Stochastic Averaging of Radiative Transfer Coefficients for Relativistic Electrons

التفاصيل البيبلوغرافية
العنوان: Stochastic Averaging of Radiative Transfer Coefficients for Relativistic Electrons
المؤلفون: Moscibrodzka, Monika, Gammie, Charles F.
سنة النشر: 2024
المجموعة: Astrophysics
مصطلحات موضوعية: Astrophysics - High Energy Astrophysical Phenomena
الوصف: Synchrotron emissivities, absorptivities, and Faraday rotation and conversion coefficients are needed in modeling a variety of astrophysical sources, including Event Horizon Telescope (EHT) sources. We develop a method for estimating transfer coefficients that exploits their linear dependence on the electron distribution function, decomposing the distribution function into a sum of parts each of whose emissivity can be calculated easily. We refer to this procedure as stochastic averaging and apply it in two contexts. First, we use it to estimate the emissivity of an isotropic $\kappa$ distribution function with a high energy cutoff. The resulting coefficients can be evaluated efficiently enough to be used directly in ray-tracing calculations, and we provide an example calculation. Second, we use stochastic averaging to assess the effect of subgrid turbulence on the volume-averaged emissivity and along the way provide a prescription for a turbulent emissivity. We find that for parameters appropriate to EHT sources turbulence reduces the emissivity slightly. In the infrared turbulence can dramatically increase the emissivity.
Comment: 10 pages, 2 figures, Accepted to ApJ, corrected acknowledgement
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2405.00499
رقم الأكسشن: edsarx.2405.00499
قاعدة البيانات: arXiv