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Land ahoy! Experiments at GSI/FAIR reveal the shoreline of the island of stability of super-heavy elements

Matter and energy from Science Daily Feed - Wed, 01/15/2025 - 9:54am
A team of researchers has succeeded in exploring the limits of the so-called island of stability within the super-heavy nuclides more precisely by measuring the super-heavy rutherfordium-252 nucleus, which is now the shortest-lived known super-heavy nucleus.
Categories: Science

Three tiny 'stellar-ghost-town' galaxies discovered

Space and time from Science Daily Feed - Wed, 01/15/2025 - 9:52am
By combining data from the DESI Legacy Imaging Surveys and the Gemini South telescope, astronomers have investigated three ultra-faint dwarf galaxies that reside in a region of space isolated from the environmental influence of larger objects. The galaxies, located in the direction of NGC 300, were found to contain only very old stars, supporting the theory that events in the early Universe cut star formation short in the smallest galaxies.
Categories: Science

Engineers develop breakthrough method for aluminum surfaces, enabling advancements in cooling, self-cleaning and anti-icing technologies

Matter and energy from Science Daily Feed - Wed, 01/15/2025 - 9:52am
An international team of engineers has developed an innovative, scalable method for creating topography-patterned aluminum surfaces, enhancing liquid transport properties critical for applications in electronics cooling, self-cleaning technologies and anti-icing systems.
Categories: Science

Nord Stream methane spread across the southern Baltic Sea

Matter and energy from Science Daily Feed - Wed, 01/15/2025 - 9:51am
Methane from the destroyed Nord Stream pipelines spread over a large part of the southern Baltic Sea and remained for several months.
Categories: Science

Sensor tech and water filtration: Graphene made permeable for ions

Matter and energy from Science Daily Feed - Wed, 01/15/2025 - 9:51am
A milestone in graphene research: Chemists have succeeded in controlling the passage of halide ions by deliberately introducing defects into a two-layer nanographene system. Their paper shows new perspectives for applications in water filtration or sensor technology.
Categories: Science

The First Supernovae Flooded the Early Universe With Water

Universe Today Feed - Wed, 01/15/2025 - 9:11am

Water is the essence of life. Every living thing on Earth contains water within it. The Earth is rich with life because it is rich with water. This fundamental connection between water and life is partly due to water’s extraordinary properties, but part of it is due to the fact that water is one of the most abundant molecules in the Universe. Made from one part oxygen and two parts hydrogen, its structure is simple and strong. The hydrogen comes from the primordial fire of the Big Bang and is by far the most common element. Oxygen is created in the cores of large stars, along with carbon and nitrogen, as part of the CNO fusion cycle.

Because of its origin, we’ve generally thought that oxygen (and correspondingly water) grew in abundance over time. From the first stars to the present day, each generation cast oxygen into space in its dying moments. So, while water was rare in the early Universe, it is relatively common now. But a new study suggests that isn’t the case.

Astronomers categorize stars into populations depending on their age and metallicity, where “metals” are any elements other than hydrogen and helium. The youngest and most metal-rich stars, such as the Sun, are called Population I. Older stars with fewer metals are Population II. The oldest stars, the very first stars to appear in the Universe, are known as Population III. Though we haven’t observed Pop III stars directly, they would have been enormous stars made entirely of hydrogen and helium. The first seeds of everything we see around us, from oceans to trees to beloved friends, formed within these first stars. A new study on the arXiv argues that Pop III stars also flooded the cosmos with water.

In their study, the team modeled the explosions of small (13 solar mass) and large (200 solar mass) early stars. The large stars would have been the very first stars formed from primordial clouds, while the smaller stars would have been the first stars to form in early stellar nurseries. Not quite Pop III stars, but with very low metallicity. When the smaller stars died, they exploded as typical supernovae, but when the large stars died, they exploded as brilliant pair-instability supernovae.

Based on simulations, these stars would have greatly enriched the environment with water. The molecular clouds formed from the remnants of these stars had 10 to 30 times the water fraction of diffuse molecular clouds seen in the Milky Way today. Based on this, the team argues that by 100 to 200 million years after the Big Bang, there was enough water and other elements in molecular clouds for life to form.

