̽��ֱ�� of Cambridge - ESA

Strongest hints yet of biological activity outside the solar system

sc604 — Thu, 17 Apr 2025 04:09:34 +0000

Astronomers have detected the most promising signs yet of a possible biosignature outside the solar system, although they remain cautious.

Farewell, Gaia: spacecraft operations come to an end

sc604 — Thu, 27 Mar 2025 10:27:38 +0000

On 27 March 2025, Gaia’s control team at ESA’s European Space Operations Centre switched off the spacecraft’s subsystems and sent it into a ‘retirement orbit’ around the Sun.

Though the spacecraft’s operations are now over, the scientific exploitation of Gaia’s data has just begun.

Launched in 2013, Gaia has transformed our understanding of the cosmos by mapping the positions, distances, motions, and properties of nearly two billion stars and other celestial objects. It has provided the largest, most precise multi-dimensional map of our galaxy ever created, revealing its structure and evolution in unprecedented detail.

̽��ֱ��mission uncovered evidence of past galactic mergers, identified new star clusters, contributed to the discovery of exoplanets and black holes, mapped millions of quasars and galaxies, and tracked hundreds of thousands of asteroids and comets. ̽��ֱ��mission has also enabled the creation of the best visualisation of how our galaxy might look to an outside observer.

“ ̽��ֱ��data from the Gaia satellite has and is transforming our understanding of the Milky Way, how it formed, how it has evolved and how it will evolve,” said Dr Nicholas Walton from Cambridge’s Institute of Astronomy, lead of the Gaia UK project team. “Gaia has been in continuous operation for over 10 years, faultless, without interruption, reflecting the quality of the engineering, with significant elements of Gaia designed and built in the UK. But now it is time for its retirement. Gaia has finished its observations of the night sky. But the analysis of the Gaia mission data continues. Later in 2026 sees the next Gaia Data Release 4, to further underpin new discovery unravelling the beauty and mystery of the cosmos.”

Gaia far exceeded its planned lifetime of five years, and its fuel reserves are dwindling. ̽��ֱ��Gaia team considered how best to dispose of the spacecraft in line with ESA’s efforts to responsibly dispose of its missions.

They wanted to find a way to prevent Gaia from drifting back towards its former home near the scientifically valuable second Lagrange point (L2) of the Sun-Earth system and minimise any potential interference with other missions in the region.

“Switching off a spacecraft at the end of its mission sounds like a simple enough job,” said Gaia Spacecraft Operator Tiago Nogueira. “But spacecraft really don’t want to be switched off.

“We had to design a decommissioning strategy that involved systematically picking apart and disabling the layers of redundancy that have safeguarded Gaia for so long, because we don’t want it to reactivate in the future and begin transmitting again if its solar panels find sunlight.”

On 27 March, the Gaia control team ran through this series of passivation activities. One final use of Gaia’s thrusters moved the spacecraft away from L2 and into a stable retirement orbit around the Sun that will minimise the chance that it comes within 10 million kilometres of Earth for at least the next century.

̽��ֱ��team then deactivated and switched off the spacecraft’s instruments and subsystems one by one, before deliberately corrupting its onboard software. ̽��ֱ��communication subsystem and the central computer were the last to be deactivated.

Gaia’s final transmission to ESOC mission control marked the conclusion of an intentional and carefully orchestrated farewell to a spacecraft that has tirelessly mapped the sky for over a decade.

Though Gaia itself has now gone silent, its contributions to astronomy will continue to shape research for decades. Its vast and expanding data archive remains a treasure trove for scientists, refining knowledge of galactic archaeology, stellar evolution, exoplanets and much more.

“No other mission has had such an impact over such a broad range of astrophysics. It continues to be the source of over 2,000 peer-reviewed papers per year, more than any other space mission,” said Gaia UK team member Dr Dafydd Wyn Evans, also from the Institute of Astronomy. “It is sad that its observing days are over, but work is continuing in Cambridge, and across Europe, to process and calibrate the final data so that Gaia will still be making its impact felt for many years in the future.”

A workhorse of galactic exploration, Gaia has charted the maps that future explorers will rely on to make new discoveries. ̽��ֱ��star trackers on ESA’s Euclid spacecraft use Gaia data to precisely orient the spacecraft. ESA’s upcoming Plato mission will explore exoplanets around stars characterised by Gaia and may follow up on new exoplanetary systems discovered by Gaia.

̽��ֱ��Gaia control team also used the spacecraft’s final weeks to run through a series of technology tests. ̽��ֱ��team tested Gaia’s micro propulsion system under different challenging conditions to examine how it had aged over more than ten years in the harsh environment of space. ̽��ֱ��results may benefit the development of future ESA missions relying on similar propulsion systems, such as the LISA mission.

̽��ֱ��Gaia spacecraft holds a deep emotional significance for those who worked on it. As part of its decommissioning, the names of around 1500 team members who contributed to its mission were used to overwrite some of the back-up software stored in Gaia’s onboard memory.

Personal farewell messages were also written into the spacecraft’s memory, ensuring that Gaia will forever carry a piece of its team with it as it drifts through space.

As Gaia Mission Manager Uwe Lammers put it: “We will never forget Gaia, and Gaia will never forget us.”

̽��ֱ��Cambridge Gaia DPAC team is responsible for the analysis and generation of the Gaia photometric and spectro-photometric data products, and it also generated the Gaia photometric science alert stream for the duration of the satellite's in-flight operations.

Adapted from a media release by the European Space Agency.

̽��ֱ��European Space Agency’s Gaia spacecraft has been powered down, after more than a decade spent gathering data that are now being used to unravel the secrets of our home galaxy.

ESA/Gaia/DPAC, Stefan Payne-Wardenaar

Artist's impression of the Milky Way

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Webb Telescope sees galaxy in mysteriously clearing fog of early Universe

sc604 — Wed, 26 Mar 2025 16:00:00 +0000

A key goal of the NASA/ESA/CSA James Webb Space Telescope has been to see further than ever before into the distant past of our Universe, when the first galaxies were forming after the Big Bang, a period know as cosmic dawn.

Researchers studying one of those very early galaxies have now made a discovery in the spectrum of its light, that challenges our established understanding of the Universe’s early history. Their results are reported in the journal Nature.

Webb discovered the incredibly distant galaxy JADES-GS-z13-1, observed at just 330 million years after the Big Bang. Researchers used the galaxy’s brightness in different infrared filters to estimate its redshift, which measures a galaxy’s distance from Earth based on how its light has been stretched out during its journey through expanding space.

̽��ֱ��NIRCam imaging yielded an initial redshift estimate of 12.9. To confirm its extreme redshift, an international team led by Dr Joris Witstok, previously of the ̽��ֱ�� of Cambridge’s Kavli Institute for Cosmology, observed the galaxy using Webb’s Near-Infrared Spectrograph (NIRSpec) instrument.

̽��ֱ��resulting spectrum confirmed the redshift to be 13.0. This equates to a galaxy seen just 330 million years after the Big Bang, a small fraction of the Universe’s present age of 13.8 billion years.

But an unexpected feature also stood out: one specific, distinctly bright wavelength of light, identified as the Lyman-α emission radiated by hydrogen atoms. This emission was far stronger than astronomers thought possible at this early stage in the Universe’s development.

“ ̽��ֱ��early Universe was bathed in a thick fog of neutral hydrogen,” said co-author Professor Roberto Maiolino from Cambridge’s Kavli Institute for Cosmology. “Most of this haze was lifted in a process called reionisation, which was completed about one billion years after the Big Bang.

“GS-z13-1 is seen when the Universe was only 330 million years old, yet it shows a surprisingly clear, telltale signature of Lyman-α emission that can only be seen once the surrounding fog has fully lifted. This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise.”

Before and during the epoch of reionisation, neutral hydrogen fog surrounding galaxies blocked any energetic ultraviolet light they emitted, much like the filtering effect of coloured glass. Until enough stars had formed and were able to ionise the hydrogen gas, no such light — including Lyman-α emission — could escape from these fledgling galaxies to reach Earth.

̽��ֱ��confirmation of Lyman-α radiation from this galaxy has great implications for our understanding of the early Universe. “We really shouldn’t have found a galaxy like this, given our understanding of the way the Universe has evolved,” said co-author Kevin Hainline from the ̽��ֱ�� of Arizona. “We could think of the early Universe as shrouded with a thick fog that would make it exceedingly difficult to find even powerful lighthouses peeking through, yet here we see the beam of light from this galaxy piercing the veil.”

̽��ֱ��source of the Lyman-α radiation from this galaxy is not yet known, but it may include the first light from the earliest generation of stars to form in the Universe. “ ̽��ֱ��large bubble of ionised hydrogen surrounding this galaxy might have been created by a peculiar population of stars — much more massive, hotter and more luminous than stars formed at later epochs, and possibly representative of the first generation of stars,” said Witstok, who is now based at the Cosmic Dawn Center at the ̽��ֱ�� of Copenhagen. A powerful active galactic nucleus, driven by one of the first supermassive black holes, is another possibility identified by the team.

̽��ֱ��team plans further follow-up observations of GS-z13-1, aiming to obtain more information about the nature of this galaxy and origin of its strong Lyman-α radiation. Whatever the galaxy is concealing, it is certain to illuminate a new frontier in cosmology.

JWST is an international partnership between NASA, ESA and the Canadian Space Agency (CSA). ̽��ֱ��data for this result were captured as part of the JWST Advanced Deep Extragalactic Survey (JADES).

Reference:
Joris Witstok et al. ‘Witnessing the onset of reionization through Lyman-α emission at redshift 13.’ Nature (2025). DOI: 10.1038/s41586-025-08779-5

Adapted from an ESA media release.

Astronomers have identified a bright hydrogen emission from a galaxy in the very early Universe. ̽��ֱ��surprise finding is challenging researchers to explain how this light could have pierced the thick fog of neutral hydrogen that filled space at that time.

This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise

Roberto Maiolino

ESA/Webb, NASA, STScI, CSA, JADES Collaboration

JADES-GS-z13-1 in the GOODS-S field

Yes

Massive black hole in the early universe spotted taking a ‘nap’ after overeating

sc604 — Wed, 18 Dec 2024 16:00:00 +0000

Like a bear gorging itself on salmon before hibernating for the winter, or a much-needed nap after Christmas dinner, this black hole has overeaten to the point that it is lying dormant in its host galaxy.

An international team of astronomers, led by the ̽��ֱ�� of Cambridge, used the NASA/ESA/CSA James Webb Space Telescope to detect this black hole in the early universe, just 800 million years after the Big Bang.

̽��ֱ��black hole is huge – 400 million times the mass of our Sun – making it one of the most massive black holes discovered by Webb at this point in the universe’s development. ̽��ֱ��black hole is so enormous that it makes up roughly 40% of the total mass of its host galaxy: in comparison, most black holes in the local universe are roughly 0.1% of their host galaxy mass.

However, despite its gigantic size, this black hole is eating, or accreting, the gas it needs to grow at a very low rate – about 100 times below its theoretical maximum limit – making it essentially dormant.

Such an over-massive black hole so early in the universe, but one that isn’t growing, challenges existing models of how black holes develop. However, the researchers say that the most likely scenario is that black holes go through short periods of ultra-fast growth, followed by long periods of dormancy. Their results are reported in the journal Nature.

When black holes are ‘napping’, they are far less luminous, making them more difficult to spot, even with highly sensitive telescopes such as Webb. Black holes cannot be directly observed, but instead they are detected by the tell-tale glow of a swirling accretion disc, which forms near the black hole’s edges. When black holes are actively growing, the gas in the accretion disc becomes extremely hot and starts to glow and radiate energy in the ultraviolet range.

“Even though this black hole is dormant, its enormous size made it possible for us to detect,” said lead author Ignas Juodžbalis from Cambridge’s Kavli Institute for Cosmology. “Its dormant state allowed us to learn about the mass of the host galaxy as well. ̽��ֱ��early universe managed to produce some absolute monsters, even in relatively tiny galaxies.”

According to standard models, black holes form from the collapsed remnants of dead stars and accrete matter up to a predicted limit, known as the Eddington limit, where the pressure of radiation on matter overcomes the gravitational pull of the black hole. However, the sheer size of this black hole suggests that standard models may not adequately explain how these monsters form and grow.

“It’s possible that black holes are ‘born big’, which could explain why Webb has spotted huge black holes in the early universe,” said co-author Professor Roberto Maiolino, from the Kavli Institute and Cambridge’s Cavendish Laboratory. “But another possibility is they go through periods of hyperactivity, followed by long periods of dormancy.”

Working with colleagues from Italy, the Cambridge researchers conducted a range of computer simulations to model how this dormant black hole could have grown to such a massive size so early in the universe. They found that the most likely scenario is that black holes can exceed the Eddington limit for short periods, during which they grow very rapidly, followed by long periods of inactivity: the researchers say that black holes such as this one likely eat for five to ten million years, and sleep for about 100 million years.

“It sounds counterintuitive to explain a dormant black hole with periods of hyperactivity, but these short bursts allow it to grow quickly while spending most of its time napping,” said Maiolino.

Because the periods of dormancy are much longer than the periods of ultra-fast growth, it is in these periods that astronomers are most likely to detect black holes. “This was the first result I had as part of my PhD, and it took me a little while to appreciate just how remarkable it was,” said Juodžbalis. “It wasn’t until I started speaking with my colleagues on the theoretical side of astronomy that I was able to see the true significance of this black hole.”

Due to their low luminosities, dormant black holes are more challenging for astronomers to detect, but the researchers say this black hole is almost certainly the tip of a much larger iceberg, if black holes in the early universe spend most of their time in a dormant state.

“It’s likely that the vast majority of black holes out there are in this dormant state – I’m surprised we found this one, but I’m excited to think that there are so many more we could find,” said Maiolino.

̽��ֱ��observations were obtained as part of the JWST Advanced Deep Extragalactic Survey (JADES). ̽��ֱ��research was supported in part by the European Research Council and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Ignas Juodžbalis et al. ‘A dormant overmassive black hole in the early Universe.’ Nature (2024). DOI: 10.1038/s41586-024-08210-5

Scientists have spotted a massive black hole in the early universe that is ‘napping’ after stuffing itself with too much food.

Jiarong Gu

Artist’s impression of a black hole during one of its short periods of rapid growth

Yes

‘Inside-out’ galaxy growth observed in the early universe

sc604 — Fri, 11 Oct 2024 09:00:00 +0000

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 ̽��ֱ�� 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. ̽��ֱ��results are reported in the journal Nature Astronomy.

“ ̽��ֱ��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.”

̽��ֱ��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.

̽��ֱ��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.

̽��ֱ��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.

NASA, ESA, CSA, Sandro Tacchella, William Baker, Ovee Tulaskar

Galaxy NGC 1549, seen today and possibly 13 billion years ago

Yes

Earliest detection of metal challenges what we know about the first galaxies

sc604 — Thu, 06 Jun 2024 14:52:26 +0000

Using the James Webb Space Telescope (JWST), an international team of astronomers led by the ̽��ֱ�� of Cambridge observed a very young galaxy in the early universe and found that it contained surprising amounts of carbon, one of the seeds of life as we know it.

In astronomy, elements heavier than hydrogen or helium are classed as metals. ̽��ֱ��very early universe was almost entirely made up of hydrogen, the simplest of the elements, with small amounts of helium and tiny amounts of lithium.

Every other element that makes up the universe we observe today was formed inside a star. When stars explode as supernovas, the elements they produce are circulated throughout their host galaxy, seeding the next generation of stars. With every new generation of stars and ‘stardust’, more metals are formed, and after billions of years, the universe evolves to a point where it can support rocky planets like Earth and life like us.

̽��ֱ��ability to trace the origin and evolution of metals will help us understand how we went from a universe made almost entirely of just two chemical elements, to the incredible complexity we see today.

“ ̽��ֱ��very first stars are the holy grail of chemical evolution,” said lead author Dr Francesco D’Eugenio, from the Kavli Institute for Cosmology at Cambridge. “Since they are made only of primordial elements, they behave very differently to modern stars. By studying how and when the first metals formed inside stars, we can set a time frame for the earliest steps on the path that led to the formation of life.”

Carbon is a fundamental element in the evolution of the universe, since it can form into grains of dust that clump together, eventually forming into the first planetesimals and the earliest planets. Carbon is also key for the formation of life on Earth.

“Earlier research suggested that carbon started to form in large quantities relatively late – about one billion years after the Big Bang,” said co-author Professor Roberto Maiolino, also from the Kavli Institute. “But we’ve found that carbon formed much earlier – it might even be the oldest metal of all.”

̽��ֱ��team used the JWST to observe a very distant galaxy – one of the most distant galaxies yet observed – just 350 million years after the Big Bang, more than 13 billion years ago. This galaxy is compact and low mass – about 100,000 times less massive than the Milky Way.

“It’s just an embryo of a galaxy when we observe it, but it could evolve into something quite big, about the size of the Milky Way,” said D’Eugenio. “But for such a young galaxy, it’s fairly massive.”

̽��ֱ��researchers used Webb’s Near Infrared Spectrograph (NIRSpec) to break down the light coming from the young galaxy into a spectrum of colours. Different elements leave different chemical fingerprints in the galaxy’s spectrum, allowing the team to determine its chemical composition. Analysis of this spectrum showed a confident detection of carbon, and tentative detections of oxygen and neon, although further observations will be required to confirm the presence of these other elements.

“We were surprised to see carbon so early in the universe, since it was thought that the earliest stars produced much more oxygen than carbon,” said Maiolino. “We had thought that carbon was enriched much later, through entirely different processes, but the fact that it appears so early tells us that the very first stars may have operated very differently.”

According to some models, when the earliest stars exploded as supernovas, they may have released less energy than initially expected. In this case, carbon, which was in the stars’ outer shell and was less gravitationally bound than oxygen, could have escaped more easily and spread throughout the galaxy, while a large amount of oxygen fell back and collapsed into a black hole.

“These observations tell us that carbon can be enriched quickly in the early universe,” said D’Eugenio. “And because carbon is fundamental to life as we know it, it’s not necessarily true that life must have evolved much later in the universe. Perhaps life emerged much earlier – although if there’s life elsewhere in the universe, it might have evolved very differently than it did here on Earth.”

̽��ֱ��results have been accepted for publication in the journal Astronomy & Astrophysics and are based on data obtained within the JWST Advanced Deep Extragalactic Survey (JADES).

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

Reference:
Francesco D’Eugenio et al. ‘JADES: Carbon enrichment 350 Myr after the Big Bang.’ Astronomy & Astrophysics (in press). DOI: 10.48550/arXiv.2311.09908

Astronomers have detected carbon in a galaxy just 350 million years after the Big Bang, the earliest detection of any element in the universe other than hydrogen.

NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA)

Deep field image from JWST

Yes

Earliest, most distant galaxy discovered with James Webb Space Telescope

Anonymous — Thu, 30 May 2024 11:04:20 +0000

Found in a region near the Hubble Ultra Deep Field by the JWST Advanced Deep Extragalactic Survey (JADES) team, these galaxies mark a major milestone in the study of the early Universe.

“These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history where we can really probe the stellar populations and the distinctive patterns of chemical elements within them,” said Dr Francesco D’Eugenio of the Kavli Institute for Cosmology at the ̽��ֱ�� of Cambridge, one of the team behind the discovery.

Because of the expansion of the Universe, the light from distant galaxies stretches to longer wavelength as it travels, an effect known as redshift. In these galaxies, the effect is extreme, stretching by a factor of 15, and moving even the ultraviolet light of the galaxies to infrared wavelengths where only JWST has the capability to see it.

