I am a radio astronomer working at Leiden Observatory, the astrophysics research institute of Leiden University in The Netherlands. My area of expertise is low-frequency radio interferometry, studying the Universe at radio frequencies below 1 GHz with telescopes like the Low-Frequency Array (LOFAR), the Very Large Array (VLA) and the Giant Metrewave Radio Telescope (GMRT). These are technically challenging observations to process, complicated by the need to image and deconvolve hundreds of sources in a typical Field Of View (FOV) of several degrees in diameter, the abundant presence of man-made Radio-Frequency Interference (RFI), and the distorting effects of the Earth's ionosphere. Over the course of several years, I have build and refined a set of software tools to process these observations in an efficient and reproducible way, typically yielding high-quality images. These tools are now systematically applied in many different science projects involving low-frequency radio interferometric observations.
My primary astronomical goal is to understand the origin of large-scale diffuse radio emission regions in clusters of galaxies, namely radio halos and radio relics. Their emission extends over areas of hundreds of kilo-parsecs – often a Mega-parsec or more – and appears to be unrelated to any individual galaxy in the cluster. Only a fraction of the known clusters harbors this kind of emission, but all of these show signs of recent merging activity. This strongly suggests that the energy required to generate these emission regions comes from the potential energy released in the merger, but the exact physical mechanisms are still debated. Understanding these mechanisms is part of the puzzle in understanding how the largest gravitationally bound structures in the Universe form and evolve.
At Leiden Observatory, I lead a project to characterize, model, suppress the effects of the ionosphere on low-frequency radio observations. This is specifically aimed at improving the quality of current LOFAR images, and to support the development of the low-frequency part of the future Square Kilometer Array (SKA). I am also a member of the LOFAR Surveys Key Science Project (LSKSP), aimed at radio imaging the Northern hemisphere at unprecedented resolution and sensitivity using both the High-Band Antennas (HBA; 120-240 MHz) and Low-Band Antennas (LBA; 30-80 MHz).
|2015 – now||LOFAR/SKA research scientist (fixed term), Leiden Observatory|
|2012 – 2015||VLA research associate, NRAO Socorro|
|2009 – 2012||Jansky fellow, NRAO Charlottesville|
|2005 – 2009||PhD candidate in radio astronomy, Leiden Observatory|
|2000 – 2004||Combined BSc/MSc degree in astronomy, Leiden University|
|1996 – 2000||Technical software engineer, High Tech Automation|
|1994 – 1996||Engineering degree in electronics, Hogeschool Utrecht|
|1993 – 1993||Military service, Royal Dutch Army|
|1989 – 1992||Partial BSc in electronics, Delft University|