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The observed long-term spin-down evolution of isolated radio pulsars cannot be explained by the standard magnetic dipole radiation with a constant braking torque. However, how and why the torque varies still remains controversial, which is…

高能天体物理现象 · 物理学 2014-03-25 Yi Xie , Shuang-Nan Zhang

We present evidence for chaotic dynamics within the spin-down rates of 17 pulsars originally presented by Lyne et al. Using techniques that allow us to re-sample the original measurements without losing structural information, we have…

太阳与恒星天体物理 · 物理学 2012-11-05 A. D. Seymour , D. R. Lorimer

Stochastic temporal wandering of the spin frequency $\nu$ of a rotation-powered pulsar (i.e.~the achromatic component of timing noise unrelated to interstellar propagation) affects the accuracy with which the secular braking torque can be…

高能天体物理现象 · 物理学 2023-05-17 Andrés F. Vargas , Andrew Melatos

Pulsars are famed for their rotational clock-like stability and their highly-repeatable pulse shapes. However, it has long been known that there are unexplained deviations (often termed "timing noise") from the rate at which we predict…

星系天体物理 · 物理学 2010-06-29 Andrew Lyne , George Hobbs , Michael Kramer , Ingrid Stairs , Ben Stappers

We model the evolution of the magnetic fields of neutron stars as consisting of a long term power-law decay modulated by short term small amplitude oscillations. Our model predictions on the timing noise $\ddot\nu$ of neutron stars agree…

高能天体物理现象 · 物理学 2015-06-04 Shuang-Nan Zhang , Yi Xie

Recent radio pulsar observations have shown that a number of pulsars display interesting long term periodicities in their spin-down rates. At least some of these pulsars also undergo sharp changes in pulse profile. This has been…

太阳与恒星天体物理 · 物理学 2015-05-28 D. I. Jones

Eight pulsars have low braking indices, which challenge the magnetic dipole braking of pulsars. 222 pulsars and 15 magnetars have abnormal distribution of frequency second derivatives, which also make contradiction with classical…

高能天体物理现象 · 物理学 2016-02-03 Z. W. Ou , H. Tong , F. F. Kou , G. Q. Ding

We report on a timing programme of 74 young pulsars that have been observed by the Parkes 64-m radio telescope over the past decade. Using modern Bayesian timing techniques, we have measured the properties of 124 glitches in 52 of these…

Pulsars are stars that emit electromagnetic radiation in well-defined time intervals. The frequency of such pulses decays with time as is quantified by the {\it braking index} ($n$). In the canonical model $n = 3$ for all pulsars, but…

高能天体物理现象 · 物理学 2018-11-28 H. O. Oliveira , N. S. Magalhaes , R. M. Marinho , G. A. Carvalho , C. Frajuca

Here we report that the observed braking indices of the 366 pulsars in the sample of Hobbs et al. range from about $-10^8$ to about $+10^8$ and are significantly correlated with their characteristic ages. Using the model of magnetic field…

高能天体物理现象 · 物理学 2013-12-12 Shuang-Nan Zhang , Yi Xie

We have observed a total of 67 pulsars at five frequencies ranging from 243 to 3100 MHz. Observations at the lower frequencies were made at the Giant Metre Wave Telescope in India and those at higher frequencies at the Parkes Telescope in…

天体物理学 · 物理学 2009-11-13 Simon Johnston , Aris Karastergiou , Dipanjan Mitra , Yashwant Gupta

We performed a timing analysis of the 2003 outburst of the accreting X-ray millisecond pulsar XTE J1807-294 observed by RXTE. Using recently refined orbital parameters we report for the first time a precise estimate of the spin frequency…

天体物理学 · 物理学 2009-11-13 A. Riggio , T. Di Salvo , L. Burderi , M. T. Menna , A. Papitto , R. Iaria , G. Lavagetto

Using pulsewidth data for 872 isolated radio pulsars we test the hypothesis that pulsars evolve through a progressive narrowing of the emission cone combined with progressive alignment of the spin and magnetic axes. The new data provide…

高能天体物理现象 · 物理学 2015-05-14 Matthew D. T. Young , Lee S. Chan , Ron R. Burman , David G. Blair

Unexpected sign, significant magnitude and time-variation of frequency second derivative exist not only in singular radio pulsars but also in Soft Gamma repeaters (SGRs) and Anomalous X-ray pulsars (AXPs). This paper shows that the these…

天体物理学 · 物理学 2016-08-30 Biping Gong

We investigate the impact of noise processes on high-precision pulsar timing. Our analysis focuses on the measurability of the second spin frequency derivative $\ddot{\nu}$. This $\ddot{\nu}$ can be induced by several factors including the…

高能天体物理现象 · 物理学 2019-07-09 X. J. Liu , M. J. Keith , C. Bassa , B. W. Stappers

The way pulsars spin down is not understood in detail, but a number of possible physical mechanisms produce a spin-down rate that scales as a power of the rotation rate ($\dot\nu\propto-\nu^n$), with the power-law index $n$ called the…

The departure of all measured pulsar braking indexes from the "canonical" dipole value 3 has been attributed to several causes in the past. Careful monitoring of the Crab pulsar has revealed permanent changes in the spin-down rate which are…

高能天体物理现象 · 物理学 2019-01-23 J. E. Horvath

The observed fraction of pulsars with interpulses, their period distribution and the observed pulse width versus pulse period correlation is shown to be inconsistent with a model in which the angle alpha between the magnetic axis and the…

天体物理学 · 物理学 2009-11-13 Patrick Weltevrede , Simon Johnston

The braking index, $n$, of a pulsar is a measure of its angular momentum loss and the value it takes corresponds to different spin-down mechanisms. For a pulsar spinning down due to gravitational wave emission from the principal mass…

高能天体物理现象 · 物理学 2025-03-27 A. L. Hewitt , M. Pitkin , I. M. Hook

Aims. We explore frequency-dependent changes in pulsar radio emission by analyzing their profile widths and emission heights, assessing whether the simple radius-to-frequency mapping (RFM) or the fan beam model can describe the data.…

高能天体物理现象 · 物理学 2026-01-14 P. Jaroenjittichai , S. Johnston , S. Dai , M. Kerr , M. E. Lower , R. N. Manchester , L. S. Oswald , R. M. Shannon , C. Sobey , P. Weltevrede