Erlangen Centre for Astroparticle Physics

ECAP Seminar: Denys Malyshev
2023-11-16 13:00 - 14:00 (Europe/Berlin) | Zoom
Search for primordial black hole dark matter with X-ray satellites and prospects for future missions
Ultralight primordial black holes (PBHs) in the mass range of 1016 – 1022 g are allowed by current observations to constitute a significant fraction, if not all, of the dark matter in the Universe. In this work, we present limits on ultralight, nonrotating PBHs which arise from the nondetection of the Hawking radiation signals from such objects in the keV – MeV energy band. Namely, we consider observations from the current-generation missions XMM-Newton and INTEGRAL/SPI and discuss the observational perspectives of the future missions Athena, eXTP, and THESEUS for PBH searches. Based on 3.4 Msec total exposure time of XMM-Newton observations of Draco dwarf spheroidal galaxy, we conclude that PBH with masses ≲ 1016 g cannot make all dark matter at 95% confidence level. Our ON-OFF-type analysis of >100 Msec of INTEGRAL/SPI data on the Milky Way halo puts significantly stronger constraints. Only ≲ 10 % of dark matter can be presented by PBHs with masses ≲ 3 × 1016 g while the majority of dark matter cannot be represented by PBHs lighter than 7 × 1016 g at 95% confidence level. We discuss the strong impact of systematic uncertainty related to the variations of instrumental and astrophysical INTEGRAL/SPI background on the derived results and estimate its level. We also show that future large field-of-view missions such as THESEUS /X-GIS will be able to improve the constraints by a factor of 10 – 100 depending on the level of control of the systematics of these instruments.
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ECAP Seminar: Esra Bulbul
2023-11-23 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
First Results from the eROSITA All-Sky Survey: An Open Window to Precision Cosmology
Clusters of galaxies trace the highest peaks in the cosmic density field and offer an independent and powerful probe of the growth of structure and cosmology. Locating clusters through well-planned multi-wavelength surveys is crucial for testing gravitational theory and cosmology. Successfully launched in July 2019, eROSITA, the German-built telescope array operating between 0.2-8 keV on board the Russian-German Spectrum-RG (SRG) mission, delivers the largest catalogs of clusters of galaxies from its All-Sky Surveys. The first eROSITA all-sky survey, yielding more than 10,000 confirmed clusters of galaxies, constrains the cosmological parameters from cluster mass function and cluster-clustering when combined with the overlapping DES, HSC, and KIDS weak lensing surveys. I will summarise the first cluster science, large scale structure, and cosmology results from eROSITA’s first All-Sky Survey and provide an outlook for future deeper surveys.

ECAP Seminar: Heinrich Päs
2023-11-30 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Neutrinos, Quantum Gravity and the Big Questions – New Ideas for New Data
Neutrinos are perfect probes of quantum gravity. The particles’ weak interactions allow to preserve quantum coherence for very long timespans, and neutrino telescopes have started to collect data of neutrinos at extreme energies that have travelled extra-galactic distances. Moreover, the expected breaking of global symmetries such as lepton number in quantum gravity may induce neutrino Majorana masses. The talk discusses how new ideas about quantum gravity could imply exotic properties or phenomena in the neutrino sector, such as altered dispersion relations, quantum-gravitational decoherence, or UV/IR mixing that may be linked to the big open questions of particle physics and cosmology like the nature of dark matter or the electroweak hierarchy problem.

ECAP Seminar: Carlos Arguelles
2023-12-05 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
News from the IceCube Neutrino Observatory and Related Phenomenology
It has been ten years since IceCube, a neutrino detector embedded in the Antarctic glacier, has detected high-energy astrophysical neutrinos. In this informal talk, I will report on the latest results from IceCube and point out opportunities for searches for new physics. In particular, I will describe the recent observation of NGC 1068 and the detection of our galaxy in neutrinos. I will present recent proposals to search for new physics with these sources. Finally, I will provide an update on searches for light sterile neutrinos with high-energy atmospheric neutrinos.

