Related papers: Polarisation of submillimetre lines from interstel…
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…
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…
Magnetism is one of the most important forces on the interstellar medium (ISM), anisotropically regulating the structure and star formation that drive galactic evolution. Recent high dynamic range observations of diffuse gas and molecular…
Fluorescence emission lines are broadly applied in observation for diffuse medium in the universe. They are normally observed around strong pumping source, tracing the gas in circumstellar medium, reflection nebula, and H\,{\sc ii} regions,…
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…
Magnetic fields permeate the entire Galaxy and are essential to, for example, the regulation of several stages of the star formation process and cosmic ray transportation. Unraveling its properties, such as intensity and topology, is an…
Observations of far-infrared (FIR) and submillimeter (SMM) polarized emission are used to study magnetic fields and dust grains in dense regions of the interstellar medium (ISM). These observations place constraints on models of molecular…
Interstellar polarization at far-infrared through millimeter wavelengths (0.1 - 1 mm) is primarily due to thermal emission from dust grains aligned with magnetic fields. This mechanism has led to studies of magnetic fields in a variety of…
Magnetic fields have important or dominant effects in many areas of astrophysics, but have been very difficult to quantify. Spectropolarimetry from Ground State Alignment (GSA) has been suggested as a direct tracer of magnetic field in…
Accurately measuring the magnetic field in the ISM is essential for understanding star-formation processes. We searched archival data of the Submillimeter Array (SMA) for evidence of circular polarization in common molecular tracers, most…
Calculations are performed for the linear polarization of starlight due to extinction by aligned dust grains when the starlight traverses a medium with irregular magnetic fields. This medium is intended to represent the optically thick…
Multi-frequency radio polarimetry of the diffuse Galactic synchrotron background gives new viewpoints on the Galactic magnetic field. Rotation measure maps reveal magnetic structures on arcminute to degree scales, such as a ring in…
Interstellar dust grains are often aligned. If the grain alignment direction varies along the line of sight, the thermal emission becomes circularly-polarized. In the diffuse interstellar medium, the circular polarization at far-infrared…
$\textit{Aims.}$ We present a case study to demonstrate the potential of multi-wavelength polarization measurements. The aim is to investigate the effects that dichroic polarization and thermal re-emission have on tracing the magnetic field…
Observations of star-forming regions by the current and upcoming generation of submillimeter polarimeters will shed new light on the evolution of magnetic fields over the cloud-to-core size scales involved in the early stages of the star…
Continuum polarization over the UV-to-microwave range is due to dichroic extinction (or emission) by asymmetric, aligned dust grains. Because of both grain alignment and scattering physics, the wavelength dependence of the polarization,…
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…
Observational studies of magnetic fields are crucial. We introduce a process "ground state alignment" as a new way to determine the magnetic field direction in diffuse medium. The alignment is due to anisotropic radiation impinging on the…
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…
Imaging polarimetry is a useful tool to reveal the 3D structure of dust distributions and to localize embedded young stellar objects. We present maps of the linear polarization at 2.2 micron for three ultra-compact HII regions…