We present high-resolution Very Large Array imaging of the molecular gas in the host galaxy of the high redshift quasar BRI 1335–0417 ( z = 4.41 ) .
Our CO ( J =2 \to 1 ) observations have a linear resolution of 0.15 ^ { \prime \prime } ( 1.0 kpc ) and resolve the molecular gas emission both spatially and in velocity .
The molecular gas in BRI 1335–0417 is extended on scales of 5 kpc , and shows a complex structure .
At least three distinct components encompassing about two thirds of the total molecular mass of 9.2 \times 10 ^ { 10 } M _ { \odot } are identified in velocity space , which are embedded in a structure that harbors about one third of the total molecular mass in the system .
The brightest CO ( J =2 \to 1 ) line emission region has a peak brightness temperature of 61 \pm 9 K within 1 kpc diameter , which is comparable to the kinetic gas temperature as predicted from the CO line excitation .
This is also comparable to the gas temperatures found in the central regions of nearby ultra-luminous infrared galaxies , which are however much more compact than 1 kpc .
The spatial and velocity structure of the molecular reservoir in BRI 1335–0417 is inconsistent with a simple gravitationally bound disk , but resembles a merging system .
Our observations are consistent with a major , gas-rich ( ‘ wet ’ ) merger that both feeds an accreting supermassive black hole ( causing the bright quasar activity ) , and fuels a massive starburst that builds up the stellar bulge in this galaxy .
Our study of this z > 4 quasar host galaxy may thus be the most direct observational evidence that ‘ wet ’ mergers at high redshift are related to AGN activity .