Whether life actually did appear in the Universe so early is an unanswered question. There is also the fact that while water formed early, ionization and other astrophysical processes may have broken up many of these molecules. Water might have been plentiful early on, but the Universe entered a dry period before Pop II and Pop I stars generated the water levels we see today. But it’s possible that much of the water around us came from the very first stars.

Reference: Whalen, Daniel J., Muhammad A. Latif, and Christopher Jessop. “Abundant Water from Early Supernovae at Cosmic Dawn.” arXiv preprint arXiv:2501.02051 (2025).

The post The First Supernovae Flooded the Early Universe With Water appeared first on Universe Today.

Categories: Science

Celtic tribe's DNA points to female empowerment in pre-Roman Britain

New Scientist Feed - Wed, 01/15/2025 - 8:00am
Genetic evidence from Iron Age Britain shows that women tended to stay within their ancestral communities, suggesting that social networks revolved around women
Categories: Science

Is a broken jet stream causing extreme weather that lasts longer?

New Scientist Feed - Wed, 01/15/2025 - 8:00am
Scientists are scrambling to understand how climate change may be interfering with the winds that carry our weather, with potentially catastrophic consequences
Categories: Science

Red Note and Lemon8 are not the TikTok refuges you are looking for

New Scientist Feed - Wed, 01/15/2025 - 7:16am
The Chinese social media apps Red Note and Lemon8 have become popular alternatives for TikTok users ahead of a US government ban on TikTok. But government restrictions loom over those apps too
Categories: Science

Astronomers See Flares Coming from the Milky Way’s Supermassive Black Hole

Universe Today Feed - Wed, 01/15/2025 - 7:10am

There’s plenty of action at the center of the galaxy, where a supermassive black hole (SMBH) known as Sagittarius A* (Sgr A*) literally holds the galaxy together. Part of that action is the creation of gigantic flares from Sgr A*, which can give off energy equivalent to 10 times the Sun’s annual energy output. However, scientists have been missing a key feature of these flares for decades – what they look like in the mid-infrared range. But now, a team led by researchers at Harvard’s Center for Astrophysics and the Max Planck Institute for Radio Astronomy has published a paper that details what a flare looks like in those frequencies for the first time.

Astronomers have been observing Sgr A* since the 1990s and have known about the flares, which were initially seen as variances in the SMBH’s brightness. It has been observed with all manner of telescopes, including the Chandra X-ray observatory and, perhaps most famously, the Event Horizon Telescope, which was responsible for the famous first image of M87*, another black hole at the center of the Messier galaxy. EHT also released an image from Sgr A* itself in May of 2022.

So far, those observations have been in visible light through infrared and from far infrared up through X-rays. There has always been a gap in the middle of the infrared range. Several factors explain this gap.

Fraser talks about imaging Sgr A*

First, Sgr A* is relatively weak in the mid-infrared range compared to other ranges, so it doesn’t stand out as much against the background noise of the universe. Second, much of the mid-infrared emissions get obscured by the dust cloud surrounding the SMBH at the galaxy’s center, blocking it from detectors at Earth 28,000 light years away. Third, there were technological limitations to infrared sensors themselves. There were ground-based telescopes that could have detected the signal, but the Earth’s atmosphere blocked even more of it.

That required scientists to wait for the long-delayed James Webb Space Telescope (JWST). When it finally launched in late 2021, it was only a matter of time before they would get observational time to watch Sgr A* and hopefully observe a flare with the most powerful infrared detector ever launched into orbit. 

JWST did indeed get observational time with Sgr A* and saw a flare, representing the first-ever recording of a flare in the mid-infrared range. But the research team didn’t stop there – they were also watching with several other telescopes for confirmation of the JWST signal.

Fraser talks about other features of Sgr A*

They didn’t find any in the X-ray range with Chandra, though that was probably because the flare wasn’t strong enough to emit a significant amount of X-rays. But they did see a signal from the Sub-Millimeter Array (SMA) in Hawai’i, which detected radio waves following along about 10 minutes behind the detected mid-infrared signal.

