摘要：Aims.The very high energy (VHE ≳100 GeV)γ-ray MAGIC observations of the blazar S4 0954+65, were triggered by an exceptionally high flux state of emission in the optical. This blazar has a disputed redshift ofz= 0.368 orz≥ 0.45 and an uncertain classification among blazar subclasses. The exceptional source state described here makes for an excellent opportunity to understand physical processes in the jet of S4 0954+65 and thus contribute to its classification.Methods.We investigated the multiwavelength (MWL) light curve and spectral energy distribution (SED) of the S4 0954+65 blazar during an enhanced state in February 2015 and have put it in context with possible emission scenarios. We collected photometric data in radio, optical, X-ray, andγ-ray. We studied both the optical polarization and the inner parsec-scale jet behavior with 43 GHz data.Results.Observations with the MAGIC telescopes led to the first detection of S4 0954+65 at VHE. Simultaneous data withFermi-LAT at high energyγ-ray (HE, 100 MeV
