A New Electron Density Model for Estimation of Pulsar and FRB Distances

Understand

We present a new model for the distribution of free electrons in the Galaxy, the Magellanic Clouds and the intergalactic medium (IGM) that can be used to estimate distances to real or simulated pulsars and fast radio bursts (FRBs) based on their dispersion measure (DM).

• The Galactic model has an extended thick disk representing the so-called warm interstellar medium, a thin disk representing the Galactic molecular ring, spiral arms based on a recent fit to Galactic HII regions, a Galactic Center disk and seven local features including the Gum Nebula, Galactic Loop I and the Local Bubble.
• An offset of the Sun from the Galactic plane and a warp of the outer Galactic disk are included in the model.
• Parameters of the Galactic model are determined by fitting to 189 pulsars with independently determined distances and DMs.