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Paper: Connecting Galaxy Disk and Extended Halo Gas Kinematics
Volume: 396, Formation and Evolution of Galaxy Disks
Page: 427
Authors: Kacprzak, G.G.; Churchill, C.W.; Steidel, C.C.; Ceverino, D.; Klypin, A.A.; Murphy, M.T.
Abstract: We have explored the galaxy disk/extended halo gas kinematic relationship using rotation curves (Keck/ESI) of ten intermediate redshift galaxies which were selected by Mg II halo gas absorption observed in quasar spectra. Previous results of six edge-on galaxies, probed along their major axis, suggest that observed halo gas velocities are consistent with extended disk-like halo rotation at galactocentric distances of 25 − 72 kpc. Using our new sample, we demonstrate that the gas velocities are by and large not consistent with being directly coupled to the galaxy kinematics. Thus, mechanisms other than corotation dynamics (i.e., gas inflow, feedback, galaxy-galaxy interactions, etc.) must be invoked to account for the overall observed kinematics of the halo gas. In order to better understand the dynamic interaction of the galaxy/halo/cosmic web environment, we performed similar mock observations of galaxies and gaseous halos in ΛCDM cosmological simulations. We discuss an example case of a z = 0.92 galaxy with various orientations probing halo gas at a range of positions. The gas dynamics inferred using simulated quasar absorption lines are consistent with observational data.
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