Faculties of University Bonn: Search
Now showing items 41-50 of 75
The non-Gaussian matter power spectrum covariance in the halo model approach
(2008)
Weak gravitational lensing is one of the most promising tools to analyze the nature of dark energy and dark matter. In order to constrain cosmological parameters with this method a good theoretical understanding of the ...
VLBI Observations of Two Prototypical AGN: The BL Lac Object S5 0716+714 and the FR II Radio Galaxy Cygnus A
(2004)
This work will summarise recent results from VLBI observations of two radio sources that are the most representatives of their AGN class: the BL Lac object 0716+714 and the FRII radio galaxy Cygnus A. Both are important ...
Gas Around Active Galactic Nuclei and New Phase Calibration Strategies for High-Frequency VLBI
(2004)
We have a project to measure magnetic fields in the obscuring tori of AGNs. We observed five free-free absorbed jets in radio galaxies with polarimetric VLBI at 15 GHz to determine Faraday rotation measures. Surprisingly, ...
Measurement of the Strangeness Spectral Function and the Mass of the Strange Quark in Hadronic τ Decays with the Opal Detector
(2004)
Tau lepton decays with open strangeness in the final state are measured with the OPAL detector at LEP to determine the strange hadronic spectral function of the t lepton and the mass of the strange quark. The decays ...
Weak gravitational lensing: Detection of mass concentrations in wide field imaging data
(2004)
The deflection and distortion of a light bundle by tidal gravitational fields is described in the framework of General Relativity. There, light bundles from a source follow exactly the curvature of spacetime, and are ...
Proper Motions in the Local Group
(2004)
In this thesis, the proper motions of two Local Group galaxies, namely M33 and IC10. The proper motions were measured by phase-referencing Very Long Baseline Interferometry (VLBI) observations of water vapour masers in the ...
Die Suche nach hochdispergierten Radio-Pulsaren in Richtung des Galaktischen Zentrums
(2005)
Obwohl bis zum heutigen Tage mehr als 1500 Radio-Pulsare in unserer Galaxie entdeckt wurden, konnte bislang nicht ein einziger Pulsar im direkten Umfeld des Galaktischen Zentrums gefunden werden. Dies ist um so mehr ...
Weak Gravitational Lensing and Galaxy Bias
(2005)
Galaxies were formed from primordial baryonic matter within the gravitational potential of the dark matter. Today a confusing wealth of different galaxy populations is known. Explaining the emergence of this zoo of galaxy ...
X-rays from Irregular Dwarf Galaxies: The Connection between Coronal Gas and High Energetic Stellar Events
(2005)
Radio observations of irregular dwarf galaxies (dIrr) in the 21 cm-line emission reveal cavities in their interstellar medium which are denoted as holes, bubbles or shells. The origin of these structures is still a matter ...
Pyrolyse von Metalloxiden und Silikaten unter Vakuum mit konzentrierter Solarstrahlung
(2005)
In der vorliegenden Arbeit wurde untersucht, ob eine solarthermische Hochtemperaturpyrolyse von Mondgestein oder anderen Gesteinen im Vakuum zur Gewinnung von Sauerstoff prinzipiell möglich ist und welche Anforderungen ...