Cold Mode Gas Accretion on Two Galaxy Groups at z$\sim$2

Understand

We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS) observations of rest-frame UV emission lines $\rm Ly\alpha$, C IV $\lambda \lambda$ 1548 \AA, 1550\AA and He II 1640 \AA observed in the circumgalactic medium (CGM) of two $z=2$ radio-loud quasar host galaxies.

• We detect extended emission on 80-90 kpc scale in $\rm Ly\alpha$ in both systems with C IV, and He II emission also detected out to 30-50 kpc.
• All emission lines show kinematics with a blue and redshifted gradient pattern consistent with velocities seen in massive dark matter halos and similar to kinematic patterns of inflowing gas seen in hydrodynamical simulations.
• Using the kinematics of both resolved $\rm Ly\alpha$ emission and absorption, we can confirm that both kinematic structures are associated with accretion.