A Turbulent Model of Time Variability in X-Ray Binary Pulsars
Abstract
It is found that the observed power spectral density of the aperiodic time variability of the X-ray pulsar can be approximated by a power-law spectrum which changes its slope at the pulsation frequency (pulsar rotation frequency). The indices of the observed spectra are, respectively, 1.4-2.0 above the pulsation frequency and 0-1.0 below the pulsation frequency. By studying the density fluctuation spectra with inverse cascades in magnetohydrodynamic turbulence, we find that the observed X-ray spectra can be interpreted as the density fluctuations in the accreting plasmas. It is shown that the structure of either disk-fed or wind-fed pulsars can be determined by comparing the observed X-ray spectra with the theoretical density fluctuation spectra of two- or three-dimensional magnetohydrodynamic turbulence, respectively.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1993
- DOI:
- 10.1086/186917
- Bibcode:
- 1993ApJ...411L..79H
- Keywords:
-
- Magnetohydrodynamic Turbulence;
- Pulsars;
- Turbulence Models;
- X Ray Binaries;
- Accretion Disks;
- Neutron Stars;
- Power Spectra;
- Astrophysics;
- ACCRETION;
- ACCRETION DISKS;
- MAGNETOHYDRODYNAMICS: MHD;
- STARS: BINARIES: GENERAL;
- STARS: NEUTRON;
- TURBULENCE;
- X-RAYS: GENERAL