Precision measurements of pulsar dispersion

  • Phillips J
  • Wolszczan A
  • 6

    Readers

    Mendeley users who have this article in their library.
  • 47

    Citations

    Citations of this article.

Abstract

Timing observations of eight pulsars over a frequency range from 25 MHz to 5 GHz are performed in order to investigate possible departures from the nu exp -2 dispersion law that applies to the propagation of radio waves through the tenuous interstellar plasma. Apparent deviations from a cold plasma law were found at high frequencies (2-5 GHz) for two pulsars: PSR 0525 + 21 and PSR 1237 + 25. The absence of LF deviations from a nu exp -2 dispersion law at the 1-ms level is consistent with a Kolmogorov spectrum of the interstellar plasma turbulence extending to scale sizes of about 10 exp 15 cm. Forms of the interstellar dispersion law which included nu exp -3 and nu exp -4 terms arising from clumping, magnetic fields, and temperature effects in the dispersing gas were examined. Pulsar dispersion was found to be an insensitive probe of gas temperature, even for a hot plasma. Dispersion delays varying as nu exp -4 could be detected at decameter wavelengths if the line of sight passes through a dense H II region.

Author-supplied keywords

  • COLD PLASMAS
  • FREQUENCY RANGES
  • H II REGIONS
  • INTERSTELLAR MATTER
  • PLASMA TURBULENCE
  • PULSARS
  • RADIO WAVES
  • TIME LAG
  • TIME MEASUREMENT
  • WAVE PROPAGATION

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • J. A. Phillips

  • A. Wolszczan

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free