Here we present a first hand look at the space distribution of some 2000 galaxies from a recently completed redshift survey in the southern hemisphere. This sample extends to the southern skies the database of high-quality radial velocities of the CfA Redshift Survey, over a comparable volume of space.

We review the current status of the Edinburgh/Durham southern galaxy catalogue. The aim of this project is to use COSMOS measurements of the UK Schmidt J survey to produce a unique data base of galaxies, complete down to bj ∼ 20.5 mag and covering ∼ 100 survey fields. We have developed the optimum procedures to classify objects as stars or galaxies and calibrate the galaxy magniudes on individual plates. We are confident that residual systematics will be ∼ 5%, thereby ensuring that this catalogue will substantially contribute to our understanding of the Universe at large. One initial finding of the survey is a probable 6 sigma density fluctuation in the galaxy distribution.

In 1986 the programme “The Northern Cone of Metagalaxy” has been finished with the 6-meter Telescope. In the course of the programme redshifts of all very rich compact clusters of galaxies inside the cone with galactic latitude and indirect estimates of redshifts ZLB < 0.28 have been measured. The total volume of the investigated region is V ≈ 500·106 Mpc3 (we accept Hubble constant H=50 km/s Mpc−1). A number of possible indications of existence of inhomogeneities in the Universe on scales greater than 100 Mpc are obtained: 1) the void of 400 Mpc in size; 2) the flat stratum of 150 Mpc thickness and 1000 Mpc diameter; 3) two-point space correlation function ξ (R = 200–300 Mpc) = 0.5±0.2. We found no indications that topology of the Universe is non-Euclidean on scales of 20–200 Mpc.

Spectral survey of 245 galaxies with mB⩽17.5 in the narrow strip {+28° 20′>DEC>+28°10′, 15h28m0>R.A>10h42Mm0} confirms a bubble-like type of the large-scale structure around the coma supercluster, have been founded by Lapparent et al. (1986). A correlation function in the volume has the power index γ=1.5 and the correlation radius rO= 29 Mpc (H=75 Km/s Mpc). For the sample of 14 voids their mean diameter <DV> equals to (33±3) Mpc. This value coincides with the correlation scale rO= 32 Mpc for Abell clusters, and also with the mean length of “God finger” for a rich cluster, 2√ 3σvH−1 = 32Mpc. We note a presence of a preferential orientation of voids toward the Coma supercluster, <Dvrad>/<Dvtan>= 1.15±0.8, that corresponds to a possible peculiar flow toward/outward Coma with Vpec∼400±200 (Km/s) at a scale ∼100 Mpc.

Wide-field surveys of galaxies and clusters are an indispensable tool for studying large scale structure in the universe. The Abell catalogue (Abell 1958), Zwicky catalogue (Zwicky et. al. 1961-1968), and the Lick survey (Shane and Wirtanen 1967, Seldner et. al. 1977) have provided many statistical results of key importance to our understanding of galaxy formation and clustering (see e.g. Peebles 1980). However, these surveys were constructed more than 20 years ago. Since then, there have been major technological developments in photographic emulsions, automatic scanning machines and computers. It is therefore possible to improve significantly on earlier surveys by generating deep galaxy catalogues with high photometric precision and uniformity over wide areas of sky. Over the last four years, we have taken advantage of these developments to construct a new survey of several million galaxies.

A study of the 3-point function, based on the analysis of momenta (as was done, e.g., in Sharp et.al. 1984) deduced from the Zwicky catalog, indicates that an expression containing a cubic term, besides the usual second degree polynomials of 2–point functions, provides a good fit of angular data.

A general nonlinear function G(X) describing the biasing of primordial Gaussian density fluctuations is considered. Arbitrary N-point correlations of the biased field are calculated in the form of a series expansion in terms of the correlations of the Gaussian field. The observed scaling of the three point correlations in the galaxy distribution is satisfied, but the scaling coefficient Q has a nontrivial value Q = J2/J12, where Jk is the k-th term in the Hermite expansion of G(X). The three point function is always accompanied by a cubic term Q3ξ1ξ2ξ3, independent of the functional form of the biasing. Its absence in the cluster 3-point correlations may be observable, in which case it rules out biasing as the major amplification mechanism of galaxy and cluster correlations.

