The radio telescope LOFAR has discovered two new pulsars - fast-spinning neutron stars, remnants of massive supernova explosions. Two of these weak but quickly flashing radio sources were spotted for the first time during the ‘warm-up' for the LOFAR all-sky survey. The results are described in the PhD thesis that astronomer Thijs Coenen will defend November 20 at the University of Amsterdam.
Published by the editorial team, 19 November 2013
The International LOFAR Telescope (ILT), designed and built by ASTRON, is a radio telescope centered in the Netherlands and spread across Europe. The telescope consists of a network of thousands of individual dipole antennas, connected over a fast network to a central supercomputer. The high sensitivity of this software telescope means it is extraordinarily suited for pulsar research.
The international team of astronomers looking for new pulsars with LOFAR is led byJason Hessels, from ASTRON and the University of Amsterdam, and Ben Stappers, from the University of Manchester. The discovery highlighted by Coenen's PhD research showcases the pulsar capabilities of LOFAR, and hints at new possibilities with its successor, the Square Kilometre Array (SKA). Hessels says: "SKA will take LOFAR technology one step further, and these discoveries show we can expect to detect a large fraction of the pulsars in our Galaxy with SKA."
Pulsars act as cosmic lighthouses, emitting radio beams that sweep the Galaxy. Their signals allow scientists to study the behaviour of gravity and matter in circumstances so extreme that they cannot be reproduced on Earth, not even in the most advanced facility. Pulsars are important because of this - they are true cosmic laboratories. So far, about 2,000 pulsars have been identified, but astronomers think there must be about 50,000 active pulsars in our Galaxy.
Using SURFsara computing resources, part of the European Grid Infrastructure, Coenen and the team needed only a month to search through a set of 2010-2013 LOFAR images that would have occupied a single computer for more than a century. Coenen says: "Analysing all that data was a huge challenge, but then to find two new pulsars with this powerful telescope was very special."
These first results show how LOFAR, with its flexible configuration, can produce more than a 1,000 images per second of a large part of the sky. That means the pulsar survey will be the most sensitive ever in this radio regime.
Joeri van Leeuwen, Coenen's PhD co-supervisor, concludes: "With these first tests so successfully wrapped up, the hunt for new pulsars is on."
On the left of the image the central LOFAR antennas. On the right the peaked signals of the two discovered pulsars. Credit: LOFAR Pulsar Working Group.
Science contacts (CET time):
Thijs Coenen MSc.
Tel: +316 42346856
Dr. Joeri van Leeuwen
Tel: +316 26154552
Dr. Jason Hessels
Tel: +316 10260062
Searching for Pulsars with LOFAR, Thijs Coenen MSc.,
Public defence: 20 November 2013 at 10am in the Agnietenkapel, Amsterdam.
Supervisor: Prof. dr. M.B.M. van der Klis
Co-supervisor: Dr. A.G.J. van Leeuwen
Co-supervisor: Dr. J.W.T. Hessels
Pulsar Working Group:
A. Alexov, A. Bilous, R. Breton, T. Coenen, H. Falcke, J.M Griessmeier, T.Hassall, J. Hessels, A. Karastergiou, E. Keane, V. Kondratiev, M. Kramer, M. Kuniyoshi, J. van Leeuwen, A. Noutsos, M. Serylak, M. Pilia, C. Sobey, B. Stappers, S. ter Veen, J. Verbiest, P. Weltevrede, K. Zagkouris.