That confirmation was necessary because it allowed the experimentalists to provide even more insight about the same flare to the theoreticians. Their job is then to confirm the models and simulations of what causes the flares in the first place. The current theory is that they occur when magnetic field lines in the SMBH’s accretion disk join up and emit massive amounts of radiation in a process known as synchrotron emission. In synchrotron emission, a bunch of charged particles – typically electrons – get pushed down the magnetic field lines like they were part of a massive particle accelerator.

The data from JWST fits nicely into that theory. However, there appear to be additional unanswered questions about whether that feature was specific to Sgr A* or whether it could be observed for other SMBHs such as M87*. For now, that remains to be seen, though given the interest in this particular black hole in this specific wavelength, while this might have been the first study published on the topic, it probably won’t be the last.

Learn More:
CfA – Scientists Make First-Ever Detection of Mid-IR Flares in Sgr A*
von Fellenberg et al – First mid-infrared detection and modeling of a flare from Sgr A*
UT – Echoes of Flares from the Milky Way’s Supermassive Black Hole
UT – A Black Hole Emitted a Flare Away From us, but its Intense Gravity Redirected the Blast Back in our Direction

Lead Image:
This artist’s conception of the mid-IR flare in Sgr A* captures the variability, or changing intensity, of the flare as the black hole’s magnetic field lines approach each other. The byproduct of this magnetic reconnection is synchrotron emission. The emission seen in the flare intensifies as energized electrons travel along the SMBH’s magnetic field lines at close to the speed of light. The labels mark how the flare’s spectral index changes from the beginning to the end of the flare.
Credit: CfA/Mel Weiss

The post Astronomers See Flares Coming from the Milky Way’s Supermassive Black Hole appeared first on Universe Today.

Categories: Science

COVID Is Still Here, But Changing

Science-based Medicine Feed - Wed, 01/15/2025 - 6:38am

My hospital just reinstituted mask mandates for all staff working with patients. They also advise patients to wear masks while in the hospital, but have not made it a requirement. I still have a stash of N95 masks so it was easy, and all too familiar, for me to comply, but I admit it created an unpleasant flash-back. All things considered, I […]

The post COVID Is Still Here, But Changing first appeared on Science-Based Medicine.
Categories: Science

Golden oyster mushrooms may stave off signs of ageing

New Scientist Feed - Wed, 01/15/2025 - 4:00am
Middle-aged mice fed golden oyster mushrooms had healthier hearts, suggesting an antioxidant in the fungi protects against the effects of ageing
Categories: Science

Wednesday: Hili dialogue

Why Evolution is True Feed - Wed, 01/15/2025 - 2:17am

Meanwhile, in Dobrzyn, Hili knows if you’ve been naughty or nice:

Hili: I can see everything.
A: What do you see?
Hili: You are sneaking chocolate again.
A: I have an important reason.

Hili: Ja wszystko widzę.
Ja: Co widzisz?
Hili: Znowu podjadasz czekoladę.
Ja: Mam ważny powód.

Categories: Science

Astronomers baffled by bizarre 'zombie star' that shouldn't exist

New Scientist Feed - Wed, 01/15/2025 - 2:00am
A newly discovered neutron star is behaving so strangely that it may alter our understanding of the dense remains left behind when stellar objects die
Categories: Science

Earth’s Temporary Moon Might Have Come from THE Moon

Universe Today Feed - Tue, 01/14/2025 - 6:45pm

A tiny asteroid loitering in a near-Earth orbit for a few months last year may have an intriguing origin on our Moon. Its characteristics led scientists to ask: is it a chip off the old lunar block, making a pass by Earth for a visit?

The object is known as Near-Earth Asteroid (NEA) 2024 PT5 (or PT5, for short) and its orbit is very similar to Earth’s. Oddly enough, that region often gets littered with rocket bodies. Interestingly, it’s also a region where debris blasted off the Moon during impacts tends to collect. So, could PT5 have come from the Moon? There’s a good chance that it did but how do we know this?

