It is now 22 years since quasars were discovered. When the ageing veterans of those pioneering investigations think back over two decades of boisterous debate, their reactions are probably rather mixed. Wonderment at the range and variety of novel phenomena revealed in all wavebands must be tinged with disappointment that we seem so slow in grasping what is really going on. Our understanding has advanced slowly, through many small steps — forward steps preponderating (fortunately) over backward ones.

A review is given of progress in surveys for quasars at frequencies from radio to x-ray. Radio results show evidence for a decline in the radio luminosity function for flat-spectrum radio sources at redshifts z > 2. The IRAS survey is uncovering hitherto unknown dusty Seyfert galaxies. Optical surveys, which yield the largest number of QSOs per square degree, may suffer from selection effects which depend on intrinsic luminosity, redshift, and spectral evolution - particularly above redshift 2. Below redshifts of about 2.3, the optical magnitude-redshift plane is being filled in to the point where the evolution of the luminosity function can be seen directly. The statistics of quasar pair separations provide the best evidence so far for quasar clustering.

The existence of many potentially significant selection effects means that a multi-frequency approach to quasar surveys is likely to prove essential to an understanding of the evolutionary behaviour of the quasar population as a whole.

We present results on a new sample of optically selected quasar candidates. The “standard” multicolor technique for selecting quasar candidates has been applied to all the objects brighter than J = 22.0 in a field of 0.69 square degrees. Additional candidates have been selected from a search on grism plates obtained in the same area. Spectroscopy for all the candidates brighter than J = 20.9 has provided a sample of 22 confirmed quasars. The redshift distribution of these objects is essentially flat from z = 0.6 up to z = 2.8. Three out of the eight quasars with redshift larger than two were selected from the grism plates and were missed by our color selection. This result, although based on a small number of objects, suggests that the luminosity functions computed in this redshift range from samples which are only color selected might have to be increased by a factor up to 1.5. On the other hand, these possible losses of the multicolor search technique are negligible (of the order of 15% only) for the estimates of the integral number counts at magnitudes of the order 20–21.

We have used the FOCAP fibre optic coupler at the Anglo-Australian Telescope (AAT) to measure redshifts for a complete sample of ∼ 170 B ≤ 21m QSO's selected using the ultraviolet excess (UVX) criterion. We present preliminary estimates of the QSO luminosity function in discrete redshift ranges and show how these observations differentiate between models of QSO evolution. We have also investigated the clustering of QSOs in this complete sample by estimating the QSO 2-point correlation function and we use this to derive direct constraints on the homogeneity of the Universe at large scales.

New results are presented based on several statistical analyses of a 25 square degree field around NGC450. They include the detection of a clustering on a small scale (⋍ 10 arcminutes) and possible large scale inhomogeneities.

Sandage and I have obtained “grism” plates that redundantly cover one square degree fields centered on ten Selected Areas. We used a grating-prism in the converging beam of the Mayall 4-meter telescope prime focus to photograph 1580 A·mm−1 slitless spectra to a limit of about B = 21.5 (cf. Hoag and Smith 1977).

A region containing the SGP, centered at α 00h 53m (1950) δ −28°03', is becoming a selected region for QSO research. Three lists of QSO candidates have been published for this field. One consists of candidates discovered visually on an objective prism plate, selected in a 25-deg2 area and with B(lim) ⋍ 20 mag (Clowes and Savage, 1983; the CS sample). The other list came from visual inspection of U and B plates (UVX stars), covering a region of 44-deg2 and with approximately the same limiting magnitude of the CS sample (Campusano and Torres, 1983; the CT sample). The third survey of QSO-candidates involved a machine selection of UVX stars (Shanks et al., 1983), whose published components correspond to two small areas of 1.6 and 8.2 deg2 with B(lim) = 19 mag (Boyle et al., 1985).

We have prepared a new catalogue of QSOs and BL Lac objects containing approximately 3400 entries. A complete update of the Hewitt-Burbidge (1980) catalogue has been made with approximately another 2000 objects with known redshifts added. The references to discovery, magnitudes, redshifts, color, spectra and polarimetry have been updated for the objects listed in 1980, and complete new references are included for the new objects. In addition to the basic optical information, the new catalogue also contains X-ray, radio and infrared information for all objects. Absorption redshifts are listed when they are available. A supplementary catalogue which is now in preparation will contain similar information for objects described variously as Seyfert galaxies, N systems and AGNs. In doubtful cases we have used the operational dividing line ƶ = 0.1. All objects with ƶ < 0.1 are put in the supplementary catalogue unless their discoverers have unambiguously defined them as QSOs. With approximately twice as many objects included it is interesting to note that:

1. a) There are still very few genuine BL Lac objects, ∼100.

