Outflows and extended [CII] halos in high redshift galaxies

Understand

Recent stacked ALMA observations have revealed that normal, star-forming galaxies at $z\approx 6$ are surrounded by extended ($\approx 10\,\mathrm{kpc}$) [CII] emitting halos which are not predicted by the most advanced, zoom-in simulations.

• We present a model in which these halos are the result of supernova-driven cooling outflows.
• Our model contains two free parameters, the outflow mass loading factor, $\eta$, and the parent galaxy dark matter halo circular velocity, $v_c$.
• The outflow model successfully matches the observed [CII] surface brightness profile if $\eta = 3.20 \pm 0.10$ and $v_c = 170 \pm 10{\,\rm km\,s^{-1}}$, corresponding to a dynamical mass of $\approx 10^{11}\, \mathrm{M}_\odot$.