Astroparticle Physics
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RESEARCH

 In the most general terms I am searching for the origin of cosmic rays. These are particles that hit the Earths atmosphere with energies orders of magnitude above those achieved in man-made accelerators. More than 100 years after their discovery their origin remains unclear and I am trying to add small pieces to the solve this puzzle.

Gamma-ray astronomy

Gamma-ray astronomy is the research domain for which I spent most of my time and efforts. Different detection techniques are used to record the highest energies photons the universe is sending us: very high-energy gamma rays in the GeV to multi-TeV energy range. We are able to record the atmospheric air showers initiated by these particles in dark, moonless nights with the help of huge telescopes (cf. H.E.S.S. and CTA) or detect the air shower particle with water Cherenkov tanks (cf. HAWC).

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H.E.S.S.

The H.E.S.S. array of imaging air Cherenkov telescopes is located on the Khomas highlands in Namibia. Its four original telescopes with their 12m diameter mirrors have been complemented by the largest optical telescope in the world: HESS-II with a diameter of 28m.
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CTA

The CTA consortium is preparing the construction of the next generation imaging air Cherenkov telescope array. Build on two sites (one on each hemisphere) it will provide an surpass the sensitivity of current instruments like H.E.S.S. by roughly one order of magnitude! 
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SGSO/SWGO

The High Altitude Water Cherenkov Observatory (HAWC) is using a complementary technique to monitor the high-energy gamma-ray sky: an array of large water tanks set up at a 4100m high plateau in Mexico. 
SGSO (now SWGO) will be a next-generation observatory employing similar techniques potentially at even higher altitudes.
Read more about my contributions to the field of gamma-ray astronomy...

Astro-COLIBRI: a novel platform for multi-messenger astrophysics in real-time

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Astronomy and astrophysics are currently undergoing several fundamental changes, such as the increasing relevance of observations of transients, i.e., short-lived astrophysical phenomena such as supernova explosions, fast radio bursts (FRBs), and gamma-ray bursts (GRBs). At the same time, an increasing number of fundamentally new cosmic messengers provide crucial information about these objects. Today, the detection of high-energy neutrinos and gravitational waves (GWs) routinely supplement traditional astronomical observations in the electromagnetic spectrum.
In this context we have developed “Astro-COLIBRI”, a modern platform that will tackle the associated challenges, facilitate multi-messenger observations and involve the large community of amateur astronomers.
Read more about Astro-COLIBRI...

Neutrino astronomy

Two major instruments searching for astrophysical neutrinos are currently in operation: IceCube at the South Pole and ANTARES in the Mediterranean Sea. They detect the Cherenkov light induced in the transparent medium (ice or water) by high-energy particles created in neutrino interactions within or close-by the instrumented volume.
Both neutrino telescopes have implemented systems for rapid event reconstructions, filtering and subsequent alert emission. Whereas the achieved latencies are at the order of several minutes for IceCube, the TAToO system of the ANTARES collaboration allows to emit alerts to external observatories within tens of seconds. I exploit these systems in searches for gamma-ray counterparts to high-energy neutrinos detected by both instruments.
Read more about my contributions to the field of neutrino astronomy...

Ultra-high energy cosmic rays

 I started my career by studying ultra-high energy cosmic rays (UHECR) with the Pierre Auger Observatory. During my diploma thesis I introduced a novel event reconstruction technique for extensive air showers (29th ICRC, 2005) and was awarded with the Edison Award 2005 (General Electric Foundation) and the Helmholtz young scientist award for the best German diploma thesis in astroparticle physics in 2005. During my PhD thesis I worked among other topics on a cross-check analysis searchinf or correlations between cosmic rays and active galactic nuclei (“Correlation of the highest-energy cosmic rays with nearby extragalactic objects”, Science 318 (2007) 938), developed the tools necessary to determine the exposure of the Pierre Auger Observatory (“The exposure of the hybrid detector of the Pierre Auger Observatory”, Astropart.Phys. 34 (2011) 368) and was able to derive the first energy spectrum of UHECRs based on hybrid measurements (i.e. combining the information from the two distinct detectors of the Pierre Auger Observatory). The corresponding paper is: “Measurement of the energy spectrum of cosmic rays above 1018 eV using the Pierre Auger Observatory”, Phys. Lett. B 685 (2010) 239).
Read more about my contributions to the field of cosmic rays...

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  • Home
  • News
  • Research
    • Gamma-ray astronomy >
      • Gamma-ray bursts
      • Fast Radio Bursts
      • Microquasars
      • SGSO + AMIGO
    • Astro-COLIBRI >
      • Amateur astronomy
    • Multi-messenger searches >
      • MOTS
    • Neutrino astronomy
    • Cosmic rays
  • Team / open positions
    • Previous team members and students
  • About me
    • Publications
  • Contact