Deep neural networks (DNNs) are increasingly used in the data analysis of physics experiments. In IceCube, such networks are used for various tasks like classification for particle identification or regression tasks like reconstructing the direction and energy of particles. In the context of adversarial attacks, it has been observed that imperceptible changes to the input of DNNs can alter the...
Imaging Atmospheric Cherenkov Telescopes (IACTs) — like the High Energy Stereoscopic System (H.E.S.S.) — observe extensive air showers initiated by gamma rays and cosmic rays (CRs) when interacting with the Earth’s atmosphere. IACTs image the distribution of Cherenkov light emitted by air shower particles as they propagate toward the Earth’s surface. The traditional reconstructions of the...
The LOw Frequency ARray (LOFAR) is a radio telescope with 38 stations of antenna fields across Europe, and it can detect the radio emission from cosmic-ray induced air showers via radio antennas in the frequency range from $30$ to $80 \ \text{MHz}$.
A current reconstruction approach is determining the shower maximum $X_\text{max}$, which can be used to deduce the mass of the primary particle....
The proposed Einstein Telescope is the first of the third-generation gravitational wave detectors. It is expected to reach a noise level at least an order of magnitude lower than current interferometers like LIGO and Virgo. The thus improved sensitivity increases the observable volume and extends the time window in which the inspiral of binary systems is measurable. To analyze the resulting...
No core-collapse supernova (CC-SN) exploded close enough to be observed by terrestrial neutrino telescopes since the first detection of neutrinos from SN 1987A. The Jiangmen Underground Neutrino Observatory (JUNO) is a next-generation liquid scintillator detector with a large target mass of 20 kt. It will provide valuable insight into the details of the SN mechanism by observing the neutrino...
The Southern Wide-field Gamma-ray Observatory (SWGO) is a planned instrument to detect astrophysical gamma rays using water Cherenkov detectors. Constructing the experiment in South America would extend the exposure of current-generation instruments to the Southern Hemisphere. Primarily, very high energy gamma rays in a range of hundreds of GeV up to a few PeV will be investigated. To ensure...
The IceCube neutrino observatory instruments 1 $km^{3}$ of Antartic ice that represents the detection target and the light propagation medium. The IceCube detector instruments several thousands optical sensors, that detect Cherenkov light emitted from secondary particles (muons) created in neutrino interactions. From these photons, it is possible to reconstruct the muon (and therefore the...
One of the biggest challenges in processing Imaging Atmospheric Cherenkov Telescope (IACT) astronomy data is avoiding as much light of the night sky background (NSB) caused by noise fluctuations, e.g. electronic noise or starlight, as possible while still keeping enough shower light to be able to reconstruct information about the gamma ray. In the current generation of IACTs, one of the...
The radiation from astrophysical sources such as blazars originates mainly from various particle interactions in the jet or in other regions of the blazar. The spectral energy distribution of a blazar shows a two-bump structure. While the low-energy emission is explained by synchrotron radiation of highly energetic electrons, the high-energy part can contain contributions from hadrons too....
The Cherenkov Telescope Array (CTA) is a next-generation atmospheric Cherenkov gamma-ray observation which will consist of two sites, one in Paranal and another one in La Palma, and three different types of telescopes (large, medium, and small size telescopes). CTA will be coordinated by the Array Control and Data Acquisition (ACADA). ACADA will collect event data from all of the CTA...
The Southern Wide-field Gamma-ray Observatory (SWGO) is a next-generation ground-based gamma-ray observatory. Currently in the R&D phase, the experiment is expected to have a large array of water Cherenkov detectors (WCD) placed at high elevations in South America. This will enable precise observations of the gamma-ray sky, mainly in the regime of ~100GeV up to the PeV region. The primary...
A TeV halo is defined as the Inverse Compton emission from $e^\pm$
diffusing in the Interstellar Medium, injected by a Pulsar Wind
Nebula (PWN). The pulsars surrounded by such halos are generally
older than those powering the TeV PWNe identified in the H.E.S.S
Galactic Plane Survey (HGPS). We revisit the HGPS sources in search
of halo candidates among coincidences between TeV components...
