SPACE
Webb discovers 'weird' galaxy with gas outshining its stars
Royal Astronomical Society
image:
The newly-discovered GS-NDG-9422 galaxy appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image. It could help astronomers better understand galaxy evolution in the early Universe.
view moreCredit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
The discovery of a "weird" and unprecedented galaxy in the early Universe could "help us understand how the cosmic story began", astronomers say.
GS-NDG-9422 (9422) was found approximately one billion years after the Big Bang and stood out because it has an odd, never-before-seen light signature — indicating that its gas is outshining its stars.
The "totally new phenomena" is significant, researchers say, because it could be the missing-link phase of galactic evolution between the Universe's first stars and familiar, well-established galaxies.
This extreme class of galaxy was spotted by the $10billion (£7.6billion) James Webb Space Telescope (JWST), a joint endeavour of the US, European and Canadian space agencies, which has been designed to peer back in time to the beginning of the Universe.
Its discovery was made public today in a research paper published in the Monthly Notices of the Royal Astronomical Society.
"My first thought in looking at the galaxy's spectrum was, 'that's weird,' which is exactly what the Webb telescope was designed to reveal: totally new phenomena in the early Universe that will help us understand how the cosmic story began," said lead researcher Dr Alex Cameron, of the University of Oxford.
Cameron reached out to colleague Dr Harley Katz, a theorist, to discuss the strange data. Working together, their team found that computer models of cosmic gas clouds heated by very hot, massive stars, to an extent that the gas shone brighter than the stars, was nearly a perfect match to Webb's observations.
"It looks like these stars must be much hotter and more massive than what we see in the local Universe, which makes sense because the early Universe was a very different environment," said Katz, of Oxford and the University of Chicago.
In the local Universe, typical hot, massive stars have a temperature ranging between 70,000 to 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). According to the team, galaxy 9422 has stars hotter than 140,000 degrees Fahrenheit (80,000 degrees Celsius).
The researchers suspect that the galaxy is in the midst of a brief phase of intense star formation inside a cloud of dense gas that is producing a large number of massive, hot stars. The gas cloud is being hit with so many photons of light from the stars that it is shining extremely brightly.
In addition to its novelty, nebular gas outshining stars is intriguing because it is something predicted in the environments of the Universe's first generation of stars, which astronomers classify as Population III stars.
"We know that this galaxy does not have Population III stars, because the Webb data shows too much chemical complexity. However, its stars are different than what we are familiar with – the exotic stars in this galaxy could be a guide for understanding how galaxies transitioned from primordial stars to the types of galaxies we already know," said Katz.
At this point, galaxy 9422 is one example of this phase of galaxy development, so there are still many questions to be answered. Are these conditions common in galaxies at this time period, or a rare occurrence? What more can they tell us about even earlier phases of galaxy evolution?
Cameron, Katz, and their research colleagues are now identifying more galaxies to add to this population to better understand what was happening in the Universe within the first billion years after the Big Bang.
"It's a very exciting time, to be able to use the Webb telescope to explore this time in the Universe that was once inaccessible," Cameron said.
"We are just at the beginning of new discoveries and understanding."
Typical galaxy vs GS-NDG-9422
Images and captions
Caption: The newly-discovered GS-NDG-9422 galaxy appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image. It could help astronomers better understand galaxy evolution in the early Universe.
Credit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
This image of galaxy GS-NDG-9422, captured by the James Webb Space Telescope's NIRCam (Near-Infrared Camera) instrument, is presented with compass arrows, scale bar, and colour key for reference.
Credit
NASA, ESA, CSA, STScI, Alex Cameron (Oxford
Caption: This comparison of the Webb data with a computer model prediction highlights the same sloping feature that first caught the eye of lead researcher Alex Cameron. The bottom graphic compares what astronomers would expect to see in a "typical" galaxy, with its light coming predominantly from stars (white line), with a theoretical model of light coming from hot nebular gas, outshining stars (yellow line).
Credit: NASA, ESA, CSA, Leah Hustak (STScI)
Caption: This image of galaxy GS-NDG-9422, captured by the James Webb Space Telescope's NIRCam (Near-Infrared Camera) instrument, is presented with compass arrows, scale bar, and colour key for reference.
Credit: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)
Further information
The new study 'Nebular dominated galaxies: insights into the stellar initial mass function at high redshift', Alex J Cameron and Harley Katz et al., has been published in Monthly Notices of the Royal Astronomical Society.
