Scattering model of scintillation arcs in pulsar secondary spectra

Fuente: arXiv
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Main Authors: Kramer, Tobias, Waltner, Daniel, Heller, Eric J., Stinebring, Dan R.
Format: Preprint
Published: 2024
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author Kramer, Tobias
Waltner, Daniel
Heller, Eric J.
Stinebring, Dan R.
author_facet Kramer, Tobias
Waltner, Daniel
Heller, Eric J.
Stinebring, Dan R.
contents The dynamic spectra of pulsars frequently exhibit diverse interference patterns, often associated with parabolic arcs in the Fourier-transformed (secondary) spectra. Our approach differs from previous ones in two ways: first, we extend beyond the traditional Fresnel-Kirchhoff method by using the Green's function of the Helmholtz equation, i.e.\ we consider spherical waves originating from three dimensional space, not from a two dimensional screen. Secondly, the discrete structures observed in the secondary spectrum result from discrete scatterer configurations, namely plasma concentrations in the interstellar medium, and not from the selection of points by the stationary phase approximation. Through advanced numerical techniques, we model both the dynamic and secondary spectra, providing a comprehensive framework that describes all components of the latter spectra in terms of physical quantities. Additionally, we provide a thorough analytical explanation of the secondary spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2402_19370
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Scattering model of scintillation arcs in pulsar secondary spectra
Kramer, Tobias
Waltner, Daniel
Heller, Eric J.
Stinebring, Dan R.
High Energy Astrophysical Phenomena
The dynamic spectra of pulsars frequently exhibit diverse interference patterns, often associated with parabolic arcs in the Fourier-transformed (secondary) spectra. Our approach differs from previous ones in two ways: first, we extend beyond the traditional Fresnel-Kirchhoff method by using the Green's function of the Helmholtz equation, i.e.\ we consider spherical waves originating from three dimensional space, not from a two dimensional screen. Secondly, the discrete structures observed in the secondary spectrum result from discrete scatterer configurations, namely plasma concentrations in the interstellar medium, and not from the selection of points by the stationary phase approximation. Through advanced numerical techniques, we model both the dynamic and secondary spectra, providing a comprehensive framework that describes all components of the latter spectra in terms of physical quantities. Additionally, we provide a thorough analytical explanation of the secondary spectrum.
title Scattering model of scintillation arcs in pulsar secondary spectra
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2402.19370