Plyades: A Python Library for Space Mission Design

Plyades: A Python Library for Space Mission Design Designing a space mission is a computation-heavy task. Software tools that conduct the necessary numerical simulations and optimizations are therefore indispensable. The usability of existing software, written in Fortran and MATLAB, suffers because of high complexity, low levels of abstraction and out-dated programming practices. We propose Python as a viable alternative for astrodynamics tools and demonstrate the proof-of-concept library Plyades which combines powerful features with Pythonic ease of use

An Empirical Investigation of UIP and PPP in Inflation Targeting Countries

This thesis consists of three empirical chapters, which study the role of central bank credibility in influencing the exchange rate parities in inflation targeting countries. Central bank credibility is considered to be of upmost importance to the success of the inflation targeting regime. The increasing popularity of inflation targeting as a monetary policy framework requires an evaluation of its wider implications on the economy compared to alternative monetary regimes. This thesis provides insight into the relation between central bank credibility and the exchange rate parities in a comparative study of inflation targeting countries and countries that operate alternative monetary regimes. The first empirical chapter investigates the extent to which deviations from the Taylor rule influence the exchange rate parities. The use of a nonlinear framework provides evidence for the strong persistence of deviations from the parities when Taylor rule deviations are large. The findings of the comparative study show that central bank credibility is more important in inflation targeting countries than in nontargeting countries. The second empirical chapter considers the role of interest rate expectations as an often overlooked measure of central bank credibility when investigating the UIP relation. Using a nonlinear framework, the findings are able to confirm the validity of UIP when the public expects the central bank to adopt a tight monetary stance with closer adherence to the inflation target. The final empirical chapter analyses the role of macroeconomic shocks including inflation expectations shocks in a nonlinear model of the real exchange rate. It is shown that the adjustment to PPP is partially influenced by central bank credibility shocks, in particular those arising from survey expectations

APEX observations of supernova remnants - I. Non-stationary MHD-shocks in W44

Aims. The interaction of supernova remnants (SNRs) with molecular clouds gives rise to strong molecular emission in the far-IR and sub-mm wavelength regimes. The application of MHD shock models in the interpretation of this line emission can yield valuable information on the energetic and chemical impact of supernova remnants. Methods. New mapping observations with the APEX telescope in CO (3-2), (4-3), (6-5), (7-6) and 13CO (3-2) towards two regions in the supernova remnant W44 are presented. Integrated intensities are extracted on five different positions, corresponding to local maxima of CO emission. The integrated intensities are compared to the outputs of a grid of models, which combine an MHD shock code with a radiative transfer module based on the large velocity gradient approximation. Results. All extracted spectra show ambient and line-of-sight components as well as blue- and red-shifted wings indicating the presence of shocked gas. Basing the shock model fits only on the highest-lying transitions that unambiguously trace the shock-heated gas, we find that the observed CO line emission is compatible with non-stationary shocks and a pre-shock density of 10^4 cm-3. The ages of the modelled shocks scatter between values of \sim1000 and \sim3000 years. The shock velocities in W44F are found to lie between 20 and 25 km/s, while in W44E fast shocks (30-35 km/s) as well as slower shocks (\sim20 km/s) are compatible with the observed spectral line energy diagrams. The pre-shock magnetic field strength components perpendicular to the line of sight in both regions have values between 100 and 200 \muG. Our best-fitting models allow us to predict the full ladder of CO transitions, the shocked gas mass in one beam as well as the momentum- and energy injection.Comment: 20 pages, 13 figures, 13 tables, accepted for publication in Astronomy and Astrophysic