We present and analyse a catalogue of 233 pulsars with proper motion measurements. The sample contains a wide variety of pulsars including recycled objects and those associated with globular clusters or supernova remnants. After taking the most precise proper motions for those pulsars for which multiple measurements are available, the majority of the proper motions (58 per cent) are derived from pulsar timing methods, 41 per cent using interferometers and the remaining 1 per cent using optical telescopes. Many of the one-dimensional (1D) and two-dimensional (2D) speeds (referring to speeds measured in one coordinate only and the magnitudes of the transverse velocities, respectively) derived from these measurements are somewhat lower than earlier estimates because of the use of the most recent electron density model in determining pulsar distances. The mean 1D speeds for the normal and recycled pulsars are 152(10) and 54(6) km s −1 , respectively. The corresponding mean 2D speeds are 246(22) and 87(13) km s −1 . PSRs B2011+38 and B2224+64 have the highest inferred 2D speeds of ∼1600 km s −1 .W estudy the mean speeds for different subsamples and find that, in general, they agree with previous results. Applying a novel deconvolution technique to the sample of 73 pulsars with characteristic ages less than 3 Myr, we find the mean threedimensional (3D) pulsar birth velocity to be 400(40) km s −1 . The distribution of velocities is well described by a Maxwellian distribution with 1D rms σ = 265 km s −1 . There is no evidence for a bimodal velocity distribution. The proper motions for PSRs B1830−08 and B2334+61 are consistent with their proposed associations with the supernova remnants W41 and G114.3+0.3, respectively. Ke yw ords: stars: kinematics ‐ pulsars: general.

A statistical study of 233 pulsar proper motions

Tempo2 is a new software package for the analysis of pulsar pulse times of arrival. In this paper we describe in detail the timing model used by tempo2, and discuss limitations on the attainable precision. In addition to the intrinsic slow-down behaviour of the pulsar, tempo2 accounts for the effects of a binary orbital motion, the secular motion of the pulsar or binary system, interstellar, Solar system and ionospheric dispersion, observatory motion (including Earth rotation, precession, nutation, polar motion and orbital motion), tropospheric propagation delay, and gravitational time dilation due to binary companions and Solar system bodies. We believe the timing model is accurate in its description of predictable systematic timing effects to better than one nanosecond, except in the case of relativistic binary systems where further theoretical development is needed. The largest remaining sources of potential error are measurement error, interstellar scattering, Solar system ephemeris errors, atomic clock instability and gravitational waves.

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tempo2, a new pulsar timing package ¿ II. The timing model and precision estimates

We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M , a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44) orbit around an unevolved companion.

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Binary and Millisecond Pulsars

We report on timing, flux density, and polarimetric observations of the transient magnetar and 5.54 s radio pulsar XTE J1810-197 using the GBT, Nancay, and Parkes radio telescopes beginning in early 2006, until its sudden disappearance as a radio source in late 2008. Repeated observations through 2016 have not detected radio pulsations again. The torque on the neutron star, as inferred from its rotation frequency derivative f-dot, decreased in an unsteady manner by a factor of 3 in the first year of radio monitoring. In contrast, during its final year as a detectable radio source, the torque decreased steadily by only 9%. The period-averaged flux density, after decreasing by a factor of 20 during the first 10 months of radio monitoring, remained steady in the next 22 months, at an average of 0.7+/-0.3 mJy at 1.4 GHz, while still showing day-to-day fluctuations by factors of a few. There is evidence that during this last phase of radio activity the magnetar had a steep radio spectrum, in contrast to earlier behavior. There was no secular decrease that presaged its radio demise. During this time the pulse profile continued to display large variations, and polarimetry indicates that the magnetic geometry remained consistent with that of earlier times. We supplement these results with X-ray timing of the pulsar from its outburst in 2003 up to 2014. For the first 4 years, XTE J1810-197 experienced non-monotonic excursions in f-dot by at least a factor of 8. But since 2007, its f-dot has remained relatively stable near its minimum observed value. The only apparent event in the X-ray record that is possibly contemporaneous with the radio shut-down is a decrease of ~20% in the hot-spot flux in 2008-2009, to a stable, minimum value. However, the permanence of the high-amplitude, thermal X-ray pulse, even after the radio demise, implies continuing magnetar activity.

