When MAGIC met IceCube
Gamma-Ray Astronomy with Neutrino Event Reconstruction Techniques
Jarred Green
Copenhagen, HAMLET-PHYSICS 2025
20 August 2025
Max Planck Institute for Physics
jgreen@mpp.mpg.de
Outline
- The Gamma-Ray Sky
- Current Event Reconstruction
- Graphs
- ML Playground
- Conclusions
Jarred Green - jgreen@mpp.mpg.de
Crab Nebula
NASA (JWST)
Centaurus A
ESO
1. The Gamma-Ray Sky
Gamma-ray Energy [log]
Flux
[log]
[ number / area / time ]
a few gamma rays every second in 1 m²
a few gamma rays every year in 1 m²
MeV
GeV
TeV
HIGH ENERGY
Our galaxy (Fermi)
1. The Gamma-Ray Sky
γ ray
e+
e-
e-
γ ray
Flux
[log]
a few gamma rays every second in 1 m²
a few gamma rays every year in 1 m²
"Imaging Atmospheric Cherenkov Telescopes"
MeV
GeV
TeV
VERY HIGH ENERGY
HIGH ENERGY
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
}
Dimensionality Reduction
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
One Pixel, 30ns
Time [ns]
Counts
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
{
'size': 546.88637,
'xc': -3.78983,
'yc': 7.29427,
'length': 7.76769,
'width': 1.76480,
'delta': -0.56875,
...
}"Hillas Parameters" (1977!)
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
{
'size': 546.88637,
'xc': -3.78983,
'yc': 7.29427,
'length': 7.76769,
'width': 1.76480,
'delta': -0.56875,
...
}
Random Forests
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
0. Raw data
1. Calibration
2. Cleaning
3. Parameterization
4. ML
5. Science
- Particle Type
- Energy
- Arrival Direction
Detections
Skymaps
Spectra
Jarred Green - jgreen@mpp.mpg.de
2. Event Reconstruction
ML
1039 \ \text{pixels} \\ \times 50 \ \text{time slices} \\ \times 2 \ \text{telescopes} \\ = 103900 \ \text{params}
{
'size': 546.88637,
'xc': -3.78983,
'yc': 7.29427,
'length': 7.76769,
'width': 1.76480,
'delta': -0.56875,
...
}- Particle Type
- Energy
- Arrival Direction
Dimensionality
reduction
tl;dr
Jarred Green - jgreen@mpp.mpg.de
3. Graphs for MAGIC?
Proton
Gamma
Muon
103900 \ \text{params per event (raw)}
\sim 300 \frac{\text{triggers}}{\text{s}}
Jarred Green - jgreen@mpp.mpg.de
\text{S/N ratio} \sim \frac{1}{10000}
3. Graphs for MAGIC
an IceCube case study
- A GNN framework for Neutrino observatories
- Easy to adapt to other detectors
DynEdge
DeepIce
Proven models
Jarred Green - jgreen@mpp.mpg.de
3. Graphs for MAGIC
We effectively deal with:
- irregular camera geometry
- sparse data
- non gridlike pixels
- arrays with different camera types
Why Graphs?
Jarred Green - jgreen@mpp.mpg.de
3. Graphs for MAGIC
time
Jarred Green - jgreen@mpp.mpg.de
4. ML Playground
Particle Classification with
Model:
- Binary classification
- DynEdge with 12 NN
- Separate each telescope
- Cross-attention
- Only need 5-10% of training data
- z = time
DynEdge
Jarred Green - jgreen@mpp.mpg.de
Confidence of gamma classification
Gammas
Protons
4. ML Playground
Direction Reconstruction with
Model:
- 2nd place winner of IceCube Kaggle Competition
- Transformer + DynEdge
- Very robust model for neutrino direction reconstruction
- z = telescope number
DeepIce
Radial Error [deg]
Cumulative Fraction
Jarred Green - jgreen@mpp.mpg.de
MC 68% containment <0.08 deg
5. Conclusions
MAGIC Raw Data
- Contains full time evolution of events
-
Saves on data processing
-
Are naturally represented as graphs
Reconstruction with GraphNET
- Apply domain knowledge from IceCube
- 'Built-in' neutrino models work on gamma-ray data
- Robust performance with minimal modifications
Further evidence for the benefits
of cross-domain collaboration
Jarred Green - jgreen@mpp.mpg.de
5. Future Motivation
70+ Telescopes!!
Cherenkov Telescope Array
Jarred Green - jgreen@mpp.mpg.de
Thank you!
Jarred Green - jgreen@mpp.mpg.de
Credit: G. Ceribella
Green HAMLET 2025
By astrojarred
