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- 13.02. Lena Saurenhaus (MPP Muenchen): P... Seyfert Galaxies as Astrophysical Neutrino Sources
Abstract: Wi...s Active galactic nuclei (AGNs) are among the most powerful objects in the Universe and are suspected to be sources of astrophysical neutrinos. Recently, the IceCube Collaboration reported an excess of neutrino events with energies between 1.5 and 15 TeV associated with NGC 1068, a nearby Seyfert galaxy with an extraordinarily high intrinsic X-ray flux. The lack of observable gamma rays in this energy range indicates that these neutrinos are likely to be produced in the AGN corona, which is opaque to high-energy gamma rays. I will give an overview over existing neutrino emission models for NGC 1068-like sources and talk about our current project, which explores the prospects of observing other hidden neutrino sources with similar neutrino production mechanisms and aims to constrain their contribution to astrophysical neutrino observations.
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- 05.03. Triantafyllos Kormpakis (IFY, NTNU): P...
Abstract: Wi..: The Particle in Cell method: Theory and astrophysical applications
Abstract: The Particle in Cell (PIC) numerical method (first developed in the 1950s) aims to simulate the behavior of plasmas in the presence of electric and magnetic fields. With it's unique architecture, moving particles on a Langrangian frame and depositing their charge and current densities on a fixed eulerian mesh, it tracks the evolution of systems where high densities of charged particles (mainly electron-positron pairs) and/or strong electromagnetic fields are present. In the parameter space where the Force free magnetic field approximation is valid, such as the magnetospheres of pulsars, magnetars and active galactic nuclei (AGN) jets, the PIC scheme accurately simulates features such as magnetic reconnection phenomena, enables the study of shock acceleration, particle flows and emission regions. In this talk I will first give a basic overview of the PIC method, particularly in its implementation on the Zeltron code. This will lead to the discussion of my application and qualitative reproduction of existing results, in magnetic reconnection in ABC magnetic fields (particular eulerian flows with stable as well as chaotic flow regimes). Lastly, I will also describe my application and results of PIC methodology to a test case: an axially symmetric magnetic field, representing a magnetic field topology present in an AGN jet.s.
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- 19.03. Ellis Owen (U Osaka): Cosmic Ray feedback in galaxy evolution
Abstract: Wi...s.
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- 21.03. Dmitri Semikoz (APC Paris): tbd
Abstract: Wi...s.
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- tbd. Jens Oluf Andersen (IFY, NTNU): Pion condensation and pion stars
Abstract: In this talk I will discuss pion condensation in the context of two and three-flavor chiral perturbation theory. I will present results for quark and pion condensates as functions of the isospin chemical potential. The results compare favorably to those of lattice QCD. As an application, I will discuss pion condensation in a dense neutrino cloud and the possibility of pion stars. These are compact objects with a mass up to 20 solar masses and radii of up to 140km.
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