With new high-resolution CO and H i data , we revisited the large-scale interstellar medium ( ISM ) environment toward the SS 433 / W50 system .
We find that two interesting molecular cloud ( MC ) concentrations , G39.315 - 1.155 and G40.331 - 4.302 , are well aligned along the precession cone of SS 433 within a smaller opening angle of \sim \pm 7 ^ { \circ } .
The kinematic features of the two MCs at \sim 73–84 km s ^ { -1 } , as well as those of the corresponding atomic-gas counterparts , are consistent with the kinematic characteristics of SS 433 .
That is , the receding gas from SS 433 jet is probably responsible for the redshifted feature of G39.315 - 1.155 near the Galactic plane and the approaching one may power the blueshifted gas of G40.331 - 4.302 toward the observer .
Moreover , the H i emission at V _ { LSR } \sim 70–90 km s ^ { -1 } displays the morphological resemblance with the radio nebula W50 .
We suggest that the V _ { LSR } =77 \pm 5 km s ^ { -1 } gas is physically associated with SS 433 / W50 , leading to a near kinematic distance of 4.9 \pm 0.4 kpc for the system .
The observed gas features , which are located outside the current radio boundaries of W50 , are probably the fossil record of jet–ISM interactions at \sim 10 ^ { 5 } years ago .
The energetic jets of the unique microquasar have profound effects on its ISM environment , which may facilitate the formation of molecular gas on the timescale of < \sim 0.1 Myr for the ram pressure of \sim 2 \times 10 ^ { 6 } { K cm ^ { -3 } } .