Magnetohydrostatic Equilibrium Structure and Mass of Polytropic Filamentary Cloud Threaded by Lateral Magnetic Field

Abstract Filamentary structures are recognized as a fundamental component of interstellar molecular clouds in observations made by the Herschel satellite. These filaments, especially massive often extend direction perpendicular to magnetic field. Furthermore, filaments sometimes have an apparently negative temperature gradient—that is, their temperatures decrease toward centers. In this paper, we study magnetohydrostatic equilibrium state negative-indexed polytropic gas with field running axis filament. The model is controlled four parameters: center-to-surface density ratio ( ρ c / s ), plasma β surrounding gas, radius parent cloud R 0 ′ normalized scale height, and index N . steepness gradient represented We found that envelope column profile becomes shallow when large. This reconciles inconsistency between observed profiles those expected from isothermal models. compared maximum line mass (mass per unit length), above which there no equilibrium, nonmagnetized obtained empirical formula express magnetized filament ${\lambda }_{{\rm{m}}{\rm{a}}{\rm{x}}}\simeq {\left[{\left({\lambda }_{0,{\rm{m}}{\rm{a}}{\rm{x}}}(N)/{M}_{\odot }{\rm{p}}{{\rm{c}}}^{-1}\right)}^{2}+{\left[5.9{\left(1.0+1.2/N\right)}^{1/2}\left({{\rm{\Phi }}}_{{\rm{c}}{\rm{l}}}/1\mu {\rm{G}}{\rm{p}}{\rm{c}}\right)\right]}^{2}\right]}^{1/2}$?> λ m mathvariant="normal">a mathvariant="normal">x ≃ close=")" open="("> , stretchy="false">( N stretchy="false">) / M ⊙ p mathvariant="normal">c − 1 2 + 5.9 1.0 1.2 mathvariant="normal">Φ mathvariant="normal">l μ mathvariant="normal">G M ⊙ pc −1 , where }_{0,\max }(N)$?> max represents Φ cl indicates one-half flux threading length. Although polytrope makes decrease, model, increases mass.