We perform a spectral analysis of the supernova remnant (SNR) J0456$-$6533 in the Large Magellanic Cloud (LMC), which was newly detected with the X-ray telescope eROSITA, using follow-up XMM-Newton observations. A comparison between the calculated luminosity for J0456$-$6533 using eROSITA and XMM-Newton data results in 1$\sigma$ compatibility. The X-ray image shows enhanced emission in the...
Even though the Pierre Auger Observatory is specifically designed to detect ultra-high-energy (UHE) cosmic rays, it also possesses excellent sensitivity to UHE neutrinos in a large portion of the sky. Using the Surface Detector array we search for highly inclined neutrino-induced air showers, not yet observed, which have clear, known characteristic signatures. Of specific scientific interest...
Recently, several observatories have discovered photons of cosmic origin with maximum energies in the PeV ($10^{15}\,\text{eV}$) range. Photons at these energies might be produced as by-products from particle acceleration in so-called PeVatrons, which are widely assumed to be the source of a large part of galactic cosmic rays. The first PeVatron to be firmly established was the Crab nebula, a...
We present a detailed study of the contribution of low- and high-luminosity jetted Active Galactic Nuclei (AGN) populations to the spectrum and composition of ultra-high-energy cosmic rays (UHECRs) and the corresponding EeV neutrino flux. We find that two AGN populations should have different properties to explain the UHECR data. Our results show that the dominant contribution to the neutrino...
As liquid xenon (LXe) dark matter detectors grow in size with each experiment, larger components come with larger challenges that new designs might solve. The Xenon Based Research Apparatus (XeBRA) is a small test platform in Freiburg where new components and configurations are explored. The test platform is now being setup to test a new kind of photosensor, a digital silicon photomultiplier,...
The SWGO collaboration aims at building a ground-based gamma-ray detector in the southern hemisphere. A promising approach to build a low-cost water Cherenkov detector with muon-tagging abilities is to deploy a two-chamber bladder containing two PMTs into an open body of water. This talk will give a short overview over the research done on large-area PMTs operated with a custom electronics...
A precise understanding of the optical properties of the instrumented Antarctic ice sheet is crucial to the performance of optical Cherenkov telescopes such as the IceCube Neutrino Observatory and its planned successor, IceCube-Gen2.
One complication arising from the large envisioned footprint of IceCube-Gen2 is the larger impact of the so-called ice tilt, which describes the undulation of...
The KATRIN experiment aims at the direct measurement of the neutrino mass scale via precision endpoint spectroscopy of tritium β-decay. The current upper limit on the neutrino mass set by KATRIN is 0.8 eV/c² (90% C.L.). Despite advances in background reduction, the elevated background level prohibits to achieve the target sensitivity of 0.2 eV/c² (90% C.L.).
Our investigations showed that the...
The XENONnT experiment, located underground at the Laboratori Nazionali del Gran Sasso, uses a total of 8.6t of high-purity liquid xenon to directly search for WIMP (weakly interacting massive particle) dark matter using a dual phase time projection chamber. A predominant part of the detector's low-energy background is caused by intrinsic contamination of the xenon with Rn-222, which is...
In the KArlsruhe TRItium Neutrino (KATRIN) experiment we perform a precision measurement of the tritium beta decay spectrum. Our goal is to determine the neutrino mass by investigating the spectrum shape near the endpoint region at around $18.6$ keV. Recently we have published a new direct upper limit on neutrino mass of $0.8$ eV/c${}^2$ (90% C.L.) which has been obtained with only 5% of the...
On the various astrophysical and cosmological scales there is compelling evidence for the existence of dark matter beyond the constituents of our Standard Model of particle physics. WIMPs are among the favored candidates which would solve also other problems of the Standard Model. The DARWIN Collaboration and/or the XLZD Consortium plan a next generation xenon detector with 40t (or up to 80t)...
The Radar Echo Telescope for Cosmic Rays (RET - CR) is currently deployed in the summit station, Greenland. RET-CR is a test bed experiment, which will further lead to the development of the Radar Echo Telescope for Neutrinos (RET - N). The ultimate goal is to detect neutrinos using radar reflections from the particle cascade produced in the wake of a neutrino interaction in ice. RET-CR aims...
