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The Auger Youngsters Meeting 2024 will be held at the University of Siegen, Germany from 4 to 6 September.
We are inviting Bachelor, Master and PhD students from Dutch and German institutes and universities working for the Pierre Auger Collaboration. Everyone is encouraged to present their work in a 15+5 minute talk.
Please register here until 30 June. You will need an account at the Siegen Indico Server (so you can later upload your abstract and slides as well).
Note: Please enter "Auger Youngsters Meeting" in the comment field when creating your Indico account. This will help us match your registration to the correct event and speed up the approval process.
The call for abstracts is open now, please upload your abstract until 18 August.
There will be a small conference fee of ~€30 which will be paid in cash on the day of your arrival when the certificate of participation will be issued.
In addition to the scientific program, there are also some social activities planned to get to know each other. More information will follow soon.
The meeting will take place at the Emmy-Noether-Campus of the University, Building D (entrance from the back) in room D-308 (on map, exact address below).
The campus can be reached by foot from the central station with a 20' walk (walking route). Alternatively (if you are not so keen on walking uphill), you can take the C114 bus (timetable, consider this a rough guideline). The stop to get off is “Siegen Emmy-Noether-Campus”.
For those arriving by car, there is also ample parking space available directly on campus.
All meals at the ENC mensa have to be pre-ordered by 8:30 of the corresponding day via the pre-ordering webpage. For a tutorial visit the page Lunch at the Mensa.
If you have any questions, feel free to contact us via our meeting email.
We investigate the energy dependent residence time of extragalactic cosmic rays entering our Galaxy using CRPropa and current galactic magnetic models. With our simulation setup, we see the onset of diffusive propagation starting below ankle energies, and a strong suppressing of extragalactic cosmic rays entering our Galaxy below 0.1 EeV. We investigate anisotropy in this framework.
Ultra high energy cosmic rays (UHECRs) coming from many different sources are deflected by the galactic magnetic field (GMF) before arriving at Earth. Every source type emits cosmic rays (CRs) with unique energies and compositions which are not known yet. This contribution focuses on UHECRs originating from positions of active galactic nuclei (AGN). Because of uncertain existing GMF models, a GMF model based on spherical harmonics is established. In order to find coherent deflection directions of UHECRs, here normalizing flows are used. The goal of this work is to find the optimal hyperparameters with which the network can reconstruct the GMF model best. Currently the results show that a big network with a higher maximum degree of spherical harmonic expansion, and therefore more trainable parameters, has a good performance. The next steps are the addition of background CRs to better mimic real data. Together with taking the exposure of the Pierre Auger Observatory into account, it will be seen which cINN works best for the purpose of finding the best reconstruction of the GMF.
Neutral particles, whose arrival directions directly indicate their origin, are valuable for investigating sources of ultra-high-energy cosmic rays (UHECRs). We expect that sources emitting UHECRs also produce neutrons through nuclear interactions and photo-pion production in their vicinity. These free neutrons, which undergo $\beta$-decay, can travel a mean distance of 9.2$\times (E$/EeV) kpc. As a result, neutron fluxes in the EeV range could be detectable on Earth from UHECR sources within our Galaxy. We explore potential neutron fluxes from various Galactic candidate sources, focusing on objects of astrophysical interest, including pulsars, microquasars, and magnetars, as well as the Galactic center, the Crab Nebula, and a subset of gamma-ray emitters identified by LHAASO. Since air showers initiated by protons and neutrons are indistinguishable, we identify a possible neutron flux by detecting an excess of cosmic ray events near the direction of a candidate source. We compare the observed signal against the expected background to identify such excesses. Our analysis considers cosmic ray events with declinations between $-90^{\circ}$ and $+45^{\circ}$ and energies starting from 0.1 EeV.
In this contribution, a simulation based method to estimate the flux of secondary photons produced during the propagation of primary cosmic rays is presented. During their propagation cosmic ray particles interact with photon background fields such as the cosmic microwave background (CMB). Through photo-pion production and the subsequent decay of neutral pions, secondary photons are created. The overall number of photons produced in these interactions varies depending on different parameters, like the propagated distance, the energy of the initial cosmic ray particle and overall cosmic ray composition. These dependencies are evaluated here in order to investigate a maximum or also minimum possible photon flux.
