Interstellar extinction and polarization -- A spheroidal dust grain approach perspective

TL;DR

This paper presents a spheroidal dust grain model to interpret interstellar extinction and polarization, enabling insights into magnetic field structures through multi-wavelength observations.

Contribution

The study extends the spheroidal dust model and demonstrates its application in fitting observational data, providing a method to infer magnetic field orientations.

Findings

Model successfully fits extinction and polarization curves.

The angle $\Omega$ can be estimated from observations.

Potential to study magnetic field spatial structure.

Abstract

We extend and investigate the spheroidal model of interstellar dust grains used to simultaneously interpret the observed interstellar extinction and polarization curves. We compare our model with similar models recently suggested by other authors, study its properties and apply it to fit the normalized extinction $A(\lambda)/A_{\rm V}$ and the polarizing efficiency $P(\lambda)/A(\lambda)$ measured in the near IR to far UV region for several stars seen through one large cloud. We conclude that the model parameter $\Omega$ being the angle between the line of sight and the magnetic field direction can be more or less reliably determined from comparison of the theory and observations. This opens a way to study the spatial structure of interstellar magnetic fields by using multi-wavelength photometric and polarimetric observations.