2. b) The largest number of additions has come from identifications using the objective prism-grism techniques.

A new Edition of the Asiago Catalogue of QSOs (Barbieri et al. 1982) is available on magnetic tape. It contains essentially all the information of the previous editions updated with the papers published before Dec.31, 1984. The catalog should be essentially complete to that date in respect to objects having slit spectra (2330 objects), while it is seriously incomplete regarding candidates discovered by objective prism or grism/grens surveys after 1982 (279 such objects included in the present version).

The automatic quasar detection system (AQD, see Clowes, 1984) has been used to successfully select quasars from prism plates taken by the United Kingdom Schmidt Telescope. Surveys compiled using this technique have a magnitude limit of B-19.5. We present work here which extends the possible survey limit to B-21. This is done by putting plates taken with the Canada-France-Hawaii Telescope's grens (see Richardson, 1984, for a description) through the AQD measuring system. We will follow this work with a comparable photometric survey of the same field.

EFOSC is a standard ESO instrument operating at the Cassegrain focus of the 3.6 m telescope since April 1st, 1985. A description of its optical design and operating modes is given in Enard and Delabre (1982) and Dekker and D'Odorico (1985). Briefly, it is a focal reducer with spectroscopic capability. The collimator produces a collimated beam with a diameter of 40 mm which passes through a filter and/or grism. The f/2.5 camera focusses the beam on the detector which is at present a thinned, back-illuminated RCA CCD with 320×512 pixels. The pixel size is 30 μm which corresponds to .675″ on the sky. There are three remotely controlled wheels in the instrument: the aperture wheel in the focal plane of the telescope, with long slits of different widths, a filter and a grism wheel with 12 positions each. The instrument can be operated in four different modes: direct imaging, slit spectroscopy, grism or multiple object spectroscopy with specially made aperture plates.

The galaxy identified with the flat-spectrum radio source PKS 2005-489 has a bright stellar nucleus with V ⋍ 13 mag. Optical, UV and X-ray observations indicate variability and power-law continua in each of these wavebands, leading to the conclusion that PKS 2005-489 is one of the brightest BL Lac objects known.

A dozen BL Lacertae objects and violently variable quasars were observed repeatedly during the last six years by obtaining simultaneous measurements from the radio through X-ray region. The relationship between the radio-millimeter, infrared-ultraviolet, and X-ray regions are determined from single epoch spectra and variability measurements. The structure of the emitting regions and the emission mechanisms are discussed. The results of this program are summarized.

X-ray to infrared continuum data for nine optically selected (PG) quasars show a form which can be simply described in terms of two components — a power law of slope ∼1 joining smoothly the 1–10 μm infrared with the 0.1–10 keV x-ray points and superimposed on this, a ‘big bump’ of optical-uv emission. The ‘big bump’ can be interpreted as thermal emission from an accretion disk. In a unique case where this ‘big bump’ extends to soft x-rays the accretion disk parameters can be constrained interestingly.

Beginning in 1980, the fluxes of over 40 bright quasars, BL Lacs and Seyferts have been monitored at radio and optical wavelengths in a Finnish-Soviet collaboration. The chief aims of the program are to provide information about the variability characteristics of active nuclei over a wide range of timescales and to fill a gap in monitoring programs at millimeter wavelengths. The results are also used as a basis for various other investigations.

The questions we wish to address with this work are: What is the shape of the continuum spectrum of an active nucleus? Can we identify thermal and non-thermal components? Previous work on this subject studied different non-overlapping samples in narrow frequency bands. A significant step forward was taken by Malkan and Sargent (1982) who studied the IR (10μm) through UV continuum of a small sample of objects. We report here results for the first part of the study of the complete continuum for a hard X-ray selected sample of 37 Seyfert 1 galaxies. This selection criterion ensures a sample unbiased for optical-IR studies, as the hard X-rays are not affected by reddening (Lawrence and Elvis 1982). The data consist of our own 1–20 μm ground-based IR observations, 100 and 60 μm IRAS fluxes and optical UBVR photometry.