Source of circular polarization in radio pulsars

ABSTRACT It is known that the concept of limiting polarization introduced 70 yr ago by K. G. Budden has the capacity to explain the magnitude of circular polarization seen in normal pulsars with light-cylinder radii of the order of 109–10 cm under the assumption of a high-multiplicity electron–positron plasma. However, a review of limiting polarization under the same assumption in millisecond pulsars indicates that it is inapplicable there because the region of limiting polarization lies far outside the light cylinder. This paper, using the ion–proton model, evaluates circular polarization both generally and specifically for J2144−3933, and gives a fairly detailed understanding of the observations in normal pulsars including the change of sign as a function of frequency seen in J0908−4913. But it also fails to explain circular polarization in millisecond pulsars owing to the smaller particle number densities and birefringence of the magnetosphere in these objects. However, the review of limiting polarization finds that, within the ion–proton model, this distinct process can describe their circular polarization. It is argued that certain features of millisecond pulsar Stokes profiles are clearly consistent with limiting polarization.

Download Full-text

The Galactic Millisecond Pulsar Population

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023769 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 237-242 ◽

Cited By ~ 4

Author(s):

Duncan R. Lorimer

Keyword(s):

Globular Clusters ◽

Gamma Ray ◽

Millisecond Pulsar ◽

Radio Pulsars ◽

Complete Understanding ◽

Parent Population ◽

Millisecond Pulsars ◽

The Galaxy ◽

Current Sample ◽

First Time

AbstractAmong the current sample of over 2000 radio pulsars known primarily in the disk of our Galaxy, millisecond pulsars now number almost 200. Due to the phenomenal success of blind surveys of the Galactic field, and targeted searches of Fermi gamma-ray sources, for the first time in over a decade, Galactic millisecond pulsars now outnumber their counterparts in globular clusters! In this paper, I briefly review earlier results from studies of the Galactic millisecond pulsar population and present new constraints based on a sample of 60 millisecond pulsars discovered by 20 cm Parkes multibeam surveys. I present a simple model of the population containing ~ 30,000 potentially observable millisecond pulsars with a luminosity function, radial distribution and scale height that matches the observed sample of objects. This study represents only a first step towards a more complete understanding of the parent population of millisecond pulsars in the Galaxy and I conclude with some suggestions for further study in this area.

Download Full-text

Millisecond Pulsars

Highlights of Astronomy ◽

10.1017/s1539299600007693 ◽

1989 ◽

Vol 8 ◽

pp. 161-165

Author(s):

J.H. Krolik

Keyword(s):

Neutron Star ◽

Stellar Evolution ◽

Close Binary ◽

Millisecond Pulsar ◽

Millisecond Pulsars ◽

Physical Conditions ◽

Cast Doubt ◽

Standard Picture ◽

The Universe ◽

New System

AbstractMillisecond pulsars are intrinsically interesting because they illustrate some of the most extreme physical conditions to be found anywhere in the Universe, and because their evolution exhibits several stages of great drama. It had been widely believed for several years that spin-up of an old neutron star by accretion from a close stellar companion explained their fast rotation, but the absence of companions in several cases cast doubt on that picture. This spring a millisecond pulsar in a close binary was discovered in which the companion appears to be evaporating, thus reconciling the existence of lone millisecond pulsars with the standard picture. Ongoing observations of this new system, and complementary calculations, promise to answer many of the questions remaining about this dramatic phase in stellar evolution.

