A Sino-German 6cm polarization survey of the Galactic plane IV. The
  region from 60deg to 129deg longitude
  Linear polarization of diffuse Galactic emission is a signature of magnetic
fields in the interstellar medium of our Galaxy. Observations at high
frequencies are less affected by Faraday depolarization than those at lower
frequencies and are able to detect polarized emission from more distant
Galactic regions. We attempt to perform a sensitive survey of the polarized
emission from the Galactic disk at 6 cm wavelength. We made polarization
observations of the Galactic plane using the Urumqi 25-m telescope at 6 cm
covering the area of 60deg< l <129deg and |b|<5deg. Missing large-scale
structures in polarization were restored by extrapolation of the WMAP
polarization data. We present the 6cm total intensity and linear polarization
maps of the surveyed region. We identify two new extended HII regions G98.3-1.6
and G119.6+0.4 in this region. Numerous polarized patches and depolarization
structures are visible in the polarization maps. Depolarization along the
periphery of a few HII complexes was detected and can be explained by a Faraday
screen model. We discuss some prominent depolarization HII regions, which have
regular magnetic fields of several $\mu$G. Structure functions of U, Q and PI
images of the entire 6cm survey region of 10deg< l < 230deg exhibit much larger
fluctuation power towards the inner Galaxy, which suggests a higher turbulence
in the arm regions of the inner Galaxy. The Sino-German 6cm survey reveals new
properties of the diffuse magnetized interstellar medium. The survey is also
very useful for studying individual objects such as HII regions, which act as
Faraday screens and have high rotation measures and therefore strong regular
magnetic fields inside the regions.
