Location of the EHT telescopes seen from the direction of the black hole in the Galactic centre as the Earth rotates.

Location of the EHT telescopes seen from the direction of the black hole in the Galactic centre as the Earth rotates. Plotted in yellow are the virtual connections between these telescopes exploited for making black hole images. The connections added by the new Africa millimetre-wave telescope in Namibia are shown in red. It builds an important bridge between the IRAM telescopes in Europe, the South Pole Telescope, and the telescopes in Chile (ALMA/APEX) and Mexico (LMT).

Credit: La Bella et al. (2023, A&A subm.)

Grant to build new telescope in Africa to enable colour movies of black holes

Astronomy and astrophysics

The European Research Council (ERC) has awarded a Synergy Grant, named BlackHolistic, of 14 million Euro to a team of British, Dutch, Finnish and Namibian astronomers to make colour movies of black holes. To do this, they will build the first ever African millimetre-wave radio telescope in Namibia. The new telescope will be part of the global Event Horizon Telescope (EHT) network that became famous for making the first image of a black hole and the new grant will help to transform the network from making still images to making movies – enhancing our understanding of black holes across the entire Universe.

Professor Rob Fender, Head of Astrophysics at the University of Oxford’s Department of Physics is one of the three principal investigators (PIs) named on the grant. Over the course of six years, Professor Fender along with fellow PIs Professor Heino Falcke from Radboud University and Professor Sera Markoff from the University of Amsterdam will conduct research on black holes from different perspectives. Black holes are key to understanding the fundamental nature of gravity, the mysterious force shaping the Universe. They are also the Universe’s most efficient power houses, turning infalling gas into energy and outflows that, together with gravity, help shape galaxies and ultimately stars and planets. The three PIs bring complementary expertise combining radio imaging with monitoring across the entire electromagnetic spectrum, astroparticle physics, and theoretical modelling.

Africa’s first millimetre-wave telescope

The ERC Synergy Grant will see the construction of the Africa Millimetre Telescope (AMT) in Namibia. The continent’s first millimetre-wave telescope, it will be located at or near the Gamsberg Mountain in the Khomas Highlands which will give it a unique vantage point making it a valuable addition to the EHT.

Professor Fender comments: ‘With this funding we will take existing and future EHT observations and compare them with multi-frequency observations of black holes across the electromagnetic and mass spectrum. These data sets will allow us, for the first time, to understand the entire process of black hole accretion and jet formation from launch to termination. We will truly bring about a new paradigm for black hole research.’

Professor Falcke adds: ‘We played a leading role in making the first image of a black hole and captured the imagination of scientists and the public alike. Since then, the Event Horizon Telescope has made a major expansion effort, but Africa has been painfully missing in this global network.  Now we can fill this glaring gap and bring these black hole pictures to life, in full colour.’

A new window on the Universe

Located in the southern hemisphere, the AMT will have a particularly good view of the black hole in the centre of our Milky Way and will be a crucial link between telescopes in Europe, South and Latin America, as well as the South Pole. The team will also look for flashes of millimetre-wave emission from cosmic explosions, providing a new window to transient phenomena in the Universe. Construction and operation of the telescopes is also supported by a 12 million Euro guarantee from Radboud University over 10 years.  

‘Via the BlackHolistic grant, we will try to understand what goes on just outside the event horizon of black holes,’ comments Professor Markoff. ‘We need a better grasp of how the complicated physics of plasmas leads to the radiation and high-energy particles we observe, before we can do things like further test theories of gravity. At the same time understanding all of that will help us develop a complete picture of how black holes affect their environments on the largest scales” says Sera Markoff.
The challenge in understanding the astrophysics of black holes and their impact on the cosmos is that they span more than eight orders of magnitude in mass, size, and timescales, and emit light more than 15 orders of magnitude in frequency. The new approach overcomes this scale separation by simultaneously addressing the dynamics of large and small black holes, in colour across the entire electromagnetic spectrum.  

An international collaboration

The lead investigators will work together with partners in Namibia and Finland. Researchers at the University of Namibia will support the construction and operation of, and science with, the AMT. They will also support the implementation of a social impact plan which focuses on skills and knowledge development in science and engineering in Namibia. The project will support several Master level and doctoral students via fellowships. ‘With the AMT, we will continue our investigation of supermassive black holes and their multi-wavelength emission properties,’ comments Michael Backes, head of the Namibian H.E.S.S. group and of astrophysics research at the University of Namibia. ‘It will complement and build upon the world-leading astrophysics research that has been conducted from Namibia with the High Energy Stereoscopic System (HESS) telescopes during the past 20 years.’

With the AMT, researchers at the University of Turku, Finland, will collaborate with the leading team to obtain high cadence observations of supermassive black holes, particularly during flaring phases that produce gamma rays and possibly neutrinos, allowing a unique new multi-messenger approach. Elina Lindfors from the University of Turku, who has served also as Science Coordinator for the Cherenkov Telescope Array (CTA) concludes: ‘We are excited by the chance to collaborate, and to provide our expertise on long-term, high-cadence monitoring of supermassive black holes, and connections to gamma rays via the upcoming CTA project.’