Notes for editors
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Journal
Monthly Notices of the Royal Astronomical Society
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Nebular dominated galaxies: insights into the stellar initial mass function at high redshift
Article Publication Date
25-Sep-2024
Astronomers catch a glimpse of a uniquely inflated and asymmetric exoplanet
image:
Artist's illustration of the exoplanet WASP-107 b based on transit observations from NASA's James Webb Space Telescope as well as other space- and ground-based telescopes, led by Matthew Murphy of the University of Arizona and a team of researchers around the world.
view moreCredit: Rachel Amaro, University of Arizona
Astronomers from the University of Arizona, along with an international group of researchers, observed the atmosphere of a hot and uniquely inflated exoplanet using NASA's James Webb Space Telescope. The exoplanet, which is the size of Jupiter but only a tenth of its mass, is found to have east-west asymmetry in its atmosphere, meaning that there is a significant difference between the two edges of its atmosphere.
The findings are published in the journal Nature Astronomy.
"This is the first time the east-west asymmetry of any exoplanet has ever been observed as it transits its star, from space," said lead study author Matthew Murphy, a graduate student at the U of A Steward Observatory. A transit is when a planet passes in front of its star – like the moon does during a solar eclipse.
"I think observations made from space have a lot of different advantages versus observations that are made from the ground," Murphy said.
East-west asymmetry of an exoplanet refers to differences in atmospheric characteristics, such as temperature or cloud properties, observed between the eastern and western hemispheres of the planet. Determining whether this asymmetry exists or not is crucial for understanding the climate, atmospheric dynamics and weather patterns of exoplanets – planets that exist beyond our solar system.
The exoplanet WASP-107b is tidally locked to its star. That means that the exoplanet always shows the same face to the star it is orbiting. One hemisphere of the tidally locked exoplanet perpetually faces the star it orbits, while the other hemisphere always faces away, resulting in a permanent day side and a permanent night side of the exoplanet.
Murphy and his team used the transmission spectroscopy technique with the James Webb Space Telescope. This is the primary tool that astronomers use to gain insights into what makes up the atmospheres of other planets, Murphy said. The telescope took a series of snapshots as the planet passed in front of its host star, encoding information about the planet's atmosphere. Taking advantage of new techniques and the unprecedented precision of the James Webb Space Telescope, the researchers were able to separate the signals of the atmosphere's eastern and western sides and get a more focused look at specific processes happening in the exoplanet's atmosphere.
"These snapshots tell us a lot about the gases in the exoplanet's atmosphere, the clouds, structure of the atmosphere, the chemistry and how everything changes when receiving different amounts of sunlight," Murphy said.
The exoplanet WASP-107b is unique in that it has a very low density and relatively low gravity, resulting in an atmosphere that is more inflated than other exoplanets of its mass would be.
"We don't have anything like it in our own solar system. It is unique, even among the exoplanet population," Murphy said.
WASP-107b is roughly 890 degrees Fahrenheit – a temperature that is intermediate between the planets of our solar system and the hottest exoplanets known.
"Traditionally, our observing techniques don't work as well for these intermediate planets, so there's been a lot of exciting open questions that we can finally start to answer," Murphy said. "For example, some of our models told us that a planet like WASP-107b shouldn't have this asymmetry at all – so we're already learning something new."
Researchers have been looking at exoplanets for almost two decades, and many observations from both the ground and space have helped astronomers guess what the atmosphere of exoplanets would look like, said Thomas Beatty, study co-author and an assistant professor of astronomy at the University of Wisconsin-Madison.
"But this is really the first time that we've seen these types of asymmetries directly in the form of transmission spectroscopy from space, which is the primary way in which we understand what exoplanet atmospheres are made of – it's actually amazing," Beatty said.
Murphy and his team have been working on the observational data they have gathered and are planning to take a much more detailed look at what's going on with the exoplanet, including additional observations, to understand what drives this asymmetry.
"For almost all exoplanets, we can't even look at them directly, let alone be able to know what's going on one side versus the other," Murphy said. "For the first time, we're able to take a much more localized view of what's going on in an exoplanet's atmosphere."
Journal
Nature Astronomy
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Evidence for morning-to-evening limb asymmetry on the cool low-density exoplanet WASP-107 b
Article Publication Date
24-Sep-2024
Can cosmic radiation in outer space affect astronauts’ long-term cognition?
