A clear keynote for our conference is given by the diagram shown in Figure 1. This year we can celebrate that it is just half a century ago that it was produced by Harlow Shapley and Adelaide Ames. This marvellous picture illustrates nearly all we know about the properties of the Universe, except its expansion. It can teach us practically all the lessons we are still learning today. Most prominent is the Virgo cluster. Also evident are structures on larger scale, such as the appendages on both sides of the cluster, spanning a total length of 20 to 30 Mpc.* They are the kernel of the Local, or Virgo, supercluster. The supercluster has a complicated structure, evident from the clumpiness in the distribution along its axis, but likewise from the arrangement of the galaxies in its environment. The centre of the local supercluster (the Virgo cluster) lies at a distance of about 20 Mpc. The supercluster probably extends somewhat beyond us. However, everything in the Shapley-Ames picture should be considered as connected with this one supercluster. Features marked A, B and C may be independent structures; A lies at a distance of roughly 50 Mpc; C, at a distance of ∼ 70 Mpc, lies similarly well outside the Local Supercluster. The strongly elongated feature B, with an average velocity of 1400 km s−1 and a dispersion of only 300 km s−1, appears also well isolated. All three are roughly 30 Mpc long, and may be considered as separate superclusters.

The imaging and spectroscopic instruments onboard the Einstein Observatory (Giacconi et al. 1979) have been extensively used to study in detail the X-ray properties of a large variety of astronomical objects. In this paper we will briefly discuss some of the most relevant results on extragalactic astronomy obtained mainly with the Imaging Proportional Counter (IPC).

The possibility that the processes responsible for the Cosmic X-ray Background (CXB) would also produce an e−-e+ annihilation feature is examined. Under the assumption that these processes are thermal, the absence of a strong e−-e+ annihilation feature places constraints on the compactness (L/R ratio) of these sources. Observations favor sources of small compactness ratio.

Recent results of QSO surveys are reviewed and QSO's cosmic evolution reconsidered.

The existing spectral searches for quasars have increased the number of quasars known very substantially but have not contributed proportionately to an understanding of the collective properties because of the selection effects. To fully exploit the spectral searches we have developed the technique of automated quasar detection (AQD) using objective-prism plates from the UK Schmidt Telescope, the COSMOS measuring machine at the Royal Observatory Edinburgh, and the STARLINK nodes at Durham and Edinburgh.

A catalogue containing the QSOs known with reasonable reliability from literature published before the end of 1981 has been compiled at the Asiago Observatory by C. Barbieri, M. Capaccioli, S. Cristiani, G. Nardon and A. Omizzolo, and will be published before the end of 1982 by the Memorie della Societá Astronomica Italiana.

The present release is an enlarged and updated version of that published by Barbieri et al. (1975). It provides basic data (names, equatorial and galactic coordinates at 1950.0, photometry, redshifts and information on radio emission, variability, morphology, presence of absorption lines, X-ray emission and finding charts) for 2004 QSOs, together with references, individual notes and cross reference tables. Two separate lists contain X-ray data for 271 QSOs (X-ray luminosity, optical-X and optical-radio spectral indexes) and absorption line data for 243 QSOs (absorption systems with their redshift, identified ions and wavelengths, spectral range, resolution and dispertion of the spectra).

The catalogue has been carefully checked for internal consistency and several discrepancies with the lists by Hewitt and Burbidge (1980) and by Véron and Véron (1975) have been resolved. The authors intend to provide a magnetic tape version of the catalogue to the Centre de Données Stellaires of the Strasbourg Observatory for distribution to the interested community.

The concept of a redshift limit for quasars was first mentioned a decade ago by Schmidt (1970, 1972) and Sandage (1972) who independently realized that faint, high redshift quasars were not being found in the numbers expected from the redshift and magnitude distribution of bright quasars. Subsequently the limit moved out in redshift to z ∼ 3.5 from z ∼ 2.5 after the discovery of OQ172 (z = 3.53, Wampler et al. 1973) and numerous other quasars with z > 3. It should be said at the outset that the limit concept is in need of definition. While it would be most interesting if an absolute limit existed, i.e., no quasars beyond a certain redshift, in reality the limit value is more likely to be the redshift at which the quasar space density turns down significantly.

PKS 2155–304 was repeatedly observed in 1979 and 1980 with the International Ultraviolet Explorer. Variations up to a factor of 2 in one year and by 20% in a day are found. The maximum amplitude of variation in X-rays is similar but the timescales are much shorter (a factor of 2 in one day; Urry and Mushotzky, 1982). In all cases the 1200–3100 A continuum is well fitted by a power law with frequency spectral index αUV between −0.7±0.03 and −0.9±0.03. Optical and ultraviolet observations taken within one day show different spectral slopes (Fig. 1). Separate power law fits in the two bands yield αopt = −0.46±0.01 and αUV = −0.80±0.02. The observations by Urry and Mushotzky indicate that the energy distribution steepens further in the soft X-ray region.