ECAP Seminar: Cosmio Nigro
2023-12-14 13:00 - 14:00 | Zoom
Community, Standardisation, and Reproducibility: does open-source software help advancing high-energy astrophysics?
In this talk, I will discuss how high-energy astrophysics, and gamma-ray astronomy in particular, are being transformed by several community-based efforts to develop standardised data and open-source software both for statistical analysis and physical modelling.
In the first part of the talk, I will focus my attention on the Data Formats for Gamma-ray Astronomy (GADF) initiative, which proposes a standardised format for gamma-ray astronomical data. This format has been successfully adopted by the current generation of gamma-ray instruments; making, for the first time, their data analysable with open-source science tools such as Gammapy. I will present some examples of technical results achieved by adopting these standardised data and tools, and argue for their potential in facilitating future multi-instruments analyses.
In the second part of the talk, I will discuss the endeavor to develop open-source tools for modelling the emission of astrophysical sources, which are effectively opening the possibility to perform physical interpretation to the community, a task previously performed by a few groups with proprietary software.
I will conclude by discussing the potential impact this new philosophy of open-source development can have on our increasingly digital science.

ECAP Seminar: Lucy Oswald
2024-01-11 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Pulsar polarization: explanations and applications
Pulsar radio emission, and particularly its polarization, is a key probe of neutron star physics. This, in turn, means that we can use it to advance searches for gravitational waves and to map out the invisible structures of the galaxy. However, new and improved observations show that the conventional model of pulsar polarization behaviour does not explain everything we see.
In this talk, I will describe how impressive new broad-band observations reveal key relationships between polarization features in pulsar radio emission, and how this is related to neutron star physics. I will explain how the “partial-coherence model” accounts for these observational results, with examples of individual and collective pulsar behaviours. Finally, I will look to the future as we move towards the arrival of the SKA telescopes. I will discuss how large-scale pulsar surveys will advance our ability to use pulsars as accurate tools to probe high energy physics and measure gravitational waves.

ECAP Seminar: Florian Marquardt
2024-01-17 15:00 - 16:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Machine Learning: from Quantum Technologies to Neuromorphic Devices

ECAP Seminar: Mirco Huennefeld
2024-01-18 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Evidence for high-energy neutrinos from the Galactic plane
The Milky Way, our home galaxy, is visible to the eye as a faint band of light in the night sky. This emission from the Galactic plane extends over a wide range of the electromagnetic spectrum, from radio to gamma rays. A fraction of the gamma-ray emission is theorized to arise from cosmic rays interacting with the interstellar medium through the decay of neutral pions. The presence of this diffuse gamma-ray emission implies the existence of Galactic neutrinos produced in associated processes. Recently, strong evidence for the emission of high-energy neutrinos in the Galactic plane was reported by IceCube, a neutrino detector instrumenting a cubic kilometer of glacial ice at the South Pole. This observation, enabled by novel tools based on deep learning, thus opens a new window to study the high-energy universe, allowing us to further probe the properties of our own Galaxy and the origin of cosmic rays.
In this contribution, I will highlight the recent observation by IceCube and the technical advances that made it possible, in addition to providing some future prospects.

ECAP Seminar: Gabrijela Zaharijas
2024-01-25 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Looking for dark matter in gamma rays – can machine learning help?
We live in a ‘golden’ time for studies of high-energy (HE) astrophysics as a series of satellite and ground based telescopes currently provide high-precision data, critical to answer the century old questions on the origin of cosmic rays and physics at the heart of most energetic accelerators in the Universe. This progress has also important implications for fundamental physics, providing a test on the nature of dark matter (DM) particles, one of the long-lasting problems in contemporary physics.
Analysis of these rich data sets in a comprehensive way, inducive to identification of telltale signs of new astro- and fundamental physics, however, presents a significant challenge. As one of the most promising avenues, the machine learning (ML) techniques have been developed and embraced in a number of fields that share availability and related challenges of large data sets. In HE astrophysics however, in particular in the subfield related to cosmic rays and their interactions in the Galaxy, as well as in indirect DM searches, these techniques were rarely taken advantage of, due to particular data analysis challenges (in particular, limited training samples).
In this talk I will discuss the application of ML techniques to gamma-ray Fermi-LAT data on two concrete scientific challenges: determination of the nature of the Galactic center excess and detection and classification of (faint) gamma-ray sources, both of high relevance in both, astro- and fundamental physics. Extension and challenges of such applications to next generation telescopes (e.g. the CTA) will also be outlined.

