Cosmology has recently entered an era of increasingly rich observational data sets, all being in agreement with a cosmological standard model that features only a small number of free parameters. One of the most powerful ...

Evolution in the mass function of galaxy clusters sensitively traces both the expansion history of the Universe and cosmological structure formation. Hence, measuring the number density of galaxy clusters as a function of ...

We embed the DFSZ axion in supersymmetry with broken R–parity. As Supersymmetry provides hundreds of free parameters we restrict ourselves to the lepton–number violating scenario in minimal supergravity models with ...

Relativistic jets are highly collimated plasma outflows that can be present in extragalactic radio sources, which are associated with active galactic nuclei (AGN). Observations give strong support for the idea that a ...

Massive stars play an important role in shaping the structure of galaxies due to the large energy output during their lifetime. However, because of the short evolutionary time scales, the large extinction toward their birth ...

In this thesis, I studied the higher order weak gravitational lensing effect,flexion, and some of its potential applications in cosmology.<br /> Flexion, as a new subject in lensing, has shown its advantages in various ...

Star-forming regions trace the spiral structure of the Galaxy. They are regions of increased column density and therefore traced well by the extinction in the mid-infrared based on the Spitzer/GLIMPSE 3.6-4.5 micron color ...

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 ...

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 ...

Stars are born within dense clumps of giant molecular clouds, constituting young stellar agglomerates known as embedded clusters. Once the parental gas is expelled through stellar feedback, they evolve into bound open ...