MAGIC telescopes for the study of the electronic cosmic flux

The IACT technique (Imaging Atmospheric Cherenkov Telescopes) allowed recent Cherenkov telescopes to obtain several relevant measurements in the field of Gamma Astronomy. The main field of investigation is the cosmic photon radiation of energy between 50 GeV and few tens of TeV. Furthermore, with a ded- icated analysis, IACTs may also be used to measure the electronic component of cosmic rays. Such particles, with energies of several hundreds of GeV, have a rather short lifetime, of the order of 105 years. The spectral structure of this radiation yields therefore information on the nearby sources, within the distance of 1kpc, giving also cosmological and fundamental physics implications. MAGIC experiment can give a contribute in the measurement of two different components: the total flux of cosmic electrons and positrons (e+ + e 12) and the ratio between positrons and electrons (e+/e 12), as here presented

The MAGIC telescope reflecting surface

The Major Atmospheric Gamma Imaging Cherenkov telescope will achieve an energy threshold lower than any other present IACT (E-Th similar to 30 Gev) thanks to the largest reflecting surface, a 17 in diameter, f/1, tessellated parabolic reflector. The tiles are 50 cm x 50 cm all-aluminum spherical mirrors with different radii of curvature to best fit the paraboloid. The technology used to make these mirrors and the method used to measure their optical properties, as the focal length, the spot size and the reflectivity, are described. The results of these measurements are shown

Using the photons from the Crab Nebula seen by GLAST to calibrate MAGIC and the imaging air Cherenkov telescopes

n this article we discuss the possibility of using the observations by GLAST of standard gamma sources, as the Crab Nebula, to calibrate imaging air Cherenkov detectors, MAGIC in particular, and optimise their energy resolution. We show that at around 100 GeV the absolute energy calibration uncertainty of Cherenkov telescopes can be reduced to less than or similar to 10% by means of such cross-calibration procedure

Very high energy gamma-ray observation of the peculiar transient event Swift J1644+57 with the MAGIC telescopes and AGILE

Context. On March 28, 2011, the BAT instrument on board the Swift satellite detected a new transient event that in the very beginning was classified as a gamma ray burst (GRB). However, the unusual X-ray flaring activity observed from a few hours up to days after the onset of the event made a different nature seem to be more likely. The long-lasting activity in the X-ray band, followed by a delayed brightening of the source in infrared and radio activity, suggested that it is better interpreted as a tidal disruption event that triggered a dormant black hole in the nucleus of the host galaxy and generated an outflowing jet of relativistic matter. Aims. Detecting a very high energy emission component from such a peculiar object would be enable us to constrain the dynamic of the emission processes and the jet model by providing information on the Doppler factor of the relativistic ejecta. Methods. The MAGIC telescopes observed the peculiar source Swift J1644+57 during the flaring phase, searching for gamma-ray emission at very-high energy (VHE, E > 100 GeV), starting observations nearly 2.5 days after the trigger time. MAGIC collected a total of 28 h of data during 12 nights. The source was observed in wobble mode during dark time at a mean zenith angle of 35 degrees. Data were reduced using a new image-cleaning algorithm, the so-called sum-cleaning, which guarantees a better noise suppression and a lower energy threshold than the standard analysis procedure. Results. No clear evidence for emission above the energy threshold of 100 GeV was found. MAGIC observations permit one to constrain the emission from the source down to 100 GeV, which favors models that explain the observed lower energy variable emission. Data analysis of simultaneous observations from AGILE, Fermi and VERITAS also provide negative detection, which additionally constrain the self-Compton emission component

MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

ISSN:0035-8711ISSN:1365-2966ISSN:1365-871