From a new mosaic image in the H-α line of the complete disc of the spiral galaxy M100, a catalogue is composed listing 1948 individual HII regions. For each HII region, the catalogue gives its position relative to the centre of the galaxy, its deprojected distance to the centre, its radius, and its calibrated luminosity. An indication is included

IAUC 6967 available at Central Bureau for Astronomical Telegrams.

El estudio de la emisión IR en las galaxias Seyfert es fundamental para entender el origen de su extraordinaria actividad, así como para discernir la relación entre los distintos tipos de galaxias Seyfert. Dos importantes cuestiones no están aun resueltas. No está claro por ejemplo si la radiación IR de las galaxias Seyfert es toda de origen

Numerical simulations of rising magnetic flux tubes in the solar convection zone have contributed significantly to our understanding of the basic properties of sunspot groups. They have provided an important clue to the operation of the solar dynamo by predicting strong (super-equipartition) magnetic fields near the bottom of the convection zone

H alpha and adjacent continuum images are presented for a sample of nearby groups of galaxies extracted from the Atlas of Compact Groups of Galaxies. Also, more detailed H alpha maps of the most remarkable galaxies are shown in this paper. A short description of the H alpha emission for each of the galaxies with accordant redshift is presented

Isophotal analyses developed in recent years (CCD images and numerical mapping techniques) have revealed that triaxial structures are frequently present in bulges of spirals and in elliptical galaxies. In the first case, these non-axisymmetric oval structures have been proposed as the corresponding sources of the energy necessary to maintain the