Thursday

I will present new results connecting Lyα halos surrounding quasars (QSOs) on the edge of the Epoch of Reionisation, to the gas and dust inside their host galaxies, using deep MUSE and ALMA observations. MUSE is particularly efficient for revealing extended low-surface brightness Lyα halos, and these have recently been detected and characterized at z~6, showing broad Lyα spectral profiles and emission extending 27 − 60 pkpc from the quasar positions. In contrast, ALMA observations of QSOs at similar redshifts typically reveal compact [CII] emission from the host-galaxies of narrow line-width, spatially extended for ~a few pkpc. By observing these two components together we can gain insights on the rapid fueling of early QSOs. Curiously, for 8 objects at the highest accessible redshifts, we see no coherence between the velocity fields of the Lyα and [CII] emission, suggesting a complete decoupling of the halo gas kinematics and the host galaxy’s ISM, i.e. the Lyα halo does not simply trace the extension of of the central structure seen in [CII]. These QSOs present ideal targets for follow-up ALMA observations, to search for an extended [CII] component which connects gas on the scale of the CGM (traced by Lyα halos) to the physical conditions within the host galaxies’ ISM.