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Special Colloquium

Submitter: Dr Ir Jaap Bregman
Description: Last week, on Dec 14th, Ir Jaap Bregman successfully defended his PhD thesis named "System Design and Wide-field Imaging Aspects of Synthesis Arrays with Phased Array Stations". The picture shows the young Doctor, flanked by his "paranymphs" and the University "pedel", in the ritual garb that is customary for such occasions. In today's colloquium Jaap will summarize his main themes for his ASTRON and JIVE colleagues:

"In this presentation, I will highlight the challengeing aspects that made LOFAR possible at all, and which form the basis for the low-frequency segment of the SKA.
After an introduction with some history and a summary of the paradigm shifts that allow high sensitivity polarization imaging at frequencies below ~0.3 GHz, I will focus on calibration and imaging approaches that are different from the conventional ones.
We need these different approaches to image large fields in a processing-efficient way, to support reliable imaging down to the thermal noise level.
It will be shown that the stations in a synthesis array need a minimum size and a minimum sensitivity, and that the array needs a minimum size and a minimum number of stations to reach the sky noise limited sensitivity."

Note from the editor: Just as an appetizer, here is a quote from Prof. George Miley (Leiden) in the recent ASTRON press release about this thesis defence. For reasons of modesty, the fulsome praise is not translated here, but the discerning reader will be able to recognize many of the key words:

"Zonder creatieve ingenieurs zoals Jaap Bregman was de uitstekende wetenschap die nu bedreven wordt met nieuwe generatie geavanceerde high-tech telescopen niet mogelijk geweest. Jaap's bijdrage aan ASTRON de afgelopen veertig jaar zijn van onschatbare waarde. Zijn briljante technische ideeen hebben LOFAR de revolutionaire ICT-telescoop gemaakt die nu over de hele wereld wordt bewonderd."
Copyright: ASTRON
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