An artist’s impression of a lunar explosion, caused by the impact of a meteorite on the surface of the Moon. Such an impact could have created asteroid PT5. Credit: NASA/Jennifer Harbaugh

Planetary scientists have long studied Near-Earth objects (NEOs) and NEAs to understand their origins. One way to do that is to determine a relationship between their current orbits, properties, and sources, One such origin is the Main Asteroid Belt, but it’s not the only place where asteroids emerge. Each object is a special case, and scientists compare them with known meteorites. Of course, you need some data about the object’s physical characteristics—including its reflectance and albedo. Those two properties can often tell you what part of an asteroid population the object came from. They’re particularly important if there are no physical samples available for analysis.

Looking at Spectra of the Suspected Moon Chunk

A team of observers used the Lowell Discovery Telescope in Flagstaff, Arizona, to take reflectance spectra of PT5. This 10-meter-wide chunk of space rock was first discovered in August of 2024 by a survey project in South Africa. Its orbit made it a perfect target for another survey called MANOS (Mission Accessible Near-Earth Object Survey). The Lowell observations took place a week later to determine reflectance properties. Those are useful to figure out its origin—either natural or artificial. Subsequent observations of the object characterized its rotation and revealed it has a rocky, silicate-rich composition. That ruled out an artificial origin.

The reflectance spectrum from the Lowell telescope does give a match to known lunar samples. PT5 does not match any known asteroid types, however. For example, it looks to be pyroxene-rich, which indicates the rock came from an igneous or possibly metamorphic environment. Other asteroids aren’t the same—they tend to be richer in olivine. Based on that data and its tumbling motion, scientists conclude that it is ejecta from an impact on the Moon. If that’s the case, it’s only the second time a NEA has been found that came from the Moon.

Reflectance data from a MANOS survey of NEA 2024 PT5 made on January 7, 2025. Courtesy MANOS/Lowell Observatory.

If only one existed, we could say it’s a space oddity. However, the presence of two such objects changes the story. It also suggests that there’s a whole population out there waiting to be observed.

What PT5 Means

So, let’s say there is this collection of lunar chunks floating around out there. They can give insight into how impacts affect the Moon or other bodies such as Earth and Mars. They would also help identify the sources of other asteroids and meteorites from this under-studied population of near-Earth objects. In a paper discussing PT5, authors Theodore Kareta of Lowell Observatory, Oscar Fuentes-Munoz from NASA JPL, and others, describe their study of this rock, its orbit, and physical characteristics. They write, “If there really is a population of Moon Rocks out there waiting to be discovered on near-Earth orbits, they almost certainly are rare members of the NEO population.”

There may well be only about 16 currently known NEOs that could have come from the Moon, but there could be more. Now, the challenge is to separate them from the general population of near-Earth objects and subject them to further study. Since the orbits of lunar ejecta pieces tend to evolve into Aten- or Apollo-type orbits, the authors point out there could be between 5 and 10 times more of these lunar chips off the old block in the neighborhood. (Aten asteroids are a group known as “Earth-crossing” asteroids because their orbits cross our planet’s orbit. Apollo asteroids also follow orbits that cross ours.)

Three classes of asteroids that pass near Earth or cross its orbit are Apollo, Aten and Amor. Apollo asteroids like 2014 SC324 routinely cross Earth’s orbit, Atens also cross but have different orbital characteristics and Amors cross Mars’ orbit but miss Earth’s. Credit: ESA Future Observations of Suspected Moon Pieces

If there is a larger population of lunar-sourced asteroids in near-Earth-type orbits, then the next step is to figure out ways to find them. Certainly, asteroid surveys will help, along with further observations of their reflectance and charts of their orbits. Since these asteroids are generally thought to be relatively small, it will take a new generation of larger telescopes and observational techniques to find them.

Probably one of the greatest results of the search for these objects is what they can tell us about impact histories in the inner solar systems. The paper’s authors point this out. “First at Mars and now at the Earth, the impact histories of the terrestrial planets appear to be partially encoded in the asteroids that orbit nearby to them. Future work to discover more of and measure the properties of this population of near-Earth objects which are sourced by the Moon will be critical to link asteroid and lunar science in the era of Artemis and the Vera Rubin Observatory’s LSST.”

