Intensity dependence of the pulse profile and polarization of the Velo pulsar

Journal Article · Tue Feb 01 00:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160682· OSTI ID:5911381

Krishnamohan, S; Downs, G S

Full polarization measurements of individual pulses from the Vela pulsar (PSR 0833--45) have been obtained at 2295 MHz using the NASA/JPL 64 m antenna at Goldstone. We have found several important features in the emission of this pulsar: (i) the pulse profile depends on the intensity of the pulsar, (ii) the modulation index and the power spectrum of the intensity fluctuations depend on the pulse-longitude, and (iii) the deviations in the observed polarization position angles from those expected from the rotating vector model depend on the intensity of the pulsar. We explain (i) and (ii) by postulating that the pulse profile is composed of four independent components. To explain (iii), we place the emission regions generating these components at different distances from the neutron star. The components arrive at diferent longitudes due to retardation, aberration, and magnetic field line curvature effects. Each component carries the position angle signature expected from the rotating vector model. However, the super position of the components gives rise to the deviations that explain the observations. The model fits to the observations suggest that component 1 is always emitted in the orthogonal polarization mode compared to the other three components, and that the four regions generating the components span about 540 km in the magnetosphere. In addition, the results suggest that each component is emitted at slightly different distances depending on its intensity. For example, the region generating component 1 moves away from the neutron star by approx.130 km as the component increases in intensity.

• OSTI ID: 5911381
• Journal Information: Astrophys. J.; (United States), Vol. 265:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
PULSARS
PULSATIONS
DATA ANALYSIS
EMISSION
NEUTRON STARS
POLARIZATION
RADIOWAVE RADIATION
SPECTRA
SPECTRAL FUNCTIONS
STAR MODELS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
FUNCTIONS
MATHEMATICAL MODELS
RADIATIONS
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources