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10 Cambridge spinouts on putting their research into practice to improve outcomes for cancer patients - and why Cambridge is a great place to do this.    

This galaxy is one hundred times smaller than the Milky Way, but is surprisingly mature for so early in the universe. Like a large city, this galaxy has a dense collection of stars at its core but becomes less dense in the galactic ‘suburbs’. And like a large city, this galaxy is starting to sprawl, with star formation accelerating in the outskirts.

This is the earliest-ever detection of inside-out galactic growth. Until Webb, it had not been possible to study galaxy growth so early in the universe’s history. Although the images obtained with Webb represent a snapshot in time, the researchers, led by the University of Cambridge, say that studying similar galaxies could help us understand how they transform from clouds of gas into the complex structures we observe today. The results are reported in the journal Nature Astronomy.

“The question of how galaxies evolve over cosmic time is an important one in astrophysics,” said co-lead author Dr Sandro Tacchella from Cambridge’s Cavendish Laboratory. “We’ve had lots of excellent data for the last ten million years and for galaxies in our corner of the universe, but now with Webb, we can get observational data from billions of years back in time, probing the first billion years of cosmic history, which opens up all kinds of new questions.”

The galaxies we observe today grow via two main mechanisms: either they pull in, or accrete, gas to form new stars, or they grow by merging with smaller galaxies. Whether different mechanisms were at work in the early universe is an open question which astronomers are hoping to address with Webb.

“You expect galaxies to start small as gas clouds collapse under their own gravity, forming very dense cores of stars and possibly black holes,” said Tacchella. “As the galaxy grows and star formation increases, it’s sort of like a spinning figure skater: as the skater pulls in their arms, they gather momentum, and they spin faster and faster. Galaxies are somewhat similar, with gas accreting later from larger and larger distances spinning the galaxy up, which is why they often form spiral or disc shapes.”

This galaxy, observed as part of the JADES (JWST Advanced Extragalactic Survey) collaboration, is actively forming stars in the early universe. It has a highly dense core, which despite its relatively young age, is of a similar density to present-day massive elliptical galaxies, which have 1000 times more stars. Most of the star formation is happening further away from the core, with a star-forming ‘clump’ even further out.

The star formation activity is strongly rising toward the outskirts, as the star formation spreads out and the galaxy grows. This type of growth had been predicted with theoretical models, but with Webb, it is now possible to observe it.

“One of the many reasons that Webb is so transformational to us as astronomers is that we’re now able to observe what had previously been predicted through modelling,” said co-author William Baker, a PhD student at the Cavendish. “It’s like being able to check your homework.”

Using Webb, the researchers extracted information from the light emitted by the galaxy at different wavelengths, which they then used to estimate the number of younger stars versus older stars, which is converted into an estimate of the stellar mass and star formation rate.

Because the galaxy is so compact, the individual images of the galaxy were ‘forward modelled’ to take into account instrumental effects. Using stellar population modelling that includes prescriptions for gas emission and dust absorption, the researchers found older stars in the core, while the surrounding disc component is undergoing very active star formation. This galaxy doubles its stellar mass in the outskirts roughly every 10 million years, which is very rapid: the Milky Way galaxy doubles its mass only every 10 billion years.

The density of the galactic core, as well as the high star formation rate, suggest that this young galaxy is rich with the gas it needs to form new stars, which may reflect different conditions in the early universe.

“Of course, this is only one galaxy, so we need to know what other galaxies at the time were doing,” said Tacchella. “Were all galaxies like this one? We’re now analysing similar data from other galaxies. By looking at different galaxies across cosmic time, we may be able to reconstruct the growth cycle and demonstrate how galaxies grow to their eventual size today.”

 

Reference:
William M. Baker, Sandro Tacchella, et al. ‘A core in a star-forming disc as evidence of inside-out growth in the early Universe.’ Nature Astronomy (2024). DOI: 10.1038/s41550-024-02384-8

Astronomers have used the NASA/ESA James Webb Space Telescope (JWST) to observe the ‘inside-out’ growth of a galaxy in the early universe, only 700 million years after the Big Bang.

William M. Baker, Sandro TacchellaGalaxy NGC 1549, seen today and 13 billion years ago

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In 2020, Hassabis and Jumper of Google DeepMind presented an AI model called AlphaFold2. With its help, they have been able to predict the structure of virtually all the 200 million proteins that researchers have identified.

Since their breakthrough, AlphaFold2 has been used by more than two million people from 190 countries. Among a myriad of scientific applications, researchers can now better understand antibiotic resistance and create images of enzymes that can decompose plastic.

The duo received the Nobel along with Prof David Baker of the University of Washington, who succeeded in using amino acids to design a new protein in 2003.

Sir Demis Hassabis read Computer Science as an undergraduate at Queens' College, Cambridge, matriculating in 1994. He went on to complete a PhD in cognitive neuroscience at University College London and create the videogame company Elixir Studios.

Hassabis co-founded DeepMind in 2010, a company that devel­oped masterful AI models for popular boardgames. The company was sold to Google in 2014 and, two years later, DeepMind came to global attention when the company achieved what many then believed to be the holy grail of AI: beating the champion player of one of the world’s oldest board­games, Go.

In 2014, Hassabis was elected as a Fellow Benefactor and, later, as an Honorary Fellow of Queens' College. In 2024, he was knighted by the King for services to artificial intelligence.

