Black hole just the beginning
Next up is to send satellites into space to get clearer images of what’s out there.
THE world can expect to see more images of the galaxy, thanks to the Event Horizon Telescope (EHT).
After successfully capturing the world’s first images of a black hole, international researchers who are part of the Earth-sized “virtual telescope” project are looking to see more.
Next up — literally — is to send satellites into space to get clearer images of what’s out there, said Dr Juan Carlos Algaba, from the Radio Cosmology Laboratory at Universiti Malaya’s (UM) Faculty of Science.
The Very Long Baseline Interferometry (VLBI) expert said sharper images are possible with better resolution. And to improve resolution, scientists can either increase the frequency, which is technologically challenging, or increase the distance of the telescopes. With the participation of the IRAM NOEMA Observatory, the Greenland Telescope, and the Kitt Peak Telescope, future EHT observations will see substantially increased sensitivity.
“We’re hoping to get better images of black holes, which warp spacetime and super-heat materials around it, and many other interesting objects in far away galaxies. We want to see if other planetary systems work like the solar system.
“The techniques we have developed can be used to see what we cannot yet see. With enough funds, we can make more antennas, see further, and in much greater detail.”
But it’s not just about buying antennas. It’s also about maintaining it, hiring personnel to man it, paying for electricity to power it up, and having hard drives to store the vast amounts of data. All these cost money, he said.
Dr Algaba, who together with over 200 researchers from around the world, has been working on the EHT project for the last eight years.
He co-authored scientific articles on the project, which was published in The Astrophysical Journal Letters recently.
Funded by the US National Science Foundation (NSF), European Research Council (ERC) and agencies in East Asia, the EHT is an international project that links telescopes deployed at high-altitude sites around the globe. Data from the telescopes are then combined using highly specialised supercomputers.
Offering a new way to study the most extreme objects in the universe predicted by Einstein’s general relativity, EHT can achieve an angular resolution of 20 micro-arcseconds – enough to read a newspaper in New York from a sidewalk café in Paris.
Dr Algaba, who is from Spain, was speaking to a packed hall on the EHT findings on April 11.
Held a day after EHT researchers unveiled the first direct visual evidence of a black hole that’s 55 million light years from Earth, and its ring-like shadow, the event at UM drew a large crowd with many standing for the two-hour session.
Explaining UM’s involvement in the EHT, its Faculty of Science Department of Physics Radio Cosmology Laboratory head and investigator Assoc Prof Dr Zamri Zainal Abidin, said the varsity has a memorandum of understanding (MoU) with the East Asian Observatory (EAO) .
The EHT collaboration consists of 13 stakeholder institutes: the Academia Sinica Institute of Astronomy and Astrophysics, University of Arizona, University of Chicago, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University, Smithsonian Astrophysical Observatory, and EAO.
EAO represents the participation of many regions in Asia, including China, Japan, Korea, Taiwan, Vietnam, Thailand, Malaysia, India and Indonesia.
“So, UM through the Radio Cosmology Laboratory, is part of the EHT. And, Dr Algaba, a senior lecturer and a member of our lab, has been working on the project all this while,” Dr Zamri said, adding that UM’s participation was a boost to Malaysian astronomy.
On how the idea to capture the world’s first black hole image came about, Dr Algaba said seeing is believing.
“There’s a common idea that at the centre of every galaxy is a black hole but our job as scientists is to make sure that what we believe, is true. So how do we make sure that there really is a black hole there? We have to see it for ourselves.
“We don’t just want suggestions or calculations that indicate the existence of a black hole. We want to make sure. And that means trying to get the best image possible,” he said, adding that it took a long time as there were many challenges.
When the EHT team started almost a decade ago, there were only three antennas. It took years to connect the antennas together at a high frequency.
“We also had to get other facilities onboard so that we could use their telescopes. We also worked continuously to develop systems for all the telescopes to work in interferometry mode. We had to keep increasing the telescopes’ sensitivity or we wouldn’t know whether the reason we’re not seeing anything was because there’s nothing there, or because our machines aren’t good enough.
“It was only in 2017 that the breakthrough came. ALMA’s 66 antennas joined the network. For the first time, we were able to get enough detailed data for an image. Without ALMA, everything would have just been a blur.”
ALMA is a partnership of the European Southern Observatory, US National Science Foundation, National Institutes of Natural Sciences of Japan, National Research Council (Canada), Ministry of Science and Technology (Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (Taiwan), and Korea Astronomy and Space Science Institute, in cooperation with the Republic of Chile.
Although the telescopes are not physically connected, they are able to synchronise their recorded data with atomic clocks — hydrogen masers — which precisely time their observations.
These observations were collected at a wavelength of 1.3 mm during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data, which was stored on high-performance helium-filled hard drives.
“We had petabytes of raw data, which was impossible to send via the Internet. We had to pack the hard drives in boxes and fly them to the Max Planck Institute for Radio Astronomy and MITHaystack Observatory where the data was combined by highly specialised supercomputers, or correlators. Analysing the data to convert it into an image was a very long process.
“Now we are still in the midst of analysing last year’s data. So what exactly will we see next? I don’t know because it’s yet to be discovered.”
Now we are still in the midst of analysing last year’s data. So what exactly will we see next? I don’t know because it’s yet to be discovered.
Dr Juan Carlos Algaba