A sharp view on the low-frequency radio sky

The study of cosmic large-scale structure formation benefits from radio observations, because it provides an unbiased view on the early Universe. Distant radio galaxies and diffuse cluster sources generally have a steep spectrum, which implies an increased brightness towards lower frequencies (below 300 MHz). The quality of low-frequency radio observations is compromised by the propagation effects on cosmic radio waves passing through the ionosphere. In this thesis, we present a calibration method for low-frequency radio interferometric observations. This method significantly improves the quality of radio maps from archival observations as compared to other existing calibration methods. The method was used to produce one of the deepest high-resolution surveys at 153 MHz to date, including the detection of 16 candidate distant radio galaxies. Furthermore, the method was used in a study of the diffuse radio sources in the merging galaxy cluster Abell 2256. These observations support the theory of revival of old radio sources through cluster merger shock compression. Finally, we present a study of the cosmic large-scale structure near a radio galaxy in the early universe by using an optical selection technique for galaxies. The projected galaxy distribution appears to trace the cosmic structure during the assembly of galaxy clusters.UBL - phd migration 201

A Multi-resolution, Multi-epoch Low Radio Frequency Survey of the Kepler K2 Mission Campaign 1 Field

GalaxiesStars and planetary system

The angular power spectrum measurement of the Galactic synchrotron emission using the TGSS survey

Large scale structure and cosmolog

A low-frequency radio halo survey of the South Pole Telescope SZ-selected clusters with the GMRT

Large scale structure and cosmolog

Radio counterparts of gamma-ray sources in the Cygnus Region

Galaxie

Probing the non-thermal emission in the Perseus cluster with the JVLA

Large scale structure and cosmolog

Barbell-shaped giant radio galaxy with ~100 kpc kink in the jet

Galaxie