D ATA A NALYSIS : E XTRACTING SCIENCE FROM MAGIC Uta Menzel YSW Ringberg 2015, 6. 7. 2015
Data Analysis: Extracting science from MAGIC O UTLINE ◮ MAGIC telescopes ⊲ Imaging Air Cherenkov Technique (IACT) ⊲ Telescope hardware ◮ Standard analysis ⊲ Signal extraction ⊲ Hillas parametrization ⊲ Determination of physical parameters ⊲ Final products ◮ My work - Template analysis Uta Menzel YSW Ringberg 2015, 6. 7. 2015 2 / 27
Data Analysis: Extracting science from MAGIC T HE A TMOSPHERE Uta Menzel YSW Ringberg 2015, 6. 7. 2015 3 / 27
Primary Data Analysis: Extracting science from MAGIC E XTENSIVE A IR S HOWERS Electromagnetic shower ◮ particle cascade with ⊲ pair production ⊲ bremsstrahlung e+ e- ◮ charged particles, faster than e+ speed of light in air e- ⇒ Cherenkov radiation e+ e+ e- e+ e- e- Uta Menzel YSW Ringberg 2015, 6. 7. 2015 4 / 27
Data Analysis: Extracting science from MAGIC I MAGING A IR C HERENKOV T ECHNIQUE ◮ image with elliptic shape ◮ stereo for better reconstruction ◮ background from cosmic rays, ~factor 1000 Christian Fruck Uta Menzel YSW Ringberg 2015, 6. 7. 2015 5 / 27
Data Analysis: Extracting science from MAGIC Main Imaging Air Cherenkov Telescopes Uta Menzel YSW Ringberg 2015, 6. 7. 2015 6 / 27
Data Analysis: Extracting science from MAGIC The MAGIC telescopes ◮ 2200 m above sea level ◮ parabolic dish: 17 m diameter ◮ 2 telescopes, 85 m apart ◮ focal length: 17 m ◮ 1m 2 and 0 . 25m 2 mirrors ◮ light structure → fast repositioning Uta Menzel YSW Ringberg 2015, 6. 7. 2015 7 / 27
Data Analysis: Extracting science from MAGIC C AMERA ◮ PMTs (photo multiplier tubes) as photon detectors ◮ 1039 pixels per camera ◮ ~1 m diameter ◮ 3.5° field of view Uta Menzel YSW Ringberg 2015, 6. 7. 2015 8 / 27
Data Analysis: Extracting science from MAGIC E LECTRONICS ◮ trigger ⊲ L0: minimum signal in single pixel ⊲ L1: signal in neighbouring pixels ⊲ L3: trigger in both telescopes ◮ readout: DRS4 chip ⊲ up to 2 GSamples/s ⊲ 1024 capacitors saved to disk: 60 time slices with charge (30 ns in total) for each pixel Uta Menzel YSW Ringberg 2015, 6. 7. 2015 9 / 27
Data Analysis: Extracting science from MAGIC D ATA A NALYSIS Uta Menzel YSW Ringberg 2015, 6. 7. 2015 10 / 27
Data Analysis: Extracting science from MAGIC S IGNAL EXTRACTION ◮ pedestal subtraction ◮ search for signal (sliding window) ⇒ for each pixel: ◮ number of photo electrons ◮ arrival time Uta Menzel YSW Ringberg 2015, 6. 7. 2015 11 / 27
Data Analysis: Extracting science from MAGIC I MAGE C LEANING Two-level image cleaning ◮ core pixel: number of photons above threshold 1 ◮ boundary pixel: neighbour of core pixel, number of photons above threshold 2 <threshold 1 ◮ include time contraints for core and boundary calibrated image core and boundary cleaned image Uta Menzel YSW Ringberg 2015, 6. 7. 2015 12 / 27
Data Analysis: Extracting science from MAGIC P ARAMETRIZATION ◮ number of photons Mono Hillas Parameters ◮ length ◮ width Source position ◮ distance to source length d i s t a n c e ◮ α α width ◮ time parameters center of gravity ◮ . . . Christian Fruck Uta Menzel YSW Ringberg 2015, 6. 7. 2015 13 / 27
Data Analysis: Extracting science from MAGIC P ARAMETRIZATION ◮ number of photons Stereo Hillas Parameters ◮ length ◮ width Reconstructed origin theta disp 2 ◮ distance to source Source position length 2 distance 2 ◮ α α 2 disp 1 distance 1 width 2 ◮ time parameters ◮ . . . length 1 center of gravity 2 α 1 Camera 1 Camera 2 center of gravity 1 width 1 Uta Menzel YSW Ringberg 2015, 6. 7. 2015 13 / 27 Christian Fruck
