Astroparticle School 2024

7 Oct 2024, 09:00 → 15 Oct 2024, 21:00 Europe/Berlin

Obertrubach-Bärnfels

Claudio Kopper (FAU Erlangen), Martin Rongen (ECAP), Christian Haack (ECAP, FAU Erlangen), Lisa Schumacher (Erlangen Centre for Astroparticle Physics (ECAP)), Heike Wilhelm (ECAP - LS für Experimentelle Astroteilchenphysik)

This year's edition will be held from 7 to 15 October 2024.

As in previous years, it will be hosted by the "Gasthof Drei Linden" in Obertrubach-Bärnfels, a small village in the countryside near Erlangen.

The School imparts broad knowledge through dedicated lectures and presents scientific highlights in presentations of 90 minutes.

Furthermore, the participants will present and discuss their own work in afternoon talks.

Accomodation at the conference venue is included in participation of the event. You will find more detailed information about the school, accommodation, and the programme on this page as soon as it is ready. 

Registration for this year has closed, but we might be able to provide last-minute spots. Please contact us by email if you are interested!

We also have a poster in PDF format available.

 

Lectures include:

• Philipp Eller (TU Munich): Statistics for experimental physicists
• Ralph Engel (KIT Cosmic): Rays and Air Shower Physics
• Alison Mitchell (FAU Erlangen-Nürnberg): Gamma-Ray Astronomy
• Juan Pablo Yanez (University of Alberta) and Lisa Schumacher (FAU Erlangen-Nürnberg): High-Energy Neutrinos

Invited Talks:

• Felix Kahlhöfer (KIT): Overview of particle dark matter models
• Nataliya Porayko (University of Milano Bicocca): Radio Astronomy
• Martin Rongen (FAU Erlangen-Nürnberg): Hardware knowledge for analysers
• Axel Schwope (AIP Potsdam): eRosita

Evening Lectures:

• Marc Hempel( PT.DESY): Research Funding in Germany & Europe
• Christian Stegmann (DESY): DZA: German Center for Astrophysics
• Doris Mischka (FAU Erlangen-Nürnberg ): Off-topic talk: Pre-History in central Europe

Mini Workshop:

• Anna Nelles (FAU Erlangen-Nürnberg): Proposal writing

as well as participants’ presentations.

Supported by

              

 

BärnfelsSpeaker.pdf

Map Baernfels.jpg

Poster.pdf

Monday 7 October

Arrival

Opening

Lecture: Hardware crash course for analyzers

Convener: Martin Rongen (ECAP)

1 HW talk

Speaker: Martin Rongen (ECAP)

HWtalk_Rongen.pdf

Short break

Participant Presentations

2 Measuring the flavor composition of ultra-high-energy cosmic neutrinos: a two-detector approach

Ultra-high-energy (UHE) cosmic neutrinos, with energies above 100 PeV, could be finally discovered in the near future. Measuring their flavor composition would reveal information about their production and propagation, but new techniques are needed for UHE neutrino telescopes to have the capabilities to do it.
In this talk I will introduce a new way to measure the UHE neutrino flavor composition. Without relying on individual telescopes to have flavor-identification capabilities, this method yields flavor sensitivity from the combined data of two detectors: one sensitive to all flavors$-$the radio array of IceCube-Gen2$-$and one mostly sensitive to $\nu_\tau$$-$GRAND.
I will present the first measurement forecasts of the UHE $\nu_\tau$ content available in the literature. Then, I will show the projected results that can be extracted from this observable. For astrophysics, it constrains the production mechanism of UHE neutrinos; for fundamental physics, it vastly improves the constraints on Lorentz-invariance violation.

Speaker: Federico Testagrossa (DESY)

