A nearby group of galaxies, centred on NGC 972 and conspicuously rich in faint dwarf spheroidal galaxies, has been investigated photometrically on B and V plates obtained with the Tautenburg 2m Schmidt telescope. For six low surface brightness galaxies, the equivalent B- and V-brightness profiles have been extracted, and asymptotic magnitudes and mean colours have been estimated. Their equivalent profiles are well fitted by modified isothermal (King) models.

Surface photometry of nearby galaxies is among the research areas that gained most from the recent advances in ‘wide-field imaging’. In fact, the demand for an accurate measure of the night-sky level all around the target galaxy — a key step in galaxy surface photometry; see Fig. 1 in Capaccioli & de Vaucouleurs (1983) — calls for at least some images covering a field wider than the size of the object under study. So far, the small field of most CCD cameras attached to the Cassegrain foci of medium-size telescopes has prevented both the mapping of the galaxian outskirts and, a fortiori, a direct measurement of the sky background μs on the galaxy image itself. Indirect methods to estimate μs — blank-sky exposures, matching of growth curves to photoelectric integrated magnitudes, assumptions on the shape of the galaxian light profiles — have proven ineffective and/or methodologically questionable (Capaccioli 1989). Until large-format CCD chips or mosaics are routinely used, the only way out of these problems is either the use of focal reducers, whose optical complexity may however be incompatible with photometric accuracy, or of large-field photographic plates.

The galaxies of the Virgo cluster have been observed extensively as members of one of the nearest moderately rich cluster. In view of the proximity of cluster members one to another, it might be expected that a significant fraction would be seen to be interacting with their neighbours, but simple inspection of deep plates of the cluster suggests otherwise. It is the intention in this note to show that a much higher number of apparent optical pairs are in fact involved in interactions but that this does not become apparent until special techniques are applied to reveal the faintest features on already deep photographs.

The investigation of environmental effects is a topic of high priority in current extragalactic research. In this connection, the study of neighbouring galaxies will result in characteristic properties of a low-density sample of extragalactic systems which may be used for comparison with other samples, with clusters of galaxies, for instance. The advantage of nearby galaxies is that they allow us to obtain an almost complete sample down to low-luminous objects because of their small distances.

The M 31 cluster system is the largest sample of globular clusters found in the Local Group, is sufficiently close to allow quite easy observations, and is negligibly affected by total reddening, at least for a large outer sub-set. Unfortunately, a complete and uncontaminated sample of M 31 clusters is not available yet for two basic reasons:

Within the framework of our studies of the stellar populations in nearby galaxies (Azzopardi 1984, 1993, and references therein), we have shown for some time that slitless spectroscopy, through either transmission gratings (grisms/grens) or prisms in combination with suitable intermediate band-pass interference filters, allows the detection of a number of objects with outstanding spectral characteristics, even in very crowded fields. We are now carrying out very deep slitless spectroscopy surveys in selected areas of nearby galaxies using both the ESO Faint Object Spectrograph and Camera (EFOSC) devices attached at the Cassegrain foci of either the ESO 3.6 m or the Max Plank Gesellschaft/ESO 2.2 m telescopes, as well as the ESO Multi-Mode Instrument (EMMI) at the Nasmyth focus of the ESO New Technology Telescope (NTT). The spectra of interest are searched for on the CCD frames by means of a semi-automatic procedure developed in the Munich Image Data Analysis System (MIDAS) environment (Muratorio & Azzopardi 1992). Each 2D-spectrum, whose position is automatically determined by means of the direct imaging frame, is background corrected, normalized and compared with some reference spectra of objects whose nature has been firmly established. All the objects, that have been identified through impersonal selection criteria, are then visually scrutinized in order to reject any possibly spurious objects. As typical examples of our field spectroscopy surveys, we present some preliminary results concerning the detection of Hα emission-line stars in the Large Magellanic Cloud (LMC) as well as the identification of very faint Wolf-Rayet (WR) stars in the Sculptor group galaxy NGC 300.

The aim of the present paper is to look for the gas-to-dust ratio in different types of galaxies and for a correlation between this ratio and the metallicity in dwarf galaxies. The recent compilation of data on nearby galaxies by Schmidt & Boller (1992, hereinafter SB) including HI and dust masses from IRAS data is used to estimate the gas-to-dust ratio in galaxies of a volume-limited sample.

Some photographic plates (resolution ∼ ) of the galaxies NGC 2805, NGC 2814, NGC 2820 and Mkn 108 from the Group Holmberg 124 were obtained with the 1-meter Ritchey-Chrétien (RC) Zeiss telescope of Maidanak Observatory. These plates were scanned with the PDS microdensitometer of Tartu Observatory, Estonia. Artamonov et al. (1993) have discussed in detail the calibration and image processing of the observed galaxies.

A programme for the surface photometry of bright galaxies has been underway at the Rozhen Observatory since 1991. In a series of papers we shall explore the optical morphology, photometric properties and some peculiarities suggestive of galaxy-galaxy interactions of the bright galaxies NGC 2976, NGC 3031, NGC 3034 and NGC 3077 in the M 81 group. Most of the plates were taken with the 2 m Rozhen Ritchey-Chrétien telescope, but at our disposal there are plates from the 6 m BTA and 2 m Tautenburg Schmidt telescope. Here we discuss some preliminary results for the optical morphology on the basis of two B-plates from the 2 m Tautenburg Schmidt telescope. It shows the edge-on like face of NGC 2976, the grand-designed spiral structure of NGC 3031 and the filament-jet peculiarities in NGC 3034 and NGC 3077.