Download Full-text

Ensemble Pulsar Time Study by Pulsar Timing Observations

Symposium - International Astronomical Union ◽

10.1017/s0074180900181604 ◽

2004 ◽

Vol 218 ◽

pp. 439-440

Author(s):

Tinggao Yang ◽

Guangren Ni

Keyword(s):

Time Scale ◽

Wavelet Decomposition ◽

Time Study ◽

Millisecond Pulsar ◽

Millisecond Pulsars ◽

Pulsar Time ◽

Pulsar Timing ◽

Timing Data ◽

Gravitational Wave Background

Long term timing of multiple millisecond pulsars can contribute to the study of an ensemble pulsar time scale PTens. A wavelet decomposition algorithm (WDA) was applied to define a PTens using the available millisecond pulsar timing datA. The PTens obtained from WDA is more stable than those resulting from other algorithms. The Chinese 50 m radio telescope is specially designed for PTens study and detection of gravitational wave background via millisecond pulsars timing observations. A scheme for multiple millisecond pulsar timing and ensemble pulsar time study is discussed in some detail.

Download Full-text

Thermal X-ray emission identified from the millisecond pulsar PSR J1909–3744

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732040 ◽

2019 ◽

Vol 627 ◽

pp. A141 ◽

Cited By ~ 2

Author(s):

N. A. Webb ◽

D. Leahy ◽

S. Guillot ◽

N. Baillot d’Etivaux ◽

D. Barret ◽

...

Keyword(s):

Neutron Star ◽

Equation Of State ◽

Thermal Emission ◽

Black Body ◽

Millisecond Pulsar ◽

Distance Measurements ◽

Millisecond Pulsars ◽

X Ray ◽

Link Type

Context. Pulsating thermal X-ray emission from millisecond pulsars can be used to obtain constraints on the neutron star equation of state, but to date only five such sources have been identified. Of these five millisecond pulsars, only two have well-constrained neutron star masses, which improve the determination of the radius via modelling of the X-ray waveform. Aims. We aim to find other millisecond pulsars that already have well-constrained mass and distance measurements that show pulsed thermal X-ray emission in order to obtain tight constraints on the neutron star equation of state. Methods. The millisecond pulsar PSR J1909–3744 has an accurately determined mass, M = 1.54 ± 0.03 M⊙ (1σ error) and distance, D = 1.07 ± 0.04 kpc. We analysed XMM-Newton data of this 2.95 ms pulsar to identify the nature of the X-ray emission. Results. We show that the X-ray emission from PSR J1909–3744 appears to be dominated by thermal emission from the polar cap. Only a single component model is required to fit the data. The black-body temperature of this emission is $ {kT}=0.26^{0.03}_{0.02} $ keV and we find a 0.2–10 keV un-absorbed flux of 1.1 × 10−14 erg cm−2 s−1 or an un-absorbed luminosity of 1.5 × 1030 erg s−1. Conclusion. Thanks to the previously determined mass and distance constraints of the neutron star PSR J1909–3744, and its predominantly thermal emission, deep observations of this object with future X-ray facilities should provide useful constraints on the neutron star equation of state.

Download Full-text

Observations of the Millisecond Pulsar PSR 1855+09 At 102 MHz

International Astronomical Union Colloquium ◽

10.1017/s0002731600155155 ◽

1992 ◽

Vol 128 ◽

pp. 213-213

Author(s):

A. D. Kuz'min ◽

Yu. I. Alekseev ◽

K. A. Lapaev ◽

B. Ya. Losovsky ◽

A. A. Salnikov

Keyword(s):

Radio Emission ◽

Interstellar Medium ◽

Short Duration ◽

Time Scale ◽

Millisecond Pulsar ◽

Rotation Effect ◽

Millisecond Pulsars ◽

Astrophysical Interest ◽

Pulsar Time

AbstractThe study of millisecond pulsars is of great astrophysical interest. One may expect that the rotation effect on the structure of the magnetosphere should be very significant. In view of the short duration of the pulses they are very suitable for investigations of the interstellar medium; at least they hold the promise for the pulsar time scale.Millisecond pulsars were discovered and have been studied on the basis of their radio-emission at decimeter wavelengths. At longer wavelengths scattering of the radio emission in the interstellar medium is the principal limitation of millisecond pulsar observations.

