Stability and Ly α emission of Cold Stream in the Circumgalactic Medium: impact of magnetic fields and thermal conduction

ABSTRACT Cold streams of gas with temperatures around 104 K play a crucial role in the gas accretion on to high-redshift galaxies. The current resolution of cosmological simulations is insufficient to fully capture the stability and Ly α emission characteristics of cold stream accretion, underscoring the imperative need for conducting idealized high-resolution simulations. We investigate the impact of magnetic fields at various angles and anisotropic thermal conduction (TC) on the dynamics of radiatively cooling streams through a comprehensive suite of two-dimensional high-resolution simulations. An initially small magnetic field ($\sim 10^{-3} \, \mu\rm G$), oriented non-parallel to the stream, can grow significantly, providing stability against Kelvin–Helmholtz instabilities and reducing the Ly α emission by a factor of