ECAP Seminar: Malte Göttsche
2024-02-01 13:30 - 14:30 | Zoom
Civilian and military use of nuclear technology
To exploit nuclear technology for civilian purposes, in particular energy production, a variety of facilities – a nuclear fuel cycle – is necessary, comprising reactors and uranium enrichment plants among others. These same facilities, however, produce the fissile materials that are required to build nuclear weapons: plutonium and highly enriched uranium. Thus, nuclear fuel cycle facilities are inherently dual-use. The civilian or military nature of a nuclear program can only be assessed by verifying nuclear programs. This is the task of the International Atomic Energy Agency, which conducts on-site inspections. The development of verification technologies is a topic of on-going research. Besides an introduction into the nuclear fuel cycle and its uses, this talk will address one particular verification approach under development which intersects with particle physics: antineutrino monitoring to verify reactors operations.

ECAP Seminar: Ellis Owen
2024-03-11 14:00 - 15:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Exploring the signatures of cosmic ray feedback effects in galaxy ecosystems
Cosmic rays go hand-in-hand with violent and energetic astrophysical conditions. They are an active agent within galactic and circumgalactic ecosystems, where they can deposit energy and momentum, modify the circulation of baryons, and even have the potential to regulate star-formation on local and galactic scales. Their influence in galaxies can be probed using observable signatures across the electromagnetic spectrum, with high energy radiation being particularly important to determine their energy budget, feedback power and hydrodynamic effects. In this talk, I will discuss some of the astrophysical impacts hadronic and leptonic cosmic rays can have in and around galaxies, how their influence can be probed using signatures in X-rays and gamma-rays, and the opportunities soon to open-up that will allow us to map-out the multi-scale effects of cosmic rays in galaxies near and far.

ECAP Seminar: Atreya Acharyya
2024-04-25 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Recent Highlights from the VERITAS AGN Program
VERITAS is one of the world’s most sensitive detectors of astrophysical very high energy (VHE; E > 100 GeV) gamma rays. This observatory began full-scale operations in 2007, and more than 8,000 hours of its good-weather observations have been targeted on active galactic nuclei (AGN). Approximately ~250 AGN were observed with VERITAS, many of these as part of a comprehensive program to discover new VHE AGN. VERITAS spectral and variability measurements, and accompanying broadband observations, are key probes of the underlying jet-powered processes in AGN. Recent scientific highlights from the VERITAS AGN discovery program will be presented.

Physics Department Colloquium: Yuri Y. Kovalev
2024-05-08 12:00 - 13:00 | Hörsaalgebäude Physikum, Staudtstr. 5, Erlangen, 91058, Germany
Multi-messenger Lighthouses of the Universe: The many extremes of Active Galactic Nuclei
Abstract: Active galactic nuclei (AGN) make the most significant contribution to the overall energy balance in the Universe in all electromagnetic bands not dominated by the cosmic microwave background. A good understanding of physical processes and phenomena driving this contribution is paramount for addressing the key challenges in astrophysics and cosmology, including accretion onto black holes, electromagnetic fields, and shock waves in relativistic plasma.
These factors can be best studied with comprehensive programs combining dedicated multi-band and multi-messenger measurements with ultra-high angular resolution imaging in the radio regime enabled by the technique of very long baseline interferometry (VLBI).
In this talk I will discuss results from several such studies which we have conducted recently, targeting different aspects of AGN physics.
The discovery of extreme brightness in blazars, made with space VLBI observations, has set new limits on the very high rates of energy release in plasma.
The mounting observational indications for extragalactic neutrino production in blazar-type AGN now begin to deliver key understanding about the physics of proton
acceleration in blazars, either nearby central supermassive black holes or in plasma shocks embedded in the relativistic jets. Deriving from these results,
the continued improvements of sensitivity and fidelity of VLBI observations, and the expected advent of a true era of multi-messenger astronomy,
I will conclude by outlining several fundamental directions for studying the physical nature of AGN which will become feasible in the coming years.

ECAP Seminar: Katharina Breininger
2024-05-16 12:30 - 13:30 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Improving our understanding of machine learning robustness – in microscopy and beyond
A central goal when applying machine learning in the biomedical research and medical imaging is to answer relevant interdisciplinary questions robustly and reliably across various setups and ideally modalities; however, this is challenged by different imaging systems, differences between a laboratory setting and the real world as well as a multitude of other factors. This talk will explore the challenge of domain generalization in digital pathology, microscopy, and beyond. Specifically, we will discuss the Mitosis Domain Generalization (MIDOG) Challenge that took place at the International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) in 2021 and 2022 as one example how we can work toward more robust machine learning approaches. Furthermore, we will explore how we can potentially transfer the corresponding machine learning insights from imaging very tiny structures close-by to structures far, far away.

