The Diffuse Supernova Neutrino Background (DSNB) is the remnant flux of neutrinos coming from all core-collapse supernovae (CCSNe) that happened in the visible universe. With the Jiangmen Underground Neutrino Observatory (JUNO), which will soon begin data taking, and the already established Super-Kamiokande (Super-K) detector there are two promising candidates to measure the DSNB in the near...
Cryogenic scintillating calorimeters (CSCs) equipped with a TES readout proved to be excellent detectors for the DM-nucleus scattering search. A modification of those detectors, proposed by the O$\nu$DES project, promises to further lower the energy threshold to be sensitive to DM-e and $\nu$-e scattering. In particular, it will be possible to study non-standard interactions of neutrinos with...
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator-based neutrino observatory. The internal radioactivity of the scintillator is measured by the OSIRIS Detector, where 64 Photomultiplier Tubes (PMTs) are monitoring a 17 t subset of the scintillator during the filling. The classification of alpha and beta decays can be performed well with machine learning,...
This work presents a data-driven approach to improve the pointing accuracy of Imaging Atmospheric Cherenkov Telescopes (IACTs), such as those in the H.E.S.S. array. These telescopes detect Cherenkov light from gamma-ray-induced atmospheric showers, but are also sensitive to diffuse and stellar background light. This Night Sky Background (NSB) contains spatial information associated with the...
The main topic of this presentation is the introduction of the development and construction of the first and second generation prototypes of the FAST telescopes (Fluorescence detector Array of Single-pixel Telescopes). These telescopes are low cost, easy-to-manufacture, large-area detectors of ultra-high energy cosmic rays. The presentation will cover a description of both designs, main...
The First G-APD Cherenkov Telescope (FACT) is a gamma-ray telescope on the Canary Island of La Palma. Equipped with a SiPM-based camera—each pixel comprising 3600 Geiger-mode avalanche photodiodes (G-APDs)—FACT monitors bright TeV gamma-ray sources. In its physics program, it combines continuous monitoring of known sources with readiness to react to external triggers.
A key feature of its...
A fundamental challenge for observations with Imaging Atmospheric Cherenkov Telescopes is the treatment of the dominant background of cosmic-ray initiated air showers. Traditional frequentist methods for signal estimation rely on gamma-hadron separation cuts to remove a large fraction of background events (reducing the efficiency of gamma-ray detection). In this work we adopt and extend a...
Following the detection of the brightest high-energy neutrino sources in the sky to date, the focus is increasingly shifting toward the search for weaker sources that are individually difficult to detect. However, this search poses a significant challenge due to dominant background signals and the low event rate. A particularly promising approach to overcoming these difficulties is the...
Supermassive black holes in active galaxies are extreme environments with strong gravity, hot plasma, and magnetic fields - ideal conditions for accelerating particles. High-energy neutrinos, detected in recent years, suggest that some active galaxies are capable of accelerating protons to very high energies. Surprisingly, neutrinos don’t only come from galaxies with powerful jets. Some appear...
The black hole at the centre of our galaxy, Sagittarius A (Sgr A), is a prime target for next-generation very-long-baseline interferometry (VLBI) missions such as the Black Hole Explorer (BHEX), which aims to observe strong lensing features of the black hole using Earth-space baselines of the order of 20G$\lambda$. However, at these baseline lengths and observing radio frequency of 320 GHz,...
The KM3NeT/ORCA neutrino telescope is currently under construction in the Mediterranean Sea. It is optimized to detect atmospheric neutrinos with energies up to 100 GeV. To this end a three dimensional grid of photomultiplier tubes detects Cherenkov radiation induced by particles that result from neutrino interactions with seawater. The data recorded by the experiment is analysed by comparing...
The Mobile Intensity Interferometer for Stellar Observations (MI²SO) was designed as a dedicated instrument for small collection area intensity interferometry measurements. Using lightweight 1 m diameter f/1.2 Fresnel lenses, a compact, cheap and mobile design was realized.
First measurements with these telescopes highlighted the capabilities and also limitations of this system. Potential...
The current cosmic-ray(CR) measurements show anomalies in secondary CRs, for example, a hardening of the ratio of boron to carbon at high energies, which deviates from the standard galactic CR propagation model: $B/C \propto E^{-\delta}$. It may suggest the generation of secondary CRs near or inside the accelerators, e.g, SNRs. We calculate the boron production in different SNRs(Type-Ia \&...
