LOFAR total-intensity surveys of nearby galaxies

• Antragsteller: Professor Dr. Ralf-Jürgen Dettmar, seit 2/2017
• Fachliche Zuordnung: Astrophysik und Astronomie
• Förderung: Förderung von 2013 bis 2018
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 108727618

In this project the low-frequency radio radiation from nearby galaxies will be investigated. This will be based upon a complete survey of the northern sky with the new LOFAR radio telescope, which will commence towards the end of 2013. This so-called "Tier 1 Survey" will utilize the 'high-band array' (HBA) in the frequency range 120 - 240 MHz and, using base lines of < 100 km, will reach an angular resolution of -10". Using this data base, two main goals are to be pursued:The total number of observed galaxies will facilitate statistical analyses. A first step will be the cross-correlation of this survey with other galaxy catalogues, in order to determine e.g. the radio luminosity function in the various radio bands. The spectral properties of the synchrotron radiation will be analyzed w.r.t the mechanisms that modify the energy and radiation spectrum of the relativistic particles (loss processes, thermal absorption, propagation effects). Application of rotation-measure synthesis will disclose the polarization properties of the radiation. Finally, this part of the project will come up with a selection of galaxies for deeper observations, to be conducted in the framework of the "Tier 2 Survey" (anticipated start: end of 2014).A further goal of this project will be the measurement of the radio continuum emission from a large number of galaxies with high spatial resolution at low radio frequencies. This permits the investigation of spatial variations of their radio continuum spectra. This will be aided by detailed investigations using the "Tier 1" HBA Survey, which will provide some T angular resolution (using baselines of < 500 km). To this end, methods towards an optimized imaging will be developed in, close collaboration with project A9 (self-calibration loops etc.), such as to produce high-resolution maps of selected galaxies and their spectral-index distributions. The technique of three-dimensional "Faraday Synthesis", developed in the framework of our Research Unit (project A8), will be applied.

• DFG-Verfahren: Forschungsgruppen
• Teilprojekt zu: FOR 1254: Magnetisation of Interstellar and Intergalactic Media: The Prospects of Low-Frequency Radio Observations
• Beteiligte Person: Dr. Rainer Beck
• Ehemaliger Antragsteller: Dr. Enno Middelberg, bis 1/2017