Topics discussed in this issue include active galaxies and cosmology, interstellar and intergalactic medium, and astronomical instrumentation. Papers are...

The image mosaics obtained with the instrument LIRIS (Long-Slit Intermediate Resolution Infrared Spectrograph) at the Williams Herschel Telescope are in the...

Assuming that photoionization is the self-limiting process for continued star formation, we estimate the maximum number of massive (OB) stars that can form...

We present a study of high-velocity gas in the direction of 13 halo sub-dwarfs located at absolute value of z approximately equals 0.5-2 kpc and of 8 early-type...

Optical spectroscopy, H-alpha interferometry, and near-IR mapping and photometry of the bipolar H II region S201 are reported. The observations are used to...

Partially ionized plasmas are found across the Universe in many different astrophysical environments. They constitute an essential ingredient of the solar...

It is reported that 8-13-micron spectra have been obtained at several positions across the extended emission region of M82. No major differences among the...

Papers on stellar spectral line formation theory are presented. The general topics considered include: frequency redistribution problems in line formation...

In the circumnuclear zones of the disks of some spirals there is an absence of neutral interstellar hydrogen. A model is devised in which gaseous outflow is...