3 Detecting ultra-high-energy cosmic ray anisotropies via harmonic correlators

One of the most interesting open questions in high-energy astrophysics concerns the origin of ultra-high energy cosmic rays: during their propagation, these charged particles are deflected by extragalactic and Galactic magnetic fields and, as a result, their arrival directions do not point directly to their sources, making their correlation with possible sources non-trivial to determine.
Nonetheless, since ultra-high-energy cosmic ray particles cannot freely travel for cosmologically long distances, their distribution should follow the local distribution of matter in the universe to some extent: dipoles, quadrupoles and higher-order multipoles of their distribution in the sky are expected.
In 2017, significant evidence of a dipole anisotropy in the arrival direction of ultra-high energy cosmic rays with energies above 8 EeV towards a direction far away from the Galactic Center was found by the Collaboration, proving the extragalactic origin of those particles. However, no significant evidence of smaller-scale anisotropies has been found so far.
In our work, we explore the possibility of using harmonic correlators, such as the auto-correlation and the cross-correlation power spectra, to detect such anisotropies. In particular, the harmonic-space cross-correlation method, which consists of detecting the anisotropy in the ultra-high-energy cosmic ray flux through the harmonic-space power spectrum of the cross-correlation between ultra-high-energy cosmic ray counts and the distribution of galaxies, has not been yet employed in this context and could be more sensitive to smaller angular scales and more robust to systematic uncertainties than previously used methods, including the auto-correlation power spectrum.

Speaker: Marta Bianciotto (Università degli Studi di Torino, Physics Department, Turin, Italy)

4 Spectral Bayesian Imaging of Perseus Cluster in X-ray

Measurement of the intracluster medium (ICM) in X-ray is being carried out with ever increasing influx of data from telescopes like Chandra, eROSITA, XRISM, XMM-Newton. The data we obtain from these telescopes is generally incomplete, uncertain (noisy) and convolved with complex instrument responses. Reconstructing multi-domain (spatial, spectral and temperature for example) images of the multiphase ICM from the data we obtain becomes a complex high dimensional, non-linear inverse problem. In this study, we use information field theory (IFT), which provides a robust mathematical framework to build a Bayesian signal inference algorithm that identifies lines on top of continuum emission. Numerical Information Field Theory (NIFTy), a python package is used to implement the signal inference algorithm.
Our developed method is used for reconstructing the multiphase ICM emission from the central regions of the Perseus cluster. The main algorithmic challenge, to split the total emission into continuum and line emission components, is dealt with a phenomenological modelling approach. For solving the degeneracy between the two components, we develop a method which first fits a purely continuum flux model, and then detects, guesses and initialises line emission components therein and automatically adds them to the total flux model. The proposed method identifies and adds 7 phenomenological lines which correspond to emission from Fe-K, Fe-L/Ne, Si, S, Mg and Ar.

Speaker: Mrinal Jetti

Dinner

Welcome evening

Tuesday 8 October

Lecture series: Statistics I/III

Convener: Philipp Eller

202410_ATschool_lschumacher.pdf

5 Statistics lecture

Erlangen_School.pdf

Coffee break

Lecture series: Cosmic ray and air-shower physics I/III

Convener: Ralph Engel

202410_ATschool_lschumacher.pdf

6 Cosmic ray I

Cosmic rays and EAS - lecture 1.pdf

Lunch & Coffee

Participant Presentations

7 Modelling Astrophysical Shocks in Stellar Explosions

Astrophysical shocks play an important role a variety of processes such as supernovae, novae, and gamma-ray bursts. A shock-capturing radiation hydrodynamics scheme based on the Euler equations is developed for simulating the dynamics of gas in astrophysical systems. The scheme's validity is demonstrated by various test cases and comparison to analytically derived solutions. Since recent detections of gamma-rays from novae have implied the involvement of shocks in their thermal and non-thermal emission, they are ideal candidates for testing the model. The model is thus applied to the example of the recent nova RS Oph in 2021, the dynamics of the system is discussed and the simulated optical light curves are compared to observations. It is found that values of ejecta mass and velocity well within the expected parameter space for novae are able to account for the optical emission from the system.

Speaker: Mr Annanay Jaitly

Slides.pdf

8 Shell-merger in 3D Core-Collapse Supernova Progenitors

We present shell events of 4$\pi$-3D non-rotating 12.28 M$_{\odot}$ and 12.98 M$_{\odot}$ supernova progenitors simulated for a period of one-hour before core-collapse. The main interest is to study the interior shell properties (from the kinematic, thermodynamic to the chemical evolution) and their interactions for a period of one-hour before collapse. The high-resolution of these models as well as the 3D geometry are important for capturing the development and evolution of low and high order convective modes. The pre-collapse shell-merger event occurs in the 12.28 M$_{\odot}$ model, while in the 12.98 M$_{\odot}$ model shells remain intact until the progenitor phase elapse. The shells of interest are Ne and Si because our studies show that violent shell-merger is triggered roughly at the Ne/Si interface. Our analysis show that at this interface, the entropy flattens out across the Ne and Si shells just before merger. As a consequence, the 12.28 M$_{\odot}$ progenitor for which shell-merger occurs has higher radial velocity fluctuations and higher turbulent Mach number, and thus higher turbulent kinetic energy compared to the 12.98 M$_{\odot}$ non-shell merger progenitor. Meaning core-collapse supernova progenitors with shell-merger are more violent than the progenitors without shell-merger.

