Related papers: Tight constraint on photon mass from pulsar spindo…
We report the discovery of the first millisecond pulsar with a pulsating white dwarf companion. Following the recent discoveries of pulsations in extremely low-mass (ELM, <0.3 Msol) white dwarfs (WDs), we targeted ELM WD companions to two…
We report on a search for pulsars at the positions of eight low-mass white dwarfs and one higher-mass white dwarf with the 100-m Effelsberg Radio Telescope. These systems have orbital parameters suggesting that their unseen companions are…
Pulsars are the fast rotating neutron stars with strong magnetic field, that emit over a wide frequency range. In spite of the efforts during 40 years after the discovery of pulsars, the mechanism of their radio emission remains to be…
PSR J0751+1807 is a millisecond pulsar in a circular 6 hr binary system with a helium white dwarf secondary. Through high precision pulse timing measurements with the Arecibo and Effelsberg radio telescopes, we have detected the decay of…
We explore the possibility that the recently discovered white dwarf pulsar AR Sco acquired its high spin and magnetic field due to repeated episodes of accretion and spin-down. An accreting white dwarf can lead to a larger mass and…
It is generally accepted that the pulsar magnetic field converts most of its rotational energy losses into radiation. In this paper, we propose an alternative emission mechanism, in which neither the pulsar rotational energy nor its…
Millisecond pulsars are old neutron stars that have been spun up to high rotational frequencies via accretion of mass from a binary companion star. An important issue for understanding the physics of the early spin evolution of millisecond…
Low-mass white dwarfs (LMWDs) are believed to be exclusive products of binary evolution, as the Universe is not yet old enough to produce them from single stars. Because of the strong tidal forces operating during the binary interaction…
We consider the population of black widow pulsars (BWPs). The large majority of these are members of globular clusters. For minimum companion masses < 0.1 Msun, adiabatic evolution and consequent mass loss under gravitational radiation…
The notable absence of radio pulsars having measured magnetic dipole surface field strengths above $B_0\sim 3\times 10^{13}$ Gauss naturally raises the question of whether this forms an upper limit to pulsar magnetization. Recently there…
As is well known, pulsars are extremely stable rotators. However, although slowly, they spin down thanks to brake mechanisms, which are in fact still subject of intense investigation in the literature. Since pulsars are usually modelled as…
The effects of a nonzero photon rest mass can be incorporated into electromagnetism in a simple way using the Proca equations. In this vein, two interesting implications regarding the possible existence of a massive photon in nature, i.e.,…
We present detailed optical photo-polarimetric observations of the recently-discovered white dwarf pulsar AR Scorpii. Our extensive dataset reveals that the polarized emission is remarkably stable and repeatable with spin, beat and orbital…
Pulsar magnetospheres are filled with relativistic pairs copiously emitting photons detected from the radio wavelengths up to high and very high energies, in the GeV and sometimes in the TeV range. Efficient particle acceleration converts…
In view of the new recent observation and measurement of the rotating and highly-magnetized white dwarf AR Scorpii \cite{Marsh:2016uhc}, we determine bounds of its moment of inertia, magnetic fields and radius. Moreover, we investigate the…
The existence of pulsars with spin period below one millisecond is expected, though they have not been detected up to now. Their formation depends on the quantity of matter accreted from the companion which, in turn, is limited by the…
An observational model is presented for the spectra of young rotation-powered pulsars and their nebulae based on a study of nine bright Crab-like pulsar systems observed with the Chandra X-ray observatory. A significant correlation is…
Binary millisecond pulsars (MSPs) provide several opportunities for research of fundamental physics. However, finding them can be challenging. Several subdwarf B (sdB) binary systems with possible neutron star companions have been…
It is proposed that there exists a class of pulsars, called weak pulsars, for which the large-scale magnetosphere, and hence the gamma-ray emission, are independent of the detailed pattern of plasma production. The weak pulsar magnetosphere…
Our understanding of the universe at large and small scales relies largely on electromagnetic observations. As photons are the messengers, fundamental physics has a concern in testing their properties, including the absence of mass. We use…