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An Integral View of Shocks

Knežević, Sladjana

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Abstract

The subject of this thesis are Balmer-dominated shocks around (super)novae. These are characterized by strong hydrogen emission lines with a narrow (~10km/s) and a broad (~1000km/s) component. Studying shock physics is important for improving distance estimates to (super)novae, for understanding their evolution and impact on the interstellar medium, and for obtaining insights into the cosmic ray origin in the remnants of supernovae. Two historical supernova remnants, SN 1006 and SN 1572 (Tycho), are investigated using high-resolution spectrophotometric imaging. Analyzing the widths and intensities of the narrow and broad H�alpha-line components, evidence of suprathermal protons – seeds of high-energy cosmic ray protons – is found in SN 1006. Those cause an underestimation of the estimated shock velocity and, hence, the distance to the remnant. In SN 1572, our observations indicate an additional intermediate-width (~100km/s) component, implying the presence of a broad-neutral precursor. Moreover, the narrow component is typically broader than the maximally expected 20 km/s and is sometimes even doublepeaked, which might be due to a cosmic-ray precursor or the shock geometry. The last part of the thesis outlines how high-spatial resolution spectrographs can be used to study and better understand outflow mechanisms of novae, here of a classical nova FH Ser. Further development of shock models that include non-thermal physics, and their application to the data presented in this thesis, are expected to provide important constraints on hadronic cosmic ray properties.

Item Type: Dissertation
Supervisor: van de Ven, Dr. Glenn
Date of thesis defense: 17 October 2014
Date Deposited: 30 Oct 2014 10:38
Date: 2014
Faculties / Institutes: The Faculty of Physics and Astronomy > Dekanat der Fakultät für Physik und Astronomie
Subjects: 520 Astronomy and allied sciences
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