Context. We present the results of a long M 87 monitoring campaign in very high energy γ-rays with the MAGIC-I Cherenkov telescope. Aims: We aim to model the persistent non-thermal jet emission by monitoring and characterizing the very high energy γ-ray emission of M 87 during a low state. Methods: A total of 150 h of data were taken between 2005

Context. It has been claimed that the nova-like cataclysmic variable AE Aquarii (AE Aqr) is a very-high-energy (VHE, E> 100 GeV) source both on observational and theoretical grounds. Aims: We search for VHE γ-ray emission from AE Aqr during different states of the source at several wavelengths to confirm or rule out previous claims of detection of

Observations of magnetically sensitive lines in the visible and the infrared yield apparently contradictory values for the intrinsic field strength in the internetwork quiet Sun. It is shown that this discrepancy can be understood if one assumes that the magnetic field is not homogeneous over the resolution element. The difference between visible

Advanced Stokes Polarimeter observations are used to study the weakest polarization signals observed in the quiet photosphere with flux densities in the range of 1.5-50 Mx cm-2, which are found in internetwork regions. Our analysis allows us to reach an unprecedented spectropolarimetric sensitivity at the cost of sacrificing spatial resolution. We

Waves observed in the photosphere and chromosphere of sunspots show complex dynamics and spatial patterns. The interpretation of high-resolution sunspot wave observations requires modeling of three-dimensional (3D) nonlinear wave propagation and mode transformation in the sunspot upper layers in realistic spot model atmospheres. Here, we present

Observations of the optical counterpart to XTE J1650-500 with the Magellan 1 telescope find it fainter than expected based on reports of it's possible detection on the DDS2 red (Groot etal IAUC 7708) and blue (Castro-Tirado etal IAUC 7707) plates. The observations were made with the Sackler MagIC CCD camera in non-photometric conditions on 03 Aug