The scintillating Fiber-Tracker (FIT) is an instrument designed for space-based tracking high-energy cosmic rays, as well as conversion of gamma rays.
Originally designed as one of many complementary instruments aboard the HERD mission, the FIT uses mats of scintillating fibers that excite silicon photomultiplier (SiPM) arrays with scintillation light induced by high-energy interactions in...
The axion is a promising candidate for cold dark matter, originating as a solution to the strong CP problem. The search for axions in neutron star magnetospheres provides a promising opportunity for detection and is complementary to existing laboratory experiments. The plasma surrounding of a neutron star and its strong magnetic field provide the environment for an axion to convert into a...
The origin of the large-scale anisotropy in ultra-high-energy cosmic rays (UHECRs) remains unclear. I study the influence of the galactic magnetic field (GMF) on their arrival direction and the spectrum observed on Earth. The emphasis lies on temporal and geometrical effects, that are not commonly taken into account in the commonly-used models. I explore the influence of a time-dependent...
We present an ongoing analysis of cosmic ray anisotropy using data from KASCADE (KArlsruhe Shower Core and Array DEtector) and IceTop, the surface array of the IceCube Neutrino Observatory. These two experiments, located in the Northern and Southern Hemispheres respectively, provide complementary coverage of the cosmic ray sky across a broad energy range. The study focuses on large-scale...
Active Galactic Nuclei (AGN) are some of the brightest objects in the universe, powered by supermassive black holes and capable of emitting radiation across the entire electromagnetic spectrum. A small fraction of AGN have strong jets; among them are radio galaxies, which are thought to be similar to blazars only with different viewing angles, making their high-energy emission sometimes harder...
The Fluorescence Detector (FD) of the Pierre Auger Observatory enables calorimetric energy measurements of primary cosmic rays by observing the longitudinal development of extensive air showers. From these measurements, the total energy of the primary particle can be determined with high accuracy, effectively setting the energy scale for the entire observatory. As a result, the accuracy of the...
I approach the model for relativistic non magnetized jets by (Mizuta,2013) and (Bromberg, 2011) and combine them with magnetic fields determined by the jets velocity based on the work of (Yuan,2024) to get the light curves from these sources. To calculate the particle densities I use the software AM3 developed in DESY Zeuthen. For this work, I will focus on a synchrotron self compton model and...
Neutrinos are neutral elementary particles that interact extremely weakly with matter and span a wide energy range, with high-energy neutrinos reaching beyond 100 TeV. At such energies, the mechanisms capable of accelerating particles to these extremes remain unknown, making this question a central challenge in astrophysics. With ground observatories like IceCube and KM3NeT continuously...
Blazars, a subclass of active galactic nuclei, are characterized by highly variable non-thermal emission originating from relativistic jets aligned with the line of sight to Earth. This variability offers valuable insights into the physical processes driving these systems. In this study, we analyze the long-term and intraday variability in the TeV blazar Mrk 421 over a period of two years,...
The KM3NeT collaboration is building two neutrino telescopes in the Mediterranean Sea: ORCA for low-energy oscillation studies and ARCA for high-energy astrophysics. Both detectors are three-dimensional arrays of photomultiplier tubes (PMTs) that detect Cherenkov light induced by secondary particles created from neutrino interactions in the water. Analyses rely on high-level variables such as...
The IceCube Neutrino Observatory has detected an astrophysical neutrino flux and identified a small number of sources. The flavour composition of this flux is a critical channel of information, providing insight into both the characteristics of the sources and neutrino oscillation processes. A full picture of the flavour composition requires an understanding of tau neutrinos. Although they are...
IceAct is an array of compact Imaging Air Cherenkov Telescopes on the ice surface above the IceCube Neutrino Observatory. Each telescope features a silicon photomultiplier-based 61-pixel camera and Fresnel lens-based optics, resulting in a 12° field of view. The design is optimized to operate in harsh environments, particularly at the South Pole.
The three main objectives are to support the...
The IceCube Neutrino Observatory is a 1km3 neutrino detector located at the South Pole. It consists of optical modules which can detect Cherenkov light from charged neutrino interaction products in the Antarctic ice. Measuring the flavor composition of astrophysical neutrinos on Earth can give significant insight in their production mechanisms. However, even though tau neutrinos exhibit a...