Speaker: Katlego Ramalatswa

Katlego_Ramalatswa_Astroparticle_2024_Abstract.pdf

Katlego_Ramalatswa_Astroparticle_2024_Presentation_updated.pdf

9 propagation and fate of cosmic rays in cosmological ecosystem connected by filaments

Cosmic rays (CRs) can be accelerated in voilent and magnetised astrophysical environment. Those with the highest energyies, up to 10^20 eV are likely associated with star-formation in galaxies and active galactic nuclei activities. Cosmological filaments connect these acceleration sites of CRs, as well as with voids. Due to hadronic pion-producing and photo-pair interactions, and entrainment by magnet fields, some CRs can not be observed directly observed on Earth. To study this elusive population of CRs, we adopt an ecological approach which treats galaxies, clusters/superclusters and voids as key components in the filament ecosystem. Each component are permeated by magnetic fields with a variety of topologies, leading to different types of interfaces between these magnetic fields. We derive the phenomenology for modelling the transport of CRs in this ecosystem, adopting various magnetic field configurations and analyse the consequent fate of CRs. Our analysis shows that CRs are constrained and guided by the magnetic fields and their tranportation between different components are determined by the energies of the CRs and the properties of the interfaces in the filament ecosystem. Notably, Filaments act as ‘highways’, channelling CRs between other components (i.e. galaxies, galaxy clusters and superclusters), and as cosmic ‘fly paper’, capturing CR protons (with energies up to 10^18 eV) from voids. We also show that there is an accumulated population of CR protons of ∼ 10^12 − 10^16 eV, as they do not suffer significant energy losses through photo-pair or pion-production and cannot be cooled efficiently. They therefore form a CR fossil record of the power generation history of the Universe.

Speaker: Qin Han (University College London)

QIn-Han-UCL-astroparticle-school-2024-final.pdf

QIn-Han-UCL-astroparticle-school-2024.pdf

10 Relic Neutrino Helicity Evolution in the Galactic Magnetic Field and Its Implications

We simulate the evolution of the helicity of relic neutrinos as they propagate to Earth
through a realistic model of the Galactic magnetic field, improving upon the rough estimates in
the literature. For magnetic moments consistent with experimental bounds and several orders of
magnitude smaller, we confirm that the helicity of relic neutrinos and anti-neutrinos rotates so
much that the spin projection changes by O(1). However, as we show, the total event rate in an
inverse tritium beta decay (ITBD) experiment changes by less than a few percent, unless the lightest
neutrino has mass of order 0.001 eV or less. Such a tiny reduction in the absolute rate relative to
the standard model value would be very difficult to establish, even if detecting relic neutrinos were
routine. However as we show, the directional anisotropy of the rate in a polarized ITBD detector
is O(10%) as long as the lightest neutrino mass is O(0.01 eV). Thus with percent-level error bars
on the absolute neutrino flux and its directional anisotropy, both the mass and magnetic moment
of the relic neutrinos can in principle be probed if they are within a few orders of magnitude of
current bounds.

Speaker: Mr Kito Liao (Student)

Research_Absract.pdf

Short break

Participant Presentations

11 Drone-Based Calibration of AugerPrime Radio Antennas at the Pierre Auger Observatory

Radio emissions of extensive air showers can be observed at the Pierre Auger Observatory with the AugerPrime radio detector (RD). As part of the AugerPrime upgrade, RD is being installed on $1660$ water-Cherenkov detectors on an area of about $3000 \text{ km}^2$ and consists of dual-polarized Short Aperiodic Loaded Loop Antennas (SALLA). To achieve high measurement precision, RD needs to be well-calibrated, which requires the antenna response pattern to be well-known. We introduce a method to measure the directional response of the SALLA using a well-defined biconical antenna mounted to a drone. The drone-based setup possesses active stabilization and precise pointing with the use of a gimbal. Additionally, the drone's position is tracked using differential GPS with $\mathcal{O}$(cm) precision. This setup allows us to precisely extract the antenna response pattern from any direction in the frequency range of $30-80$ MHz. In a recent in-situ campaign, calibration measurements of the AugerPrime radio detector have been performed. First results of these measurements are presented and compared to simulations.