Data Analysis: Extracting science from MAGIC R ECONSTRUCTION ◮ based on Monte Carlo simulations ⊲ atmosphere as part of the detector ⊲ simulate the telescope response ⊲ analyze like data ◮ parameters to reconstruct: ⊲ energy of the primary particle: look-up table ⊲ direction the of primary particle: stereo disp method ⊲ hadronness: Random Forest Uta Menzel YSW Ringberg 2015, 6. 7. 2015 14 / 27
Data Analysis: Extracting science from MAGIC D IRECTION RECONSTRUCTION geometrical stereo reconstruction mono DISP reconstruction with Random Forest stereo DISP ⇒ combine DISP of both telescopes to get direction Uta Menzel YSW Ringberg 2015, 6. 7. 2015 15 / 27
, Fe ...) Cosmic Ray (p, Primary Data Analysis: Extracting science from MAGIC G AMMA -H ADRON SEPARATION Electromagnetic shower Hadron shower Atmospheric Nucleus e+ e- e+ EM Shower e- Nucleons, K , etc. e+ e- e+ e+ Atmospheric Nucleus e- EM Shower e- Nucleons, e - K , etc. e+ e+ e - + EM Shower Uta Menzel YSW Ringberg 2015, 6. 7. 2015 16 / 27
Data Analysis: Extracting science from MAGIC G AMMA -H ADRON SEPARATION Gamma Hadron Uta Menzel YSW Ringberg 2015, 6. 7. 2015 17 / 27
Data Analysis: Extracting science from MAGIC G AMMA -H ADRON SEPARATION Decision tree ◮ Random Forest = many decision trees ◮ build with MC-gammas and real background ◮ determine hadronness of each event Uta Menzel YSW Ringberg 2015, 6. 7. 2015 18 / 27
Data Analysis: Extracting science from MAGIC S IGNAL DETECTION θ 2 -plot Skymap angular resolution ~0.1° background estimated from camera region without source Uta Menzel YSW Ringberg 2015, 6. 7. 2015 19 / 27
Data Analysis: Extracting science from MAGIC E FFECTIVE COLLECTION AREA A eff [m 2 ] ◮ determined from MCs (same analysis as data) ◮ A eff = N survived N simulated ∗ A simulated Uta Menzel YSW Ringberg 2015, 6. 7. 2015 20 / 27
Data Analysis: Extracting science from MAGIC M IGRATION MATRIX ◮ relation between simulated and reconstructed energy ◮ energy spectrum needs unfolding ◮ energy resolution ~15% Uta Menzel YSW Ringberg 2015, 6. 7. 2015 21 / 27
Data Analysis: Extracting science from MAGIC S PECTRUM Uta Menzel YSW Ringberg 2015, 6. 7. 2015 22 / 27
Data Analysis: Extracting science from MAGIC A LTERNATIVE ANALYSIS METHOD Uta Menzel YSW Ringberg 2015, 6. 7. 2015 23 / 27
Data Analysis: Extracting science from MAGIC Current analysis ⇒ Calibrated data Hillas method Template analysis ⇒ compare to template images Calibrated data Uta Menzel YSW Ringberg 2015, 6. 7. 2015 24 / 27
Data Analysis: Extracting science from MAGIC T EMPLATE DATABASE parameters that change the image: energy azimuth zenith angle impact parameter impact angle ( ϕ ) first interaction height ⇒ 6D-database + pointing: (x cam , y cam ) source Uta Menzel YSW Ringberg 2015, 6. 7. 2015 25 / 27
Data Analysis: Extracting science from MAGIC T EMPLATE A NALYSIS PROCEDURE Hillas E, source pos. direction, ... compare data template with template database data - Energy new starting - Source position point - Fit quality? ◮ comparison: likelihood function ◮ maximization of the likelihood Uta Menzel YSW Ringberg 2015, 6. 7. 2015 26 / 27
Data Analysis: Extracting science from MAGIC C ONCLUSION ◮ IACT: new window to gamma-ray astronomy ◮ MAGIC: largest IACT stereo system ◮ standard analysis: based on image parameters ◮ possible improvement: template analysis ⊲ better angular resolution ⊲ better energy resolution ⊲ higher sensitivity Uta Menzel YSW Ringberg 2015, 6. 7. 2015 27 / 27
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