| MAGIC 1 | |
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The first MAGIC telescope
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| Organization | MAGIC collaboration |
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| Location | La Palma, Canary Islands |
| Altitude | 2200 m |
| Wavelength | Gamma rays |
| Built | 2004 |
| Telescope style | Reflector |
| Diameter | 17m |
| Collecting area | 240 m² |
| Focal length | f/D 1.03 |
| Mounting | metal structure |
| Website | http://wwwmagic.mppmu.mpg.de/ |
MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes) is a system of two Imaging Atmospheric Cherenkov telescopes situated at the Roque de los Muchachos Observatory on La Palma, one of the Canary Islands, at about 2200 m above sea level. MAGIC detects particle showers released by gamma rays, using the Cherenkov radiation, i.e., faint light radiated by the charged particles in the showers. With a diameter of 17 meters for the reflecting surface, it is the largest in the world.
The first telescope was built in 2004 and operated for five years in standalone mode. A second MAGIC telescope (MAGIC-II), at a distance of 85 m from the first one, started taking data in July 2009. Together they integrate the MAGIC telescope stereoscopic system.[1]
MAGIC is sensitive to cosmic gamma rays with energies between 50 GeV and 30 TeV due to its large mirror; other ground-based gamma-ray telescopes typically observe gamma energies above 200-300 GeV. Satellite-based detectors detect gamma-rays in the energy range from keV up to several GeV.
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The goals of the telescope are to detect and study primarily photons coming from:
MAGIC has found pulsed gamma-rays at energies higher than 25 GeV coming from the Crab Pulsar.[4] The presence of such high energies indicates that the gamma-ray source is far out in the pulsar's magnetosphere, in contradiction with many models.
MAGIC detected[5] very high energy cosmic rays from the quasar 3C 279, which is 5 billion light years from Earth. This doubles the previous record distance from which very high energy cosmic rays have been detected. The signal indicated that the universe is more transparent than previously thought based on data from optical and infrared telescopes.
MAGIC did not observe cosmic rays resulting from dark matter decays in the dwarf galaxy Draco.[6] This strengthens the known constraints on dark matter models.
A much more controversial observation is an energy dependence in the speed of light of cosmic rays coming from a short burst of the blazar Markarian 501 on July 9, 2005. Photons with energies between 1.2 and 10 TeV arrived 4 minutes after those in a band between .25 and .6 TeV. The average delay was .030±.012 seconds per GeV of energy of the photon. If the relation between the space velocity of a photon and its energy is linear, then this translates into the fractional difference in the speed of light being equal to minus the photon's energy divided by 2×1017 GeV.
Each telescope has the following specifications:
(diameter: 2.54 cm) surrounded by 180 larger photomultiplier detectors (diameter: 3.81 cm).
Physicists from over twenty institutions in Germany, Spain, Italy, Switzerland, Croatia, Finland, Poland, Bulgaria and Armenia collaborate in using MAGIC; the largest groups are at