  We compared the molecular clouds in the western part of SS 433 with
near-ultraviolet radiation data obtained from GALEX. Near-ultraviolet radiation
is prominently confirmed toward only N4, while no near-ultraviolet radiation is
detected toward N1, N2, and N3. The radiative region of near-ultraviolet
radiation is nearly the same as the CO-emitting region in N4, and does not
extend beyond the jet seen in X-ray radiation. Near-ultraviolet radiation
cannot be explained solely by broadband continuous radiation and may originate
from line emissions. The intensity of near-ultraviolet radiation exhibits an
anti-correlation with that of 13CO(J=3-2) emission. This anti-correlation,
along with strong far-infrared radiation in the region with weaker
near-ultraviolet radiation intensity compared to its surroundings, suggests
that near-ultraviolet radiation originates from behind the molecular cloud,
heating up the interstellar dust in N4. Subsequently, the dust in N4
re-radiates in the far-infrared band. In the same region, a high peak T_MB
ratio of 12CO(J=3-2)/12CO(J=1-0) of ~0.9, and a high kinetic temperature of T_k
~56 K in the molecular cloud indicate that CO molecules are highly excited, and
the molecular cloud is heated through photoelectric heating. This heating
results from electrons released due to the photoelectric effect caused by the
phenomenon where interstellar dust absorbs near-ultraviolet radiation. In terms
of the timescale of near-ultraviolet radiation originating from line emissions,
near-ultraviolet radiation towards N4 cannot be explained by the shock of the
blast wave from a supernova that created W 50. These findings also suggest that
N4 directly interacts with the jet from SS 433. As a result of this direct
interaction, near-ultraviolet radiation is emitted from an interacting layer
between the jet and N4.