Modern theory holds that galaxies develop in special regions where gravity has concentrated the cosmic gas and dark matter into dense lumps known as ‘halos’. These halos evolved quickly in the early Universe, rapidly merging into more and more massive collections of matter. This fast development is why astronomers are so eager to find yet earlier galaxies: each small increment moves our eyes to a less developed period, where luminous galaxies are even more distinctive and unusual.

̽��ֱ��two newly discovered galaxies have been confirmed spectroscopically. In keeping with the collaboration’s standard naming practice, the galaxies are now known as JADES-GS-z14-0 and JADES-GS-z14-1, the former being the more distant of the two.

In addition to being the new distance record holder, JADES-GS-z14-0 is remarkable for how big and bright it is. JWST measures the galaxy at over 1,600 light-years in diameter. Many of the most luminous galaxies produce the bulk of their light via gas falling into a supermassive black hole, producing a quasar, but at this size JADES-GS-z14-0 cannot be this. Instead, the researchers believe the light is being produced by young stars.

̽��ֱ��combination of the high luminosity and the stellar origin makes JADES-GS-z14-0 the most distinctive evidence yet found for the rapid formation of large, massive galaxies in the early Universe. This trend runs counter to the pre-JWST expectations of theories of galaxy formation. Evidence for surprisingly vigorous early galaxies appeared even in the first JWST images and has been mounting in the first two years of the mission.

“JADES-GS-z14-0 now becomes the archetype of this phenomenon,” said Dr Stefano Carniani of the Scuola Normale Superiore in Pisa, lead author on the discovery paper. “It is stunning that the Universe can make such a galaxy in only 300 million years.”

Despite its luminosity, JADES-GS-z14-0 was a puzzle for the JADES team when they first spotted it over a year ago, as it appears close enough on the sky to a foreground galaxy that the team couldn’t be sure that the two weren’t neighbours. But in October 2023, the JADES team conducted even deeper imaging—five full days with the JWST Near-Infrared Camera on just one field—to form the “JADES Origins Field.” With the use of filters designed to better isolate the earliest galaxies, confidence grew that JADES-GS-z14-0 was indeed very distant.

“We just couldn’t see any plausible way to explain this galaxy as being merely a neighbour of the more nearby galaxy,” said Dr Kevin Hainline, research professor at the ̽��ֱ�� of Arizona.

Fortunately, the galaxy happened to fall in a region where the team had conducted ultra-deep imaging with the JWST Mid-Infrared Instrument. ̽��ֱ��galaxy was bright enough to be detected in 7.7 micron light, with a higher intensity than extrapolation from lower wavelengths would predict.

“We are seeing extra emission from hydrogen and possibly even oxygen atoms, as is common in star-forming galaxies, but here shifted out to an unprecedented wavelength,” said Jakob Helton, graduate student at the ̽��ֱ�� of Arizona and lead author of a second paper on this finding.

These combined imaging results convinced the team to include the galaxy in what was planned to be the capstone observation of JADES, a 75-hour campaign to conduct spectroscopy on faint early galaxies. ̽��ֱ��spectroscopy confirmed their hopes that JADES-GS-z14-0 was indeed a record-breaking galaxy and that the fainter candidate, JADES-GS-z14-1, was nearly as far away.

Beyond the confirmation of distance, the spectroscopy allows further insight into the properties of the two galaxies. Being comparatively bright, JADES-GS-z14-0 will permit detailed study.

“We could have detected this galaxy even if it were 10 times fainter, which means that we could see other examples yet earlier in the Universe—probably into the first 200 million years,” says Brant Robertson, professor of astronomy and astrophysics at the ̽��ֱ�� of California-Santa Cruz, and lead author of a third paper on the team’s study of the evolution of this early population of galaxies. “ ̽��ֱ��early Universe has so much more to offer.”