Speaker: Mr Alex Reuzki (RWTH Aachen University)

AstroSchool2024_Reuzki_v2.pdf

12 Adding interferometric lightning detection to the Pierre Auger Observatory

The Pierre Auger Observatory has detected downward terrestrial gamma-ray flashes (TGFs) with its Surface Detector. A key to understanding this high-energy radiation in thunderstorms is to combine such measurements with measurements of lightning processes in their earliest stages. With eleven modified Auger Engineering Radio Array (AERA) stations we can build an interferometric lightning detection array working in the bandwidth range 30 - 80 MHz inside the Surface Detector array to precisely measure lightning stepped leaders in 3D. These measurements allow us to decipher the cause of TGFs and clarify the reason for the observed high-energy particles in thunderstorms.
We will present the current status of the detection plans including the configuration of the interferometric lightning detection array, together with future steps and the reconstruction characteristics obtained with AERA.

Speaker: Ms Melanie Joan Weitz (Bergische Universität Wuppertal)

AstroparticleSchool2024_Talk_WeitzMelanieJoan_Final.pdf

AstroparticleSchool2024_Talk_WeitzMelanieJoan_PreRehersal.pdf

13 Lightning Broadband Radio Interferometry at the Pierre Auger Observatory

Previous efforts at the Pierre Auger Observatory have shown that lightning related phenomena can be picked up by, and affect, each of its detector systems. Therefore as part of its monitoring, a system has been rolled out to detect thunderstorm conditions, enabling the investigation of thunderstorms and lightning using the Observatory’s hybrid detectors.

As a successful testbed for air shower measurements using radio detectors, the Auger Engineering Radio Array (AERA) is a direct precursor to the Radio Detector package of the AugerPrime upgrade that is currently in deployment. To expand the existing lightning detection infrastructure, we aim to repurpose a subset of AERA stations and strategically redistribute them within the Auger field to establish a precision interferometric lightning physics facility.

In this contribution, I will present the interplay between thunderstorms and air shower physics and the motivation for further developing such lightning facilities. Additionally, the currently foreseen obstacles will be discussed.

Speaker: Eric-Teunis de Boone (Center for Particle Physics Siegen, University of Siegen)

2410_Baernfels-AstroParticle-school_presentation_etdeboone.pdf

abstract.pdf

14 In-Ice Radio Detection of Neutrinos with IceCube-Gen2 and the Implementation of a Deep Learning Based Trigger DAQ System

The IceCube Neutrino Observatory is a cubic kilometer detector built into the Antarctic ice at the geographic south pole. By means of Cherenkov photon detection, the observatory detects charged secondaries that are emitted as a consequence of astrophysical neutrinos interacting with the ice. As a result of IceCube's successes, the next generation of the observatory, IceCube-Gen2, is foreseen and is in development. It will span a volume of ~ 10 cubic kilometers and incorporate a new method of neutrino detection, namely via the Askaryan effect. This is to be achieved via radio wave detection in ice, similar to that of the RNO-G experiment. This talk expands on the working principle of radio detection in IceCube-Gen2, and the planned implementation of a Deep learning-based real-time trigger DAQ system.

Speaker: Mr Adam Rifaie (Bergische Universität Wuppertal)

