We report the discovery of a new hysteresis effect in black hole X-ray binary state transitions, that of the near-infrared (NIR) flux (which most likely originates in the jets) versus X-ray flux. We find, looking at existing data sets, that the IR emission of black hole X-ray transients appears to be weaker in the low/hard state rise of an outburst

Advancements in infrared (IR) interferometry open up the possibility to spatially resolve active galactic nuclei (AGNs) on the parsec-scale level and study the circumnuclear dust distribution, commonly referred to as the "dust torus," that is held responsible for the type 1/type 2 dichotomy of AGNs. We used the mid-IR beam combiner MIDI together

The Cosmic Microwave Background (CMB) is one of the main pillars of modern Cosmology. Soon after its discovery in 1965, it was recognized as evidence of cosmic evolution, and that our Universe went, at some time in the past, through a very hot phase where matter and radiation were in very intense interaction. Here, I briefly review the history of

Aims: Our main objective is to develop a denoising strategy to increase the signal to noise ratio of individual spectral lines of stellar spectropolarimetric observations. Methods: We use a multivariate statistics technique called Principal Component Analysis. The cross-product matrix of the observations is diagonalized to obtain the eigenvectors

The use of AO in Extremely Large Telescopes, used to improve performances in smaller telescopes, becomes now mandatory to achieve diffraction limited images according to the large apertures. On the other hand, the new dimensions push the specifications of the AO systems to new frontiers where the order of magnitude in terms of computation power

IAUC 4830 available at Central Bureau for Astronomical Telegrams.