A stochastic model for the energy source of QSO's is used to fit the light curves of 43 objects taken from long-period photometry (minimum duration of observations, 8 years per object). The model fits are encouraging enough to allow us to derive absolute luminosities for individual QSO's and to re-plot the Hubble Diagram with the values thus computed. We find a significantly improved fit to the expected unit slope in the plot of log z against 1/5(mB - MB), and a best fit value of qo = 0.1 (±0.4).

The idea that there may be a cut-off in the distribution of quasars at high redshifts (z∼4) has been of some recent interest through the work of Osmer (1982). The observation of such an epoch of quasar creation is potentially of great importance in relation to theories of galaxy formation, but the evidence from optically-selected quasar samples remains uncertain: quite apart from the notorious problems in achieving quantifiable completeness in objective-prism surveys, any observed lack of high-redshift quasars may always be attributed to absorption either by a neutral IGM or by dust in intervening galaxies. Radio-selected samples, however, do not suffer from these problems, and this paper aims to review what studies of extragalactic radio sources can tell us about the numbers of objects at the highest redshifts.

The existing schemes to express the evolution of radio sources are either too simple to fit all the data (multi-frequency counts, identifications, spectra etc.) or have too many parameters and little predictive value. They do not also fit the identification statistics at different flux-densities (Swarup, Subrahmanya & Kapahi 1982, in ‘Astrophysical Cosmology’, Proc. Vatican Study Week) and the counts from recent deep surveys (van der Laan 1982, in ‘Astrophysical Cosmology’). Here, we report a preliminary attempt to derive a model that retains the simplicity of a small number of parameters and ease of refinement when new data are added.

Studies of quasar images which have adequate spatial resolution and reach sufficiently faint surface brightness levels indicate that virtually all low redshift (z ≲ 0.6) quasars are surrounded by faint nebulosities extending ∼ 3–20 arcsec from the quasar nucleus (at 26 R mag arcsec−2) (Wyckoff et al. 1980, 1981, Hutchings et al. 1981, Wehinger et al. 1983). Furthermore, the average integrated absolute magnitude and average metric diameter of the quasar nebulosities (quasar nucleus removed) are roughly those expected for galaxies at the corresponding (cosmological) quasar distances. Moreover, statistical support for the cosmological interpretation of the redshifts as well as the galaxy interpretation of the fuzz was found in correlations between the angular isophotal diameters of the quasar nebulosities and the redshifts, and between the integrated apparent magnitudes and the angular isophotal diameters (Wyckoff et al. 1981). Spectroscopic observations of quasar fuzz now convincingly support the galaxy interpretation for the quasar nebulosities (Boroson and Oke 1982, Oke et al. 1983).

The results discussed here are based on observations at λ 1 mm of 36 optically selected quasars (Sherwood et al., 1982; in preparation) and of 24 flat spectrum radio sources with Sν (5 GHz) ≥ 1 Jy (Kühr et al., 1979, 1981). H = 50 km/(s Mpc) and qo = 0 are used.

The FIB cosmology was conceived half a century ago, to explain the origin and spectrum of the ultrahigh energy cosmic ray particles we observed in deep mines. It succeeded in explaining quantitatively the 3°K microwave background radiation (IAU Symposium No. 44), the redshift periodicity (PASP 1976), and the cutoff of QSO's beyond z=3.5 (AAS 1982).

Nearly a decade elapsed between the discovery by Wampler at al. (1973) that the QSO OQ172 has a redshift of 3.53 and the discovery by Peterson et al. (1982) that the QSO Pks 2000–330 has a redshift of 3.78. During that time, radio and optical searches were vigorously pursued to find QSO's with redshifts greater than 3.5, but none were found. In this paper, we discuss selection effects in optical and radio searches and show how these selection effects have limited the redshift range of previous surveys. We propose a combination of radio and optical techniques that may be used to find high redshift QSO's and provide us with an undistorted view of the Universe beyond a redshift of 3.5.

It is my intention in this brief paper to present once again some of the evidence which appears to show that a major contribution to the redshifts of QSOs and perhaps some galaxies is not associated with the expansion of the universe. The evidence continues to grow and it is of four kinds:

1. (a) Evidence concerning galaxies with discrepant redshifts.

2. (b) Connections between QSOs and galaxies.

3. (c) Statistical information concerning the association of QSOs with galaxies.

4. (d) Individual and very striking examples of pairings between QSOs and bright galaxies.

A first step in the study of the evolution of the radio galaxy population is the determination of the radio luminosity function (RLF), i.e. ρ(log P, z), which results from (and must finally be interpreted in terms of) ‘light curves’ of individual objects (i.e. P(t)) and the ‘birth rate’ function ṅ (log P, t).