Wiley
During missions into outer space, galactic cosmic radiation (GCR) will penetrate current spacecraft shielding and thus pose a significant risk to human health. Previous studies have shown that GCR can cause short-term cognitive deficits in male rodents. Now a study published in the Journal of Neurochemistry reveals that GCR exposure can also cause long-lasting learning deficits in female rodents.
The impact of GCR on cognition was lessened when mice were fed an antioxidant and anti-inflammatory compound called CDDO-EA.
Beyond its immediate implications for space exploration, the findings contribute to a broader understanding of radiation’s long-term impact on cognitive health.
“Our study lays the groundwork for future causal delineation of how the brain responds to complex GCR exposure and how these brain adaptations result in altered behaviors,” said co-corresponding author Sanghee Yun, PhD, of the Children’s Hospital of Philadelphia Research Institute and the University of Pennsylvania Perelman School of Medicine.
URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/jnc.16225
Additional Information
NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.
About the Journal
Owned by the International Society for Neurochemistry, the Journal of Neurochemistry is dedicated to disseminating research covering all aspects of neurochemistry. This includes genetic, molecular, cellular, biochemical and behavioural aspects of the nervous system, with a focus on pathogenesis, biomarkers and treatment of neurological and psychiatric disorders. We prioritize original research that mechanistically demonstrates an advance as well as critical reviews that highlight progression of knowledge in the field.
About Wiley
Wiley is a knowledge company and a global leader in research, publishing, and knowledge solutions. Dedicated to the creation and application of knowledge, Wiley serves the world’s researchers, learners, innovators, and leaders, helping them achieve their goals and solve the world's most important challenges. For more than two centuries, Wiley has been delivering on its timeless mission to unlock human potential. Visit us at Wiley.com. Follow us on Facebook, X, LinkedIn and Instagram.
Journal
Journal of Neurochemistry
Article Title
The longitudinal behavioral effects of acute exposure to galactic cosmic radiation in female C57BL/6J mice: implications for deep space missions, female crews, and potential antioxidant countermeasures
Article Publication Date
25-Sep-2024
New map of distant planets unveiled by University of Warwick scientists
image:
Artistic illustration of the Neptunian desert (left) and the Neptunian savanna (right) separated by the Neptunian ridge
view moreCredit: Artistic illustration of the Neptunian desert (left) and the Neptunian savanna (right) separated by the Neptunian ridge identified in this work. © Elsa Bersier / ERC project SPICE DUNE.
A new ‘map’ of distant planets has been unveiled by scientists from The University of Warwick, which finds a ridge of planets in deep space, separating a desert of planets from a more populated savannah.
Researchers from Warwick and other universities examined Neptunian exoplanets – these planets share similar characteristics to our own Neptune, but orbit outside of our solar system.
Scientists discovered a new area called the ‘Neptunian Ridge’ – in between the ‘Neptunian desert’ and the ‘Neptunian Savannah’.
Planets in the desert are very rare, as intense radiation has eroded their atmospheres to the point of destroying them, turning these planets into bare rocky cores.
The savannah is a region located further away from the intense radiation. In this region, environmental conditions are more favourable and allow planets to maintain their atmospheres for millions of years.
In between these two regions, researchers have discovered a new pile-up called the ridge, where there is a large concentration of planets.
Current evidence suggests that many of the planets in the ridge could have arrived from their birthplace through a mechanism called high-eccentricity tidal migration, which can bring planets closer to their stars at any stage of their life.
In contrast, planets in the savannah could have been brought mainly through another type of migration, called disk-driven migration, which occurs just after planets are formed.
Therefore, these two systems driving the movement of planets are populating the savannah and the desert differently. The few planets in the desert could be rare extreme cases pushing the edges of these broad models.
David Armstrong, Associate Professor of Physics at Warwick, commented: “Our work to observe this new structure in space is highly significant in helping us map the exoplanet landscape.
“As scientists, we’re always striving to understand why planets are in the condition they are in, and how they ended up where they are.
“The discovery of the Neptunian ridge helps answer these questions, unveiling part of the geography of exoplanets out there, and is a hugely exciting discovery.”
The full paper was a collaboration between the Centro de Astrobiologia (CAB) annd the Universities of Geneva, Warwick, Coimbra and Paris. It can be read here.
ENDS
Notes to Editors
Artistic illustration of the Neptunian desert (left) and the Neptunian savanna (right) separated by the Neptunian ridge identified in this work. © Elsa Bersier / ERC project SPICE DUNE.
Journal
Astronomy and Astrophysics
Method of Research
Data/statistical analysis
