We present near-infrared colour-magnitude diagrams and star counts for a number of regions along the Galactic plane. It is shown that along the l=27°, b=0° line of sight there is a feature at 5.7+/-0.7kpc with a density of stars at least a factor of 2 and probably more than a factor of 5 times that of the disc at the same position. This feature

We present subarcsecond-resolution, ground-based, near-infrared images of the central regions of a sample of 12 barred galaxies with circumnuclear star formation activity, which is organized in ring-like regions typically 1kpc in diameter. We also present Hubble Space Telescope near-infrared images of 10 of our sample galaxies, and compare them

Detailed surface photometry has been carried out for three barred galaxies with use of high resolution CCD broad-band images in the B, V and I bands. Using azimuthal luminosity profiles and their decomposition into Fourier Series, the structural parameters (length and strength) of the bars in the three galaxies have been obtained. We have also

CCD photometry of 18 Jupiter family comets, observed at medium and large heliocentric distances, was carried out between April 1990 and July 1995. This is part of a long-term observational program designed to obtain their nuclear magnitudes. The observations were made with the 1.54-m Danish Telescope at ESO La Silla, the 2.5-m Nordic Optical

We present 53 simultaneous photometric (I band) and spectroscopic (6900-9500Å) observations of GRO J0422+32, taken during 1997 December. From these we determine that J0422+32 was in its lowest state yet observed, at I=20.44+/-0.08. Using relative spectrophotometry, we show that it is possible to correct very accurately for telluric absorption

We analyze the Zff vertex in the framework of models that add a new bottom quark in a non-sequential way and we evaluate the tree level contribution to the LEP/SLC observables ΓZ, Rb and Rl. We obtain bounds for the mixing angles from the experimentally allowed contour regions of the parameters ΛL,R introduced here. In order to get a more