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1 Observation of the Crab Nebula with the MAGIC Telescope M. López-Moya Univ. Complutense de Madrid, on behalf of the MAGIC Collaboration.

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Presentation on theme: "1 Observation of the Crab Nebula with the MAGIC Telescope M. López-Moya Univ. Complutense de Madrid, on behalf of the MAGIC Collaboration."— Presentation transcript:

1 1 Observation of the Crab Nebula with the MAGIC Telescope M. López-Moya Univ. Complutense de Madrid, on behalf of the MAGIC Collaboration

2 XXXXth Rencontres de Moriond2 Outline Introduction Introduction Analysis Analysis Data Set Data Set First Results First Results

3 XXXXth Rencontres de Moriond3 Crab Nebula: the standard candle (I) Remnant of a supernova explosion, occurred in Pulsar injecting relativistic electrons into the nebula. Emission predominantly by non- thermal processes, covering a huge energy range (radio to TeV). First TeV source (Whipple Telescope, 1989). Very strong and stable at TeV our standard candle

4 XXXXth Rencontres de Moriond4 Crab Nebula: the standard candle (II) SSC model fits the observed spectrum. SSC model fits the observed spectrum. Inverse Compton peak expected below 100 GeV. Inverse Compton peak expected below 100 GeV. Inverse-Compton Emission SynchrotronE mission MAGIC should see the IC- peak. MAGIC should see the IC- peak.

5 577 pixels, 3.5 deg FOV camera 577 pixels, 3.5 deg FOV camera Fast pulse sampling: 300MHz Fast pulse sampling: 300MHz Optical signal transport Optical signal transport 17 m diameter dish 17 m diameter dish Active mirror control Active mirror control The MAGIC Telescope Located at 2220m at La Palma (Canary islands) Located at 2220m at La Palma (Canary islands) Threshold: 30 GeV Threshold: 30 GeV Characteristics: Characteristics:

6 XXXXth Rencontres de Moriond6 Imaging Cherenkov Technique (I) -like -like hadron-like -arc -arc

7 XXXXth Rencontres de Moriond7 Imaging Cherenkov Technique (II) Alpha

8 XXXXth Rencontres de Moriond8 Background reduction (I) Down to ~150 GeV, the traditional techniques based on simple image parameter cuts, still work well. Down to ~150 GeV, the traditional techniques based on simple image parameter cuts, still work well. E>180 GeV

9 XXXXth Rencontres de Moriond9 Background reduction (II) At lower energies the traditional techniques start to be not so effective. At lower energies the traditional techniques start to be not so effective.

10 XXXXth Rencontres de Moriond10 Background reduction (III) A new approach has been used for the gamma/hadron separation: A new approach has been used for the gamma/hadron separation: Random Forest Random Forest Train in the parameters: SIZE, DISTANCE, LENGTH, WIDTH, CONC, ASYM Train in the parameters: SIZE, DISTANCE, LENGTH, WIDTH, CONC, ASYM (no ALPHA used). No a priori parameterization needed. No a priori parameterization needed. For each shower we get its hadronness. For each shower we get its hadronness.

11 XXXXth Rencontres de Moriond11 Background reduction (IV) For each energy bin we cut in different Hadronness and Alpha For each energy bin we cut in different Hadronness and Alpha All Energies E>200 GeV Gammas Hadrons

12 XXXXth Rencontres de Moriond12 Energy Estimation Basic principle: Energy light content of the shower (SIZE). Basic principle: Energy light content of the shower (SIZE). We use a Taylor expansion on the more relevant image parameters: We use a Taylor expansion on the more relevant image parameters: Coefficients obtained by minimizing: Coefficients obtained by minimizing: Resolution ~30% Resolution ~30% Bias at very low energies, since very low size events are rejected (by trigger and analysis cuts). Bias at very low energies, since very low size events are rejected (by trigger and analysis cuts).

13 XXXXth Rencontres de Moriond13 Energy Estimation

14 XXXXth Rencontres de Moriond14 Energy Estimation Basic principle: Energy light content of the shower (SIZE). Basic principle: Energy light content of the shower (SIZE). We use a Taylor expansion on the more relevant image parameters: We use a Taylor expansion on the more relevant image parameters: Coefficients obtained by minimizing: Coefficients obtained by minimizing: Resolution ~30% Resolution ~30% Bias at very low energies, since very low size events are discarded (by trigger and analysis cuts). Bias at very low energies, since very low size events are discarded (by trigger and analysis cuts). Currently applying new methods, like Random Forest energy estimation, giving similar results. Currently applying new methods, like Random Forest energy estimation, giving similar results.

15 XXXXth Rencontres de Moriond15 Data Set date Zd. [ 0 ] Nº events [·10 3 ] T obs [min] ON13,14, OFF18, First data set after full mirror installation: Sept First data set after full mirror installation: Sept Background rate ~200 Hz Background rate ~200 Hz

16 XXXXth Rencontres de Moriond16 Collection Area & Expected Rates

17 XXXXth Rencontres de Moriond17 Alpha plots vs. Energy ON OFF

18 XXXXth Rencontres de Moriond18 Spectrum

19 XXXXth Rencontres de Moriond19 Conclusions MAGIC already operational and taking its first data since MAGIC already operational and taking its first data since Crab Nebula spectrum measured by MAGIC consistent with previous experiments, and compatible with SSC emission model. Crab Nebula spectrum measured by MAGIC consistent with previous experiments, and compatible with SSC emission model. First signals obtained well below 100 GeV with a Cherenkov telescope. First signals obtained well below 100 GeV with a Cherenkov telescope. Analysis still can improve to push down more the analysis threshold. Analysis still can improve to push down more the analysis threshold.


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