White dwarf with partner flashes every two hours
An international team of astronomers has shown that a white dwarf and a red dwarf orbiting each other every two hours are emitting radio pulses. Through the discovery, astronomers now know that the monopoly on bright radio bursts is not solely held by neutron stars. The team of international scientists includes two researchers of Leiden Observatory: Joseph Callingham and Timothy Shimwell.
Thanks to observations with several telescopes, the researchers were able to determine the origin of these pulses with certainty for the first time. Their results are published in Nature Astronomy.
In recent years, thanks to better analysis techniques researchers have detected radio pulses that last from seconds to minutes and seem to come from stars in the Milky Way. There have been many hypotheses about what triggers these pulses, but until now there has been no hard evidence. An international study led by Iris de Ruiter of the Netherlands changes this. De Ruiter obtained their PhD in October 2024 at the University of Amsterdam and is now a postdoctoral researcher at the University of Sydney in Australia.
De Ruiter developed a method to search for radio pulses of seconds to minutes in the LOFAR archive. While improving the method, she discovered a single pulse in the 2015 observations. When she subsequently sifted through more archive data from the same patch of sky, she discovered six more pulses. All the pulses came from a source called ILTJ1101.
With their expertise, the Leiden researchers helped to comprehend and interpret the LOFAR data, giving shape to this discovery.
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Sporadic radio pulses from a white dwarf binary at the orbital period. Door: I. de Ruiter, K.M. Rajwade, C.G. Bassa, A. Rowlinson, R.A.M.J. Wijers, C.D. Kilpatrick, G. Stefansson, J.R. Callingham, J.W.T. Hessels, T.E. Clarke, W. Peters, R.A.D. Wijnands, T.W. Shimwell, S. ter Veen, V. Morello, G.R. Zeimann, S. Mahadevan. In: Nature Astronomy.