Astronomer Joeri van Leeuwen of the Netherlands Institute for Radio Astronomy (ASTRON) receives a Vici grant of 1.5 million euros to hunt for the source of gravitational waves. In the next five years he will study the afterglow of fused neutron stars with the radio telescopes in Westerbork, the Netherlands, with a team of six researchers.
Published by the editorial team, 23 February 2018
Gravitational waves occur when two heavy objects in the Universe, such as neutron stars or black holes, revolve around each other and merge together. With the instruments Virgo and LIGO it is already possible to detect these ripples in space-time. But where they come from, and how they are made, is still largely unknown.
Van Leeuwen is able to study one of the causes of gravitational waves with the radio telescopes in Westerbork: the fusion of two neutron stars. "Colliding neutron stars cause big explosions, which we can also see in radio light," says Van Leeuwen. "By studying the afterglow of these explosions, we can determine very precisely where the gravitational waves come from, which is not possible using gravitational wave detectors alone."
Visualization of the five most important research concepts. Two neutron stars curve the space-time (1). They spiral in (2), and melt together, with the radio light emitting and afterglowing (3). Gravitational waves roar over the earth, but their origin and direction is unknown (4). The radio source is discovered, with which the explosion is located and studied (5)
In October 2017, colliding neutron stars that caused gravitational waves were observed for the first time in different types of light with multiple telescopes. A special feature of the radio telescopes in Westerbork is that they can search an even larger part of the sky than other telescopes with the most sensitive widescreen cameras in the world (Apertif).
Apertif, the new widescreen cameras on the Westerbork radio telescope, have increased the field of view by a factor of 40.
By studying the neutron star explosions, Van Leeuwen also hopes to learn more about the matter of neutron stars. "This matter is the same stuff that our bodies are made off, but we do not yet fully understand that. By measuring the afterglow of the explosions, we will learn more about the mass and the stability of the neutrons in the star."
Clashing neutron stars can also cause very energetic radio flashes. "Neutron stars have very strong magnetic fields, and when they merge into a black hole, this magnetic field is thrown out, which is probably a super strong magnetic pulse that we might see as a radio burst with our radio telescopes."
The Vici grant allows Van Leeuwen to set up a new team of six researchers with whom he will hunt down the afterglow of gravitational wave sources. The observations start after the summer, when the Virgo and LIGO detectors start looking for gravitational waves again. "As soon as they find one, we get a signal, and then we will try to find the source immediately with our telescopes."
Projection on the celestial sphere of the field of view of the radio telescopes (white hexagons combined). This allows the area where the gravitational wave may come from to be searched in one go (black ellipse, based on GW150914).
Text: Iris Nijman