Narrow-band H-alpha images and long-slit spectroscopy of the Seyfert galaxy NGC 985 are presented. Large-scale extended ionized zones are seen to cover a significant fraction of the ring of this object. These ionized zones are responsible for a considerable fraction (greater than 35 percent) of the far-infrared emission of NGC 985. These ionized

A generalized formulation of stellar speckle interferometry (SSI) and related techniques in terms of joint spatial/spatial-frequency energy representations are proposed. It is shown how, within this formulation, techniques such as that of Knox-Thompson, or even standard SSI, appear to be particular implementations of a more general method. This

In this paper we present the Johnson-Cousins UBVR CCD photometry of the stars in King 2, an old open cluster towards the galactic anticenter. We have obtained the colour- magnitude diagram, the colour excess, the reddening, an estimate of the metallicity, and the distance modulus. The comparison of the observational colour- magnitude diagram with

The photoionization of extended narrow-line regions in Seyfert galaxies by the radiation produced in a thick accretion disk is studied. The emission-line spectrum is calculated for a range of black hole masses, varying the values of the ionization parameter and the disk size. It is found that models with a million solar masses fit observations of

The discovery of a very high velocity, low-intensity gas feature in the giant extragalactic H II region NGC 5471 is reported. A broad component in the emission lines of H-alpha + forbidden N II 6548, 6584 A is located within an area less than 1 arcsec in diameter at the position known as knot C. The broad component is characterized by its low

As part of a systematic survey for the search of high velocity gas in giant extragalactic H II regions, the authors have observed the five largest and brightest H II regions in M101. They have found two types of peculiar emission profiles: (1) a broadening of the Hα emission line at low intensity, in excess of the values expected for the typical