Search

The development of radio astronomy in Poland took some time to occur, in view of the destruction of the country during World War II. Also, the shift of the country's borders in favor of the Soviet Union led to the loss of two important astronomy observatories: the historic centers of astronomy in Wilno and Lwów. The relocation of these important astronomical centers to Toruń and Wrocław in the West needed considerable effort. Hence radio astronomy was a second priority as the optical astronomers had to become operational first. Nevertheless, in the 1950s groups in Kraków and Toruń started to erect radio telescopes. In Kraków solar radio astronomy became established. In Toruń, there were experiments with low frequency parabolic antennas. First, a 15-m dish was built, and later a 32-m dish became operational. In Kraków the solar patrol continued and a LOFAR station was added. Contacts with radio observatories in other parts of the world were established. In 1988 a new regional university was established in Zielona Góra, and a group involved in pulsar research was built up there. Astrophysics departments existed at Warszawa (Warsaw) University and at the Nicolaus Copernicus Astronomical Center (CAMK) of the Polish Academy of Sciences, and the universities in Poznań, Gdańsk and Lublin had astronomical departments, but none of these was involved in radio astronomy.

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.

Continuum observations of the edge-on spiral galaxy NGC 4945 with the Australia Telescope National Facility's Compact Array (ATCA) and the Parkes 64-m radio telescope are presented. The ATCA maps are currently the highest resolution wide-band radio continuum maps of this galaxy. A compact, non-thermal core of less than 60 pc diameter has been detected. The luminosity of the central 90 pc is 2 × 10 erg s, equivalent to almost half the total value of the galaxy. 90 per cent of the galaxy's λ = 3 cm radio emission originates from the nuclear bulge (central 4 kpc), the radio disc measuring 23 ± 2 kpc in diameter. The nuclear bulge of the galaxy has a spectral index of a = - 0.57 ± 0.04 (S ∝ v), similar to the core value. The disc emission of the galaxy has a much steeper spectral index of α= -1.1 ± 0.1, indicative of either a high-energy cut-off to the disc population of cosmic rays or differing source energetics in the disc. The large-scale radio morphology resembles that of the majority of edge-on spirals in that no radio halo has been detected. The average total equipartition magnetic field strength of the disc is 13 μG, whilst our polarization results indicate that the regular component of the magnetic field is about 3 μG. We conclude that NGC 4945 is one of a number of edge-on spiral galaxies with a magnetic field (and hence cosmic rays) confined to the disc.

The Sino-German 6cm 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 6cm data together with the observations with the Effelsberg telescope at 11 cm and 21 cm. Both G178.2-4.2 and G25.1-2.3 are faint and have an apparent diameter greater than 1deg. 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 6cm survey data were also very important to identify two other new SNRs, G152.4-2.1 and G190.9-2.2., Comment: 4 pages, 3 figures, contributed talk at the IAU Symp. 296: Supernova Environmental Impacts

Un modele simple est developpe pour l'origine des anneaux de gaz moleculaire des regions centrales de galaxies. Les galaxies sont considerees comme constituees d'une region centrale avec une rotation de corps solide et d'un disque en rotation differentielle. Le transport du moment cinetique visqueux dans le disque est analyse

We have observed the continuum emission of the interacting galaxy NGC4631 at 0.87 and 1.23mm using the Heinrich-Hertz-Telescope on Mt. Graham and the IRAM 30-m telescope on Pico Veleta. We have obtained fully sampled maps which cover the optical emission out to a radius of about 7' at both wavelengths. For a detailed analysis, we carefully subtracted the line contributions and synchrotron and free-free emission from the data, which added up to 6% at 1.23mm and 10% at 0.87mm. We combined the flux densities with FIR data to obtain dust spectra and calculate dust temperatures, absorption cross sections, and masses. Assuming a ``standard'' dust model, which consists of two populations of big grains at moderate and warm temperatures, we obtained temperatures of 18K and 50K for the both components. However, such a model suffers from an excess of the radiation at 1.23mm, and the dust absorption cross section seems to be enhanced by a factor 3 compared to previous results and theoretical expectations. At large galactocentric radii, where the galaxy shows disturbances as a result of gravitational interaction, this effect seems to be even stronger. Some possibilities to resolve these problems are discussed. The data could be explained by a very cold dust component at a temperature of 4-6K, an increased abundance of very small grains, or a component of grains with unusual optical properties. We favour the latter possibility, since the first two lead to inconsistencies., 12 pages, 6 figures, accepted for publication in Astronomy & Astrophysics. Updated version with minor errors corrected (typos, LaTeX formatting, missing citation)

I present the results of recent 9 mm observations of the starburst galaxy M 82 with the Effelsberg 100-m radio telescope. The magnetic fields deduced from these observations are in good agreement with previous multifrequency VLA observations. The general pattern of azimuthal magnetic fields along the disc of the galaxy and vertical fields in the central region, as seen in most nearby galaxies, is confirmed to exist also in M 82. Since the starburst galaxy M 82 is a very powerful radio source similar objects should be visible at large distances. Possibly the distant magnetic Universe could be probed by observing sources similar to M 82 with the new generation of radio telescopes. Here the ALMA telescope holds great promise for the near future. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High-resolution, high-sensitivity observations of the CO(J=2-1) lines in the galaxy M82 have revealed that the rotation of the gas disk is Keplerian, which suggests that the galaxy has no massive halo. The extended molecular gas halo, extending up to ±2 kpc above the galactic plane, shows very slow rotation and indicates that the halo gas has been ejected from the central region in angular momentum conservation

On presente les techniques d'observations, les donnees d'observations courantes et les methodes utilisees pour obtenir la configuration du champ dans les galaxies spirales. On discute de la configuration du champ et de ses implications sur la dynamique, l'evolution et l'activite dans les galaxies spirales

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.

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.

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.