ECAP Seminar: Lucy Fortson
2024-05-23 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Muon Hunting with the Crowd: Combining Humans and Machines to Solve Big Data Problems
In this presentation, I will describe the Zooniverse.org citizen science platform as a tool to gather labels from over 2.7 million dedicated volunteers worldwide who are motivated to participate in scientific research. Hundreds of research teams now turn to Zooniverse for crowdsourcing tasks such as image classification and annotation, which provide the large labeled data sets needed for optimal training of machine algorithms. I will demonstrate the ease with which a project can be developed with the Zooniverse Project Builder tools and describe the infrastructure available for integrating machine learning with Zooniverse including sophisticated active learning techniques. I will provide examples from across several projects in astronomy and astroparticle physics, with a focus on the Muon Hunter project used to gather millions of labels to train a machine algorithm for an imaging air Cherenkov telescope calibration pipeline. I will finish with a look at how we are working to combine human and machine intelligence to probe large data sets, including those from Cherenkov telescopes, for scientifically interesting anomalous events.

ECAP Seminar: Ekaterina Makarenko
2024-06-06 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Thermal X-ray emission from supernova remnants in 3D (M)HD simulations
Every supernova (SN) injects around 10^51 ergs into the interstellar medium (ISM), shaping the ISM’s chemical, thermal, and dynamic evolution. Around 70% of the injected energy is subsequently lost by radiative cooling. However, the fate of the emitted cooling photons is usually neglected in simulations as the surrounding ISM is treated as optically thin. This makes high-resolution 3D simulations quite unphysical. The growing ability of X-ray spectroscopy allows observations of SN remnants (SNRs) to define pixel-by-pixel based parameters (such as plasma temperature, ionisation state, and abundance of different elements). We therefore urgently need more realistic simulations of SNRs.
In this talk, I will present state-of-the-art (magneto-)hydrodynamic simulations of SN explosions using the FLASH code, which include radiative cooling from the SN event. Radiative cooling is calculated on-the-fly and is fully consistent with the code’s radiative transfer, physics, and chemistry modules. Therefore, we created synthetic maps of the simulated SNR in several X-ray energy bands (e.g. Chandra energy bands in the range 0.1-10 keV) as well as for selected lines. These synthetic X-ray maps provide unique information about the physics of shock/cloud interactions, the general morphology of the remnants, as well as a better comparison (and prediction) for SNR observations.

ECAP Seminar: Philipp Frank
2024-06-07 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Signal reconstruction for fields using probabilistic forward modeling
Many inference tasks in observational astronomy take the form of reconstruction problems where the underlying quantities of interest are fields (functions of space, time and/or frequency) that have to be recovered from noisy and incomplete observational data. These problems are in general ill-posed, as many different field configurations may be consistent with the observed data, and therefore their solutions are inherently of probabilistic nature. Forward modeling, that is combining an accurate description of the observing instrument’s response to a field configuration occurring in nature with the rules of probability & information theory provides a robust and scalable framework to solve such problems. I will give a brief overview on the involved theoretical concepts and numerical techniques employed to do so in practice, and show a selection of applications to real-world astrophysical data-analysis problems ranging from results in the radio- up to the gamma-ray-regime.

ECAP Seminar: Martin Mayer
2024-06-27 13:00 - 14:00 | ECAP, room 307, Erwin-Rommel-Str 1, Erlangen, 91058, Germany
Rotation-powered pulsars and their nebulae – the eROSITA view
SRG/eROSITA is a soft X-ray (0.2 – 10 keV) telescope which has carried out the deepest X-ray all-sky survey to date. In this talk, I will present how the eROSITA data can be used to study rotation-powered pulsars and their pulsar wind nebulae, exemplified by two projects:
Firstly, the surveying power of eROSITA has allowed us to carry out a systematic search for new high-energy pulsars through a cross-match with gamma-ray sources detected by Fermi-LAT. The resulting candidate list is expected to yield detections of several tens of new pulsars, and can ideally be followed up by looking for signatures of pulsed radio emission, or orbitally modulated optical emission from a binary companion, at the candidate positions.
Secondly, eROSITA’s sensitivity has enabled us to study the X-ray synchrotron emission of Vela X, the wind nebula of the Vela pulsar, at unprecedented detail. This study led to the discovery of an extremely extended nonthermally emitting component, reaching radii up to 15 pc from the Vela pulsar. Its large size can possibly be explained through particle transport by diffusion, akin to the halos discovered around older pulsars in gamma-rays.