The next chance to observe PT5 is coming up this month when it lingers near Earth again. NASA has plans to track it with radar and undoubtedly others will be studying it to understand more about this “mini-Moon”.

For More Information

On The Lunar Origin of Near-Earth Asteroid 2024 PT5
NASA to Track Asteroid 2024 PT5 on Next Close Pass, January 2025

The post Earth’s Temporary Moon Might Have Come from THE Moon appeared first on Universe Today.

Categories: Science

Galaxy Cores May be Giant Fuzzy Dark Stars

Universe Today Feed - Tue, 01/14/2025 - 6:20pm

A fuzzy form of dark matter may clump up to become the cores of galaxies, according to new research.

The traditional dark matter hypothesis, that it’s some form of cold, massive particle that hardly ever interacts with itself or with normal matter, has some difficulties. In particular, it can’t quite explain the dense cores of galaxies. Cold, heavy dark matter tends to produce extremely dense cores, far denser than what we observe.

But dark matter might be something else. Recently astronomers have hypothesized that dark matter might instead be incredibly light, far lighter than any known particle. This “fuzzy” dark matter would allow the quantum wave nature of the particles to manifest on macroscopic – even galactic – scales, allowing them to form large, diffuse clumps known as “dark stars.”

Dark stars can be incredibly huge, stretching for thousands of light-years, while still having relatively low density. This would match observations of galaxy cores, which makes this an intriguing hypothesis to follow.

In a recent letter appearing in the preprint server arXiv in December, an international collaboration of astrophysicists explored how galaxies might evolve in response to fuzzy dark matter. For this first step, they did not attempt to fully recreate an entire complex galaxy. Instead they built a simple toy model containing only two components: a large fraction of fuzzy dark matter and a smaller fraction of a simple, ideal gas.

They then simulated how these two components would interact with each other and evolve. They found that no matter how they start off, normal matter and fuzzy dark matter quickly find an equilibrium, with the two kinds of matter mixing together to make a large, stable core, surrounded by a cloud of dark matter.

The researchers pointed out that this would serve as the ideal representation of a galactic core, which contains higher – but not too high – densities of normal matter. This is the first step to confirming a key prediction of the fuzzy dark matter model. However, there is still a lot of work to be done. The next step is to build even more realistic simulations of the growth and evolution of galaxies, tracking how fuzzy dark matter, and the dark stars they create, influences their local environments. Then we can take those results and compare to observations to see if this idea is worth investigating even more.

The post Galaxy Cores May be Giant Fuzzy Dark Stars appeared first on Universe Today.

Categories: Science

This Quasar Helped End the Dark Ages of the Universe

Universe Today Feed - Tue, 01/14/2025 - 3:47pm

After the Big Bang came the Dark Ages, a period lasting hundreds of millions of years when the universe was largely without light. It ended in the epoch of reionization when neutral hydrogen atoms became charged for the first time and the first generation of stars started to form. The question that has perplexed astronomers is what caused the first hydrogen atoms to charge. A team of researchers have observed an early quasar that pumped out enormous amounts of x-ray radiation helping to drive the reionization. 

The universe began with the Big Bang around 13.8 billion years ago, starting as a hot, dense point that was infinitely small. In the first few minutes, light elements like hydrogen and helium formed, and a few hundred million years later – possibly as early as 380,000 years, the Cosmic Microwave Background (CMB) marked the end of the Dark Ages. Gravity then pulled matter together, forming the first stars and galaxies during the Epoch of Reionization. These early stars ionized hydrogen, making the universe transparent. Over billions of years, galaxies merged and structures formed, with our solar system emerging around 4.6 billion years ago. 

The full-sky image of the temperature fluctuations (shown as color differences) in the cosmic microwave background, made from nine years of WMAP observations. These are the seeds of galaxies, from a time when the universe was under 400,000 years old. Credit: NASA/WMAP

The transition between the Dark Age and the Reionization phase has been the subject of study by a team of astronomers from Yale University. They have detected intense periods of brightening and dimming of a quasar about 12 billion light years away. The observation sheds some light on the accelerated rate of growth experienced by some objects in the early universe.

