D ATA A NALYSIS : E XTRACTING SCIENCE FROM MAGIC Uta Menzel YSW - - PowerPoint PPT Presentation

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D ATA A NALYSIS : E XTRACTING SCIENCE FROM MAGIC Uta Menzel YSW - - PowerPoint PPT Presentation

Oct 08, 2023 120 likes •406 views

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

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DATA ANALYSIS: EXTRACTING SCIENCE FROM MAGIC

Uta Menzel YSW Ringberg 2015, 6. 7. 2015

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Data Analysis: Extracting science from MAGIC

OUTLINE

◮ 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

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Data Analysis: Extracting science from MAGIC

THE ATMOSPHERE

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 3 / 27

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Data Analysis: Extracting science from MAGIC

EXTENSIVE AIR SHOWERS

Electromagnetic shower

e+ e+ e- Primary e- e+ e+ e- e+ e- e-

◮ particle cascade with

⊲ pair production ⊲ bremsstrahlung

◮ charged particles, faster than

speed of light in air ⇒ Cherenkov radiation

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 4 / 27

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Data Analysis: Extracting science from MAGIC

IMAGING AIR CHERENKOV TECHNIQUE

Christian Fruck

◮ image with elliptic

shape

◮ stereo for better

reconstruction

◮ background from

cosmic rays, ~factor 1000

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 5 / 27

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Data Analysis: Extracting science from MAGIC

Main Imaging Air Cherenkov Telescopes

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 6 / 27

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Data Analysis: Extracting science from MAGIC

The MAGIC telescopes

◮ 2200 m above sea level ◮ 2 telescopes, 85 m apart ◮ light structure → fast repositioning ◮ parabolic dish: 17 m diameter ◮ focal length: 17 m ◮ 1m2 and 0.25m2 mirrors

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 7 / 27

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Data Analysis: Extracting science from MAGIC

CAMERA

◮ 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

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Data Analysis: Extracting science from MAGIC

ELECTRONICS

◮ 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

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Data Analysis: Extracting science from MAGIC

DATA ANALYSIS

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 10 / 27

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Data Analysis: Extracting science from MAGIC

SIGNAL 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

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Data Analysis: Extracting science from MAGIC

IMAGE CLEANING

Two-level image cleaning

◮ core pixel: number of photons above threshold1 ◮ boundary pixel: neighbour of core pixel,

number of photons above threshold2<threshold1

◮ include time contraints for core and boundary

calibrated image core and boundary cleaned image

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 12 / 27

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Data Analysis: Extracting science from MAGIC

PARAMETRIZATION

Mono Hillas Parameters

Source position center of gravity α d i s t a n c e width length Christian Fruck

◮ number of photons ◮ length ◮ width ◮ distance to source ◮ α ◮ time parameters ◮ . . .

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 13 / 27

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Data Analysis: Extracting science from MAGIC

PARAMETRIZATION

Stereo Hillas Parameters

Source position distance 2 distance 1 center of gravity 2 length 2 length 1 width 2 center of gravity 1 α2 α1 Reconstructed origin theta

Camera 1 Camera 2

disp 2 disp 1 width 1

Christian Fruck

◮ number of photons ◮ length ◮ width ◮ distance to source ◮ α ◮ time parameters ◮ . . .

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 13 / 27

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Data Analysis: Extracting science from MAGIC

RECONSTRUCTION

◮ 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

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Data Analysis: Extracting science from MAGIC

DIRECTION 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

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Data Analysis: Extracting science from MAGIC

GAMMA-HADRON SEPARATION

Electromagnetic shower

e+ e+ e- Primary e- e+ e+ e- e+ e- e-

Hadron shower

e- e- e+ e+

+ K , etc. Nucleons, K , etc. Nucleons,

Cosmic Ray (p, , Fe ...)

Atmospheric Nucleus EM Shower EM Shower EM Shower Atmospheric Nucleus Uta Menzel YSW Ringberg 2015, 6. 7. 2015 16 / 27

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Data Analysis: Extracting science from MAGIC

GAMMA-HADRON SEPARATION

Gamma Hadron

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 17 / 27

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Data Analysis: Extracting science from MAGIC

GAMMA-HADRON 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

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Data Analysis: Extracting science from MAGIC

SIGNAL 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

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Data Analysis: Extracting science from MAGIC

EFFECTIVE COLLECTION AREA

Aeff [m2]

◮ determined from MCs

(same analysis as data)

◮ Aeff = Nsurvived Nsimulated ∗Asimulated

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 20 / 27

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Data Analysis: Extracting science from MAGIC

MIGRATION MATRIX

◮ relation between simulated and reconstructed energy ◮ energy spectrum needs unfolding ◮ energy resolution ~15%

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 21 / 27

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Data Analysis: Extracting science from MAGIC

SPECTRUM

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 22 / 27

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Data Analysis: Extracting science from MAGIC

ALTERNATIVE ANALYSIS METHOD

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 23 / 27

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Data Analysis: Extracting science from MAGIC

Current analysis

Calibrated data

⇒

Hillas method

Template analysis

Calibrated data

⇒

compare to template images Uta Menzel YSW Ringberg 2015, 6. 7. 2015 24 / 27

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Data Analysis: Extracting science from MAGIC

TEMPLATE DATABASE

parameters that change the image:

energy azimuth zenith angle impact parameter impact angle (ϕ) first interaction height

⇒ 6D-database

+ pointing: (xcam, ycam)source

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 25 / 27

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Data Analysis: Extracting science from MAGIC

TEMPLATE ANALYSIS PROCEDURE

template database

E, source pos. direction, ... compare data with template new starting point

  • Energy
  • Source position
  • Fit quality?

data

Hillas

◮ comparison: likelihood function ◮ maximization of the likelihood

Uta Menzel YSW Ringberg 2015, 6. 7. 2015 26 / 27

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Data Analysis: Extracting science from MAGIC

CONCLUSION

◮ 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