The BL Lacertae object AO 0235+16 is well known for its extreme optical and radio variability. New optical and radio data have been collected in the last four years by a wide international collaboration, which confirm the intense activity of this source: on the long term, overall variations of 5mag in the R band and up to a factor 18 in the radio

We present the optical and UV emission-line properties of 160 X-ray-selected active galactic nuclei (AGN) taken from the RIXOS survey (including Hα, Hβ, [Oiii] lambda5007, Mgii lambda2798 and Ciii] lambda1909). This sample is believed to contain a mixture of absorbed and unabsorbed objects, with column densities up to ~4x10^21cm^-2. Although the

We present VLT observations of the optical counterpart of th X-ray millisecond pulsar XTE J0929-314 in quiescence. We detected a very faint candidate in agreement with the position given by radio and X observation. From the observed optical flux we inferred un upper limit to the magnetic field of the system.

An infrared liquid nitrogen (LN2) cooled focal reducer camera has been designed to be used at the 1.5 m (f/13.8) Carlos Sanchez IR Telescope (CST) at the Observatorio del Teide. The image quality is better than 30 micrometers (typical pixel size of the detector) with an image scale of 0.5 arcsec/pixel. The final design is a very compact system

In order to fully understand the gravitational collapse of molecular clouds, the star formation process, and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of stellar contents and positions in the Galaxy. The young massive association Cygnus OB2, in the Cygnus-X region, is a

Observations of the gravitational lens system 0957+561A, B in the R band are presented in this Letter. The observations, taken with the 82 cm IAC-80 telescope, at Teide Observatory, Spain, were made from the beginning of 1996 February to June, as part of an on-going lens monitoring program to obtain the time delay between the two components of the