  This study shows the existence of an additional thermal component found in
the synchrotron emission from the M87 jet. Using Chandra, thermal
bremsstrahlung is detected in four out of six fields. X-rays for the nucleus
and HST-1 are well described with a power law model. Neutral density, plasma
density, and the density of accelerated electrons for the nucleus and each part
of the jet are obtained. The mass of the thermal gas is estimated to be
3.9x10^6 M. The possibility that the thermal gas is injected into the jet from
the black-hole is excluded because the nucleus and the field HST-1 do not
contain thermal components. It is possible that the interstellar medium is
compressed by the jet and is heated by the shock. The energy density of the gas
is comparable to that of the magnetic field with 1 mG. For the field D, a high
density of accelerated electrons of 1.5x10^11 (2 d / tval )^3 ( 6 / delta )^3 (
3 /Gamma )^2 m^-3 GeV^(p-1), a high upper limit of neutral density of 8 cm^-3,
and a high ion density of 195 cm^-3 are obtained. A possible contribution of
non-thermal bremsstrahlung from the jet, especially the field D to the observed
flux with Fermi is suggested. This scenario matches with non-flux variability
in the GeV energy range.
