Aivin Gast, a Somerville classicist-turned-scientist, has played an important part in the discovery of the biggest pair of black hole jets ever seen. Together, these jets form the largest object of astrophysical origin ever identified.
‘This pair is not just the size of a solar system, or a Milky Way; we are talking about 140 Milky Way diameters in total,’ says Martijn Oei, a Caltech postdoctoral scholar and lead author of a new Nature paper reporting the findings. ‘The Milky Way would be a little dot in these two giant eruptions.’
Porphyrion
The jet megastructure dates to when our universe was 6.3 billion years old, less than half its present age. These fierce outflows—with a total power output equivalent to trillions of suns—shoot out from above and below a supermassive black hole at the heart of a remote galaxy. (Black hole jet systems are also referred to as radio galaxies; however, the term can be misleading, as the jets are no longer part of the galaxy itself.)
Aivin was a Somerville undergraduate in Classical Archaeology and Ancient History when he became involved in radio astronomy after meeting Martijn Oei. When the pandemic delayed the pursuit of Aivin’s primary academic interests, he joined Martijn’s team as a research assistant, eager to learn more about astronomy.
The work involved scanning a vast number of radio telescope images by eye – or what Aivin refers to as ‘searching the sky’ – for giant radio outflows and their host galaxies. He compiled a long list with data which Martijn could use to determine which giant radio galaxies were already known in literature: however, many of them turned out to be new discoveries.
Aivin next to a copy of a relief of Porphyrion on the Pergamon Altar (now in Berlin; this copy in Leiden) Credit: Martijn Oei
Aivin was the first to flag the jets for follow-up observations, as the largest of the objects on his candidate list. As it was hard to locate the jets’ host galaxy, Martijn requested follow-up observations. By the time these were conducted, Aivin had resumed his main studies at Oxford. However, after the reality and scale of the jet system was confirmed, he used his classical knowledge to name it ‘Porphyrion’. This pairs beautifully with another jet system, ‘Alcyoneus’, which Aivin had discovered and named as part of the same project: both are named after the greatest of the Giants who battled with the Olympian gods in Ancient Greek mythology.
Once Martijn had completed further analysis, Aivin also assisted him with writing the article, now titled ‘Black hole jets on the scale of the cosmic web’. Using his language skills, Aivin helped Martijn choose effective formulations and pointed out ambiguities, providing a useful ‘non-expert’ eye to make the article as clear and readable as possible. Whilst Aivin did not contribute new scientific content to the article, Martijn refers to him as an ‘engaged co-author’. Together, the two have published several articles.
Aivin reflected, ‘When I saw this radio blob for the first time in my Somerville room, it was hard to imagine that it would grace the cover of Nature! It was an exciting journey, but for my own career I prefer to “stay on Earth”: after graduating from Oxford, I studied international cultural relations in Italy and Germany and next month I will start an MPhil in Heritage Studies at St John’s College, Cambridge. Of course, I won’t forget to visit Somerville again!’
The Nature article is now available to read here. This news story was written with the help of Nature, Martijn Oei and Aivin Gast.