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The (planned) seminars in 2024 are
- 06.02: . Michael UngerUnger (KIT and IFY, NTNU): News from the Galactic Magnetic Magntic Field (...and the Origin of the Amaterasu Particle)
Abstract: Galaxies are known to be permeated by large-scale magnetic fields with energy densities comparable to the turbulent and thermal energy densities of the interstellar medium. A good knowledge of the global structure of these fields is important to understand their origin and to infer their effect on galactic dynamics and the propagation of charged particles in galaxies. In this talk I will present new studies of the global structure of the magnetic field of our Galaxy based on the analysis of recent new full-sky data of extragalactic rotation measures and the final polarized intensity maps from WMAP and Planck. The analysis employs the latest models for the thermal electron density tuned to the dispersion measures of Galactic pulsars and state-of-the-art cosmic-ray electrons models, needed to predict the rotation measures and synchrotron emission from the Galaxy, respectively. As a result, I will present a major revision of the widely-used Jannson-Farrar 2012 model of the magnetic field of the Galaxy. In addition to a fiducial magnetic field model, a suite of alternative models was studied that fit the data with similar quality, but use different model assumption. This suite of models is then used to place a lower limit on the model uncertainties. As an application, I will discuss the uncertainties of the predicted deflection of ultrahigh-energy cosmic rays in the Galaxy, in particular the origin of the extremely energetic "Amaterasu particle" recently reported by the Telescope Array Collaboration.
slides
- 13.02. Lena Saurenhaus (MPP Muenchen): Seyfert Galaxies as Astrophysical Neutrino Sources
Abstract: 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.
slides
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