Ultra-cool dwarfs with effective temperatures between ~1400 K and ~2200 K are known to have dusty atmospheres. Asymmetries of the dwarf surface may arise from rotationally-induced flattening and dust-cloud coverage, and may result in non-zero linear polarisation through dust scattering. Here we present our linear polarimetric imaging measurements

Measurements of the polarised emission from Compact Steep-Spectrum (CSS) sources can give important information about the physical conditions inside and around the region of radio emission, essentially on the Narrow Line Region. We have observed the sample of CSS sources constructed by Fanti et al. (1990) with the Effelsberg 100-m radio telescope

Aims: We obtained phase-resolved spectroscopy of the accreting millisecond X-ray pulsar SAX J1808.4-3658 during its outburst in 2008 to find a signature of the donor star, constrain its radial velocity semi-amplitude (K_2), and derive estimates for the pulsar mass. Methods: Using Doppler images of the Bowen region, we find a significant (≥8σ)

In the coming years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number of

We present long-slit intermediate resolution spectroscopy of the visual binary V1123. We confirm that component A is a W UMa eclipsing star with spectral type G0V, while component B is a K0V. We infer a distance to the system of 125 pc, and then a projected separation between both components of 520 AU. The difference in radial velocities of

Context: Early-type dwarf (dE) galaxies are the most common type of galaxies observed in the Universe. Their study has important cosmological implications because according to hierarchical galaxy evolution theories they are the progenitors of brighter galaxies. Nevertheless, the origin of this kind of system is still not well understood. Aims: The