Astroparticle_school_2024_Rifaie.pdf

Dinner

Evening talks: Research Funding in Germany and Europe

Convener: Marc Hempel

Wednesday 9 October

Lecture series: Statistics II/III

Convener: Philipp Eller

202410_ATschool_lschumacher.pdf

Coffee break

Lecture series: Cosmic ray and air-shower physics II/III

Convener: Ralph Engel

202410_ATschool_lschumacher.pdf

15 Air showers II

Cosmic rays and EAS - lecture 2.pdf

Lunch & Coffee

Lecture series: Gamma rays I/III

Convener: Alison Mitchell

202410_ATschool_lschumacher.pdf

16 Gamma rays I/III

ATschule_GammaRayAstro_2024_part1.pdf

Short break

Workshop: Exercises on Cosmic ray and air shower physics

Convener: Ralph Engel

Funding_Proposal_Workshop.pdf

Dinner

Thursday 10 October

Workshop: Proposal writing I/III

Convener: Anna Nelles

Funding_Proposal_Workshop.pdf

Coffee break

Workshop: Proposal writing II/III

Convener: Anna Nelles

Funding_Proposal_Workshop.pdf

Lunch & Coffee

Lecture series: Statistics III/III

Convener: Philipp Eller

202410_ATschool_lschumacher.pdf

Short break

Lecture series: Cosmic ray and air-shower physics III/III

Convener: Ralph Engel

202410_ATschool_lschumacher.pdf

17 Cosmic ray and air-shower physics III/III

Cosmic rays and EAS - lecture 3.pdf

Dinner

Evening talks: Christian Stegmann

Convener: Christian Stegmann

Friday 11 October

Free

Saturday 12 October

Lecture series: High-Energy Neutrinos I/III

Convener: Juan Pablo Yanez

202410_ATschool_lschumacher.pdf

18 High Energy Neutrinos

2024_1_Introduction_nu_physics_yanez.pdf

Coffee break

Lecture series: Gamma rays II/III

Convener: Alison Mitchell

202410_ATschool_lschumacher.pdf

19 Gamma rays II/III

ATschule_GammaRayAstro_2024_part2-3.pdf

Lunch & Coffee

Participant Presentations

20 Development and Enhancement of the Northern-track Event Selection in IceCube Neutrino Observatory

The northern track event selection utilizes the event topology in the IceCube to select track-like up-going events, which are produced by high-energy muons induced by muon-neutrinos which penetrated the Earth and reach the detector from the Northern sky. The Efficiency of the selection is limited by the quality of event reconstructions, which might misidentify down-going muon tracks as up-going. To improve the efficiency of this selection method, we investigate the application of deep neuron network, which enables a selection without the prerequisite of event-reconstruction. The initial tests demonstrated an increasing efficiency in the event selection.

Speaker: Shuyang Deng (RWTH Aachen University)

21 Investigating the blazar-neutrino connection with public IceCube data

The IceCube collaboration has recently found evidence for connecting the blazar TXS 0506+056 to high-energy neutrino events. Several other studies have independently investigated the hypothesis of blazars and specific subclasses thereof as neutrino emitters with mixed results, including constraints on the contribution of these sources to the observed astrophysical neutrino flux. As such, open questions remain regarding the proposed neutrino production mechanisms, connection to multi-messenger signals, and population properties. Motivated by these challenges, we present an open-source statistical analysis framework to investigate possible sources with publicly available IceCube data. Complementary to existing methods we employ a Bayesian hierarchical model, allowing for more complex modelling and a unique perspective on source discovery. We showcase results of fits to simulated neutrino data of generic source populations, highlighting the benefit of possible inputs from multi-messenger studies as priors. In light of recent developments in multi-messenger modelling of source candidates, we go beyond simple power-law models and analyse 10 years of public IceCube data for possible point source contributions.

Speaker: Julian Kuhlmann (MPP)

22 Spectral Energy Distribution Study of Blazar PKS 2155-304

Blazars are a unique subclass of active galactic nuclei (AGN) characterised by their relativistic jets oriented towards Earth. This study focuses on the blazar PKS 2155-304, a high synchrotron-peaked BL Lac object located at a redshift of z = 0.116. We utilised multiwavelength observations, ranging from optical to gamma-ray, primarily from the Fermi Large Area Telescope (LAT) and the Swift Observatory. The objective was to study the spectral energy distributions (SEDs) at various flux states, specifically selecting periods of varying gamma-ray and/or X-ray flux, including low, medium, and flaring states. The SEDs were modelled using a one-zone leptonic framework with a broken power-law electron distribution within the JetSeT framework, an open-source tool for simulating radiative processes in relativistic jets. This tool was employed to fit the numerical model to the observed data. Upon completion of the epoch modelling, we obtained distributions for several important parameters, including the jet magnetic field, particle injection, and maximum energy of the relativistic particles. This analysis aims to uncover the underlying physical processes driving the observed variability in PKS 2155-304, contributing to our understanding of blazar behaviour and their emission mechanisms.

