Cosmology from radio sky surveys
The Bielefeld cosmology group joined the International Low Frequency Array (LOFAR) Telescope in 2010. We are interested in various aspects of observational cosmology with radio surveys. The International LOFAR Telescope (ILT) is an advanced radio interferometer (consisting of 43 stations combined by a computer network). LOFAR is the most important Square Kilometre Array (SKA) pathfinder telescope in Europe. Core stations are located in the Netherlands. Five international stations in Germany and one in Sweden, France and United Kingdom respectively are operational since 2011. Probably more stations will be added. These international stations provide long baselines for LOFAR's exquisite resolution (down to one arcsecond). Each LOFAR station consists of High (110-240 MHz) and Low (15-80 MHz) Band Antennas (HBA and LBA). These frequencies are low, compared to other radio telescopes like the Very Large Array (VLA) in New Mexico, the Karoo Array Telescope (MeerKAT) in South Africa or the Australian Square Kilometre Array Pathfinder (ASKAP) in Australia. LOFAR has a huge field of view, which is ideal for detecting transients and for creating large area surveys.
A major task in 2012, as part of the commissioning process, is the creation of the Multifrequency Snapshot Sky Survey (MSSS). For MSSS the whole Northern sky will be measured with HBA and LBA antennas.
In Germany twelve institutions, including Bielefeld University, are forming the German Long Wavelength consortium (GLOW). This consortium coordinates the German contribution to the ILT.
Sternwarte Hamburg and Bielefeld University are planing to build a sixth German LOFAR station near Hamburg.
The Bielefeld cosmology group is participating in the LOFAR Key Science Project Surveys / Cosmology. We work on:
1. Quality control of LOFAR catalogues used for cosmology.
2. Cosmic radio dipole.
3. Autocorrelation function.
4. Theoretical predictions.
On 13th - 17th February 2012 we organized GLOW Interferometry School.