Motions of nearby elliptical galaxies reveal a large-scale velocity flow relative to cosmic rest towards the point 1=307±10, b = 9±10. The data are fit best by a two-component flow model. The smaller component is due to Virgo, which induces a velocity at the Local Group of 250 km/s. The main flow is due to a more massive concentration located a distance of 4350±350 km/s towards 1=307, b=9, which induces a local velocity here of 570±60 km/s. This larger component falls off away from the mass concentration roughly as r−1. The Centaurus double cluster and its neighbors are in the direction of the mass concentration but are in the foreground and are falling into it. Galaxy counts, radial velocity surveys, and the motions of nearby spirals are consistent with the above model. The IRAS dipole results are less clear but may also be consistent. There is evidence that the distant mass concentration is non-spherical, with the Centaurus cloud a substantial sub-condensation in the foreground. The formal agreement of the large-scale flow with biased (b=2) cold dark matter is low, but the simple methods used so far to assess this are uncertain. The main weakness of the present data in comparing to theory is the fact that they do not penetrate far enough to show the velocity field on all sides of the mass concentration. Sphericity and total extent of the flow are therefore still unknown.

The peculiar motions for spiral galaxies and elliptical galaxies within V = 3500 km/s are compared to the model predictions of the mass concentration (MC) velocity field model of Lynden-Bell et al. The large-scale motions defined by over 600 galaxies from three independent sets of data (Aaronson et al.; de Vaucouleurs and Peters and elliptical galaxies) are in substantial agreement with this model.

“The stellar milky way, in the region of which, according to Argelander's admirable observations, the brightest stars of the firmament appear to be congregated, is almost at right angles with another milky way, composed of nebulae… the milky way composed of nebulae does not belong to our starry stratum, but surrounds it at great distance without being physically connected with it, passing almost in the form of a large cross through the dense nebulae of Virgo, especially the northern wing, through Coma Berenicis, Ursa Major, Andromeda's girdle, and Pisces Boreales”. These words, published 140 years ago by Alexander von Humboldt (1849), outline the program which brings us all to Hungary for this conference.

Six clusters forming part of the Hydra-Cen Supercluster and its extension on the opposite side of the galactic plane are under study at 21 cm with the Parkes radiotelescope. The infrared Tully-Fisher relation is used to determine the relative distances of the clusters. These clusters exhibit significant and generally positive peculiar velocities ranging from essentially zero for the Hydra cluster to as much as 1000 km/sec for the Pavo and Centaurus clusters. An upper limit of 500 km/sec was previously found in the study of clusters accessible from Arecibo. Data collection is not yet complete, however, and is further subject to unstudied systematic errors due to present reliance on photographic galaxy diameters. Nevertheless, these preliminary results support the notion of a large scale (and presumably gravitationally) disturbed velocity field in the second and third quadrants of the supergalactic plane.

We have completed a redshift survey of approximately 2200 IRAS galaxies, flux limited at 60μ. The survey covers 76% of the sky and has a characteristic depth of ≈ 6000 km s−1, making it ideal for large scale structure studies requiring whole sky coverage. We have calculated the gravitational acceleration on us due to the inhomogeneous distribution of galaxies in the sample by summing the dipole acceleration in successive shells centered on us. The acceleration converges at ≈ 4000 km s−1 and we derive density estimates in the range 0.4 < Ω < 0.9. We discuss the various biases of the sample in detail: the paucity of elliptical galaxies, the problem of extended sources, and hysteresis, and suggest ways to accommodate them and thus decrease the uncertainty in Ω. Finally, we discuss the use of the survey to make predictions for the peculiar velocity flowfield in space.

At present there are in use three different models to characterize the large scale structure of the universe. The clustering model (Soneira and Peebles, 1978) assumes that the superclusters are high density islands in a low density sea. The void model (Joeveer and Einasto, 1978), on the other hand, assumes that the voids are isolated low density islands in a high density sea. The sponge model (Gott et al., 1986) assumes that high and low density regions occupy equal volumes, and that the high and low density regions are both connected. The straightforward way to decide among these three models is the direct investigation of the spatial distribution of the galaxies. Nevertheless, there is an essentially different observational method that may also be useful to obtain some information about these models. The X-ray background radiation (XRB) is due either to the bremsstrahlung of hot intergalactic gas, or to the sum of the radiation of unresolved discrete sources (E.G. Boldt 1987). If the “discrete” origin is correct, then obviously the actual number of sources, and hence their total intensity, may vary from one part of the sky to another. Thus, in this case one has the possibility to estimate the number of sources in a given volume from the observed isotropy of the XRB. For example, Hamilton and Helfand (1987) suggest that the number of sources must be larger than 5000/(degree)2. Any such estimate needs several assumptions. In the previous works one usually assumed that the sources were distributed completely randomly; see, e.g. Fabian (1972). Nevertheless, if the XRB is generated by young galaxies (Bookbinder et al. 1980), it is not excluded that the sources of the SRB are also grouped similarly to galaxies. Because in this case the distribution of sources of the XRB is not completely random, one may expect a different type of fluctuations in the intensity of the XRB. In addition, since the grouping may be quite different for the three structure models, the expected fluctuations may also be different. There is a chance to discriminate among them using the observed isotropy of XRB. The basic observational datum concerning the isotropy of the XRB is well-known: the fluctuations in the intensity are smaller than 3%, if 3° × 3° pixels are used Shafer (1983).