DISCO (Directionality in Scintillation Observer) is a lab-scale experiment built at the University of Mainz to characterize water-based liquid scintillators (WbLS) and demonstrate the ability to separate Cherenkov and Scintillation light. It consists of three main components: the muon tracker, the test cell, and the light detection system. The test cell can be filled with water, a...
The Institut für Astronomie und Astrophysik Tübingen (IAAT) participates in CTA (Cherenkov Telescope Array) via mirror actuator testing and test stand development for CTA MSTs (Mid-Sized Telescopes) & LSTs (Large-Sized Telescopes), as well as development and testing for the FlashCam camera system used in CTA MSTs (and already used in H.E.S.S. CT-5). Regarding the actuator testing, we are...
The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is a neutrino detector at the Booster Neutrino Beam at Fermilab. It is designed to fulfill two main purposes: The first is an improvement of the systematics in neutrino-nucleus interactions by a precise measurement of the neutron multiplicity. The second purpose is the use as a test-bed for new detector technologies: Water-based...
Astrophysical neutrinos are a great tool to study physics beyond the standard model of particle physics (BSM), one such source being galactic supernovae (SN). While these neutrinos can be detected by traditional neutrino detectors via the production of their charged lepton partners, they undergo the neutral current (NC) Coherent Elastic Neutrino Nucleus Scattering (CE$\nu$NS) process. These...
\documentclass{article}
\usepackage{graphicx} % Required for inserting images
\usepackage{hyperref}
\usepackage{siunitx}
\usepackage{gensymb}
\pagenumbering{gobble}
\DeclareSIUnit\parsec{pc}
\title{Analysing the Fermi Bubbles\
\large using improved models and datasets}
\author{Paul-Simon Blomenkamp\ ...
The magnetorotational instability (MRI) plays a crucial role in the outward transport of angular momentum in various astrophysical accretion disks. In low-luminosity accretion disks around black holes, where the luminosity is much smaller than the Eddington limit (e.g., Sgr A* and M87), particle collisions are very infrequent, making the disk effectively collisionless. This characteristic...
In recent years, there has been evidence pointing towards an anisotropic component in the Ultra-High-Energy Cosmic Ray (UHECR) sky, particularly for energies above a few EeV. However, the identification of cosmic accelerators capable of generating such energies remains a challenge, primarily due to the intricate interplay of interactions with background photons and the magnetic deflection...
Ultra high energy cosmic rays are charged particles originating from various astrophysical sources and they exhibit anisotropic distributions in their arrival directions at Earth. Several studies have been conducted by the Pierre Auger Observatory on the arrival directions of such particles by employing a likelihood analysis which showed that the starburst galaxies (SBG) model have a better...
The existing discrepancies between the observation of local and extraction of global cosmological parameters motivate an extension of the ΛCDM cosmological model. A proposed extension called SU(2)_CMB describes cosmic microwave background (CMB) photons with an SU(2) instead of a U(1) gauge group. This mitigates some of these tensions, for example 𝐻0, Ω𝑚, 𝜎8, pushes the recombination epoch to...
Very Special Relativity (VSR) is a particular realization of Lorentz violation, which was presented for the first time by Cohen and Glashow in 2006 with the idea of introducing an alternative mechanism for neutrinos' masses. Since then, the ideas of VSR have been applied to many different areas. In this talk, after a short introduction to the key features of VSR, I will present its application...
Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of Blazars with specific spectral properties, characterized by synchrotron emission peaking in the hard X-rays band and inverse compton emission peaking at TeV energies, possible sources energy extra-galactic neutrinos. The presence of a jet extending up to hundreds of Kiloparsec can guarantee the acceleration of CRs up to...
The new Faint Particle Trigger (FPT) in IceCube was developed with the intention of reaching a higher sensitivity for faint signals in the IceCube detector. Instead of customary triggers, which are based on local coincidences between multiple modules in the detector, it also uses isolated hits. Therefore it is especially suited for the search for faint signals in the detector. Examples are...
Understanding the properties of extensive air showers (EAS) is of prime importance for extracting the properties of ultra high-energy cosmic rays from data, such as collected by the Pierre Auger Observatory. Inferring their primary energy and, most importantly, their primary mass relies on detailed comparisons of EAS measurements with corresponding air shower simulations. The largest...
