R. Zanin

MAGIC measurement of the Crab Nebula spectrum over three decades in energy

The Crab Pulsar Wind Nebula is the best studied source of γ-ray astrophysics. The contribution of the various soft radiation fields to the Inverse Compton component of its high energy emission, the strenght of the internal magnetic field and the maximum energies reached by primary electrons are however still matter of study. The MAGIC stereoscopic system recorded almost 50 hours of Crab Nebula data in the last two years, between October 2009 and April 2011. Analysis of this data sample using the latest improvements in the MAGIC stereo software provided an unprecedented differential energy spectrum spanning three decades in energy, from 50 GeV up to 45 TeV. At low ener- gies, the MAGIC results, combined with the Fermi/LAT data, yield a precise measurement of the Inverse Compton peak. In addition, we present light curves of the Crab Nebula at different time scales, including a measurement simultaneous to one of the Crab Nebula flares recently detected by both Fermi/LAT and AGILE. Using the MAGIC spectrum together with multiwavelength data, we discuss the implications for the modeling of the Crab Nebula.

MAGIC VHE Gamma-Ray Observations Of Binary Systems

There are several types of Galactic sources that can potentially accelerate charged particles up to GeV and TeV energies. These accelerated particles can produce Very High Energy (VHE, E >100 GeV) γ-ray emission through different processes like for example inverse Compton scattering of ambient photon fields by accelerated electrons. We present here the results of our obser-vations of the source class of γ-ray binaries and the subclass of binary systems known as novae with the MAGIC telescopes. The focus lies on the five sources: nova V339 Del, AE Aquarii, SS 433, MWC 656 and LS I +61°303. The binary system LS I +61◦303 was observed in a long-term monitoring campaign for 8 years. We show the newest results on our search for superorbital variability also in context with contemporaneous optical observations. MWC 656 is a unique detected high-mass X-ray binary system, since it is up to now the only one known composed of a Be star and a black hole. Furthermore, we present the observations of the only super-critical accretion system known in our galaxy: SS 433. Finally, results of our multiwavelength observation campaign regarding the cataclysmic variable AE Aquarii and the results of the follow-up observations of the nova V339 Del will be discussed in these proceedings.

Phase-resolved Crab pulsar measurements from 25 to 400 GeV with the MAGIC telescopes

We report on observations of the Crab pulsar with the MAGIC telescopes. Our data were taken in both monoscopic (> 25 GeV) and stereoscopic (> 50 GeV) observation modes. Two peaks were detected with both modes and phase-resolved energy spectra were calculated. By comparing with Fermi-LAT measurements, we find that the energy spectrum of the Crab pulsar does not follow a power law with an exponential cutoff, but has an additional hard component, extending up to at least 400 GeV. This suggests that the emission above 25 GeV is not dominated by curvature radiation, as suggested in the standard scenarios of the OG and SG models.

VHE gamma-ray measurements of the Crab nebula and pulsar by MAGIC

In the last two years 2010 and 2011 the Crab nebula and its pulsar have surprised the gamma-ray astrophysics community at least twice: the former with GeV flares detected by AGILE and Fermi-LAT, the latter with very high energy (VHE, E > 100 GeV) pulsed emission extending up to 400 GeV detected by MAGIC and VERITAS. These exciting results show that there is still much left to understand about this object. We report here the results of the MAGIC stereoscopic observations of the Crab nebula and pulsar carried on between October 2009 and April 2011. For the nebula, the analysis of these data yields a differential energy spectrum with an unprecedented precision spanning from 50 GeV to 45 TeV, a precise determination of its inverse Compton (IC) peak, and the measurement of the VHE emission during the GeV flare of April 2011. Implications on the modeling of the Crab nebula, especially regarding the strength of the magnetic field, are discussed. For the pulsar, a phase-resolved energy spectrum and a lightcurve i...