The microquasar Cygnus X-1 displays the two typical soft and hard X-ray states of a black hole transient. During the latter, Cygnus X-1 shows a one-sided relativistic radio-jet. Recent detection of the system in the high energy (HE; E ≳ 60 MeV) gamma-ray range with Fermi-LAT associates this emission with the outflow. Former MAGIC observations

Context. The total mass of a cluster, which is the main parameter determining its ability to host more than one stellar generation, may constitute a threshold below which the cluster is able to form only a single stellar population. Aims: Our goal is to investigate the existence of star-to-star variations in CN and CH band strengths, which are

Distant clusters of galaxies provide a powerful method to study the formation and evolution of galaxies, and large scale structure of the Universe. However, the number of known clusters at high redshift (z > 0.5) is still very reduced. As a preparatory work for detailed studies with GTC, we are searching for high redshift clusters in public wide

We have made a search (to Y=19.6) of the UKIDSS Large Area Survey (LAS DR7) for objects detected only in the Y-band. We have identified and removed contamination due to solar system objects, dust specs in the WFCAM optical path, persistence in the WFCAM detectors, and other sources of spurious single source Y-detections in the UKIDSS LAS data-base

Context. Historically, galaxy bulges were thought to be single-component objects at the center of galaxies. However, this picture is now questioned since different bulge types with different formation paths, namely classical and pseudobulges, have been found coexisting within the same galaxy. Aims: We study the incidence and nature of composite

We compute UV to radio continuum spectral energy distributions of 51 nearby galaxies recently observed with SPIRE onboard Herschel and present infrared colours (in the 25-500 μm spectral range). SPIRE data of normal galaxies are well reproduced with a modified black body (β=2) of temperature T≃q 20 K. In ellipticals hosting a radio galaxy, the far