulsar wind nebulae (PWN). Thus, it is suggested that the turnover phenomenon is associated with the environment than being related intrinsically to the radio emission mechanism. Having noticed the apparent resemblance between the B1259-63 spectrum and the GPS, we suggest that the same mechanisms should be responsible for both cases. Therefore, the case of B1259-63 can be treated as a key factor to explain the GPS phenomenon observed for the solitary pulsars with interesting environments and also another types of spectra (e.g. with break).

Pulsars are arguably the only astrophysical sources whose emission spans the entire electromagnetic spectrum, from decameter radio wavelengths to TeV energies. The LOw Frequency ARray (LOFAR) offers the unique possibility to study pulsars over a huge fractional bandwidth in the bottom 4 octaves of the radio window, from 15–240 MHz. Here we present a LOFAR study of pulsar single pulses, focussing specifically on the bright nearby pulsar B0809+74. We show that the spectral width of bright low-frequency pulses can be as narrow as 1 MHz and scales with increasing frequency as Δ f/fc ~ 0.15, at least in the case of the PSR B0809+74. This appears to be intrinsic to the pulsar, as opposed to being due to propagation effects. If so, this behavior is consistent with predictions by the strong plasma turbulence model of pulsar radio emission. We also present other observed properties of the single pulses and discuss their relation to other single-pulse phenomena like giant pulses.

We present high-sensitivity XMM/LOFAR observations that show for the first time that mode switching extends from radio to X-ray. In pulsar B0943+10, the known changes in radio profile and drift rate are confidently tied to simultaneous changes in X-ray emission.

In mode switching, seen in many pulsars, profile and subpulse-drift behavior change almost instantaneously. The mechanism for these drastic changes, or for the bi-stable emission behavior, is not understood; while even for the basic emission mechanism different families of theories (e.g. vacuum gap, or space-charge limited flow models) exist.

To discriminate between such models, we carried out a campaign of 42 hours of simultaneous LOFAR/XMM-Newton observations on PSR B0943+10. Through LOFAR's unparalleled low-frequency sensitivity, mode changes were pinpointed to 10-second accuracy. XMM X-ray photons were next separated by the two radio modes. We discovered large modal differences in the X-ray pulsations, flux, and spectral shapes: in the radio-bright mode, no X-ray pulsations are detected – but in the radio-quiet mode, B0943+10 is strongly pulsating in X-ray.

We are currently undertaking a monitoring campaign with NASA 70-m antennas to capture a large sample of Crab Giant Pulses (CGP) at multiple radio wavelengths. The goal of this campaign is to carry out a correlation study of CGPs at radio frequencies with pulsed emission from the Crab pulsar with Fermi photons at X-ray. After a year of this study, we expect around 200 Fermi photons to coincide with a CGP radio-frequency detection, allowing us to either confirm a predicted correlation in average gamma-ray pulsed flux increase with GP emission, or place a tight upper limit, at least a factor of 10 more constraining than previous work. We will report on the status of this campaign and will present our preliminary results and prospects for future improvements in receivers and back-end instrumentation.

The National Astronomical Observatories, Chinese Academy of Science (NAOC), has started building the largest antenna in the world. Known as FAST, the Five-hundred-meter Aperture Spherical radio Telescope is a Chinese mega-science project funded by the National Development and Reform Commission (NDRC). FAST also represents part of Chinese contribution to the international efforts to build the square kilometer array (SKA). Upon its finishing around September of 2016, FAST will be the most sensitive single-dish radio telescope in the low frequency radio bands between 70 MHz and 3 GHz. The design specifications of FAST, its expected capabilities, and its main scientific aspirations were described in an overview paper by Nan et al. (2011). In this paper, we briefly review the design and the key science goals of FAST, speculate the likely limitations at the initial stages of FAST operation, and discuss the opportunities for astronomical discoveries in the so-called early science phase.

NASA's NuSTAR observatory is the first focusing hard X-ray telescope. Launched in June 2012, NuSTAR is sensitive in the 3–79 keV range with unprecedented ~17″ FWHM angular resolution above 12 keV, a result of its multilayer-coated optics and 10-m focal length. With its large effective area (900 cm2 at 10 keV), NuSTAR has point-source sensitivity ~100 times better than previous hard X-ray telescopes. Here we describe NuSTAR and its planned work on rotation-powered pulsars and magnetars during its nominal 2-yr baseline mission that has just commenced.

The Square Kilometre Array (SKA) is a global project to design and construct the next-generation international radio telescope operating at metre to cm wavelengths. The SKA will be an interferometric array with a collecting area of up to one million square metres and maximum baseline of at least 3000 km, and is designed to address fundamental questions in cosmology, physics and astronomy. The key science goals range from the epoch of re-ionization, dark energy, the formation and evolution of galaxies and large-scale structure, the origin and evolution of cosmic magnetism, strong-field tests of gravity and detection of gravity waves.

The SKA project is now entering a final design for an SKA Observatory to begin to be built in the latter half of this decade that will include facilities in South Africa and Western Australia. The SKA design relies on advances in several technologies that will be prototyped over the next few years, and demonstrated for astronomical observations on SKA precursor telescopes. Scientific operations of the first 10% scale phase of the SKA is targeted for 2020.

