A search for tau neutrino induced showers with the MAGIC telescopes is presented. The MAGIC telescopes located at an altitude of 2200 m a.s.l. in the Canary Island of La Palma, can point towards the horizon or a few degrees below across an azimuthal range of about 80°. This provides a possibility to search for air showers induced by tau leptons

L-type ultra-cool dwarfs are known to have a dusty atmosphere. Surface heterogeneities, due to cloud patterns or rotationally-induced oblateness, would result in an imperfect polarization cancellation and a small, but non-zero net polarization. The measurement of linear polarization could shed light on the dust distribution and oblateness of those

We present a critical analysis of linearization and preconditioning, the two most used approaches proposed for achieving the required linearity in the iterative solution of the multilevel transfer problem. By distinguishing from the outset between the response of the radiation field to the source function and opacity perturbations, we are able to

We report the detection of the LiI λ6708 resonance line in the K4V secondary of the black-hole binary Nova Muscae 1991. The LiI feature changes with orbital phase, being stronger (EW ∼ 400 mÅ) around φ = 0.0 (observing the dark side of the secondary) and weaker (EW ≤ 190 mÅ) around φ = 0.5 (observing the side facing the compact object). This effect

We present preliminary results of VLT spectroscopy follow-up of Planetary Nebulae (PNe) and HII regions in the dwarf Irregular galaxy NGC 3109. In total we have observed 15 PNe (of a total of 18) and about 50 HII: at least for 10 PNe and 10 HII regions the very faint [O III]4363 line is observed allowing to derive accurate abundances. The

We present long-term photometric observations of the young open cluster IC 348 with a baseline time-scale of 2.4 yr. Our study was conducted with several telescopes from the Young Exoplanet Transit Initiative (YETI) network in the Bessel R band to find periodic variability of young stars. We identified 87 stars in IC 348 to be periodically variable