Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-06-23
Astronomy and Astrophysics
Astrophysics
9 pages, 5 figures, submitted to "Magnetic Fields In The Universe II", RevMexAA
Scientific paper
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 ($1{\rm G}\gtrsim B\gtrsim0.1\mu$G). The alignment reveals itself in terms of the polarization of the absorbed and emitted light. A variety of atoms with fine or hyperfine splitting of the ground or metastable states exhibit the alignment and the resulting polarization degree in some cases exceeds 20%. We show that in the case of absorption the polarization direction is either parallel or perpendicular to magnetic field, while more complex dependencies emerge for the case of emission of aligned atoms. We show that the corresponding studies of magnetic fields can be performed with optical and UV polarimetry. A unique feature of these studies is that they can reveal the 3D orientation of magnetic field. In addition, we point out that the polarization of the radiation arising from the transitions between fine and hyperfine states of the ground level can provide yet another promising diagnostics of magnetic fields, including the magnetic fields in the Early Universe. We mention several cases of interplanetary, circumstellar and interstellar magnetic fields for which the studies of magnetic fields using ground state atomic alignment effect are promising.
Lazarian Alex
Yan Huirong
No associations
LandOfFree
Ground-state alignment of atoms and ions: New Diagnostics of Astrophysical Magnetic field in diffuse medium does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Ground-state alignment of atoms and ions: New Diagnostics of Astrophysical Magnetic field in diffuse medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ground-state alignment of atoms and ions: New Diagnostics of Astrophysical Magnetic field in diffuse medium will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-673851