The Effects of Plasma Lensing on the Inferred Dispersion Measures of Fast Radiobursts

  title={The Effects of Plasma Lensing on the Inferred Dispersion Measures of Fast Radiobursts},
  author={Xinzhong Er and Yuan-Pei Yang and Adam Rogers},
  journal={The Astrophysical Journal},
Radio signals are delayed when propagating through plasma. This type of delay is frequency-dependent and is usually used for estimating the projected number density of electrons along the line of sight, called the dispersion measure. The dense and clumpy distribution of plasma can cause refractive deflections of radio signals, analogous to lensing effects. Similar to gravitational lensing, there are two contributions to the time delay effect in plasma lensing: a geometric delay, due to… Expand

Figures from this paper

FRBs Lensed by Point Masses I. Lens Mass Estimation for Doubly Imaged FRBs
Fast radio bursts (FRBs) are bright radio transient events with durations on the order of milliseconds. The majority of FRB sources discovered so far have a single peak, with the exception of a fewExpand
The physics of fast radio bursts
In 2007, a very bright radio pulse was identified in the archival data of the Parkes Telescope in Australia, marking the beginning of a new research branch in astrophysics. In 2013, this kind ofExpand


Dynamic spectral mapping of interstellar plasma lenses
Compact radio sources sometimes exhibit intervals of large, rapid changes in their flux-density, due to lensing by interstellar plasma crossing the line-of-sight. A novel survey program has made itExpand
The Gaussian Plasma Lens in Astrophysics: Refraction
We present the geometrical optics for refraction of a distant background radio source by an interstellar plasma lens, with specific application to a lens with a Gaussian profile of free-electronExpand
Dual-component plasma lens models
  • A. Rogers, X. Er
  • Physics
  • Monthly Notices of the Royal Astronomical Society
  • 2019
In contrast to the converging, achromatic behaviour of axisymmetric gravitational lenses, diverging frequency-dependent lensing occurs from refraction due to a distribution of over-dense axisymmetricExpand
Two families of astrophysical diverging lens models
In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in theExpand
An extreme scattering event in the direction of the millisecond pulsar 1937 + 21
LARGE fluctuations in the radio emissions from the quasar 0954 + 658 (ref. 1) attest to the existence of large-scale inhomogeneities in the ionized interstellar medium. These fluctuations, termedExpand
Gravitational lensing in plasmic medium
The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula forExpand
Extreme scattering events from axisymmetric plasma lenses
Frequency-dependent brightness fluctuations of radio sources, the so-called extreme scattering events (ESEs), have been observed over the last three decades. They are caused by Galactic plasmaExpand
Scattering of Pulsar Radio Emission by the Interstellar Plasma
We present simulations of scattering phenomena which are important in pulsar observations, but which are analytically intractable. The simulation code, which has also been used for solar wind andExpand
Pulsar Observations of Extreme Scattering Events
Extreme scattering events (ESEs) in the interstellar medium (ISM) were first observed in regular flux measurements of compact extragalactic sources. They are characterized by a flux variation over aExpand
Frequency-Dependent Dispersion Measures and Implications for Pulsar Timing
We analyze the frequency dependence of the dispersion measure (DM), the column density of free electrons to a pulsar, caused by multipath scattering from small scale electron-density fluctuations.Expand