1 Multi-messenger High-Energy Astrophysics 9

Contents

I Cosmic Rays, Neutrinos and IceCube 5

1 Multi-messenger High-Energy Astrophysics 9

1.1 Brief history of neutrino telescopes . . . 10

1.2 Multi-messenger Astrophysics . . . 12

1.2.1 Cosmic Rays . . . 14

1.2.2 Gamma Rays . . . 20

1.2.3 The CR- -Neutrino Connection: Neutrino Astronomy . . . 22

1.3 High-Energy Neutrino sources . . . 23

1.3.1 Galactic Sources . . . 24

1.3.2 Extragalactic Sources . . . 29

1.4 Extended Sources . . . 32

1.4.1 Extended Sources in the High-Energy Gamma-Ray Sky . . . . 32

1.4.2 Extended Sources in the High-Energy Cosmic-Ray Sky . . . . 33

2 Principles of Neutrino Detection 35 2.1 Neutrino-nucleon Interaction . . . 35

2.2 Particle Interactions and Event Topologies in IceCube . . . 37

2.2.1 Cherenkov Radiation . . . 39

2.2.2 CC ⌫

interactions . . . 39

2.2.3 CC ⌫

interactions . . . 40

2.2.4 CC ⌫

interactions . . . 41

2.3 Coordinate systems, background signals and the role of Earth . . . . 42

2.3.1 Coordinate systems . . . 42

2.3.2 Background signals and the role of Earth . . . 44

3 The IceCube Neutrino Observatory 47 3.1 The IceCube Detector . . . 47

3.2 Antarctic Ice Properties . . . 50

3.3 Data Acquisition (DAQ) . . . 52

3.3.1 An IceCube hit . . . 53

3.3.2 DOM Main Board (DOM MB) . . . 54

3.3.3 Local Coincidence . . . 57

3.3.4 Trigger Algorithms . . . 57

3.4 Online and Offline Processing . . . 59

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3.4.1 Reconstructing Particle Directions and Energies . . . 61

II Search for Extended Sources with the IceCube Neutrino Obser- vatory 69 4 Physics Case 73 5 Point Source Samples 75 5.1 Characteristics and Performance of the Final Event Samples . . . 76

5.2 Simulation . . . 80

6 Analysis Method 83 6.1 Likelihood Method: the Standard Point Source Approach . . . 83

6.2 Hypothesis Testing and Test Statistic . . . 90

6.2.1 Test Statistic . . . 92

6.3 Background TS Distributions and Signal-subtracted Likelihood . . . . 94

6.4 Extended Source Injector . . . 96

6.5 Sensitivity and Discovery Potential . . . 100

7 Results 103 7.1 Systematic Uncertainties . . . 109

III Feasibility Study of a New Communication System for the IceCube-Gen2 Project 113 8 The IceCube-Gen2 Project 117 8.1 Gen2 Baseline detector . . . 118

9 Current IceCube Communications Design 121 9.1 Entities involved: The DOR and DOM . . . 122

9.2 Transmission medium: IceCube Cable System . . . 123

9.3 Protocol: NRZ-like custom packet-based . . . 124

10 Binary Phase Shift Keying Studies 129 10.1 From Filter Box to Filter Board . . . 130

10.1.1 Phase and amplitude measurements . . . 131

10.2 Binary Phase Shift Keying (BPSK) . . . 132

10.2.1 Instrumental set up . . . 134

10.2.2 Modulation . . . 134

10.2.3 Demodulation and bit recovery . . . 136

10.2.4 Bit Error Rate . . . 138

10.3 Higher frequencies . . . 139

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IV Conclusions and Outlook 143

A Appendix 149

Bibliography 151

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