Dutch astronomers observe giant jets emanating from black hole
An international team of astronomers led by Dutch scientist Martijn Oei has discovered the largest pair of jets from a black hole ever seen. The 'jumbojets' extend a combined length of 140 Milky Ways. The Leiden Observatory played a prominent role in this research. The publication will feature on the cover of Nature on 19 September.
The researchers made their findings using the LOFAR telescope network, naming the megastructure Porphyrion after a giant from Greek mythology. These massive jets were likely expelled by an ultra-massive black hole at the centre of a galaxy when the universe was approximately 6.3 billion years old.
‘The black hole at the centre of a galaxy devours stars, dust, and gas, but it doesn’t consume everything,’ explains lead researcher Martijn Oei, now a postdoc at the California Institute of Technology in the United States. He earned his PhD with honours from Leiden University last year. ‘A small portion of the material that gets close is ejected upwards and downwards in the form of jets.’
Martin Hardcastle, second author and professor of astrophysics at the University of Hertfordshire (UK), and an expert on jets produced by black holes, finds it difficult to explain how the jets could be so large: ‘There must have been an unusually long period of billions of years during which the black hole could continuously consume material and eject it.’
This discovery in 1 minute
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Watch the video on the original website orSurprising discovery
The gigantic jets were discovered by Oei and his colleagues while analysing radio images taken with LOFAR. ‘We were surprised by the existence of Porphyrion,’ says Oei. ‘Physics suggests that jets quickly destabilise. It’s unexpected that these jets could extend over such a vast distance without falling apart.’
The discovery came to light after the team searched for jets using three different methods. They inspected the radio images visually, employed machine learning, and enlisted the help of citizen scientists.
8.000 new megastructures
The search yielded an astonishing number of more than 8,000 new megastructures. The researchers believe this is just the tip of the iceberg, especially since LOFAR images cover only about 15 per cent of the sky, and large, distant jets are challenging to observe.
To locate the galaxy hosting Porphyrion, the authors conducted follow-up observations with the Giant Metrewave Radio Telescope in India and the Keck I Telescope on Mauna Kea in Hawaii.
A decade of Leiden effort
The Leiden contribution to the research is substantial. Most of the work was carried out at the Leiden Observatory, supported by two local ERC projects led by professors Huub Röttgering and Reinout van Weeren. ‘We have been working on this for over ten years,’ says Röttgering. ‘The large LOFAR surveys of the radio sky, which form the basis of this breakthrough, were developed and coordinated by our team. This required significant technical and software efforts – with many impressive results.’
Significant impact on surroundings
Earlier, in 2022, the team published findings on Alcyoneus, which at 100 Milky Ways long was the largest radio galaxy known at the time. The new megastructure Porphyrion is not only much larger but also more distant. The researchers calculated that Porphyrion likely had a substantial impact on its surroundings, partly because the universe was much smaller at that time and everything was closer together.
As the next step, Oei aims to better understand the interaction between these megastructures and their environments. The jets spread cosmic radiation, heat, heavy atoms, and magnetic fields into the intergalactic space. ‘I am particularly interested in the magnetism,’ he says. ‘We know that magnetism travels through the cosmic web to galaxies and stars, eventually reaching planets – and that it is important for life on Earth. But where does this magnetism actually begin? Are the jets at the root of it? I want to investigate that.’
Headerbeeld: Artistic rendering of Porphyrion, the largest structure ever detected from a black hole. The two 'jumbo jets' together span 140 Milky Ways in length. (c) Erik Wernquist, Dylan Nelson (IllustrisTNG Collaboration), Martijn Oei.
Source: astronomie.nl.
Wetenschappelijk artikel
Black hole jets on the scale of the cosmic web. Door: Martijn S.S.L. Oei, Martin J. Hardcastle, Roland Timmerman, Aivin R.D.J.G.I.B. Gast, Andrea Botteon, Antonio C. Rodriguez, Daniel Stern, Gabriela Calistro Rivera, Reinout J. van Weeren, Huub J.A. Röttgering, Huib T. Intema, Francesco de Gasperin & S.G. Djorgovski. In: Nature, 18 september 2024. [origineel | preprint (pdf)]