The lights of the night sky have formed our view of the cosmos, and together with matter, these electromagnetic waves fill the Universe. Yet the metric of space and time are equally substantial and real – we feel their curvature -- their stretch -- as gravity. Like other stretchy things, space-time can also flutter. These are gravitational waves. Mergers of black holes and neutron stars whip up such waves. From recent direct gravitational-wave detections, we know the stellar masses and the merger distance; but we have basically no idea where in the sky these mergers took place. We thus know very little about how these massive binary systems get closer and merge, while more importantly, the impact of these cosmic explosions remains an outright mystery – we have no clue in which direction to look.
Our primary goal is to identify the underlying
astrophysical mergers. For this I aim to discover the
accompanying electro-magnetic flashes.
Over much more sky than the competition, I will identify the blast position
100,000 times (!) more accurately than now, to localize
gravitational-wave events for the first time, and understand
their origin.
Our secondary goal is to study the preceding spiral-in of
double neutron stars. The most promising such system I have
previously discovered. Now I will precisely measure their gravitational-wave emission using pulsar timing.
To achieve these goals, we will carry out a highly innovative survey with Apertif, the revolutionary new front-end receivers for the Westerbork telescope. I will combine the Apertif detectors with the Fly’s Eye method I have pioneered, to discover prompt radio emission from gravitational-wave events. Through real-time triggers my team and I will next determine the precise localization that is essential for radio, optical and high-energy follow-up to, for the first time, shed light on the astrophysics driving these exotic events.
Our dedication to enthusing the general audience through television is quite unique. We co-produced/wrote/presented two series of “Heel Nederland Kijkt Sterren”, an annual prime-time, live astronomy TV show. In my 2016 series for “Klokhuis” we flew from the inner planets out to the Big Bang, showing and explaining along the way: planets and stars, gravity, dark matter (!), dark energy (!), and black holes – for 6-12 yr olds! Over 400,000 children watched the series. For this work van Leeuwen received our astronomical society's Willem de Graaff Outreach Prize.