Imaging Atomic and Highly Excited Molecular Gas in a z=6.42 Quasar Host Galaxy: Copious Fuel for an Eddington-Limited Starburst at the End of Cosmic Reionization

Understand

We have imaged CO(J=7-6) and CI(3P2-3P1) emission in the host galaxy of the z=6.42 quasar SDSS J114816.64+525150.3 (hereafter: J1148+5251) through observations with the Plateau de Bure Interferometer.

• The region showing CO(J=7-6) emission is spatially resolved, and its size of 5 kpc is in good agreement with earlier CO(J=3-2) observations.
• In combination with a revised model of the collisional line excitation in this source, this indicates that the highly excited molecular gas traced by the CO J=7-6 line is subthermally excited (showing only 58+/-8% of the CO J=3-2 luminosity), but not more centrally concentrated.
• We also detect CI(3P2-3P1) emission in the host galaxy of J1148+5251, but the line is too faint to enable a reliable size measurement.