The recent commissioning of the 327 MHz (or P band) system at the NRAO Very Large Array opens the possibility for a new search for the 21 cm of H I redshifted to z ≈ 3.3 and perhaps observing the birth of galaxies as initially suggested by Sunyaev and Zel'dovich (1972, 1975). We present and discuss the results of our first observing run in January 1986, and report on the progress on our second run in April 1987.

The origin and evolution of the large-scale structures in the universe (from galaxies up to superclusters) forms one of the outstanding problems of present-day cosmology. Several attempts have been made to observe the precursors of the structures observed today, at epochs as early as possible. Results of a search for redshifted HI associated with “protoclusters” or “pancakes” were first reported by Davies et al. (1978). They used the Jodrell Bank Mark 1A-telescope at frequencies of 328 and 240 MHz (z=3.3 and 4.9 respectively). More recently Bebbington (1986) used the Cambridge 6C synthesis radio telescope for a search at 151 MHz (z=8.4). Both experiments gave negative results and raised the question whether the observations were matched to the “expected” properties of the structures that they looked for.

The luminosity function of galaxies and clusters as well as their correlations can be calculated assuming the many-body correlation functions are scale invariant. The same hypothesis leads to predictions on the fractal dimension of the galaxy distribution. The latter is found to be bifractal that is characterized by two dimensions D=3−γ in the cluster region, and D = (3−γ)(2+α) in the nearly empty regions, α being the index introduced by Schechter for the galaxy luminosity function. Finally, the same models lead to predictions for the evolution of the cluster and x-ray luminosity functions, as well as for the Sunyaev-Zeldovich effect due to all virialized clusters, which is found to be large and to produce fluctuations of order 10−5 at sub-arc minute scalar in the microwave background.

Number counts, colors, and angular correlations of field galaxies fainter than 20th mag are summarized. Resulting conclusions regarding the presence and nature of luminosity, spectral, and clustering evolution remain controversial. Preliminary analysis of two major spectroscopic surveys near completion suggests that by z ∼ 0.5, larger numbers of very-blue galaxies of moderate luminosities are found than today. These skewer-like surveys also provide new probes of galaxy clustering on scales previously unexplored (>200 Mpc) and over lookback times of several billion years.

The evidence for the existence of very large scale structures, ∼ 100h−1 Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. A “shell model” of galaxy clustering is described in which clusters of galaxies are located at shell intersections; the model yields results consistent with cluster observations. Detection of a ∼ 2000 km s−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1 Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016,5M⊙ and may contain a larger amount of dark matter than previously anticipated.

The alignment of galaxies with the main plane of supercluster can contribute to recovering information on the structure origin. The positive result of the preliminary search for galaxy alignment in the Local Supercluster /Flin and Godlowski 1986, hereafter FG/ have stimulated further studies. Following Jaaniste and Saar /1977/, the both parameters, the position angle of the galaxy major axis p and the axial ratio b/a of the galaxy image, were used for the better determination of the actual spatial orientation of the galaxy disc. This approach also permit to consider “face-on” objects, whose discounting leads to obvious incompleteness of the analysed data. Each galaxy has two possible orientations and both were taken into account during calculations. The analysis is perfomed by transforming position angle p and coordinates α, δ of galaxies expressed in the equatorial coordinates into coordinate system connected with each parent supercluster separately, which gives parameters P, l and b respectively. The main supercluster plane should be determined, which resticts the present study to the three superclusters with a known spatial geometry, i.e. LSC /Tully 1982/, Perseus and Coma/A1367 /Chincarini et al. 1983/.

It has been proposed in two recent articles by this author (Tully 1986, 1987) that rich clusters of galaxies tend to congregate in complexes involving of order 50 clusters over regions roughly 300 h75−1 Mpc across. The particular complex that we reside in has the additional remarkable property that the clusters are concentrated in a plane that is coincident with the plane described by the distribution of nearby galaxies. The extraordinary coincidence between the plane defined by rich clusters at a characteristic velocity of 15,000 km s−1 and the plane defined by galaxies at a characteristic velocity of 1500 km s−1 suggests a causal connection.