NE2001. II. Using Radio Propagation Data to Construct a Model for the Galactic Distribution of Free Electrons

TL;DR

This paper details the methodology and data used to develop a model of the Galactic free electron distribution, highlighting the importance of specific structures affecting radio wave propagation.

Contribution

It introduces a new model for Galactic free electrons based on radio propagation data, with detailed input data and analysis of structures influencing dispersion and scattering.

Findings

Identification of discrete regions affecting dispersion and scattering.

Most structures influencing electron density are below detection thresholds.

The model improves understanding of Galactic electron distribution.

Abstract

In Paper I we present a new model for the Galactic distribution of free electrons. In this paper we describe the input data and methodology for determining the structure and parameters of the model. Tables of the input data are provided and several figures are used to demonstrate why particular Galactic structures are needed. We identify lines of sight on which discrete regions either enhance or diminish the dispersion or the scattering. Most do not coincide with known \ion{H}{2} regions or supershells, most likely because the enhancements correspond to column densities smaller than detection thresholds for the emission measure in recombination-line surveys.