The quasar identified by the team goes by the catchy title J1429+5447. It’s found in the constellation of Lyra and is so far away that its light takes 12 billion years to reach us, this means we see it now as it was just 1.6 billion years after the Big Bang. Studying it gives us a real insight into the early evolution of the universe. At its centre is a supermassive black hole which accretes matter and in the process emits intense amounts of radiation across the whole electromagnetic spectrum. The team announced their discovery on 14 January at a meeting of the American Astronomical Society. 

Artist’s impression of a quasar core. Quasars are powered by interactions between supermassive black holes and their accretion disks at the hearts of galaxies. JWST observed one in infrared light to reveal its feeding mechanism. Courtesy T. Mueller/MPIA.

Using NuSTAR, an X-ray space telescope to study the quasar they compared their observations with previous studies 4 months earlier using the Chandra X-ray telescope. To their surprise, in just 4 months, the X-ray emissions from the quasar doubled! 

The spectral ranges of the XMM-Newton and NuSTAR Telescopes. (Credits: NASA, ESA)

Meg Urry, Professor of Physics and Astronomy and co-author explained ‘The level fo X-ray variability in terms of intensity and rapidity is extreme.  It is almost certainly explained by a jet pointing toward — a cone in which particles are transported up to a million light years away from the central, supermassive black hole. Because the jet moves at nearly the speed of light, effects of Einstein’s theory of special relativity speed up and amplify the variability.”

The team believe these early quasars like J1429+5447 provided the energy to end the Dark Ages and herald in the Reionisation period. Their study has revealed how crucial quasars were to the early evolution of the universe.

Source : This quasar may have helped turn the lights on for the universe

The post This Quasar Helped End the Dark Ages of the Universe appeared first on Universe Today.

Categories: Science

Webb Provides an Explanation for “Little Red Dots”

Universe Today Feed - Tue, 01/14/2025 - 3:42pm

When a new space telescope is launched, it’s designed to address specific issues in astronomy and provide critical answers to important questions. The JWST was built with four overarching science goals in mind. However, when anticipating new telescopes, astronomers are quick to point out that they’re also excited by the unexpected discoveries that new telescopes make.

There has been no shortage of unexpected discoveries regarding the JWST, especially regarding the very early Universe.

In December 2022, after the JWST had been performing science operations for just six months, the telescope revealed the presence of small red objects in the high-redshift sky. Astronomers called them Little Red Dots (LRDs). The nature of these objects wasn’t obvious, but they’re abundant, and astronomers are curious about what they can tell us about the early Universe.

Recently, a team of researchers compiled a large sample of these LRDs. Most of them existed only 1.5 billion years after the Big Bang. According to observations, a large number of the LRDs may contain growing supermassive black holes (SMBHs). There is no class of corresponding objects at lower redshifts, which only deepens their mysterious nature.

The new research is “The Rise of Faint, Red AGN at z>4: A Sample of Little Red Dots in the JWST Extragalactic Legacy Fields.” It’s been accepted for publication in The Astrophysical Journal, and the lead author is Dale Kocevski of Colby College in Waterville, Maine. The paper is available on the pre-print server arxiv.org.

“We’re confounded by this new population of objects that Webb has found. We don’t see analogs of them at lower redshifts, which is why we haven’t seen them prior to Webb,” said lead author Kocevski. “There’s a substantial amount of work being done to try to determine the nature of these little red dots and whether their light is dominated by accreting black holes.”

The JWST has generated an enormous amount of data during its observations. The astronomers behind the sample of LRDs used publicly available data from the CEERS, PRIMER, JADES, UNCOVER and NGDEEP surveys. While they’re not the first to probe datasets for LRDs, the team used a different methodology that identified LRDs over a wider redshift range. They identified 341 LRDs spanning from about redshift 2 to 11. The researchers found that LRDs emerged in large numbers only 600 million years after the Big Bang, before their number rapidly around 1.5 billion years after the Big Bang.

These images from the research show a subset of the 341 Little Red Dots from the various surveys. Image Credit: Kocevski et al. 2024.

