Highly ionized large scale structures have recently been observed in many active galaxies. There is evidence that photoionization by the active nucleus may be the most relevant mechanism, responsible of the excitation of the gas. The authors use a simple model for a thick accretion disk around a supermassive black hole and a photoionization code to

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Observations of the nucleus of M82 obtained with the 12-m Kitt Peak antenna show that the CO J = 1 to 2 peak temperature structure possesses a dual-core morphology similar to that found at J = 1 to 0. The results indicate that the predominant regime of low opacity gas is located to the north of the star-burst zone, suggesting that material to the

This paper reports on extensive spectroscopic observations of the WR-ring nebulae NGC 2359 and RCW 78, respectively, excited by the WN5 stars HD 56925 and WN8 HD 117688. For the first object, abundances were determined for O/H, Ne/H, N/H, and He/H in many different positions, including the ionized gas in the bubble, inside the optical shell

Morphology and elliptically averaged luminosity profiles have been derived from CCD surface photometry of thirteen Seyfert galaxies. Apparent V and I magnitudes, V - I color index, as well as absolute Mv and MI magnitudes have been calculated. V and I luminosity profiles of Mk 10, Mk 79, Mk 358, Mk 618, Mk 352, and Mk 110, are adjusted by the usual

This paper presents observations of the 3130 A Be II resonance doublet in stars of intermediate metal deficiency, with Fe/H values between -0.6 and -1.1, obtained with the Intermediate Dispersion Spectrographs and IPCS detector at the 2.5 m Isaac Newton Telescope on La Palma. The derived beryllium abundances range from 5.6 x 10 to the -12th (one