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- 29.08. Benedikt Schroer (U Chicago): Transport of Galactic Cosmic-Ray Nuclei
Abstract: Understanding the cosmic-ray transport properties in our Galaxy is of utmost importance for many different observations. Using a well-motivated, semi-analytical model, we prove that a single population of cosmic-ray sources accelerating all elements with the same slope is able to explain the available data. We further test the self-consistency of our model by investigating particle transport on intermediate scales with a special focus on the escape of accelerated particles into the interstellar medium. These escaping particles are able to excite the non-resonant streaming instability inside a flux tube. As a result, one expects efficient self-confinement of high-energy particles, which we confirm by performing 2D and 3D hybrid particle-in-cell simulations with the code dHybridR. These bubbles of self-confinement might introduce some modifications to the previously described model of transport on Galactic scales.
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- 12.09. Anlaug Amanda Anlaug Djupvik (NOT): Star formation studies with the Nordic Optical Telescope
Abstract: I will present the Nordic Optical Telescope and two ongoing star formation studies using the NOT. One is based on infrared observations of embedded protostellar jets and another on high-resolution optical spectroscopy to study the UXOR phenomenon. 1) Protostellar jets serve as footprints of the ejection history of a protostar, believed to reflect also the accretion history. A kinematic study of jet knots with infrared imaging and spectroscopy in a dense cloud in Serpes reveals space velocities and locate their driving sources. We find time-variable ejection/accretion and deduce a higher accretion rate, by orders of magnitude, for the youngest protostar. 2) The UXOR phenomenon, a specific and irregular variability in intermediate-mass young stars, is believed to be caused by variable circumstellar extinction. We monitor the variable emission line profiles of hydrogen and other lines formed in the inner part of the circumstellar disk as the star is going through a fading event. Simulations based on hybrid models of magnetospheric accretion and magnetocentrifugal disk winds are used with variable obscuration scenarios. Modelling finds that the disk wind plays a dominant role in the emission line profiles. An obscuration scenario where dust moves vertically up from the disk fits the data best for one of our targets, RR Tau, and it is suggested that the dust is lifted by the disk wind.
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