Aims. This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form and we hope that it will be useful to all workers in this field. Methods. Like the eleventh edition, it includes position and redshift as well as photometry (U, B, V) and 6 cm flux densities when available. We now give 20 cm rather than 11 cm flux densities.Results. The present version contains 85 221 quasars, 1122 BL Lac objects and 21 737 active galaxies (including 9628 Seyfert 1s), almost doubling the number listed in the 11th edition. We also give a list of all known lensed and double quasars.

Abstract.We have compiled a list of 83 objects classified as Narrow-Line Seyfert 1 galaxies (NLS1s) or known to have a broad Balmer component narrower than 2 000 km s −1 . Of these, 19 turned out to have been spectroscopically misidentified in previous studies; only 64 of the selected objects are genuine NLS1s. We have spectroscopically observed 59 of them and tried to characterize their Narrow and Broad-Line Regions (NLR and BLR) by fitting the emission-lines with Gaussian and/or Lorentzian profiles. In most cases, the broad Balmer components are well fitted by a single Lorentzian profile, confirming previous claims that Lorentzian rather than Gaussian profiles are better suited to reproduce the shape of the NLS1s broad emission lines. This has consequences concerning their FWHMs and line ratios: when the broad Balmer components are fitted with a Lorentzian, most narrow line regions have line ratios typical of Seyfert 2s while, when a Gaussian profile is used for fitting the broad Balmer components, the line ratios are widely scattered in the usual diagnostic diagrams (Veilleux & Osterbrock 1987); moreover, the FWHM of the best fitting Lorentzian is systematically smaller than the FWHM of the Gaussian. We find that, in general, the [O III] lines have a relatively narrow Gaussian profile (∼200-500 km s −1 FWHM) with often, in addition, a second broad (∼500-1 800 km s −1 FWHM), blueshifted Gaussian component. We do not confirm that the [O III] lines are weak in NLS1s. As previously suggested, there is a continuous transition of all properties between NLS1s and classical Broad-Line Seyfert 1 Galaxies (BLS1s) and the limit of 2000 km s −1 used to separate the two species is arbitrary; R4570, the ratio of the Fe II to the Hβ fluxes, could be a physically more meaningful parameter to distinguish them.

Abstract. Most Seyfert 1 galaxies show strong Fe II lines in their spectrum having the velocity and width of the broad emission lines. To remove the Fe II contribution in these objects, an accurate template is necessary. We used very high signal-to-noise, medium resolution archive optical spectra of I Zw 1 to build such a template. I Zw 1 is a bright narrow-line Seyfert 1 galaxy. As such it is well suited for a detailed analysis of its emission line spectrum. Furthermore it is known to have a very peculiar spectrum with, in addition to the usual broad and narrow line regions, two emission regions emitting broad and blue shifted [O III] lines making it a peculiarly interesting object. While analysing the spectra, we found that the narrow-line region is, unlike the NLR of most Seyfert 1 galaxies, a very low excitation region dominated by both permitted and forbidden Fe II lines. It is very similar to the emission spectrum of a blob in η Carinae which is a low temperature (T e ∼ 6500 K), relatively high density (N e = 10 6 cm −3 ) cloud. The Fe II lines in this cloud are mainly due to pumping via the stellar continuum radiation field (Verner et al. 2002). We did not succeed in modelling the spectrum of the broad-line region, and we suggest that a non radiative heating mechanism increases the temperature in the excited H I region, thus providing the necessary additional excitation of the Fe II lines. For the low-excitation narrow-line region, we are able to apply boundaries to the physical conditions accounting for the forbidden and permitted Fe II lines (10 6 < N e < 10 7 cm −3 ; 10 −6 < U < 10 −5 ).

Aims. This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form, and we hope that it will be useful to all workers in this field. Methods. Like the twelfth edition, it includes position and redshift, as well as photometry (U, B, V) and 6 cm and 20 cm flux densities, when available.Results. The present version contains 133 336 quasars, 1 374 BL Lac objects, and 34 231 active galaxies (including 16 517 Seyfert 1s), almost doubling the number listed in the 12th edition. We also give a list of all known lensed and double quasars.

No abstract

Abstract. The recent publication of the first release of the 2dF quasar catalogue (Croom et al. 2001) containing nearly 10 000 new QSOs, almost doubling the number of known such objects, led us to prepare an updated version of our catalogue of quasars and active nuclei which now contains 23 760 quasars, 608 BL Lac objects and 5751 active galaxies (of which 2765 are Seyfert 1s). Like the ninth edition, it includes position and redshift as well as photometry (U, B, V ) and 6 and 11 cm flux densities when available. We also give a list of all known lensed and double quasars.

Abstract. The recent release of the final installement of the 2dF quasar catalogue and of the first part of the Sloan catalogue, almost doubling the number of known QSOs, led us to prepare an updated version of our Catalogue of quasars and active nuclei which now contains 48 921 quasars, 876 BL Lac objects and 15 069 active galaxies (including 11 777 Seyfert 1s). Like the tenth edition, it includes position and redshift as well as photometry (U, B, V) and 6 and 11 cm flux densities when available. We also give a list of all known lensed and double quasars.

Abstract. In a previous paper (Véron et al. 1997) we presented medium resolution (3.4Å F W HM) spectroscopic observations of 15 "transition objects", selected for having an ambiguous location in the Veilleux & Osterbrock (1987) diagnostic diagrams, and showed that most of them were in fact "composite", this being due to the simultaneous presence on the slit of both a Seyfert or Liner nucleus and a H ii region. Here, we report new spectroscopic observations of 53 emission-line galaxies with a "transition" spectrum, bringing up to 61 the total number of observed objects in an unbiased sample of 88 "transition objects". Almost all of the observed galaxies have a "composite" nature, confirming the finding that true "transition" spectra may not exist at all.By eliminating "composite objects" from the diagnostic diagrams, a clear separation between the different classes of nuclear emission-line regions (Seyfert 2s, Liners and H ii regions) becomes apparent; by restricting the volume occupied by the different line-emitting regions in the 3-dimensional diagnostic diagrams, we are also restricting the range of possible physical parameters in these regions. There seems to be no continuity between Seyfert 2s and Liners, the two classes occupying distinct volumes in the 3-dimensional space defined by λ5007/Hβ, λ6583/Hα, and λ6300/Hα.