We present bidimensional spectroscopy of the circumnuclear region of the Seyfert galaxy NGC 3227. The physical and kinematical characteristics of the two gaseous components reported recently by Mediavilla & Arribas are discussed. One of the components seems to be directly related to activity. We propose that it represents gas streaming from the

We present a procedure for obtaining the mean density of clusters and their associated structures in a very general type of distribution. We first consider the one-dimensional case, and then use it to develop the procedure according to the d-dimensional case. These procedures require the probability that a randomly placed body should contain no

This work undertakes the study of the galaxy NGC 4861, using imaging centered at the strong lines H-alpha, H-beta, (O III) lambda 5007 and nearby continua. Integrated, absolute fluxes of 28 H II regions, and the region known as the bright knot, have been measured showing correlations between the equivalent width of H-beta and the excitation index

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We present the first results of a combined HST/IUE/ground-based spectroscopic monitoring campaign on the Seyfert 1 galaxy NGC 5548 that was undertaken in order to address questions that require both higher temporal resolution and higher signal-to-noise ratios than were obtained in our previous multiwavelength monitoring of this galaxy in 1988 -- 89

IAUC 6106 available at Central Bureau for Astronomical Telegrams. IAUC 6106 available at Central Bureau for Astronomical Telegrams.