ECAP Seminar: Christopher Burger-Scheidlin
2024-09-12 13:00 - 14:00 | ECAP, room 307, Erwin-Rommel-Str 1, Erlangen, 91058, Germany
Intricacies of searching for supernova remnants at (very) high energies off the Galactic plane
Supernova remnants (SNRs) have traditionally been considered prime candidates for the acceleration of particles to high energies and to thus significantly contribute to the Galactic cosmic ray (CR) density. Most of them are first seen at radio wavelengths, around 10% are subsequently also detected at γ-ray energies. Current-generation radio surveys, such as the EMU survey with ASKAP, are revealing an increasing number of low-surface-brightness radio SNRs at high Galactic latitudes. We are searching for high-energy counterparts, which can provide important insights into understanding cosmic ray physics and constraining theories of CR acceleration and escape. These objects expanding in low-density media probe unperturbed environments that complement the population of (very-)high-energy-emitting SNRs in the Galactic plane.

Tag der offenen Tür der Dr. Karl Remeis-Sternwarte
2024-10-26 15:00 - 23:59 | Dr. Karl Remeis-Sternwarte, Sternwartstr. 7 96049 Bamberg, Sternwartstr. 7, Bamberg, Bavaria, 96049, Germany
Wir laden ein zum:
Tag der offenen Tür der Dr. Karl Remeis-Sternwarte Bamberg
Astronomisches Institut der Friedrich-Alexander Universität Erlangen-Nürnberg
Samstag, 26. Oktober 2024 von 15 – 24 Uhr
Programm:

Kinderprogramm (15-19 Uhr)
Kurzvorträge zu jeder vollen Stunde
Sonnen- und Himmelsbeobachtung
Rundgang durch die historische Sammlung
Tombola

Vortragsprogramm:

Vortragsthema
Vortragender
Uhrzeit

135 Jahre Dr. Remeis-Sternwarte: Forschung und Lehre
Prof. Dr. Ulrich Heber
16:00 Uhr

Explosion in unserer Nachbarschaft – Supernova 1987A
Dr. Martin Mayer
17:00 Uhr

Expedition zum Schwarzen Loch
Dr. Thomas Dauser
18:00 Uhr

Die unermessliche Größe des Universums
M.Sc. Roman Laktionov
19:00 Uhr

Neutronensterne
Dr. Ingo Kreykenbohm
20:00 Uhr

Expedition zum Schwarzen Loch (Wiederholung)
Dr. Thomas Dauser
21:00 Uhr

Der Himmel im Roentgenlicht
Prof. Dr. Jörn Wilms
22:00 Uhr

Poster: OpenDay_SternwarteBamberg_2024

ECAP Seminar: Jonas Neuser
2024-10-31 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Black hole evaporation and quantum gravity
Hawking’s seminal result, that black holes behave as black bodies with a non-vanishing temperature, suggests that black holes should evaporate. However, Hawking’s derivation is incomplete as it neglects the backreaction between radiation and geometry. Including it requires to incorporate quantum gravity. This talk focuses on the description of the conceptual challenges associated with black hole evaporation and sketches a recent proposal designed for meeting them. The intention is to eventually derive quantum gravity triggered deviations from Hawking’s evaporation formula and to convert them into measurable data.

