We present high-resolution ( 0.3 ^ { \prime \prime } ) Very Large Array ( VLA ) imaging of the molecular gas in the host galaxy of the high redshift quasar PSS J2322+1944 ( z = 4.12 ) .
These observations confirm that the molecular gas ( CO ) in the host galaxy of this quasar is lensed into a full Einstein ring , and reveal the internal dynamics of the molecular gas in this system .
The ring has a diameter of \sim 1.5 ^ { \prime \prime } , and thus is sampled over \sim 20 resolution elements by our observations .
Through a model-based lens inversion , we recover the velocity gradient of the molecular reservoir in the quasar host galaxy of PSS J2322+1944 .
The Einstein ring lens configuration enables us to zoom in on the emission and to resolve scales down to \lesssim 1 kpc .
From the model-reconstructed source , we find that the molecular gas is distributed on a scale of 5 kpc , and has a total mass of M ( { H _ { 2 } } ) = 1.7 \times 10 ^ { 10 } M _ { \odot } .
A basic estimate of the dynamical mass gives M _ { dyn } = 4.4 \times 10 ^ { 10 } \sin ^ { -2 } i M _ { \odot } , that is , only \sim 2.5 times the molecular gas mass , and \sim 30 times the black hole mass ( assuming that the dynamical structure is highly inclined ) .
The lens configuration also allows us to tie the optical emission to the molecular gas emission , which suggests that the active galactic nucleus ( AGN ) does reside within , but not close to the center of the molecular reservoir .
Together with the ( at least partially ) disturbed structure of the CO , this suggests that the system is interacting .
Such an interaction , possibly caused by a major ‘ wet ’ merger , may be responsible for both feeding the quasar and fueling the massive starburst of 680 M _ { \odot } yr ^ { -1 } in this system , in agreement with recently suggested scenarios of quasar activity and galaxy assembly in the early universe .