Universe’s hidden supermassive black holes revealed
Astronomers have found evidence for a large population of hidden supermassive black holes in the Universe. Using NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) satellite observatory, the team of international scientists detected the high-energy x-rays from five supermassive black holes previously clouded from direct view by dust and gas. The findings were presented today at the Royal Astronomical Society’s National Astronomy Meeting, at Venue Cymru, in Llandudno, Wales (Monday 6 July).
The research, led by astronomers at Durham University, UK, supports the theory that potentially millions more supermassive black holes exist in the Universe, but are hidden from view.
The scientists pointed NuSTAR at nine candidate hidden supermassive black holes that were thought to be extremely active at the centre of galaxies, but where the full extent of this activity was potentially obscured from view.
High-energy x-rays found for five of the black holes confirmed that they had been hidden by dust and gas. The five were much brighter and more active than previously thought as they rapidly feasted on surrounding material and emitted large amounts of radiation.
Such observations were not possible before NuSTAR, which launched in 2012 and is able to detect much higher energy x-rays than previous satellite observatories.
Lead author George Lansbury, a postgraduate student in the Centre for Extragalactic Astronomy, at Durham University, said: “For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view.
“Thanks to NuSTAR for the first time we have been able to clearly see these hidden monsters that are predicted to be there, but have previously been elusive because of their ‘buried’ state.
“Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole Universe then the predicted numbers are huge and in agreement with what we would expect to see.”
Daniel Stern, the project scientist for NuSTAR at NASA's Jet Propulsion Laboratory in Pasadena, California, added: "High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes. NuSTAR allows us to see how big the hidden monsters are and is helping us learn why only some black holes appear obscured."
The research was funded by the Science and Technology Facilities Council (STFC) and has been accepted for publication in The Astrophysical Journal.
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George Lansbury (at the National Astronomy Meeting from 6 to 9 July)
Professor Dave Alexander
The new work appears in: “NuSTAR reveals extreme absorption in z < 0.5 Type 2 Quasars”, Lansbury, G, et al, presented at the Royal Astronomical Society’s National Astronomy Meeting, in Llandudno, Wales, today (Monday, July 6, 2015). This paper has been accepted for publication in the Astrophysical Journal.
A pre-print copy of the paper is available from Durham University Marketing and Communications Office (details above).
Notes for editors
The Royal Astronomical Society National Astronomy Meeting (NAM 2015) will take place in Llandudno, Wales, from 5-9 July. NAM 2015 will be held in conjunction with the annual meetings of the UK Solar Physics (UKSP) and Magnetosphere Ionosphere Solar-Terrestrial physics (MIST) groups. The conference is principally sponsored by the Royal Astronomical Society (RAS) and the Science and Technology Facilities Council (STFC). Follow the conference on Twitter via @RASNAM2015
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3800 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others. Follow the RAS on Twitter
The Science and Technology Facilities Council (STFC) is keeping the UK at the forefront of international science and tackling some of the most significant challenges facing society such as meeting our future energy needs, monitoring and understanding climate change, and global security. The Council has a broad science portfolio and works with the academic and industrial communities to share its expertise in materials science, space and ground-based astronomy technologies, laser science, microelectronics, wafer scale manufacturing, particle and nuclear physics, alternative energy production, radio communications and radar. It enables UK researchers to access leading international science facilities for example in the area of astronomy, the European Southern Observatory. Follow STFC on Twitter
• The Durham astronomy group, including the Centre for Extragalactic Astronomy, as well as the Institute for Computational Cosmology, is one of the leading research centres in the world and was ranked first in Europe and 6th in the world based on impact in the Space Sciences.