On the natural line width of absorption lines in strong magnetic stellar fields

In the last years, the interest in explaining the existence of a singularity at low frequencies ( = 0) in the differential cross section of photon scattering by electrons, in a homogeneous magnetic field, for the transitions between the Landau levelsN = 1 andN = 0, has greatly increased. It is the purpose of this paper to present a calculation of the cross section for the absorption of radiation by an electron in a strong magnetic stellar field, using the Wigner-Weisskopf approximation to better understand this kind of singularity in the Compton cross section.Presented at the 2nd UN/ESA Workshop, held in Bogotá, Colombia, 9-13 November, 1992.