Speaker: Mr Navaneeth P K (Janusz Gil Institute of Astronomy, University of Zielona Góra)

23 Investigating the astrosphere of $\lambda$ Cephei: effects of relative velocity and ISM magnetic field strength

Astrospheres are bullet-shaped structures resulting from the relative motion through the interstellar medium and comprise of three distinct features: a termination shock, astropause, and a bow shock. This work investigates the astrosphere of λ Cephei. λ Cephei is a bright runaway star. Previous 3D magnetohydrodynamic (MHD) simulations by Baalmann et al. (2021) showed the position of the termination shock (TS), astropause (AP), and bow shock (BS) of λ Cephei. A comparison between the simulations by Baalmann et al. (2021) is done using the Pen et al. (2003) model work shows similar results. Due to the Pen et al. (2003) model excluding the radiative cooling process and also being solved on a Cartesian grid, the bow shock width is somewhat different compared to the Baalmann et al. (2021). Additionally, the study shows how variations in relative velocity and interstellar medium (ISM) magnetic field strength affect λ Cephei’s astrosphere. Decreasing relative velocity from 80 km/s to 40 km/s leads to an enlarged astrosphere, particularly evident in bow shock regions. Investigation of ISM magnetic field effects shows that increasing field strength alters the astrosphere’s structure, resulting in asymmetry under high ISM magnetic field conditions.

Speaker: Mr Douglas Velile Moyeni (North-West University)

Douglas_Moyeni_presentation.pptx

Short break

Lecture series: High-Energy Neutrinos II/III

Convener: Juan Pablo Yanez

202410_ATschool_lschumacher.pdf

24 High Energy Neutrinos

Speaker: Juan Pablo Yanez

2024_2_Physics_HE_neutrinos_yanez.pdf

Dinner

Sunday 13 October

Lecture series: Gamma rays III/III

Convener: Alison Mitchell

202410_ATschool_lschumacher.pdf

Coffee break

Workshop: High-Energy Neutrinos

Convener: Juan Pablo Yanez

Funding_Proposal_Workshop.pdf

25 Workshop: High-Energy Neutrinos

2024_3_HE_exercise_yanez.pdf

Lunch & Coffee

Participant Presentations

26 Directional Search for Ultra-High-Energy Photons Using the Surface Detector of the Pierre Auger Observatory

In addition to its capabilities for precise measurement of ultra-high-energy (UHE, $E > 10^{17}\:\mathrm{eV}$) cosmic rays with the observation of extensive air showers, the Pierre Auger Observatory also encompasses the potential of effectively detecting UHE photons. These are closely connected to the origin or propagation of hadronic cosmic rays. Moreover, such UHE photons are also theorized to be emitted during transient events, offering an additional channel in the context of multimessenger astronomy. Several efforts by the Pierre Auger Collaboration have utilized the Observatory's various detector systems to search for UHE photons. Although no UHE photons have been unambiguously identified so far, stringent upper limits have been established on both the diffuse photon flux and the flux from specific arrival directions, including near source candidates. During my PhD studies, I aim to design a new direction-dependent UHE photon search, based on air-shower universality. This principle states that the development of every air shower can be characterized by only a handful of parameters, regardless of its apparent complexity, due to the averaging of the innumerable individual particle-level processes. With this approach, data of the Surface Detector (SD) can be used to reconstruct central quantities like primary energy and atmospheric depth of the shower maximum, which are essential for primary particle classification, with a significantly improved precision. Moreover, with sole dependence on the SD, one can take advantage of its extensive duty cycle for a UHE photon search. The ongoing work and forthcoming steps involved in constructing such an analysis will be discussed in this contribution.

Speaker: Tim Fehler (Center for Particle Physics Siegen, University of Siegen, Germany)

tfehler_directional_photon_search.pdf

27 On the winding angle of the Heliospheric Magnetic Field at Earth

The winding angle of the heliospheric magnetic field (HMF) is investigated by analyzing approximately 60 years of in situ spacecraft observations of the solar wind and the HMF at Earth. Yearly averages of the winding angle of the Low-Resolution OMNI (LRO) dataset, hosted on the NASA OMNIWeb website, are calculated taking into consideration the sector structure of the magnetic field measurements. The Lomb-Scargle periodogram is employed as a statistical method to determine whether the yearly averaged results show a dependence on the 11-year solar cycle. The results of previous analyses of the winding angle defined by the Parker model of the HMF at Earth are reproduced within reasonable agreement, after which the analysis is extended to the full LRO dataset for the case of a two-dimensional (2D) winding angle, and a three-dimensional (3D) model of the winding angle. In general, the 2D winding angle was found to be overwound from the average value predicted by the Parker model and to a similar degree as reported by previous studies, while also showing a statistically significant dependence on the solar cycle. The 3D winding angle was found to be underwound from the average value predicted by the Parker model, with no statistically significant dependence on the solar cycle. The underwound result of the 3D HMF can, in principle, be explained by a simple model of the HMF that accounts for the influence of turbulent fluctuations transverse to the Parker HMF that yields similar deviations from the winding angles predicted by the Parker HMF as those of the 3D winding angle model.

