The accuracy of the absolute value of solar flux depends on the temperature calibration techniques and the knowledge of the gain of the aerial used for the measurements. Recent advances in low-noise receivers, microwave components, and amplifier stability have reduced considerably the errors due to temperature calibration techniques. At present the knowledge of the gain of the aerial used for calibrations (usually a pyramidal horn) presents the largest source of doubt of an absolute calibration. Investigations of this problem suggest that a ‘standard gain horn’ should be employed at all observatories in absolute solar calibrations.

High-resolution surveys of the galactic radio emission show detailed structure both near the galactic plane and at high galactic latitudes. Some of this structure is describable as ‘spurs’ while the rest comprises isolated features. We describe here measurements of the spectral index of the background radiation with a resolution of 3°.5. These measurements are aimed at a detailed understanding of the high-latitude synchrotron emission.

Observations of polarized emission and consequently the investigation of magnetic fields in northern galaxies, have been conducted successfully for some time with, for example, the 100-m Effelsberg telescope of the Max-Planck-Institut-für Radioastronomie and the VLA. However, the opportunity to make corresponding studies in the southern hemisphere has only recently become possible. Therefore, we have begun a long-range project aimed at studying the morphology and dynamics of southern galaxies using the facilities of the Parkes and Molonglo radio telescopes, the Siding Spring optical facilities and the Australia Telescope. Here we present preliminary results from Parkes observations of the three well known galaxies: NGC 253, NGC 4945 and M 83.

The highest frequency at which a radiotelescope can be used depends on the surface accuracy. The rms error of the surface should be less then l/16th of the shortest wavelength. This should be not only under static conditions but also when the telescope is being driven, under the influence of wind and temperature changes. With this in mind we can trace back the development of the paraboloidal dish since the time when Grote Reber constructed his antenna in Wheaton, Illinois.

In recent years two 408 MHz surveys of the northern sky have been made to study the large-scale, low-surface-brightness features of the galactic background such as the loops and spurs (Haslam et al. 1970; Haslam et al. 1974). These surveys were designed to make maps down to the confusion limits of the telescopes used and to provide as far as practicable accurate calibration of the temperature scale and zero level for large-scale features. This work is complementary to the work of the large array telescopes; these telescopes can provide high resolution detail but they have lower surface brightness sensitivity, and have problems in determining the low-order terms which define the large-scale structure. The Parkes 408 MHz sourthern survey continues this work using the 64-m telescope to complete the coverage of the sky to the south pole. The project is a joint venture between the Max-Planck-Institut and CSIRO. For the southern survey it was felt desirable to measure the linear polarization distribution, besides making an accurate average temperature map in left-hand circular polarization (which is insensitive to variations of ionospheric Faraday effects). The previous surveys did not include linear polarization measurements.

We present preliminary results from a number of deep radio polarization surveys being made of the Magellanic Clouds at 2.3 GHz, 4.75 GHz and 8.55 GHz. Extended and linearly polarized radio emission has been found at 2.3 and 4.75 GHz from both the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). However, as the analysis of these data is not yet complete we present only some of the 4.75 GHz results at this time.

We are studying the distribution and morphology of magnetic fields in southern face-on and edge-on galaxies with the intention of clarifying the distribution, lifetimes and transport mechanisms of cosmic rays, and investigating the intensity and orientation of the disc, halo and poloidal magnetic fields. As a preliminary study, before the Australia Telescope was available, we observed a sample of well-known southern spiral galaxies with the Parkes radio telescope.

Here, we present the resulting polarisation images for three galaxies, NGC 253, M 83 and NGC 4945, which were observed at 4.75 GHz and 8.55 GHz. The corresponding total power contour plots have been already published by Harnett et al. (1989a, 1990).

Pulsars display a complicated pattern of amplitude variations. The scale of variations range from months through hours to sub-milliseconds. The purpose of this note is to present polarization data for CP 1919 and intensity distribution data for PSR 0833—45 which are relevant to pulse-to-pulse variations and the variation over periods of hours respectively.

We have mapped the southern galaxies NGC 613, 1313, 1433, 1566, 1672 and 2442 in the 12CO(J = 1 → 0) transition with the 15-m Swedish European Submillimetre Telescope (SEST). The sample is based on galaxies previously observed in radio continuum with the Molonglo Observatory Synthesis Telescope (MOST). Strong emission is seen from the barred galaxies NGC 613 and NGC 2442 and from the active galaxies NGC 1566 and 1672. The weakest emission was from NGC 1433, while the Sd spiral NGC 1313 was not detected.

We have observed 79 supernova remnants (SNRs) with the Urumqi 25 m telescope at λ6 cm during the Sino-German λ6 cm polarization survey of the Galactic plane. We measured flux densities of SNRs at λ6 cm, some of which are the first ever measured or the measurements at the highest frequency, so that we can determine or improve spectra of SNRs. Our observations have ruled out spectral breaks or spectral flattening that were suggested for a few SNRs, and confirmed the spectral break of S147. By combining our λ6 cm maps with λ11 cm and λ21 cm maps from the Effelsberg 100 m telescope, we calculated the spectral index maps of several large SNRs. For many remnants we obtained for the first time polarization images, which show the intrinsic magnetic field structures at λ6 cm. We disapproved three objects as being SNRs, OA184, G192.8−1.1 and G16.8−1.1, which show a thermal spectrum and no polarization. We have discovered two large supernova remnants, G178.2−4.2 and G25.1−2.3., in the survey maps.

