On The Method Of Estimating Emission Altitude from Relativistic Phase Shift in Pulsars

Gangadhara, R. T.

doi:10.1086/431138

Cited by 33 publications

(46 citation statements)

References 23 publications

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“…The heights of the emission region have been estimated with different methods (Cordes 1978;Blaskiewicz 1991;Phillips 1992;Gil & Kijak 1993;Kijak & Gil 1997;Gupta & Gangadhara 2001;Gupta & Gangadhara 2003;Dyks et al 2004;Gangadhara 2005). In this paper we present a three-dimensional method to calculate the emission height.…”

Section: Introductionmentioning

confidence: 99%

PSR B2111+46: a test of the inverse Compton scattering model of radio emission

Zhang

Qiao²,

Han

et al. 2007

A&A

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The region in which pulsars radiate is very important to constrain pulsar emission mechanisms. A three-dimensional (3D) method to calculate emission heights is developed in this paper. As an example, radiation regions for different components at different frequencies have been calculated for PSR B2111+46. Emission components at seven frequencies are fitted with Gaussian components, then the radiation heights for emission components are calculated. We found that different emission components, even if at the same radio frequency, are radiated from different heights. This is probably a common phenomena and challenges any emission mechanisms. The inverse Compton scattering emission model for pulsar radio emission can explain these results well.

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Section: Introductionmentioning

confidence: 99%

PSR B2111+46: a test of the inverse Compton scattering model of radio emission

Zhang

Qiao²,

Han

et al. 2007

A&A

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“…A finite height of emission introduces the spin velocity v s = β s c, since the emission region corotates with the pulsar. In the case of millisecond pulsars this spin velocity is a considerable fraction of the speed of light [16] even if emission takes place at the surface of the neutron star (v s ≈ 0.2c for an orthogonal rotator with spin period 1 ms and h ∼ 10 km, which is much larger than v o ∼ 10 −3 c). In the general case of nonzero orbital and spin velocities of the emitting region unit vectorsr andm can be written asr…”

Section: Geometrical Model Of Radio Emissionmentioning

confidence: 96%

Effects of finite emission height in precision pulsar timing

D’Angelo

Rafikov

2007

Phys. Rev. D

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Precision timing is the key ingredient of ongoing pulsar-based gravitational wave searches and tests of general relativity using binary pulsars. The conventional approach to timing explicitly assumes that the radio emitting region is located at the center of the pulsar, while polarimetric observations suggest that radio emission is in fact produced at altitudes ranging from tens to thousands of kilometers above the neutron star surface. Here we present a calculation of the effects of finite emission height on the timing of binary pulsars using a simple model for the emitting region geometry. Finite height of emission h changes the propagation path of radio photons through the binary and gives rise to a large spin velocity of the emission region co-rotating with the neutron star. Under favorable conditions these two effects introduce corrections to the conventional time delays at the microsecond level (for a millisecond pulsar in a double neutron star binary with a period of several hours and assuming h = 100 km). Exploiting the dependence of the emission height on frequency (radius-to-frequency mapping) and using multi-frequency observations one should be able to detect these timing corrections even though they are formally degenerate with conventional time delays. Although even in the most accurately timed systems the magnitude of the finite emission height effects is currently somewhat below timing precision, longer-term observations and future facilities like SKA will make measurement of these effects possible, providing an independent check of existing emission height estimates.

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“…To coordinate the total velocity with the light speed, Gangadhara (2005) introduced the evolvement of κ with height by assuming the Lorentz factor to be a constant, as shown with the dotted line Fig. 1(c).…”

Section: The Particle Velocity Acceleration and Emission Locationmentioning

confidence: 99%

Curvature radiation in rotating pulsar magnetosphere

Wang

Han

2012

Proc. IAU

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We consider the curvature emission properties from relativistic particles streaming along magnetic field lines and co-rotating with pulsar magnetosphere. The co-rotation affects the trajectories of the particles and hence the emission properties, especially the polarization. We consider the modification of the particle velocity and acceleration due to the co-rotation. Curvature radiation from a single particle is calculated using the approximation of a circular path to the particle trajectory. Curvature radiation from particles at a given height actually contains the contributions from particles streaming along all the nearby field lines around the tangential point, forming the emission cone of 1/γ. The polarization patterns from the emission cone are distorted by the additional rotation, more serious for emission from a larger height. Net circular polarization can be generated by the density gradient in the emission cone. For three typical density models in the form of core, cone and patches, we calculate the polarization profiles for emission generated at a given height. We find that the circular polarization could have a single sign or sign reversal, depending on the density gradient along the rotation phase. The polarization profiles of the total curvature radiation from the whole open field line region, calculated by adding the emission from all possible heights, are similar to that from a dominating emission height. The circular polarization of curvature radiation has sign reversals in the patchy emission, while it has a single sign for the core emission, and is negligible for the cone emission.

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On The Method Of Estimating Emission Altitude from Relativistic Phase Shift in Pulsars

Cited by 33 publications

References 23 publications

PSR B2111+46: a test of the inverse Compton scattering model of radio emission

PSR B2111+46: a test of the inverse Compton scattering model of radio emission

Effects of finite emission height in precision pulsar timing

Curvature radiation in rotating pulsar magnetosphere

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