We have analyzed high spatial and spectral resolution Hα emission-line TAURUS data on two nearby giant H II regions, NGC 604 and NGC 588. Previous work shows that while NGC 604 is a relatively young system whose emission line kinematics is due to a combination of gravity and stellar wind-blown shells, NGC 588 seems more evolved, with its ionized

We present optical and near-infrared spectroscopy (600-1000 nm) of eight faint (I > 18) very red (R - I > 2.2) objects discovered in a recent deep CCD survey of the Pleiades cluster by ZapateroOsorio, Rebolo, & Martin. We compare them with reliable cluster members like PP1 15 and Teide 1, and with several field very late type dwarfs (M4-M9.5)

We present a set of face-on models of the radiative transfer of stellar light in exponential discs, taking into account absorption and multiple scattering (diffusion) by dust. Attention has been directed towards the effects on the observable photometric properties of different distributions of stars and dust perpendicular to the galactic plane. A

Observations of the gravitational lens system 0957+561A, B in the R band are presented in this Letter. The observations, taken with the 82 cm IAC-80 telescope, at Teide Observatory, Spain, were made from the beginning of 1996 February to June, as part of an on-going lens monitoring program to obtain the time delay between the two components of the

We investigate the influence of scattering processes in the continuum on the formation of lines in static, one dimensional atmosphere. It is shown that the Schuster mechanism of emission line formation can work under certain physical conditions. We derive formulae for the calculation of the line profiles in atmospheres with an ad hoc temperature

This paper combines data from the three preceding papers in order to analyze the multi-wave-band variability and spectral energy distribution of the Seyfert I galaxy NGC 4151 during the 1993 December monitoring campaign. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and