ECAP Seminar: Olivier Hainaut
2024-11-14 13:00 - 14:00 | ECAP, room 307, Erwin-Rommel-Str 1, Erlangen, 91058, Germany
Satellite Constellations & Astronomy: What is the problem? What are we doing about it?
In recent years, large satellite constellations have been launched into low-Earth orbit to provide low-latency, global communication coverage. As a result, the number of satellites in orbit has surged from approximately 2,500 to over 10,000, raising concerns about the sustainability of this endeavor and its impact on astronomical observations and the night sky.
I will discuss the current situation, the effects of key constellation parameters (number of satellites, altitude, inclination, satellite size, etc.), and the impact on astronomical observations. I will also explore various mitigation methods. While this talk primarily focuses on astronomy, I will briefly touch on non-astronomical aspects.
Background information: https://www.eso.org/~ohainaut/satellites/

ECAP Seminar: Eli Kasai
2024-12-05 13:00 - 14:00 | Physikum, Hörsaal HF, Staudtstr. 5, Erlangen, 91058, Germany
Optical spectroscopy and imaging of blazars for the Cherenkov Telescope Array Observatory
Blazars are the brightest persistent sources in the high-energy and very-high-energy (VHE) gamma-ray sky. Because their UV/optical radiation is often dominated by non-thermal, and, in the case of BL Lacs, featureless continuum radiation, the determination of their redshift is extremely difficult. Only about 50% of gamma-ray blazars have a firm measurement of their redshift. This strongly reduces the precision in the modelling of their VHE emission, involving the absorption due to the extragalactic background light, which is dependent on redshift. Furthermore, the effects on their radiation of proposed physics beyond the Standard Model such as Lorentz Invariance Violation and Axion-Like Particles cannot be reliably investigated. During the Cherenkov Telescope Array Observatory (CTAO) operations, several hundreds of new blazars will be detected, most of them without redshift. In order to mitigate this condition, we devised an optical observing campaign. Likely targets were selected through simulations of CTAO observations using the Fermi-LAT 3FHL catalog as a starting point. Our campaign, started in 2019, has been recognized as necessary support for the AGN Key Science Project of the CTAO. It involves deep observations using, among others, 10-m class telescopes such as Keck, SALT, GTC and the VLT. In this talk, I will present the status of our campaign, its future developments and other activities we are pursuing.

ECAP Seminar: Katarzyna Nowak
2024-12-12 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Finding evidence for self-enrichment and supermassive stars in forming globular clusters
Self-enrichment is one of the leading explanations for chemical anomalies in globular clusters. In this scenario, a polluter star enriches a forming cluster with its yields, likely ejecting radioactive 26Al into its surroundings. Young massive star clusters, as potential progenitors of globular clusters, provide a valuable setting to investigate self-enrichment processes and assess the role of supermassive stars (>1000 M), which are considered likely polluters contributing to these chemical anomalies.
In the first part of this talk, I will focus on 26Al as a potential tracer of ongoing self-enrichment in young massive star clusters. Detecting 26Al, particularly through its gamma-ray decay lines at 1.8 MeV and 511 keV, as well as 26AlF molecules and positronium radio recombination lines, could provide direct evidence of active self-enrichment. These detections, especially in nearby clusters like R136 in the Large Magellanic Cloud, would offer strong support for self-enrichment scenarios.
The second part of the talk will explore the potential of using 22.2 GHz water kilomasers as tracers of supermassive stars within forming young massive star clusters. Kilomasers, such as the W1 source found in NGC 253, may originate from accretion discs around supermassive stars. Using 2D hydrodynamic simulations, I model the maser spectra for accretion discs around these stars and find that the kilomaser features align well with observed sources like W1, suggesting that kilomasers could indeed signal the presence of supermassive stars.
By examining these two detection methods, I aim to demonstrate how 26Al and kilomasers together provide complementary insights into the processes of self-enrichment and the potential role of supermassive stars in the formation and chemical evolution of globular clusters.

ECAP Seminar: Sebastian Schoenen
2025-01-09 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
From Research to Practice: Applying Artificial Intelligence in the Insurance Industry
This presentation provides insights into the practical applications of artificial intelligence (AI) and machine learning in the insurance sector. Using examples from our work at ControlExpert, I will demonstrate how advanced image recognition and natural language processing (NLP) technologies are leveraged to automate and optimize processes. Additionally, the talk will highlight how data scientists with backgrounds in physics, mathematics, and other disciplines can effectively translate their skills into valuable contributions within the industry.

ECAP Seminar: Elisa Pueschel
2025-01-23 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Dark Matter Searches with VERITAS and Dark100
Indirect dark matter searches are an important piece of the search for dark matter. One indirect search method is to use very-high-energy (E > 100 GeV) gamma rays as a probe of dark matter annihilation or decay in dark-matter-rich astrophysical systems. Gamma rays in this energy range can be used to search for both classical TeV-scale weakly interacting particles and for ultra-heavy dark matter particles predicted in e.g. models of composite dark matter. I will describe efforts to chase light from dark matter using ground-based imaging atmospheric Cherenkov telescopes, including the current generation VERITAS instrument and the upcoming Dark100 array.