Reference
Carniani, S et al. A shining cosmic dawn: spectroscopic confirmation of two luminous galaxies at z∼14. arXiv:2405.18485 [astro-ph.GA]

̽��ֱ��two earliest and most distant galaxies yet confirmed, dating back to only 300 million years after the Big Bang, have been discovered using NASA’s James Webb Space Telescope (JWST), an international team of astronomers today announced.

These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history where we can really probe the stellar populations and the distinctive patterns of chemical elements within them

Francesco D’Eugenio

NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA)

Infrared image showing JADES-GS-z14-0 galaxy

Yes

Astronomers detect oldest black hole ever observed

sc604 — Wed, 17 Jan 2024 15:59:26 +0000

̽��ֱ��international team, led by the ̽��ֱ�� of Cambridge, used the NASA/ESA/CSA James Webb Space Telescope (JWST) to detect the black hole, which dates from 400 million years after the big bang, more than 13 billion years ago. ̽��ֱ��results, which lead author Professor Roberto Maiolino says are “a giant leap forward”, are reported in the journal Nature.

That this surprisingly massive black hole – a few million times the mass of our Sun – even exists so early in the universe challenges our assumptions about how black holes form and grow. Astronomers believe that the supermassive black holes found at the centre of galaxies like the Milky Way grew to their current size over billions of years. But the size of this newly-discovered black hole suggests that they might form in other ways: they might be ‘born big’ or they can eat matter at a rate that’s five times higher than had been thought possible.

According to standard models, supermassive black holes form from the remnants of dead stars, which collapse and may form a black hole about a hundred times the mass of the Sun. If it grew in an expected way, this newly-detected black hole would take about a billion years to grow to its observed size. However, the universe was not yet a billion years old when this black hole was detected.

“It’s very early in the universe to see a black hole this massive, so we’ve got to consider other ways they might form,” said Maiolino, from Cambridge’s Cavendish Laboratory and Kavli Institute for Cosmology. “Very early galaxies were extremely gas-rich, so they would have been like a buffet for black holes.”

Like all black holes, this young black hole is devouring material from its host galaxy to fuel its growth. Yet, this ancient black hole is found to gobble matter much more vigorously than its siblings at later epochs.

̽��ֱ��young host galaxy, called GN-z11, glows from such an energetic black hole at its centre. Black holes cannot be directly observed, but instead they are detected by the tell-tale glow of a swirling accretion disc, which forms near the edges of a black hole. ̽��ֱ��gas in the accretion disc becomes extremely hot and starts to glow and radiate energy in the ultraviolet range. This strong glow is how astronomers are able to detect black holes.

GN-z11 is a compact galaxy, about one hundred times smaller than the Milky Way, but the black hole is likely harming its development. When black holes consume too much gas, it pushes the gas away like an ultra-fast wind. This ‘wind’ could stop the process of star formation, slowly killing the galaxy, but it will also kill the black hole itself, as it would also cut off the black hole’s source of ‘food’.

Maiolino says that the gigantic leap forward provided by JWST makes this the most exciting time in his career. “It’s a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo’s telescope to a modern telescope overnight,” he said. “Before Webb came online, I thought maybe the universe isn’t so interesting when you go beyond what we could see with the Hubble Space Telescope. But that hasn’t been the case at all: the universe has been quite generous in what it’s showing us, and this is just the beginning.”

Maiolino says that the sensitivity of JWST means that even older black holes may be found in the coming months and years. Maiolino and his team are hoping to use future observations from JWST to try to find smaller ‘seeds’ of black holes, which may help them untangle the different ways that black holes might form: whether they start out large or they grow fast.

Reference:
Roberto Maiolino et al. ‘A small and vigorous black hole in the early Universe.’ Nature (2024). DOI: 10.1038/s41586-024-07052-5

Researchers have discovered the oldest black hole ever observed, dating from the dawn of the universe, and found that it is ‘eating’ its host galaxy to death.

It’s a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo’s telescope to a modern telescope overnight

Roberto Maiolino

NASA, ESA, and P. Oesch (Yale ̽��ֱ��)

̽��ֱ��GN-z11 galaxy, taken by the Hubble Space Telescope

Yes

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