Density waves in galaxy disks have been proposed over the years, in a variety of specific models, to explain spiral arm structure and its relation to the mass distribution, notably in barred galaxies. An important parameter in dynamical density wave theories is the corotation radius, the galactocentric distance at which the stars and gas rotate at

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Context. The available set of spin and shape modelled asteroids is strongly biased against slowly rotating targets and those with low lightcurve amplitudes. This is due to the observing selection effects. As a consequence, the current picture of asteroid spin axis distribution, rotation rates, radiometric properties, or aspects related to the

We report the design of OPTEL-D which is an optical communication system for direct data transfer from deep space to earth. OPTEL-D extends the link distances of current optical communication systems to the deep space. The design covers the electrical, thermal, mechanical and optical challenges that such a link distance imposes to both the ground

The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 35.9 fb-1 collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. Events are selected by requiring exactly two leptons (electrons or muons) of the

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