Aims. Polarization measurements of the Galactic plane at λ6 cm probe the interstellar medium (ISM) to larger distances compared to measurements at longer wavelengths, enabling us to investigate properties of the Galactic magnetic fields and electron density. Methods. We are conducting a new λ6 cm continuum and polarization survey of the Galactic plane covering 10• ≤ l ≤ 230• and |b| ≤ 5• . Missing large-scale structures in the U and Q maps are restored based on extrapolated polarization K-band maps from the WMAP satellite. The λ6 cm data are analyzed together with maps in other bands. Results. We discuss some results for the first survey region, 7• × 10 • in size, centered at (l, b) = (125.• 5, 0 • ). Two new passive Faraday screens, G125.6−1.8 and G124.9+0.1, were detected. They cause significant rotation of background polarization angles but little depolarization. G124.9+0.1 was identified as a new faint HII region at a distance of 2.8 kpc. G125.6−1.8, with a size of about 46 pc, has neither a counterpart in enhanced Hα emission nor in total intensity. A model combining foreground and background polarization modulated by the Faraday screen was developed. Using this model, we estimated the strength of the ordered magnetic field along the line of sight to be 3.9 µG for G124.9+0.1, and exceeding 6.4 µG for G125.6−1.8. We obtained an estimate of 2.5 and 6.3 mK kpcfor the average polarized and total synchrotron emissivity towards G124.9+0.1. The synchrotron emission beyond the Perseus arm is quite weak. A spectral curvature previously reported for SNR G126.2+1.6 is ruled out by our new data, which prove a straight spectrum. Conclusions. The new λ6 cm survey will play an important role in improving the understanding of the properties of the magnetoionic ISM. The magnetic fields in HII regions can be measured. Faraday screens with very low electron densities but large rotation measures were detected indicating strong and regular magnetic fields in the ISM. Information about the local synchrotron emissivity can be obtained.Key words. surveys -polarization -radio continuum: general -methods: observational -ISM: magnetic fields -ISM: supernova remnants IntroductionThe first detection of diffuse polarized emission from the Milky Way Galaxy (Westerhout et al. 1962;Wielebinski et al. 1962) confirmed that its non-thermal radiation originates from synchrotron emission. The two major sources of polarized emission from our Galaxy are diffuse radio emission associated with the Galactic disk produced by relativistic electrons spiraling in interstellar magnetic fields, and discrete sources such as supernova remnants (SNRs) with compressed interstellar magnetic fields, where relativistic electrons are accelerated by shocks.To understand the properties of the ISM in our Galaxy a number of whole sky surveys (e.g. as reviewed by Reich 2003) have been made. Also large-scale radio surveys of the Galactic plane with higher angular resolution have been performed. The large-scale surveys clearly show the concentration of emission ...

Abstract. The Orion local spiral arm is seen tangential towards the Cygnus region. Intense radio emission with quite a complex morphology is observed, which appears to be surrounded by strong soft X-ray emission. This remarkable X-ray structure is known as the Cygnus superbubble. We compare a recent 1.4 GHz radio continuum and polarization map from the Effelsberg 100-m telescope with X-ray data from the ROSAT all-sky survey of this area. Including available survey data of the infrared, H i and CO emission, we investigate a number of high latitude features, which are physically related to one of the Cygnus OB associations. These OB associations, however, are located along the local arm at different distances. Our results support the view that the Cygnus superbubble is not a physical unity, but results from a projection of unrelated X-ray emitting features at different distances blown out from the local arm seen along the line of sight.

Abstract. We present the first section of a radio continuum and polarization survey at medium Galactic latitudes carried out with the Effelsberg 100-m telescope at 1.4 GHz. Four large fields have been observed, which all together cover an area of about 1100 . The rms-sensitivity is about 15 mK T B (about 7 mJy/beam area) in total intensity and is limited by confusion. A sensitivity of 8 mK T B is obtained in linear polarization. The angular resolution of the observations is 9. 35. The maps in total intensity and linear polarization have been absolutely calibrated by low resolution data where available. Significant linear polarization is seen in all the maps. In general, the intensity fluctuations measured in linear polarization are not correlated with total intensity structures. Areas of high polarization of some degrees extent are seen, again with no apparent corresponding total intensity feature. Modulation of polarized background emission by spatially varying Faraday rotation seems the most likely explanation. Quite unexpected is the detection of filamentary and ring-like depolarization structures in the direction of the anticentre region, whose extents are up to about 3• .

Context. Observations of polarized emission are a significant source of information on the magnetic field that pervades the interstellar medium of the Galaxy. Despite the acknowledged importance of magnetic fields in interstellar processes, our knowledge of field configurations on all scales is seriously limited. Aims. This paper describes an extensive survey of polarized Galactic emission at 1.4 GHz that provides data with arcminute resolution and complete coverage of all structures from the broadest angular scales to the resolution limit, giving information on the magnetoionic medium over a wide range of interstellar environments. • 5. This is the first extensive polarization survey to present aperture-synthesis data combined with data from single antennas, and the techniques developed to achieve this combination are described. Results. The appearance of the extended polarized emission at 1.4 GHz is dominated by Faraday rotation along the propagation path, and the diffuse polarized sky bears little resemblance to the total-intensity sky. There is extensive depolarization, arising from vector averaging on long lines of sight, from H ii regions, and from diffuse ionized gas seen in Hα images. Preliminary interpretation is presented of selected polarization features on scales from parsecs (the planetary nebula Sh 2-216) to hundreds of parsecs (a superbubble GSH 166−01−17), to kiloparsecs (polarized emission in the direction of Cygnus X).

The Effelsberg 21 cm radio continuum survey of the Galactic plane between l = 95.• 5 and l = 240 Abstract. We present the results of a radio continuum survey at 21 cm wavelength of the Galactic plane between 95.• 5 ≤ l ≤ 240• with the Effelsberg 100-m telescope. The data have been absolutely calibrated by using the Stockert northern sky survey at the same wavelength. This survey complements the Effelsberg 21 cm Galactic plane survey for l ≤ 95.• 5 by Reich et al. (1990a). The results are presented as contour maps with a sensitivity of 100 mK T B at an angular resolution (HPBW) of 9. 4. In addition we extend the list of compact sources given by Reich et al. (1990a) by 1830 new entries. These sources have peak flux densities exceeding 160 mK T B (or 79 mJy/beam area) and apparent sizes of less than 16 .