We present results from a case study comparing different multivariate classification methods. The input is a set of Monte Carlo data, generated and approximately triggered and pre-processed for an ...imaging gamma-ray Cherenkov telescope. Such data belong to two classes, originating either from incident gamma rays or caused by hadronic showers. There is only a weak discrimination between signal (gamma) and background (hadrons), making the data an excellent proving ground for classification techniques.
The data and methods are described, and a comparison of the results is made. Several methods give results comparable in quality within small fluctuations, suggesting that they perform at or close to the Bayesian limit of achievable separation. Other methods give clearly inferior or inconclusive results. Some problems that this study can not address are also discussed.
The nearby dwarf spheroidal galaxy Draco, with its high mass to light ratio, is one of the most auspicious targets for indirect dark matter (DM) searches. Annihilation of hypothetical DM particles ...can result in high-energy -rays, e.g., from neutralino annihilation in the supersymmetric framework. A search for a possible DM signal originating from Draco was performed with the MAGIC telescope during 2007. Analysis of the data results in a flux upper limit (2 capital sigma ) of image photons cm super(-2) s super(-1) for photon energies above 140 GeV, assuming a pointlike source. A comparison with predictions from supersymmetric models is also given. While our results do not constrain the mSUGRA phase parameter space, a very high flux enhancement can be ruled out.
Aims. We searched for very high energy (VHE) \gamma-ray emission from the supernova remnant Cassiopeia A Methods. The shell-type supernova remnant Cassiopeia A was observed with the 17 m MAGIC ...telescope between July 2006 and January 2007 for a total time of 47 h. Results. The source was detected above an energy of 250 GeV with a significance of 5.2\sigma and a photon flux above 1 TeV of (7.3 \pm 0.7_{\rm stat} \pm 2.2_{\rm sys}) \times 10 super(-13) cm super(-2) s super(-1). The photon spectrum is compatible with a power law d N /d E \propto E-\Gamma} with a photon index \Gamma = 2.3 \pm 0.2_{\rm stat} \pm 0.2_{\rm sys}. The source is point-like within the angular resolution of the telescope.
The MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescope was designed to close the energy gap (~ 10–250 GeV) between ground based and satellite gamma detectors. It is situated on the Roque de ...los Muchachos, La Palma, Canary Islands at altitude of 2200 m. The main subjects of the investigations with the telescope are: Gamma Ray Bursts, Supernova Remnants, Plerions, Pulsars, Active Galactic Nuclei (AGNs), unidentied EGRET sources, Dark matter and Quantum gravity. More details about physics with a low threshold gamma ray telescope one can nd in 2. The telescope hardware installation was nished in October 2003. Since that time the observations of the dierent classes of objects have been carried out but the experiment is still in the commission phase.
The MAGIC Project: Contributions to ICRC 2007, Merida, Mexico. Contents pages for the Contribution on behalf of the MAGIC Collaboration to the 30th ICRC that took place in July 2007 in Merida, ...Mexico. The contents are in html form with clickable links to the papers that exist on the Astrophysics archive. We hope that this will make it easier to access the output of the conference in a systematic way. Comments on how useful this is/ how it could be improved should be sent to michela.demaria@iuav.it.
Astrophys.J.667:358-366,2007 The fast repositioning system of the MAGIC Telescope has allowed during its
first data cycle, between 2005 and the beginning of year 2006, observing nine
different GRBs ...as possible sources of very high energy gammas. These
observations were triggered by alerts from Swift, HETE-II, and Integral; they
started as fast as possible after the alerts and lasted for several minutes,
with an energy threshold varying between 80 and 200 GeV, depending upon the
zenith angle of the burst. No evidence for gamma signals was found, and upper
limits for the flux were derived for all events, using the standard analysis
chain of MAGIC. For the bursts with measured redshift, the upper limits are
compatible with a power law extrapolation, when the intrinsic fluxes are
evaluated taking into account the attenuation due to the scattering in the
Metagalactic Radiation Field (MRF).
Astrophys.J.642:L119-L122,2006 The MAGIC collaboration has studied the high peaked BL-Lac object
1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov
telescope located on the ...Canary island of La Palma. A gamma-ray signal was
observed with 6.4sigma significance. The differential energy spectrum for an
energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E)
= (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days
of observation in January 2005 no time variability on time scales of days was
found within the statistical errors. The observed integral flux above 350GeV is
nearly a factor two below the the upper limit reported by the Whipple
Collaboration in 2003.
Astrophys.J.641:L9-L12,2006 The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds
after the burst onset, and followed up for 37 minutes, until twilight. The
observation, ...triggered by a SWIFT alert, covered energies above ~175 GeV. Using
standard MAGIC analysis, no evidence for a gamma signal was found. As the
redshift of the GRB was not measured directly, the flux upper limit, estimated
by MAGIC, is still compatible with the assumption of an unbroken power-law
spectrum extending from a few hundred keV to our energy range.
The MAGIC collaboration has studied the high peaked BL-Lac object 1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov telescope located on the Canary island of La Palma. A ...gamma-ray signal was observed with 6.4sigma significance. The differential energy spectrum for an energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E) = (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days of observation in January 2005 no time variability on time scales of days was found within the statistical errors. The observed integral flux above 350GeV is nearly a factor two below the the upper limit reported by the Whipple Collaboration in 2003.
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