Huirong Yan (Uni. Potsdam & DESY)

Tracing astrophysical magnetic field with atomic alignment
Wann Am 03.03.2016 von 14:30 bis 15:30
  • Kolloquium
Wo SH Lecture Hall
Termin übernehmen vCal / iCal

I would like to present a new technique of studying magnetic fields in interstellar and intergalactic gas/plasma. This technique is based on the alignment (in terms of their angular momentum in the ground state) of atoms and ions with fine or hyperfine splitting of the ground state. A unique feature of this technique is that the properties of the polarized radiation (both absorption and emission) depend on the 3D geometry of the magnetic field as well as the direction and anisotropy of incident radiation. I shall outline the prospects of the technique and its possible application to studies magnetic fields within circumstellar regions, interplanetary medium, interstellar medium, intergalactic medium. Both spatial and temporal variations of turbulent magnetic field can be traced with this technique as well. In addition, I shall demonstrate that atomic alignment induced by anisotropic radiation can cause polarisation of the radio/far-infrared magnetic dipole transitions within the ground state, thus providing a possible way to study magnetic fields in environments where other techniques fail, e.g. at the epoch of Universe reionization. Last but not the least, we find line intensities are modulated by magnetic alignment as well. Chemistry studies based on spectrometry should thereby account for the influence of magnetic field.