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Recently, many different pulsar timing array (PTA) collaborations have reported strong evidence for a common stochastic process in their data sets. The reported amplitudes are in tension with previously computed upper limits. In this paper,…

High Energy Astrophysical Phenomena · Physics 2022-06-29 Aaron D. Johnson , Sarah J. Vigeland , Xavier Siemens , Stephen R. Taylor

Pulsar glitches, sudden jumps in frequency in otherwise steadily spinning down radio pulsars, offer a unique glimpse into the superfluid interior of neutron stars. The exact trigger of these events remains, however, elusive and this has…

High Energy Astrophysical Phenomena · Physics 2018-02-16 Pierre Pizzochero , Marco Antonelli , Brynmor Haskell , Stefano Seveso

Pulsars are known to display short-term variability. Recently, examples of longer-term emission variability have emerged that are often correlated with changes in the rotational properties of the pulsar. To further illuminate this…

High Energy Astrophysical Phenomena · Physics 2016-01-27 P. R. Brook , A. Karastergiou , S. Johnston , M. Kerr , R. M. Shannon , S. J. Roberts

The magnitude of the topological charge of the vortex of a ring-shaped pulse is found to be limited by the squared mean frequency of the pulse spectrum at the ring relative to its variance. This limitation implies a upper bound to the…

Optics · Physics 2019-04-03 Miguel A. Porras

The majority of fast millisecond pulsars are in binary systems, so that any periodic signal they emit is modulated by both Doppler and relativistic effects. Here we show how well-established binary models can be used to account for these…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Matthew Pitkin , Graham Woan

Magnetars are a kind of pulsars powered mainly by superhigh magnetic fields. They are popular sources with many unsolved issues in themselves, but also linked to various high energy phenomena, such as QPOs, giant flares, fast radio bursts…

High Energy Astrophysical Phenomena · Physics 2021-03-31 Zhi-Fu Gao , Hao Shan , Hui Wang

We study the effect of retardation of gravity in binary pulsars. It appears in pulsar timing formula as a periodic excess time delay to the Shapiro effect. The retardation of gravity effect can be large enough for observation in binary…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sergei M. Kopeikin

Aims. To investigate the flux density modulation from pulsars and the existence of specific behaviour of modulation index versus frequency. Methods. Several pulsars have been observed with the Effelsberg radio telescope at 8.35 GHz. Their…

Solar and Stellar Astrophysics · Physics 2015-06-15 O. Maron , M. Serylak , J. Kijak , K. Krzeszowski , D. Mitra , A. Jessner

It is now known that the emission from radio pulsars can vary over a wide range of timescales, from fractions of seconds to decades. However, it is not yet known if long- and short-term emission variability are caused by the same physical…

High Energy Astrophysical Phenomena · Physics 2019-08-28 Paul Brook , Aris Karastergiou , Simon Johnston

The gravitational wave emission by a distorted rotating fluid star is computed. The distortion is supposed to be symmetric around some axis inclined with respect to the rotation axis. In the general case, the gravitational radiation is…

Astrophysics · Physics 2014-10-13 S. Bonazzola , E. Gourgoulhon

Pulsars are remarkably precise "celestial clocks" that can be used to explore many different aspects of physics and astrophysics. In this article I give a brief summary of pulsar properties and describe some of the applications of pulsar…

High Energy Astrophysical Phenomena · Physics 2018-01-16 R N Manchester

The prospects for detection of gravitational waves from precessing pulsars have been considered by constructing fully relativistic rotating neutron star models and evaluating the expected wave amplitude $h$ from a galactic source. For a…

Astrophysics · Physics 2016-06-08 J. C. N. de Araújo , J. A. de Freitas Pacheco , J. E. Horvath , M. Cattani

We revisit the decay of the orbital period in binary systems that occurs due to the emission of gravitational waves in the context of modified gravity models where the coupling $G_{gw}$ between matter and on-shell gravitons is allowed to…

General Relativity and Quantum Cosmology · Physics 2022-11-22 Diego Santos de Jesus , Hermano Velten , Federico Piazza

We present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near-zone torques associated with the inertia of dipole and quadrupole magnetic fields. We incorporate these…

Solar and Stellar Astrophysics · Physics 2015-06-12 J. J. Zanazzi , Dong Lai

The pulsar magnetic inclination angle is a key parameter for pulsar physics. It influences the observable properties of pulsars, such as the pulse beam width, braking index, polarisation, and emission geometry. In this study, we give a…

High Energy Astrophysical Phenomena · Physics 2024-04-24 Biao-Peng Li , Wen-Qi Ma , Zhi-Fu Gao

The following results of dissertation are submitted for defense: 1. Precise measurements of coordinates and proper motion of the pulsar PSR 0329+54 using the VLBI method. 2. Establishing of the reason for the discrepancy between the…

Instrumentation and Methods for Astrophysics · Physics 2024-01-25 Alexander Evgenievich Rodin

Though pulsars spin regularly, the differences between the observed and predicted ToA (time of arrival), known as "timing noise", can still reach a few milliseconds or more. We try to understand the noise in this paper. As proposed by Xu &…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Xiongwei Liu , Xuesen Na , Renxin Xu , Guojun Qiao

The observed values of the rate of change of the orbital and the spin periods of pulsars are affected by different dynamical effects, for example, the line-of-sight acceleration and the proper motion of the pulsar relative to the sun. We…

Instrumentation and Methods for Astrophysics · Physics 2018-12-04 Dhruv Pathak , Manjari Bagchi

I summarize recent observations of the kinematics of hot tracers in elliptical galaxy halos (globular clusters, planetary nebulae, and integrated stellar light), and what these tell us about the dynamics, dark matter content, and formation…

Astrophysics · Physics 2007-05-23 Terry Bridges

Providing a link between magnetars and radio pulsars, high magnetic field neutron stars are ideal targets to investigate how bursting/magnetospheric activity and braking torque variations are connected to rotational glitches. The last…

High Energy Astrophysical Phenomena · Physics 2015-06-23 D. Antonopoulou , P. Weltevrede , C. M. Espinoza , A. L. Watts , S. Johnston , R. M. Shannon , M. Kerr