In 2018, the University announced the establishment of a DeepMind Chair of Machine Learning, thanks to a benefaction from Hassabis’s company, and appointed Prof Neil Lawrence to the position the following year.

“I have many happy memories from my time as an undergraduate at Cambridge, so it’s now a real honour for DeepMind to be able to contribute back to the Department of Computer Science and Technology and support others through their studies,” said Hassabis in 2018.    

Dr John Jumper completed an MPhil in theoretical condensed matter physics at Cambridge's famous Cavendish Laboratory in 2011, during which time he was a member of St Edmund’s College, before receiving his PhD in Chemistry from the University of Chicago.  

Professor Deborah Prentice, Vice-Chancellor of the University of Cambridge: “I’d like to congratulate Demis Hassabis and John Jumper, who, alongside Geoffrey Hinton yesterday, are all alumni of our University. Together, their pioneering work in the development and application of machine learning is transforming our understanding of the world around us. They join an illustrious line-up of Cambridge people to have received Nobel Prizes – now totalling 124 individuals – for which we can be very proud.”

Two University alumni, Sir Demis Hassabis and Dr John Jumper, have been jointly awarded this year’s Nobel Prize in Chemistry for developing an AI model to solve a 50-year-old problem: predicting proteins’ complex structures.

I have many happy memories from my time as an undergraduate at CambridgeSir Demis Hassabis Left: Demis Hassabis; Right: John Jumper

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Professor Sam Stranks is developing next-generation solar cell technology, which could drive down renewable energy prices even further.

Cambridge researchers are working to solve one of technology’s biggest puzzles: how to build next-generation batteries that could power a green revolution. 

The international team, co-led by the University of Cambridge, used Webb to observe a galaxy roughly the size of the Milky Way in the early universe, about two billion years after the Big Bang. Like most large galaxies, it has a supermassive black hole at its centre. However, this galaxy is essentially ‘dead’: it has mostly stopped forming new stars.

“Based on earlier observations, we knew this galaxy was in a quenched state: it’s not forming many stars given its size, and we expect there is a link between the black hole and the end of star formation,” said co-lead author Dr Francesco D’Eugenio from Cambridge’s Kavli Institute for Cosmology. “However, until Webb, we haven’t been able to study this galaxy in enough detail to confirm that link, and we haven’t known whether this quenched state is temporary or permanent.”

This galaxy, officially named GS-10578 but nicknamed ‘Pablo’s Galaxy’ after the colleague who decided to observe it in detail, is massive for such an early period in the universe: its total mass is about 200 billion times the mass of our Sun, and most of its stars formed between 12.5 and 11.5 billion years ago.

“In the early universe, most galaxies are forming lots of stars, so it’s interesting to see such a massive dead galaxy at this period in time,” said co-author Professor Roberto Maiolino, also from the Kavli Institute for Cosmology. “If it had enough time to get to this massive size, whatever process that stopped star formation likely happened relatively quickly.”

Using Webb, the researchers detected that this galaxy is expelling large amounts of gas at speeds of about 1,000 kilometres per second, which is fast enough to escape the galaxy’s gravitational pull. These fast-moving winds are being ‘pushed’ out of the galaxy by the black hole.

Like other galaxies with accreting black holes, ‘Pablo’s Galaxy’ has fast outflowing winds of hot gas, but these gas clouds are tenuous and have little mass. Webb detected the presence of a new wind component, which could not be seen with earlier telescopes. This gas is colder, which means it’s denser and – crucially – does not emit any light. Webb, with its superior sensitivity, can see these dark gas clouds because they block some of the light from the galaxy behind them.

The mass of gas being ejected from the galaxy is greater than what the galaxy would require to keep forming new stars. In essence, the black hole is starving the galaxy to death. The results are reported in the journal Nature Astronomy.

“We found the culprit,” said D’Eugenio. “The black hole is killing this galaxy and keeping it dormant, by cutting off the source of ‘food’ the galaxy needs to form new stars.”

Although earlier theoretical models had predicted that black holes had this effect on galaxies, before Webb, it had not been possible to detect this effect directly.

Earlier models had predicted that the end of star formation has a violent, turbulent effect on galaxies, destroying their shape in the process. But the stars in this disc-shaped galaxy are still moving in an orderly way, suggesting that this is not always the case.

“We knew that black holes have a massive impact on galaxies, and perhaps it’s common that they stop star formation, but until Webb, we weren’t able to directly confirm this,” said Maiolino. “It’s yet another way that Webb is such a giant leap forward in terms of our ability to study the early universe and how it evolved.”

New observations with the Atacama Large Millimeter-Submillimiter Array (ALMA), targeting the coldest, darkest gas components of the galaxy, will tell us more about if and where any fuel for star formation is still hidden in this galaxy, and what is the effect of the supermassive black hole in the region surrounding the galaxy.

The research was supported in part by the Royal Society, the European Union, the European Research Council, and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Francesco D’Eugenio, Pablo G. Pérez-González et al. ‘A fast-rotator post-starburst galaxy quenched by supermassive black-hole feedback at z=3.’ Nature Astronomy (2024). DOI: 10.1038/s41550-024-02345-1

Astronomers have used the NASA/ESA James Webb Space Telescope to confirm that supermassive black holes can starve their host galaxies of the fuel they need to form new stars.

JADES Collaboration'Pablo's Galaxy'

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