  We present X-ray and radio monitoring observations of the gamma-ray binary
PSR J2032+4127/MT91 213 during its periastron passage in late 2017. Dedicated
Chandra, XMM-Newton,NuSTAR X-ray observations and VLA radio observations of
this long orbit (50 years), 143 ms pulsar/Be star system clearly revealed flux
and spectral variability during the passage. The X-ray spectrum hardened near
periastron, with a significant decrease in the power-law photon index from
\Gamma ~ 2 to 1.2 and evidence of an increased absorption column density. We
identified a possible spectral break at a few keV in the spectrum that suggests
synchrotron cooling. A coincident radio and X-ray flare occurred one week after
periastron, which is possibly the result of the pulsar wind interacting with
the Be stellar disk and generating synchrotron radiation. However, a
multi-wavelength comparison indicate that the X-ray and radio spectra cannot be
simply connected by a single power-law component. Hence, the emission in these
two energy bands must originate from different particle populations.