The contributions focus on the implementation of graph neural networks to search for photons using the SD-433 and the Underground Muon Detector.
In this contribution we study the performance of convolutional neural networks discrimination of photon induced events from the hadronic background. We use simulated showers for the SD-1500 detector. We also investigate the influence of different input information and try to understand of which information the network is making use of.
The effects of isotropic, non-birefringent Lorentz violation in the photon sector can be studied with air showers induced by ultra-high-energy cosmic rays.
Using the 1-dimensional air shower simulation program CONEX, bounds on the studied Lorentz violation were set based on the significant reduction of the average atmospheric depth of the shower maximum $\langle X_\text{max}\rangle$ and its shower-to-shower fluctuations $\sigma(X_\text{max})$.
In order to improve the search for the Lorentz violation, these modifications, which achieve Lorentz violation, have been implemented in the 3-dimensional air shower simulation program CORSIKA. This allows the inclusion of observables unavailable to a 1-dimensional simulation such as those connected to the lateral particle distribution.
Preliminary results from the 3-dimensional shower simulations will be presented.
The study of ultra-high-energy cosmic rays allows for the probing of hadronic interactions at energies far exceeding those achievable by human-made accelerators.
Different models can be tested by measuring the electromagnetic or muonic signal in air showers.
In the Scintillator Surface Detectors (SSDs), we observe subluminal pulses that could originate from a late neutron component.
This opens up a new possibility of testing hadronic interaction models through the hadronic component of air showers.
In this talk, we will examine the measurements of subluminal pulses and make a first attempt to compare them to predictions of dedicated neutron simulations.
In this study, we measured the cosmic ray energy spectrum at the Pierre Auger Observatory using a surface detector array composed of Water-Cherenkov detectors, with the energy scale calibrated by a fluorescence detector. This contribution presents the spectrum measured with the 433 m array, which lowers the energy threshold from previous measurements to 63 PeV, enabling the characterization of the flux steepening around 230 PeV, a feature known as the "second knee."
The origin of the UHECRs remains unknown. Yet the properties of the detected spectra can provide us with useful clues. We aim to study the features of the energy spectra in dependence on arrival air showers using artificial neural network mass estimators. Obtaining the elemental group of the primary particle on a single-event basis allows for the separation of the lightest particles which are minimally deflected on the extragalactic magnetic fields. We are searching for small- and large-scale correlation patterns in the sky in comparison with existing object catalogs.
The Fluorescence Detector (FD) of the Pierre Auger Observatory provides energy measurements of primary cosmic rays that are largely independent of specific models. These FD energy measurements are crucial for calibrating the energy reconstruction process of the Surface Detector. Consequently, the accuracy of the FD energy calibration plays a significant role in the systematic uncertainties associated with nearly all scientific results from the Observatory. To achieve high precision in calibration, a laser with a well-defined energy output is fired in front of the FD telescopes. This method has the advantage that the camera’s response to the laser closely simulates its reaction to an actual cosmic ray air shower, something that is difficult to achieve with other calibration methods.
The system, originally developed by Alina Esfahani, was designed with special attention given to the depolarization of the laser beam to ensure a consistent relationship between energy output and directional light emission. Additionally, the use of a telescope mount allows laser shots at various angles. This presentation covers the ongoing development of the mobile laser system and outlines plans for upcoming measurement campaigns.
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.
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.
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.
Primarily designed to detect ultra-high energy (UHE) cosmic rays, the Pierre Auger Observatory also possesses excellent sensitivity to UHE neutrinos. The Surface Detector array is used to search for highly inclined neutrino-induced air showers, which, though not observed yet, have clear characteristic signatures. Follow-up searches of UHE neutrinos in Gravitational Wave (GW) events are of unique scientific interest.
The fourth observational run (O4) by the gravitational wave network LIGO-Virgo-KAGRA of interferometric detectors started in May 2023. With the substantial increase in sensitivity in the O4 run, a higher frequency of GW alerts is expected. This creates a need for the development of software to reply to the General Coordinates Network (GCN) circulars. This talk presents the work being done by the Pierre Auger Collaboration to get an automated response to these GCN notices. Following the alerts, a specific analysis is conducted to calculate a one-day fluence limit for a point source, in the case no neutrino candidate was identified.
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. 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.