Synthetic observations of spiral arm tracers of a simulated Milky Way analog

摘要: Context: The Faraday rotation measure (RM) is often used to study the magnetic field strength and orientation within ionized medium of Milky Way. Observations indicate a RM in spiral arms that exceeds commonly assumed range. This raises question under what conditions create such strong RM. Aims: We investigate effect on Galactic RMs through shock compression interstellar (ISM). It has recently been suggested Sagittarius arm creates peak where line sight (LOS) tangent arm, enhanced follows along an intersecting LOS. seek understand physical give rise this role viewing geometry. Methods: apply MHD simulation multi-phase ISM Way type galaxy disk combination with radiative transfer evaluate different tracers structures. For observers embedded disk, dust intensity, synchrotron emission kinematics molecular gas observations are derived identify tangents. calculated evaluated for observer positions. observer's perspective related parameters local bubble surrounding observer. Results: reproduce scattering points about $6^\circ$ per similar As RM, model shows associated amplification enhances by few hundred rad $m^{-2}$ top mean contribution disk. arm-inter-arm contrast LOS approximately 10 inner Galaxy, fading ~2 outer Galaxy. shark-fin like pattern as well synthetic data characteristic arms.