ECAP Seminar: Foteini Oikonomou
2025-02-06 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Ultra-high energy cosmic rays: Constraints on the maximum-energy distribution of the sources and the possible role of ultra-fast outflows in active galactic nuclei
An open question in the search for ultra-high-energy cosmic-ray (UHECR) sources is whether they are few and prominent or if a large population of sources collectively contributes to the diffuse flux. Motivated by this question, we investigated whether the latest UHECR data are consistent with originating from a population of sources that exhibit substantial diversity in terms of the cosmic-ray spectra they produce. We found that the fit to the cosmic ray data requires sources that are intrinsically very similar in terms of the maximum energy reached. This is surprising, considering the sizeable astrophysical diversity exhibited by the candidate astrophysical source populations. One source class that may satisfy the constraints imposed by the UHECR observations is non-jetted active galactic nuclei. An increasing number of observations suggest that semi-relativistic winds, termed ultra-fast outflows, are present in a large fraction of these sources. In this talk, I will show that cosmic ray nuclei can be accelerated to ultra-high energies in such ultra-fast outflows. Ultra-fast outflows can, therefore, possibly account for a substantial fraction of the observed diffuse UHECR flux.

ECAP Seminar: Oliver Friedrich, LMU Sternwarte
2025-05-08 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Forcing neutrinos to obey the holographic principle
Gravity does not like the vast amounts of states present in QFT, and
quantum gravitational effects are expected to drastically reduce the
dimension of the QFT Hilbert space. This is e.g. achieved by “operator
dressing”, which changes the commutation relations of quantum fields.
In https://arxiv.org/abs/2402.11016 we build a model for neutrinos,
that incorporates this dressing and fixes it such that neutrinos obey
a cosmic entropy bound. A key consequence of this construction is that
particles scatter in the vacuum. This e.g. implies a finite mean free
path of cosmic neutrinos. We confront this result with observed
neutrino emissions and find that the holographic principle is
potentially in tension with current neutrino data.

ECAP Seminar: Philipp Windischhofer, U Chicago
2025-05-22 13:00 - 14:00 | Physikum, Hörsaal HF, Staudtstr. 5, Erlangen, 91058, Germany
Exploring the Universe at the Highest Energies: when Particle Physics and Astronomy meet
High-energy neutrinos propagating over cosmological distances are the ideal messenger particles for astrophysical phenomena, but the neutrino landscape above 10 PeV is still mostly unexplored. At these extreme energies, neutrinos can image the most extreme objects in remote corners of our cosmos and help access fundamental physics at extremely short distances.In this talk, I will show how we are presently constructing the Radio Neutrino Observatory in Greenland, the largest-ever terrestrial neutrino detector, and how the century-old physics of electrodynamics plays a central role in its operation. Combining ideas from particle collider instrumentation with high-performance computing, we will see what it takes to fully exploit the science potential of this unique instrument and thereby extend neutrino astronomy into the regime of the exaelectronvolt.

ECAP Seminar: Benedikt Bergmann, IEAP/CTU, Prague
2025-06-05 13:00 - 14:00 | ECAP Laboratory, 00.061, Nikolaus-Fiebiger-Str. 2, Erlangen, 91058, Germany
Particle tracking and identification with Timepix-series detector setups in nuclear, particle and astrophysics
In high energy physics experiments, hybrid pixel detectors are an integral part of the tracking systems closest to the interaction points, where their good spatial resolution and high radiation resilience allow for particle tracking by connection of “dots” registered in different layers of an onion-like detector. Another approach to particle detection and tracking relies on a complex analysis of the imprints seen in the pixel matrices (tracks), which provide a rich set of features. These allow for identification of impinging particles, particle trajectory or reaction kinematics reconstruction. The latter is particularly valuable for applications with limited resources, for example in space experiments, but it also enables fundamental-science-reach measurements with simple table-top experiments. In this contribution, I will present the latest results from Timepix-type detectors used within LHC experiments, as space radiation monitors in low Earth orbit, their possible application for measurement for galactic-cosmic-ray properties or as an X-ray polarimeter.
