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Observations of the 1.083-micron He I line in WR140 (HD 193793) show P-Cygni profiles which varied as the binary system went through periastron passage. A sub-peak appeared on the normally flat-topped emission component and then moved across the profile consistent with its formation in the wind-collision region. Variation of the absorption component provided constraints on the opening angle (theta) of the wind-collision region. Infrared (2-10 micron) images observed with a variety of instruments in 2001-04 resolve the dust cloud formed in 2001, and show it to be expanding at a constant rate. Owing to the high eccentricity of the binary orbit, the dust is spread around the orbital plane in a splash and we compare the dust images with the orientation of the orbit.
The size of the dust torus in Active Galactic Nuclei (AGN) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared (MIR) torus e
We present the results of two complementary ground-based programmes to determine the host galaxy properties of radio-quiet and radio-loud quasars and to compare them with those of radio galaxies. Both infrared images and optical off-nuclear spectra w
Studies of transiting extrasolar planets are of key importance for understanding the nature of planets outside our solar system because their masses, diameters, and bulk densities can be measured. An important part of transit-search programmes is the
We present high resolution images of NGC 2071-IR in the $J$, $H$, and $K$ bands and in the emission at 2.12 $mu$m of the v=$1-0$ $S$(1) line of molecular hydrogen. We also present moderate resolution K-band spectra of two young stellar objects, IRS 1
Combining high-resolution spectropolarimetric and imaging data is key to understanding the decay process of sunspots as it allows us scrutinizing the velocity and magnetic fields of sunspots and their surroundings. Active region NOAA 12597 was observ