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High-precision timing of 42 millisecond pulsars with the European Pulsar Timing Array

The highly stable spin of neutron stars can be exploited for a variety of (astro)physical investigations. In particular, arrays of pulsars with rotational periods of the order of milliseconds can be used to detect correlated signals such as those caused by gravitational waves. Three such 'pulsar timing arrays' (PTAs) have been set up around the world over the past decades and collectively form the 'International' PTA (IPTA). In this paper, we describe the first joint analysis of the data from the three regional PTAs, i.e. of the first IPTA data set. We describe the available PTA data, the approach presently followed for its combination and suggest improvements for future PTA research. Particular attention is paid to subtle details (such as underestimation of measurement uncertainty and long-period noise) that have often been ignored but which become important in this unprecedentedly large and inhomogeneous data set. We identify and describe in detail several factors that complicate IPTA research and provide recommendations for future pulsar timing efforts. The first IPTA data release presented here (and available on-line) is used to demonstrate the IPTA's potential of improving upon gravitational-wave limits

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The International Pulsar Timing Array: First Data Release

We present long-term timing observations of four millisecond radio pulsars with the 305 m Arecibo and the 100 m Effelsberg radiotelescopes. Our analysis of the combined pulse time-of-arrival data from the two telescopes has led to improvements of the precision of timing parameter determination for all the four pulsars. A new, much more significant measurement of a third-order spin frequency derivative of PSR B1257+12 adds to the existing evidence that a fourth, distant planet may orbit this pulsar. Proper motions have been measured for PSR J1640+2224, PSR B1953+29, and PSR J2229+2643. The derived low transverse velocities of these objects agree with the kinematic characteristics of the observed millisecond pulsar population. Exceptionally low spindown rates of PSR J1640+2224 and PSR J2229+2634 have been used to derive useful limits on the initial spin periods of these objects and on the variation of the gravitational constant G.

Timing Observations of Four Millisecond Pulsars with the Arecibo and Effelsberg Radio Telescopes

Multifrequency observations of the planet pulsar PSR B1257+12 have been made to examine a possibility that the 25.3 day periodicity observed in its pulse timing residuals represents a variable delay generated by solar rotation-induced density fluctuations in the solar wind. New timing measurements of the pulsar show that the amplitude of these residuals is frequency independent, implying that the periodicity cannot be caused by any arrival time delays related to the pulse propagation through an ionized medium. Therefore, in agreement with the original assumption, the observed 25.3 day pulse timing periodicity is most plausibly explained in terms of the orbital motion of a low-mass planet around the pulsar.

A 25.3 day periodicity in the timing of the pulsar PSR B1257+12: A planet or a heliospheric propagation effect?

Using the pulse arrival time measurements of the pulsar PSR B0329+54 made between 1994 and 1998 with the 100 m Effelsberg and the 32 m Torun radio telescopes supplemented with the archival JPL data, we demonstrate that the planets suggested to orbit this ~ 5 × 106 yr old object are unlikely to be real. The previously proposed timing models, including 3 and 16.8 yr orbits of terrestrial-mass planets, fail to predict the pulse arrival times at later epochs. If this pulsar has planetary companions, the remaining possibilities include low-mass objects that are below the current detection threshold, multiple terrestrial-mass planets in orbits whose superposition could produce the timing noiselike effects, and any planets with orbital periods significantly exceeding the 30 yr data span. However, it is likely that the observed variations in timing residuals of PSR B0329+54 are caused by spin irregularities that are intrinsic to this relatively young neutron star.

/pdf/are-there-planets-around-the-pulsar-psr-b0329-54-17uk4bxk90.pdf

Are There Planets around the Pulsar PSR B0329+54?

We present a new analysis of the dynamics of the planetary system around the pulsar B1257+12. A semianalytical theory of perturbation between terrestrial-mass planets B and C is developed and applied to improve the multiorbit timing formula for this object. We use numerical simulations of the pulse arrival times for PSR B1257+12 to demonstrate that our new timing model can serve as a tool to determine the masses of the two planets.

http://iopscience.iop.org/article/10.1086/317233/pdf

Improved Timing Formula for the PSR B1257+12 Planetary System

In this paper we present a new method that can be used for analysis of times of arrival (TOAs) of pulsar pulses. It is especially designed to detect quasi-periodic variations of TOAs. We apply our method to timing observations of PSR B1257+12 and demonstrate that by using it, it is possible to detect not only first harmonics of a periodic variations, but also the presence of a resonance effect. The resonance effect detected independently of its physical origin can appear only when there is a nonlinear interaction between two periodic modes. The explanation of TOAs variations as an effect of the existence of planets was, until now, the only known and well-justified explanation. In this context, the existence of the resonance frequency in TOAs is the most significant signature of the gravitational interaction of planets.

Maciej Konacki

Papers

Timing Observations of Four Millisecond Pulsars with the Arecibo and Effelsberg Radio Telescopes

A 25.3 day periodicity in the timing of the pulsar PSR B1257+12: A planet or a heliospheric propagation effect?

Are There Planets around the Pulsar PSR B0329+54?

Improved Timing Formula for the PSR B1257+12 Planetary System

Resonance in PSR B1257+12 Planetary System