E-Dissertationen: Search
Now showing items 1-10 of 111
Dynamical Studies of the Globular Cluster Systems around the Giant Elliptical Galaxies NGC4636 and NGC1399
(2011-08-02)
Dark matter studies in elliptical galaxies were long hampered by the lack of suitable dynamical tracers. The advent of 8 m-class telescopes equipped with multi-object spectrographs has made it possible to use globular ...
Third-order Cosmic Shear Statistics: Covariance, Nulling, and E/B-mode decomposition
(2012-02-17)
Weak gravitational lensing has emerged in the last decade as a competitive cosmological probe to observationally constrain the properties of dark energy, probably the one with the most statistical power when the results ...
The Dusty, Molecular Envelopes of Red Supergiant Stars: VY Canis Majoris as the Archetypal Example
(2011-11-15)
Red supergiant stars are surrounded by dusty envelopes, which harbor a multitude of molecules. Often, they are also known to show maser emission. We collect a sample of 88 red supergiants associated with Galactic open ...
High resolution magnetic field measurements in high-mass star-forming regions
(2011-09-22)
Three different scenarios have been proposed to explain the formation of high-mass stars. In one of these scenarios, core accretion, massive stars form through gravitational collapse, which involves disk-assisted accretion ...
Study of two radio gravitational lenses: insight into the high-redshift Universe and properties of mass distribution
(2011-10-11)
Similarly to a magnifying glass, a gravitational field deflects light rays that travel through it. This phenomenon, predicted by the theory of General Relativity by A. Einstein (1915), is referred to as gravitational ...
Modeling Gas-Grain Chemistry in Dark Cloud Conditions
(2012-08-23)
I first wrote a gas phase chemical code, which solves for the gas phase composition of an interstellar cloud as a function of time. We used this code to study the abundance ratios between the H3+ ...
Testing X-Ray Scaling Relations with a Sample of Chandra Galaxy Groups and Detailed Analysis of A2244 with Chandra and Suzaku
(2012-08-12)
Groups and clusters of galaxies are valuable tools for cosmology, especially with respect to their mass and other global properties. Individual clusters are also useful to study the complex gravitational and non-gravitational ...
A Detailed Study of Galaxy Clusters with Weak Gravitational Lensing and X-rays
(2012-07-17)
Galaxy clusters represent the top of hierarchical structure formation with the largest dark matter halos. Their abundance with respect to mass and redshift can be used to constrain cosmological parameters. The most extensive ...
Small-scale studies of the Milky Way disc and halo gas with absorption-line spectroscopy
(2012-12-13)
Progressive studies in the last decades have shown that the interstellar medium (ISM) is more complex and dynamic than previously thought. The presence of the small-scale structures, structures on scales below 1 pc, has ...
Physical and Chemical Properties of Protocluster Clumps and Massive Young Stellar Objects Associated to Infrared Dark Clouds
(2012-08-10)
The study of high-mass stars is important not only because of the effects they produce in their environment through outflows, expanding HII regions, stellar winds, and eventually supernova shock waves, but also because ...