Context. We recently presented evidence that stable umbra-penumbra boundaries are characterised by a distinct canonical value of the vertical component of the magnetic field, Bstablever. In order to trigger the formation of a penumbra, large inclinations in the magnetic field are necessary. In sunspots, the penumbra develops and establishes by

A series of alkylnaphthalenes, namely 1,4-dimethylnaphthalene, 2,6-diethylnaphthalene, 2-ethylnaphthalene and pure naphthalene are not able to form Diels-Alder adducts with C60 fullerene but produce a series of 1:1 charge-transfer complexes (CTC) where the aromatic compounds act as donor and C60 as acceptor. The spectrophotometric analysis of these

Deep imaging is a fundamental tool in the study of the outermost structures of galaxies. We review recent developments in ultra-deep imaging of galaxy disks and haloes, highlighting the technical advances as well as the challenges and summarizing observational results in the context of modern theory and simulations. The deepest modern galaxy

Far infrared and sub-millimeter observations of quasars and normal star forming galaxies at z>6 have revealed the presence of large amounts of dust. At such high redshifts, the inferred 107-109 M_ȯ masses of dust must have formed in less than one billion years. Explaining this rapid chemical evolution is a challenge for both observations and

It is now about 30 years ago that photometric and spectroscopic surveys of asymptotic giant branch (AGB) stars in the Magellanic Clouds (MCs) uncovered the first examples of truly massive (> 3-4 M_ȯ) O-rich AGB stars experiencing hot bottom burning (HBB). Massive (Li-rich) HBB AGB stars were later identified in our own Galaxy and they pertain to

We present the preliminary results from observing the nearby radio galaxy M 87 for 156 hours (between the years 2012 and 2015) with the MAGIC telescopes, which lead to a significant very high energy (VHE, E > 100 GeV) detection of the source in quiescent states each year. Our VHE analysis combined with quasi-simultaneous data at other energies