Long-Term Intensity Variations of 20 Pulsars
Abstract
Intensity fluctuations of 20 pulsars at 0.43 GHz are analyzed over a 4 yr time span. The objects were selected from a long-term timing study of pulsars performed at the Arecibo Observatory covering a range of dispersion measures between 8 and 403 pc/cc. A structure function analysis was used to determine the characteristic time scales and modulation indices of long-term (greater than or equal to few days) intensity variations. Variability generally agrees with a model where refractive scintillations superpose with diffractive interstellar scintillations, with the latter quenched to varying degrees from the finite bandwidth. The refractive scintillations, or limits, are consistent with amplitudes expected from a Kolmogorov spectrum for the electron density.
- Publication:
-
The Astronomical Journal
- Pub Date:
- November 1994
- DOI:
- 10.1086/117198
- Bibcode:
- 1994AJ....108.1854L
- Keywords:
-
- Astronomical Models;
- Electron Flux Density;
- Interstellar Matter;
- Pulsars;
- Radio Astronomy;
- Time Series Analysis;
- Variability;
- Variations;
- Radio Telescopes;
- Refractivity;
- Wave Diffraction;
- Astronomy;
- PULSARS: GENERAL;
- ISM: KINEMATICS AND DYNAMICS