We present the results of hydrodynamical model calculations of the barred galaxy NGC 5850 and compare to HI observations. The models assume a mass distribution for the galaxy which was obtained from photometrical I band observations. A pure bar perturbation model reproduces the HI observations in the inner 80'' of the galaxy. The reproduced

We discuss the mechanism for the oscillatory behavior of the static interparticle potential in a degenerate electron plasma. This behavior, observed in metallic alloys, is commonly referred to as 'Friedel oscillations', and its origin associated to the Kohn singularity. We show that, although this interpretation is adequate for large distances, the

We present RIJHK imaging of seven radio galaxies from the 7C Redshift Survey (7CRS) which lack strong emission lines and we use these data to investigate their spectral energy distributions (SEDs) with models that constrain their redshifts. Six of these seven galaxies have extremely red colours (R-K>5.5) and we find that almost all of them lie in

The principal components analysis (PCA) technique is used to develop an extremely fast and stable Stokes inversion code, suitable for application to large data sets from instruments that operate under standard conditions. This paper provides some tips on reducing the dimensionality of the problem, which are then used to develop a practical

Multi-epoch near-infrared photometry for a sample of long period variables (SR, L, Mira). Data have been obtained at the Observatorio del Teide using the 1.5m "Carlos Sanchez Telescope" with the "CVF Photometer-Spectrophotometer". The sample has been selected based on three observing programs at the ISO satellite. (5 data files).

We have measured the periods and light curves of 148 RR Lyrae variables from V=13.5 to 19.7 from the first 100 deg2 of the Quasar Equatorial Survey Team RR Lyrae survey. Approximately 55% of these stars belong to the clump of stars detected earlier by the Sloan Digital Sky Survey. According to our measurements, this feature has ~10 times the