Speaker: Mr Frans van der Merwe (Centre for Space Research, North-West University)

Frans_vd_Merwe_Erlangen_winding_angle_slides.pdf

28 Leveraging Transformer Models for Gamma/Hadron Separation in SWGO

The Southern Wide-field Gamma-ray Observatory (SWGO) is a proposed next-generation water-Cherenkov gamma-ray observatory in the Southern Hemisphere, thus being complementary to other water-Cherenkov detectors like HAWC (Mexico) and LHAASO (China), which are both located in the Northern Hemisphere.
One of the primary challenges of the water-Cherenkov technique, is the effective discrimination of gamma-ray signals from the prevalent hadronic background.
Several techniques have been developed in the past, primarily relying on human-designed discrimination variables.
In other scientific areas, recent advancements in deep learning have revealed that employing an end-to-end learning approach, which involves using raw data without the inclusion of handcrafted designed features, frequently improves the results. One specific deep learning architecture is the Transformer.
The self-attention mechanism of the Transformer, initially developed for tasks in natural language processing, offers a promising approach to efficiently handle the complex and variable-sized data in a ground-based observatory with high multiplicities.
In this work, this approach will be investigated specifically for Gamma-Hadron separation in SWGO. The performance will be evaluated and additionally the inner workings, meaning the individual building blocks, of the Transformer will be explained.

Speaker: Mr Markus Pirke (ECAP, FAU)

29 Astrophysical X-ray Polarimetry with IXPE

The Imaging X-ray Polarimetry Explorer (IXPE) is the state-of-the-art of astrophysical X-ray polarimetry. Launched on 9 December 2021, IXPE is the product of a collaboration between NASA and ASI. It can measure the linear polarization of different astrophysical sources over the photon energy range 2-8 keV. Polarization can provide a new observable to get information about the geometry both of the emitting matter and of the magnetic and gravitational fields of the source. Some examples are the Active Galactic Nuclei and the X-ray binaries. In the first case, polarization allows us to study the magnetic field in the jet of Blazars, investigating the possible time variability of the polarization angle. In the second case it can provide information about the emission region geometry.
The heart of IXPE Detector Unit is the Gas Pixel Detector, that can be characterized and studied using the X-ray Calibration Facility at the Physics Department of the University of Turin. XCF is also suitable for calibration and test of energy-, position- and polarization- sensitive detectors.

Speaker: Stefano Tugliani (Università degli studi di Torino, Dipartimento di Fisica, Italia, Istituto Nazionale di Fisica Nucleare)

Short break

Workshop: Proposal writing III/III

Convener: Anna Nelles

Funding_Proposal_Workshop.pdf

Dinner

Evening talks: Pre-history north of the Alps

Convener: Doris Mischka

Monday 14 October

Lecture series: High-Energy Neutrinos III/III

Convener: Lisa Schumacher

202410_ATschool_lschumacher.pdf

30 High-Energy Neutrinos III/III

Coffee break

Participant Presentations

31 Reconstruction of Neutrino Properties from Radio Detector Data using Deep Learning

The last decade has seen tremendous advances in astroparticle physics and neutrino detection. The IceCube neutrino observatory has successfully measured the cosmic neutrino flux and identified several new sources. The next generation of neutrino telescopes aim at even more energetic neutrinos in the EeV range. In-ice radio detection is a promising approach to tap into the rapidly decreasing neutrino flux at these ultra-high energies. To get the most out of these new detectors I have developed a deep learning-based reconstruction algorithm using normalizing-flows. The reconstruction can predict the neutrino energy, direction, and flavor from simulated neutrino signals. As normalizing-flows can predict the full posterior pdf for every single event, the reconstruction does not only give the best-fit values for the predicted quantities but also their uncertainties. These uncertainties can be non-Gaussian for both the neutrino direction and energy.