Download Full-text

Energy Loss of Radio Pulsars

International Astronomical Union Colloquium ◽

10.1017/s0252921100060024 ◽

2000 ◽

Vol 177 ◽

pp. 371-374

Author(s):

V.S. Beskin ◽

R.R. Rafikov

Keyword(s):

Boundary Layer ◽

Energy Loss ◽

Electric Current ◽

Relativistic Electron ◽

Electromagnetic Energy ◽

Radio Pulsars ◽

Electron Positron ◽

Light Surface ◽

Almost All ◽

Two Fluid

AbstractTwo-fluid effects on the radial 2D outflow of relativistic electron–positron plasma are considered. It is shown that when the longitudinal electric current is smaller than the Goldreich–Julian one, almost all electromagnetic energy is transformed into the energy of particles in the narrow boundary layer near the light surface |E| = |B|.

Download Full-text

High-Precision Timing of Millisecond Pulsars and Precision Astrometry

Symposium - International Astronomical Union ◽

10.1017/s0074180900228027 ◽

1995 ◽

Vol 166 ◽

pp. 163-171 ◽

Cited By ~ 2

Author(s):

V. M. Kaspi

Keyword(s):

Solar System ◽

High Precision ◽

Reference Frames ◽

Millisecond Pulsar ◽

Millisecond Pulsars ◽

Pulsar Timing ◽

Solar System Objects ◽

Optical Reference ◽

Precision Astrometry

We present the technique of long-term, high-precision timing of millisecond pulsars as applied to precision astrometry. We provide a tutorial on pulsars and pulsar timing, as well as up-to-date results of long-term timing observations of two millisecond pulsars, PSRs B1855+09 and B1937+21. We consider the feasibility of tying the extragalactic and optical reference frames to that defined by solar system objects, and we conclude that precision astrometry from millisecond pulsar timing has a bright future.

Download Full-text

Millisecond Pulsar Timing in Effelsberg

International Astronomical Union Colloquium ◽

10.1017/s0252921100041117 ◽

1996 ◽

Vol 160 ◽

pp. 95-96 ◽

Cited By ~ 3

Author(s):

M. Kramer ◽

O. Doroshenko ◽

A. Jessner ◽

R. Wielebinski ◽

A. Wolszczan ◽

...

Keyword(s):

Millisecond Pulsar ◽

Millisecond Pulsars ◽

Polarization Measurements ◽

Pulsar Timing ◽

Short Period

Millisecond pulsar as clocks are excellent tools for studying a variety of phenomena in physics and astrophysics (e.g. Foster & Backer 1990). We have been observing millisecond pulsars with the 100–m Effelsberg radiotelescope since April 1994. Initially, the goal of this program was to help continuing the timing of Arecibo pulsars during the upgrade–related shutdown period of the 305–m radiotelescope. Gradually, the program has evolved to time and study the emission physics of all short period pulsars detectable from Effelsberg. In particular, polarization measurements are used to make inferences about the emission physics of millisecond pulsars (cf. Xilouris & Kramer, this proceeding). At present, the programme involves approximately monthly observations of a set of 22 sources.

Download Full-text

The Bologna submillisecond pulsar survey

International Astronomical Union Colloquium ◽

10.1017/s0252921100058905 ◽

2000 ◽

Vol 177 ◽

pp. 27-30 ◽

Cited By ~ 1

Author(s):

Nichi D’Amico

Keyword(s):

Neutron Star ◽

Large Scale ◽

Equations Of State ◽

The Other ◽

Millisecond Pulsar ◽

Millisecond Pulsars ◽

Spin Period ◽

Other Hand

AbstractSince the discovery of the original millisecond pulsar, no pulsars with a shorter spin period (P<1.56 ms) were found. However, according to the most popular equations of state, the theoretical limiting spin period of a neutron star can be much shorter. On the other hand, most of the large scale searches for millisecond pulsars carried out so far were strongly biased against the detection of ultrashort periodicities. In this paper we describe a new large scale pulsar survey with a minimum detectable period much shorter than previous searches.

Download Full-text