  PSRJ 2032+4127 is only the second known gamma-ray binary where it is
confirmed that a young radio pulsar is in orbit around a Be-star. The
interaction of the pulsar wind with the mass outflow from the companion leads
to broad band emission from radio up to TeV energies. In the current paper we
present results of optical monitoring of the 2017 periastron passage with the
Nordic Optical Telescope. These observations are complemented by X-ray
(Swift/XRT, NuSTAR) and GeV (Fermi/LAT) monitoring. Joint analysis of the
evolution of the parameters of the Halpha line and the broadband (X-ray to TeV)
spectral shape allows us to propose a model linking the observed emission to
the interaction of the pulsar and Be-star winds under the assumption of the
inclined disc geometry. Our model allows the observed flux and spectral
evolution of the system to be explained in a self-consistent way.