UBV photographic plates of galaxies (resolution ∼ ) for the M 81 Group were obtained with the 1-metre Ritchey-Chrétien (RC) Zeiss telescope at Maidanak Observatory. Some plates show a resolution ∼ . Artamonov et al. (1990) have distinguished and measured positions of starlike objects in the central regions of M 82 (69 spots) and NGC 3077 (19 spots). We have measured the position of 120 blue starlike objects in NGC 2976. Image processing was carried out using a PC 286/386 with calibration using the data of Notni & Bronkalla, 1985; Bronkalla et al. 1992. The observed galaxies show active star formation which are related with intergalactic interaction. We have carried out UBV photometry of starlike objects in these galaxies. All objects emulate a population of young stars with different reddening. Figure 1 shows the two-colour plot of starlike objects in M 82 and the central regions of NGC 3077 (Price & Gullixson 1989). The colours of these objects lie along the line of reddening.

We present the results of wide-field imaging of nearby galaxies observed in the near-infrared using a large format array. The total magnitudes and mass-to-luminosity ratios of NGC 253, M 82, NGC 891, and some cluster members are discussed.

We have obtained B-band photographic surface photometry of ∼ 2000 galaxies in the Pisces-Perseus region. Combining these photometry data with redshift and HI 21 cm line-width data for spiral galaxies in the region, we have studied the Hubble constant and large-scale peculiar motions. Taking biases into account quantitatively we obtain H0 = 80 ±9+17−22 km/s−1Mpc−1. The prevalent infalling motion in the region is found to be still controversial if the biases are carefully considered.

The most unambiguous way to discover new emission-line galaxies (ELGs) is directly by the presence of their lines, using objective-prism plates of adequate resolution. The first survey using this technique was developed by Smith in 1975 with the 0.6 m CTIO Curtis Schmidt Telescope. The Universidad Complutense de Madrid (UCM) is carrying out a survey of ELGs with the Schmidt Telescope at Calar Alto (Almería, Spain) using the presence of Ha in emission in IIIa-F prism plates as selection criterion. The observational procedure and results are described in Rego et al. 1989; Zamorano et al. 1990; Zamorano et al. 1993.

We have detected 8,968 ultraviolet-excess galaxies in a sky area of some 5,100 square degrees by means of the UGR three-image photographs with the 105 cm Kiso Schmidt, giving a number density of 1.8 per square degree. A net count of the objects is 8,162, deleting those which appear repeatedly in the neighbouring survey area. For each of these galaxies which we call KUGs, data including morphological type and UV-excess degree are listed in a catalogue series of 18 volumes. Some statistics of these KUGs are also given in the last volume.

Deep CCD photometry and kinematical observations can be used to constrain the dynamical status of compact groups of galaxies. In the case of Hickson 90 the main interaction is taking place between NGC 7174 and NGC 7173 while NGC 7176 appears to be virtually undisturbed.

X-ray emission has been detected from 12 compact groups of galaxies of the Shakhbazian catalogue (out of 27 investigated groups) with the ROSAT PSPC all-sky survey. The groups Shkh 30 (Shakhbazian 1973) and Shkh 360 (Petrosian 1978) are presented here (Figs. 1 and 2).

In the last decade quite a large number of clusters of galaxies have been studied photometrically. Extensive investigations have been carried out by Oemler (1974), MacGillivray et al. (1976), Dressler (1978), Godwin & Peach (1977), Hoffman & Crane (1977), Couch & Newell (1984), Butcher & Oemler (1985), Butcher, Oemler & Wells (1983) and others in order to reveal global photometric properties of clusters.

The ratio of contributions from cannibalism and from cooling flows to the final cD galaxies in diverse clusters seems to be different. It should be determined by some general cluster properties as for instance the central mass concentration. Assuming that mass distribution is tantamount to luminosity distribution we have analyzed the question of possible luminosity segregation in the radial galaxy distribution of galaxy clusters (Baier & Schmidt 1992; Baier & MacGillivray 1994).

We have recently completed a catalogue of ∼ 5 million galaxies in the Southern sky down to a limit of bj = 20.5. The catalogue is based on the ROE/NRL Southern Sky Object Catalogue (Yentis et al. 1992), which is the result of processing of scans made with the COSMOS machine at the Royal Observatory Edinburgh (ROE) on glass copies of the IIIa-J survey carried out with the UK Schmidt Telescope (UKST) in Australia. The ‘COSMOS/UKST Southern Sky Galaxy Catalogue’ is based on 500 fields with |b| > 25 degrees and outwith the Magellanic Clouds.

The angular two-point correlation function, ω(θ), for galaxies can be used as a probe of their redshift distribution N(z) and, therefore, of galaxy luminosity evolution. Without redshift data, we can still observe the projection onto the two-dimensional sky of the three-dimensional clustering of galaxies. The autocorrelation of this projected distribution is described by ω(θ). Observations have indicated that ω(θ) follows a θ−0.8 power-law (Peebles 1980) and that the index of the power-law remains approximately constant to the faintest limits of photographic surveys (Jones, Shanks & Fong 1987).