Optical polarization from aligned atoms as a new diagnostic of interstellar and circumstellar magnetic fields
نویسنده
چکیده
Population of levels of the hyperfine and fine split ground state of an atom is affected by radiative transitions induced by anisotropic radiation flux. Such aligned atoms precess in the external magnetic field and this affects properties of polarized radiation arising from both scattering and absorption by atoms. As the result the degree of light polarization depends on the direction of the magnetic field. This provides a perspective tool for studies of astrophysical magnetic fields using optical and UV polarimetry. We provide calculations for several atoms and ions that can be used to study magnetic fields in interplanetary medium, interstellar medium, circumstellar regions and quasars.
منابع مشابه
Optical Polarization from Aligned Atoms as a New Diagnostic of Astrophysical Magnetic Fields
Population of levels of the hyperfine and fine split ground state of an atom is affected by radiative transitions induced by anisotropic radiation flux. Such aligned atoms precess in the external magnetic field and this affects properties of polarized radiation arising from both scattering and absorption by atoms. As the result the degree of light polarization depends on the direction of the ma...
متن کاملPolarization from Aligned Atoms as a Diagnostics of Circumstellar, Agn and Interstellar Magnetic Fields: Ii. Atoms with Hyperfine Structure
We show that atomic alignment presents a reliable way to study topology of astrophysical magnetic fields. The effect of atomic alignment arises from modulation of the relative population of the sublevels of atomic ground state pumped by anisotropic radiation flux. As such aligned atoms precess in the external magnetic field and this affects the properties of the polarized radiation arising from...
متن کاملGround-state Alignment of Atoms and Ions: New Diagnostics of Astrophysical Magnetic Field in Diffuse Medium
We discuss a new technique of studying magnetic fields in diffuse astrophysical media, e.g. interstellar and intergalactic gas/plasma. This technique is based on the angular momentum alignment of atoms and ions in their ground or metastable states. As the life-time of atoms in such states is long, the alignment induced by anisotropic radiation is susceptible to weak magnetic fields (1G ∼ > B ∼ ...
متن کاملAtomic Alignment and Diagnostics of Magnetic Fields in Diffuse Media
We continue our studies of atomic alignment in diffuse media, in particularly, in interstellar and circumstellar media, with the goal of developing new diagnostics of magnetic fields in these environments. We understand atomic alignment as alignment of atoms or ions in their ground state. Such atoms are sensitive to weak magnetic fields. In particular, we provide predictions of the polarization...
متن کاملPolarization of Absorption Lines as a Diagnostics of Circumstellar, Interstellar and Intergalactic Magnetic Fields: Fine Structure Atoms
The relative population of the fine structure sublevels of an atom’s ground state is affected by radiative transitions induced by an anisotropic radiation flux. This causes the alignment of atomic angular momentum. In terms of observational consequences for the interstellar and intergalactic medium, this results in the polarization of the absorption lines. In the paper we consider the condition...
متن کامل