A 1.4 GHz radio continuum and polarization survey at medium Galactic latitudes: II. First section

摘要

We present the first section of a radio continuum and polarization survey atmedium Galactic latitudes carried out with the Effelsberg 100-m telescope at1.4 GHz. Four large fields have been observed, which all together cover an areaof about 1100 square degree. The rms-sensitivity is about 15 mK TB (about 7mJy/beam area) in total intensity and is limited by confusion. A sensitivity of8 mK TB is obtained in linear polarization. The angular resolution of theobservations is 9.35 arcminute. The maps in total intensity and linearpolarization have been absolutely calibrated by low resolution data whereavailable. Significant linear polarization is seen in all the maps. In general,the intensity fluctuations measured in linear polarization are not correlatedwith total intensity structures. Areas of high polarization of some degreesextent are seen, again with no apparent corresponding total intensity feature.Modulation of polarized background emission by spatially varying Faradayrotation seems the most likely explanation. Quite unexpected is the detectionof filamentary and ring-like depolarization structures in the direction of theanticentre region, whose extents are up to about 3 degree.