The Sino-German λ6 cm polarization survey has mapped in total intensity and polarization intensity over an area of approximately 2200 square degrees in the Galactic disk. This survey provides an opportunity to search for Galactic supernova remnants (SNRs) that were previously unknown. We discovered the new SNRs G178.2−4.2 and G25.1−2.3 which have non-thermal spectra, using the λ6 cm data together with the observations with the Effelsberg telescope at λ11 cm and λ21 cm. Both G178.2−4.2 and G25.1−2.3 are faint and have an apparent diameter greater than 1°. G178.2−4.2 shows a polarized shell. HI data suggest that G25.1−2.3 might have a distance of about 3 kpc. The λ6 cm survey data were also very important to identify two other new SNRs, G152.4−2.1 and G190.9−2.2.

After Prof. R. Wielebinski visited China in 1999, we started to plan the Sino-German λ6 cm polarization survey of the Galactic plane, using the Urumqi 25-m radio telescope of Xinjiang (formerly Urumqi) Astronomical Observatory, Chinese Academy of Sciences. It is a high-frequency complement of previous Effelsberg 21-cm and 11-cm surveys, using the same observing and processing methods. The telescope is located at an altitude of 2029 m above sea level at geographic longitude of 87°E and latitude 43°N. The dual-channel λ6 cm receiver with a polarimeter and a bandwidth of 600 MHz was designed by O. Lochner and constructed at the MPIfR in Germany with involvements by the Urumqi engineers M.Z. Chen and J. Ma. In August 2004, the receiver was installed at the secondary focus of the Urumqi 25-m telescope.

Radio astronomy gave us new methods to study magnetic fields. Synchrotron radiation, the main cause of comic radio waves, is highly linearly polarised with the ‘E’ vector normal to the magnetic field. The Faraday Effect rotates the ‘E’ vector in thermal regions by the magnetic field in the line of sight. Also the radio Zeeman Effect has been observed.

As part of the Canadian Galactic Plane Survey (CGPS) we have imaged the polarized emission from the plane of the Milky Way at 1420 MHz, covering 1200 square degrees with arc-minute resolution. Structure on all scales is represented by combining aperture-synthesis data with single-antenna data. The survey depicts the Magneto-Ionic Medium at a resolution that matches images of other components of the Interstellar Medium within the CGPS database (http://www4.cadc.hia.nrc.gc.ca).

Magnetic fields are found everywhere in the cosmic Universe. They have been known to exist on the Earth for centuries. They were detected in the Sun, measured in situ in the planets, observed in stars, galaxies and clusters of galaxies. Magnetic fields are responsible for many observed effects like radio continuum emission, jets, beamed emission in pulsars, star formation, etc. Possibly the whole universe is intimately governed by the presence of magnetic fields. This review will summarize the observational results and discuss the present interpretation for the origin of the magnetic fields.

We present high quality polarimetric observations with the Effelsberg radio telescope of the Crab pulsar at 8.35 GHz using a new sensitive receiver with a very large bandwidth. We present our observations and discuss them in the context of the conclusions reached by Moffett & Hankins (1999) about the geometry and the origin of the various pulse components.

We report on the progress of our search for highly dispersed pulsars near the Galactic Center at 5 GHz using the 100-m radio telescope in Effelsberg. We also present key aspects of our new survey for millisecond pulsars at 21 cm in parts of the northern sky. This survey will greatly benefit from the L-band multibeam receiver and a new FFT-based backend which are currently under construction at the MPIfR.

Of all the methods available to observe magnetic fields in the Milky Way, the mapping of linear polarization at cm wavelengths has proven to be most successful. The instruments that have contributed most of the new data are the 100 m Effelsberg telescope and the Parkes 64 m dish. Their Galactic plane surveys gave us a new conception of the linear polarization distribution. A new Effelsberg 1.4 GHz ‘medium latitude polarization survey’ now being made gives us data about large sections of the Galaxy. Polarization maps of selected regions of the Galaxy are now being made at several frequencies up to 32 GHz. Data from Westerbork at ∼ 325 MHz, as well as data from the Canadian Galactic Plane Survey (CGPS) at 1.4 GHz give new exciting information.

I present a unique data set for the study of molecular gas in galaxies: a complete, high-resolution survey of the CO in M 31 and additional local studies. The fully sampled survey has an angular resolution of 23 FWHM and the interferometric data attain the pc-scale with sub-arcsecond resolution. For the first time it is now possible to study large and small scales in conjunction. Thus we are able to derive the global structure and study the links down to the individual cloud complexes and star formation regions.

This report covers the period July 1996 to June 1999. It has been prepared by the President of the Commission with contributions from the members of the Organizing Committee and Dr. E.M. Corsini. As discussed in Kyoto and decided by the Organizing Committee, the report is meant to be in the “short” version.