This meeting started with a bang, with the announcement of what appears to be another ‘Lorimer burst’. Two more ‘diamond planets’, white dwarf binary companions made of crystalline carbon, quickly followed. This drama in the first session gave way to numerous interesting, surprising results. We still have not found a pulsar orbiting a black hole, but we do have the first triple system with the pulsar in the inner binary and a main sequence star forming the outer part of the binary; it may allow tests of the Equivalence Principle. Another close binary may allow checking for dipolar gravitational radiation. Work on the spin-up of millisecond pulsars is better determining the mass accreted during the spin-up and more sophisticated determination of their ages. Indications of more high mass (~2M⊙) pulsars will allow constraints to be placed on the Equation of State for a neutron star. As was remarked, ‘We keep finding cool new pulsars wherever we look!’; Duncan Lorimer predicted we would know of 4000 pulsars by 2020, a doubling of the present number.

To study the origin of magnetars, a unique opportunity is provided by detecting an excess of X-ray thermal radiation of the radio pulsars (rotation powered pulsars) with dipolar magnetic fields as high as magnetars. The excess is probably caused by decay of the magnetic field as seen in magnetars. In order to investigate whether the rotation powered pulsars have the excess flux and the hard-tail component similar to magnetars, we observed PSR J0726-2612 which has a 3.44 s period and a 3 × 1013 G inferred dipolar magnetic field, with Suzaku for 44 ks on 2011 November 16-17. We report this observational result. We also compare with other observations and discuss a decaying of the magnetic field for normal radio pulsars.

It is generally acknowledged that Type II supernovae result from the collapse of iron core of a massive star which, at least in some cases, produces a neutron star. At this stage, the neutrinos are produced by neutronization which speeds up as collapse continues. During collapse an outward bound shock wave forms in the matter falling onto the nearly stationary core. The conditions behind the shock at 100 to 200 km are suitable for neutrino heating. This neutrino heating blows a hot bubble above the protoneutron star and is the most important source of energy for Supernova explosion. At this stage, we try to attain the r-process (rapid neutron capture process) path responsible for the production of heavy elements beyond iron, which are otherwise not possible to be formed by fusion reactions. The most interesting evolution occurs as temperature falls from 1010 K to 109 K. At these high temperature conditions, the critical fluids after fusion reactions are forbidden and transform into the respective atoms by r-process path which on beta decaying produce the ultimate elements of the periodic chart.

Another astrophysical parameter needed for our analysis is neutron number density which we take to be greater than 1020 cm−3. With these, at different entropy environments, we assign the neutron binding energy that represents the r-process path in the chart of nuclides. Along the path, the experimental data of observed elements matches our calculated one. We find that an entropy of ~300 with Ye ≃ 0.45 can lead to a successful r-process. It produced heavy neutron-rich nuclei with A ≃ 80 – 240. Later ejecta are neutron-rich (Ye ≤ 0.5) and leaves behind a compact neutron star.

We report on the long term X-ray monitoring with Swift, RXTE, Suzaku, Chandra, and XMM-Newton of the outburst of the newly discovered magnetar Swift J1822.3–1606 (SGR 1822-1606), from the first observations soon after the detection of the short X-ray bursts which led to its discovery (July 2011), through the first stages of its outburst decay (April 2012). Our X-ray timing analysis finds the source rotating with a period of P = 8.43772016(2) s and a period derivative Ṗ = 8.3(2) × 10−14 ss−1, which entails an inferred dipolar surface magnetic field of B ≃ 2.7 × 1013 G at the equator. This measurement makes Swift J1822.3–1606 the second lowest magnetic field magnetar (after SGR 0418+5729; Rea et al. 2010). Following the flux and spectral evolution from the beginning of the outburst, we find that the flux decreased by about an order of magnitude, with a subtle softening of the spectrum, both typical of the outburst decay of magnetars. By modeling the secular thermal evolution of Swift J1822.3–1606, we find that the observed timing properties of the source, as well as its quiescent X-ray luminosity, can be reproduced if it was born with a poloidal and crustal toroidal fields of Bp ~ 1.5 × 1014 G and Btor ~ 7 × 1014 G, respectively, and if its current age is ~550 kyr (Rea et al. 2012).

We study the impact of a hadron-quark phase transition on the maximum neutron-star mass. The hadronic part of the equation of state relies on the most up-to-date Skyrme nuclear energy density functionals, fitted to essentially all experimental nuclear mass data and constrained to reproduce the properties of infinite nuclear matter as obtained from microscopic calculations using realistic forces. We show that the softening of the dense matter equation of state due to the phase transition is not necessarily incompatible with the existence of massive neutron stars like PSR J1614–2230.

We have recently developed a set of equations of state based on the nuclear energy density functional theory providing a unified description of the different regions constituting the interior of neutron stars and magnetars. The nuclear functionals, which were constructed from generalized Skyrme effective nucleon-nucleon interactions, yield not only an excellent fit to essentially all experimental atomic mass data but were also constrained to reproduce the neutron-matter equation of state as obtained from realistic many-body calculations.