Speaker: Nils Heyer

Erlangen_school.pdf

32 Reconstructing the Longitudinal Profile of Air Showers using an IFT-based Imaging Algorithm for Radio Data

Radio detection of cosmic rays has not only been shown to be complementary to classical detection methods but also advantageous as the full shower profile can be extracted, which in turn can provide more physical knowledge about the air shower than already known today. However, the full reconstruction of the profile requires an efficient 4-D imaging algorithm due to the strong spatial and temporal dependence on the shower evolution and emission. Classical radio interferometric algorithms cannot fully extract the shower profile due to the non-repeating and near-field nature of the radio pulses, even when utilising dense detector layouts such as the LOw Frequency ARray (LOFAR) or the upcoming Square Kilometre Array (SKA). However, with the recent development of Information Field Theory (IFT), a Bayesian framework applied on field-like structures, we can not only perform 4-D interferometric imaging in a timely manner but also incorporate the well-known physical characteristics of the emission for reconstruction.

In this work, we develop an IFT-based imaging algorithm for extensive air showers that utilises prior physical information of the emission process to reconstruct the longitudinal profile of the air shower. We utilise the template synthesis approach (Desmet et al. 2024, Astroparticle Physics 157, 102923) to construct a fast-forward model that generates electric field traces at each radio antenna from a shower profile following the Gaisser-Hillas function. The longitudinal profile is reconstructed by using IFT to infer the model parameters that describe the shower profile. We apply our approach to reconstruct the profile from realistic simulated events generated from CoREAS simulations based on the CORSIKA simulation framework with the LOFAR detector layout. We analyse the reconstruction efficiency of our model to standard profile parameters such as $X_\mathrm{max}$ to highlight the performance of our model. We plan to optimise our algorithm to efficiently reconstruct the profile on the planned SKA detector layout.

Speaker: Keito Watanabe (Institute of Astroparticle Physics, Karlsruhe Institute of Technology)

AstroparticleSchool2024.key

AstroparticleSchool2024.pdf

33 4D air shower interferometry with SKA

Extensive air showers (EAS), created from interactions of highly energetic cosmic particles with the atmosphere, produce radio emission via the geomagnetic and Askaryan effect. These radio signals provide valuable information about the properties of the primary particle that started the air shower. Dense radio detector arrays such as LOFAR and the future SKA-low allow high-precision reconstruction of shower parameters such as the depth of the shower maximum. However, current reconstruction methods rely heavily on simulations and hadronic interaction models. Thus, a model-agnostic reconstruction approach is of great interest. Furthermore, current state-of-the-art reconstruction algorithms are able to reconstruct air showers in at most three dimensions. Additionally, the time evolution of the air shower may also provide crucial information. The goal of our project is therefore to develop a time-resolved 3D imaging method in order to reconstruct air showers in 4D. In order to tackle this endeavour, a vast abundance of high-precision data is required, which the future SKA-low array with its roughly 60000 antennas is expected to deliver. The reconstruction algorithm itself will employ Information Field Theory (IFT), a novel reconstruction framework based on Bayesian inference.

Speaker: Mr Philipp Laub (ECAP, FAU Erlangen-Nürnberg)

AstroparticleSchool2024PhilippLaub.pdf

34 FlashCam: Camera characterisation and the search for GRB's

Very high energy gamma-rays induce an air-shower in our atmosphere. These particles, traveling faster than light in the medium, emit Cherenkov light. Using Cherenkov telescopes, this radiation can be measured and properties such as energy or direction from the primary gamma-ray can be deducted. A proposed camera for such a telescope is FlashCam. In this talk, FlashCam and the tests we want to do will be shortly introduced, as well as a proposed search for GRB's using CT5 (HESS) in which a prototype of FlashCam is embedded.

Speaker: Anne Timmermans

Erlangen_summer_school_2.pptx

Lunch & Coffee

Lecture: Overview of dark matter theories

Convener: Felix Kahlhöfer

35 Overview of Dark Matter Theories

Short break

Lecture: Radio astronomy

Convener: Nataliya Porayko

Dinner

Feedback evening

Tuesday 15 October

Lecture: eROSITA

Convener: Axel Schwope

Coffee break

Participant Presentations

Lunch & Coffee

Departure