The discovery of an astrophysical flux of high-energy neutrinos by the IceCube Collaboration marks a major breakthrough in the ongoing search for the origin of cosmic rays. Presumably, the neutrinos, together with gamma rays, result from pion decay, following hadronic interactions of protons accelerated in astrophysical objects to ultra

Context. Wide-range spectral coverage of blazar-type active galactic nuclei is of paramount importance for understanding the particle acceleration mechanisms assumed to take place in their jets. The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn)

During its first data cycle, between 2005 and the beginning of 2006, the fast repositioning system of the MAGIC telescope allowed the observation of nine different gamma-ray bursts as possible sources of very high energy γ-rays. These observations were triggered by alerts from Swift, HETE-2, and INTEGRAL; they started as quickly as possible after

This article summarizes results of studies presented in two papers already published: Lites et al. (2007a); Lites et al. (2007b). Please see these for further details.

Recent observations of coronal holes with Hinode show with unprecedented detail the launching of fast and hot jets. Many of these jets are found to coincide with the emergence of new magnetic flux, and it is generally assumed that the jets are initiated by magnetic reconnection between the new emerging flux and the existing open magnetic field

We present simultaneous spectropolarimetric observations of four visible (630 nm) and three infrared (1565 nm) spectral lines from the German Vacuum Tower Telescope, together with speckle-reconstructed filtergrams in the G-band and the Ca II H line core from the Dutch Open Telescope. After alignment of the data sets, we used the G-band intensity to