The Helmholtz-University Young Investigator Group on "Multi-messenger studies of point sources of cosmic rays using data from IceCube" is working at DESY and focuses on the study of the very high energy emission of individual astrophysical sources by participating to two astrophysical projects: the IceCube neutrino telescope at the South Pole and the MAGIC gamma-ray telescope in La Palma. The idea is to extend the "multi-wavelength" concept to the observation of neutrinos and ultimately develop a "multi-messenger" approach. The goal is to increase the discovery potential of IceCube, confirm the hadronic nature of cosmic accelerators, and allow to alert electromagnetic observations by neutrino signals, i.e. providing a clear "hadron trigger".

The main topics of activity of the group are the analysis of data from IceCube (neutrino telescope) and from gamma-ray telescopes (public data from different gamma-ray telescopes and active participation in the analysis of MAGIC data) along three different lines of study:
  1. Optimization of the sensitivity of the IceCube telescope to point sources of neutrinos and analysis of data from AMANDA and IceCube.

  2. Identification of the most promising periods and sources to search for coincident neutrinos based on data from gamma-ray telescopes.

  3. Development of common Target Of Opportunity strategies with the gamma-ray community.

  4. Analysis of MAGIC data from AGN monitoring

This project belongs to the Young Investigators programm of the Helmholtz Association.

being built...

being built...


Gamma-rays are produced by a variety of Galactic and extra-galactic objects. As for neutrinos, the directional information is not lost, so that gamma-rays point back to their production site, which can help us unveiling the origin of Cosmic Rays. What we define as gamma-rays is electro-magnetic radiation with energies above 1MeV. The High Energy (HE) gamma-ray regime extends from 100MeV to several tens of GeV. Beyond a few tens of GeV it is general consensus to talk about Very High Energy (VHE) gamma-rays.

HE gamma-rays from 271 pointsources as well as diffuse emission from the Galactic plane have been observed with the EGRET satellite onboard the Compton Gamma-Ray Observatory. The successor experiment GLAST is expected to increase the number of known HE gamma-ray sources by a factor of 10.

Due to the flux falling off with a power-law to higher energies, large detection areas are needed in the VHE regime. This is achieved with Cherenkov Telescopes (CTs) that use the atmosphere as a calorimeter. A primary gamma-ray hitting the atmosphere produces an extended air-shower. The secondary shower particles produce Cherenkov radiation that is imaged by the CTs on the ground. The imaging atmospheric Cherenkov technique was pioneered by the Whipple collaboration that could, for the first time ever, detect VHE gamma-rays from a point source in our galaxy, the Crab-Nebula. This technique was subsequently adopted by several experiments, including HEGRA (that pioneered the stereoscopic technique), CAT, CANGAROO in the first generation, and H.E.S.S., MAGIC, VERITAS and CANGAROO-II/III in the second generation. With many new point-sources as well as extended and diffuse emission detected by H.E.S.S. and also first results from MAGIC, the field is currently flourishing.

The most popular models explaining the observed gamma-ray emission are mainly based on two production mechanisms:
  • leptonic: accelerated electrons inverse-Compton (IC) scatter off photons from a local radiation field. Thereby, energy is transferred from the electrons to the photons, boosting the electromagnetic radiation to the VHE regime. The local radiation field can be either external (e.g. infra-red radiation from the surrounding medium, cosmic micro-wave background radiation) or internal (e.g. synchrotron emission from the accelerated electrons moving in a magnetic field).
  • hadronic: in the frame of shock-front acceleration (fermi second order), hadrons are accelerated and interact with the surrounding medium. Neutral pions are then produced in hadron-hadron interactions or via photo-pion production. The neutral pions then decay into gamma-rays. Neutrinos from the decay of charged mesons are also produced in this process (see above).
  • gin tonic: try it out. Anything will feel accelerated.


Please check here the current job openings (code NUASTRO).


Email Background Office Phone
Elisa Bernardini om2
Several years of research at the Gran Sasso underground laboratory (MACRO and ICARUS experiments). In 2002 joined the astroparticle group at DESY to work for the AMANDA and IceCube experiments. Since 2006 founder and leader of the young investigator group. 2A/01 7483
Pratik Majumdar om2
Several years in Gamma-Ray Astronomy with PACT, GLAST and MAGIC. joined the group as Post Doc in April 2008 2A/01 7483
Robert Franke om2
PhD student 2L/21 7268
Robert Lauer om2
PhD student since 09/2006, theory Diploma thesis. 2A/06 7344
Konstancja Satalecka om2
PhD student starting 1st of October, Diploma thesis in experimental neutrino physics 2A/06 7344
Jose Luis Bazo om2
PhD student 2L/26 7242
Sirin Odrowski om2
Diploma student 2L/26 7242

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