Fortunately, some spectroscopic data are already available for a portion of the LRDs in the Red Unknowns: Bright Infrared Extragalactic Survey (RUBIES), which contains JWST/NIRSpec spectroscopy of red sources. The spectroscopic data showed that about 70% of the LRDs show evidence of rapidly rotating gas. The gas is moving at about 1,000 km per second, indicating that these could be accretion disks around supermassive black holes.

The conclusion seems pretty clear: LRDs are active galactic nuclei (AGN), which are black holes that are actively feeding. But why do they peter out after about 1.5 billion years after the Big Bang?

“The most exciting thing for me is the redshift distributions. These really red, high-redshift sources basically stop existing at a certain point after the big bang,” said Steven Finkelstein, a co-author of the study at the University of Texas at Austin. “If they are growing black holes, and we think at least 70 percent of them are, this hints at an era of obscured black hole growth in the early universe.”

Most of us remember when some overeager headlines claimed that the JWST had “broken cosmology.” The discovery of LRDs was responsible for some of this thinking. If the light coming from the LRDs was from stars, then some galaxies had to have grown very large very fast. Our theories couldn’t account for them.

If these results are true, then the light is coming from active galactic nuclei rather than large, rapidly growing galaxies. In this case, our theories are safe (for now).

“This is how you solve the universe-breaking problem,” said Anthony Taylor, a co-author of the study at the University of Texas at Austin.

In their paper, the authors highlight some of their important points.

“One of our primary findings is that the red compact objects that have come to be known as little red dots appear in large numbers at z > 4,” they write. “The redshift distribution that we observe for our sample of LRDs may provide insight into the nature of their obscuration and the mechanisms fueling their nuclear activity.”

This figure shows the redshift distribution of the final sample of LRDs in the research. Image Credit: Kocevski et al. 2024.

Their obscuration could result from what’s called “inside-out growth.” In that model, stars begin forming in a galaxy’s central regions first, and they are created more rapidly in those regions. Eventually, star birth moves outward to a galaxy’s periphery. This is because gas collapses inward due to gravity, fuelling star birth in the center. That same collapsing gas could also trigger the concurrent growth of the galaxy’s SMBH. This can also explain the red colour we see. “The rapid accumulation of metals in the proto-bulge then provides the reddening we observe,” the authors write.

As star birth moves outward, less dust is deposited near the AGN, meaning that over time, there are fewer LRDs.

However, inside-out growth is only one potential explanation for LRDs, though it’s a good fit with much of the existing data. The team intends to follow up on this work with mid-infrared imaging and spectroscopy. That will help them understand the number density of these faint AGN and shed more light on what’s obscuring them.

“There’s always two or more potential ways to explain the confounding properties of little red dots,” said Kocevski. “It’s a continuous exchange between models and observations, finding a balance between what aligns well between the two and what conflicts.”

Whatever exactly is going on with LRDs, the issue shows how powerful unexpected discoveries can be. It also shows, again, how valuable the JWST is.

“While much remains to be determined about the nature of LRDs, the prevalence of broad emission lines in their spectra suggests this population is shedding light on a phase of obscured black hole growth in the early universe that was largely undetected prior to the JWST era,” the authors conclude.

The post Webb Provides an Explanation for “Little Red Dots” appeared first on Universe Today.

Categories: Science

A new definition of obesity could help treat millions of people

New Scientist Feed - Tue, 01/14/2025 - 3:30pm
Obesity is typically assessed by measuring someone's body mass index, but now researchers are calling for a more nuanced approach that could help with treatment
Categories: Science

Researchers invent soft, bioelectronic sensor implant

Computers and Math from Science Daily Feed - Tue, 01/14/2025 - 3:17pm
Scientists describe their construction of complementary, internal, ion-gated, organic electrochemical transistors that are more amenable chemically, biologically and electronically to living tissues than rigid, silicon-based technologies. The medical device based on these transistors can function in sensitive parts of the body and conform to organ structures even as they grow. The result is a biocompatible sensor that can monitor brain functions in pediatric patients as they develop and grow.
Categories: Science

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