The cold molecular gas in z$\gtrsim$6 quasar host galaxies

Understand

Probing the molecular gas reservoirs of z>~6 quasar (QSO) host galaxies is fundamental to understanding the coevolution of star formation and black hole growth in these extreme systems.

• Yet, there is still an inhomogeneous coverage of molecular gas tracers.
• To measure the average excitation and mass of the molecular gas reservoirs in the brightest z>6.5 QSO hosts, we combined new observations of CO(2-1) emission with existing observations of CO(6-5), CO(7-6), [C I], [C II], and dust-continuum emission.
• We reduced and analysed the VLA observations of CO(2-1) in three z=6.5-6.9 QSO hosts -- the highest redshift observations of CO(2-1) to date.