Physical properties of the molecular cloud, N4, in SS433; Evidence for
  an interaction of molecular cloud with the jet from SS433
  We conducted observations and analyses of the molecular cloud, N4, which is
located at ~40 pc from SS433 and the same line of sight as that of the radio
shell, in 12CO(J=1-0), 12CO(J=3-2), 13CO(J=3-2), and grand-state OH
emissions.N4 has a strong gradient of the integrated intensity of 12CO(J=1-0,
3-2) emission at the northern, eastern and western edges. The main body of N4
also has a velocity gradient of ~0.16 km s^-1 20"^-1. A velocity shift by up to
3 km s^-1 from the systemic velocity at ~49 km s^-1 is detected at only the
northwestern part of N4. The volume density of the molecular hydrogen gas and
the kinematic temperature are estimated at eight local peaks of 12CO(J=1-0) and
13CO(J=3-2) emissions by the RADEX code. The calculated n(H2) is an order of
10^3 cm^-3, and T_k ranges ~20 K to ~56 K. The mass of N4 is estimated to be
~7300 Mo. The thermal and turbulent pressures in N4 are estimated to be ~10^5 K
cm^-3 and ~10^7 K cm^-3, respectively. The relation of the thermal and
turbulent pressures in N4 tends to be similar to that of the molecular clouds
in the Galactic plane. However, these values are higher than those in the
typical molecular clouds in the Galactic plane. Several pieces of
circumstantial evidence representing the physical properties of N4 and
comparison with the data of infrared and X-ray radiation suggest that N4 is
interacting with a jet from SS433. However, no gamma-ray radiation is detected
toward N4. Compared to the previous study, it is hard to detect the gamma-ray
radiation by cosmic-ray proton origin due to the low sensitivity of the current
gamma-ray observatories. Any OH emission was not detected toward N4 due to the
low sensitivity of the observation and antenna beam dilution.
