| The structure and kinematics of cold gas with T~10^4 K are crucial for understanding the multiphase flows within the galactic ecosystem and, thus, galaxy evolution and star formation as a whole. While traditionally, most observational constraints come from absorption line studies of the structure of galactic winds and the circumgalactic medium (CGM), the advent of novel instruments and techniques provides us now with a unique view of gas flows around galaxies via emission lines, mainly thanks for prominent emission lines such as Hydrogen Lyman-α (Lyα) and Mg II resonance doublet. Due to the resonant nature of these lines, photons suffer scattering in cold gas residing on the outskirts of galaxies. Furthermore, resonant line observables, such as the spectrum, are directly affected by the density and kinematics of the gas. To decode this information, we developed a 3D Monte-Carlo radiative transfer simulation for Mg II and Lyɑ. During my presentation, I will show simulated results of Mg II and Lyɑ through homogeneous and multiphase media resembling CGM. Apart from showing synthetic spectra and escaping fractions, I will, in particular, focus on the powerful observables to which less attention has been paid in the past: the Lyɑ polarization signal and the Mg II doublet ratio. I will show in my talk how these observables can help to constrain gas flows in the CGM and break otherwise existing degeneracies. In the time provided, I will discuss the implications of our results on other resonant doublets, such as C IV, O VI, and N V. |
