We have mapped the molecular gas content in the host galaxy of the strongly lensed high redshift quasar APM 08279+5255 ( z = 3.911 ) with the Very Large Array at 0.3 ^ { \prime \prime } resolution .
The CO ( J =1 \to 0 ) emission is clearly resolved in our maps .
The CO ( J =1 \to 0 ) line luminosity derived from these maps is in good agreement with a previous single-dish measurement .
In contrast to previous interferometer-based studies , we find that the full molecular gas reservoir is situated in two compact peaks separated by \lesssim 0.4 ^ { \prime \prime } .
Our observations reveal , for the first time , that the emission from cold molecular gas is virtually cospatial with the optical/near-infrared continuum emission of the central AGN in this source .
This striking similarity in morphology indicates that the molecular gas is situated in a compact region close to the AGN .
Based on the high resolution CO maps , we present a revised model for the gravitational lensing in this system , which indicates that the molecular gas emission is magnified by only a factor of 4 ( in contrast to previously suggested factors of 100 ) .
This model suggests that the CO is situated in a circumnuclear disk of \sim 550 pc radius that is possibly seen at an inclination of \lesssim 25 ^ { \circ } , i.e. , relatively close to face-on .
From the CO luminosity , we derive a molecular gas mass of M _ { gas } =1.3 \times 10 ^ { 11 } M _ { \odot } for this galaxy .
From the CO structure and linewidth , we derive a dynamical mass of M _ { dyn } sin ^ { 2 } i =4.0 \times 10 ^ { 10 } M _ { \odot } .
Based on a revised mass estimate for the central black hole of M _ { BH } =2.3 \times 10 ^ { 10 } M _ { \odot } and the results of our molecular line study , we find that the mass of the stellar bulge of APM 08279+5255 falls short of the local M _ { BH } – \sigma _ { bulge } relationship of nearby galaxies by more than an order of magnitude , lending support to recent suggestions that this relation may evolve with cosmic time and/or change toward the high mass end .