James Webb captures dramatic image of newborn star | Digital Trends

James Webb captures dramatic image of newborn star | Digital Trends

A new image of a Herbig-Haro object captured by the James Webb Space Telescope shows the dramatic outflows from a young star. These luminous flares are created when stellar winds shoot off in opposite directions from newborn stars, as the jets of gas slam into nearby dust and gas at tremendous speed. These objects can be huge, up to several light-years across, and they glow brightly in the infrared wavelengths in which James Webb operates.

This image shows Herbig-Haro object HH 797, which is located close to the IC 348 star cluster, and is also nearby to another Herbig-Haro object that Webb captured recently: HH 211.

The NASA/European Space Agency/Canadian Space Agency’s James Webb Space Telescope reveals intricate details of Herbig Haro object 797 (HH 797). Herbig-Haro objects are luminous regions surrounding newborn stars (known as protostars), and are formed when stellar winds or jets of gas spewing from these newborn stars form shock waves colliding with nearby gas and dust at high speeds. ESA/Webb, NASA & CSA, T. Ray (Dublin Institute for Advanced Studies)

The image was taken using Webb’s Near-Infrared Camera (NIRCam) instrument, which is particularly suited to investigating young stars, Webb scientists explain in a statement, : “Infrared imaging is a powerful way to study newborn stars and their outflows, because the youngest stars are invariably still embedded within the gas and dust from which they are formed. The infrared emission of the star’s outflows penetrates the obscuring gas and dust, making Herbig-Haro objects ideal for observation with Webb’s sensitive infrared instruments.

“Molecules excited by the turbulent conditions, including molecular hydrogen and carbon monoxide, emit infrared light that Webb can collect to visualize the structure of the outflows. NIRCam is particularly good at observing the hot (thousands of degree Celsius) molecules that are excited as a result of shocks.”

This particular Herbig-Haro object is unusual in that scientists originally believed that it was created from a single young star, as most such objects are. But these detailed observations reveal that there are actually two sets of outflows, coming from a pair of stars at the center.

In addition to the bright ripples of the Herbig-Haro object in the lower half of the image, there are also thought to be more new stars being born in the upper half of the image. The bright smudge in shades of yellow and green is believed to host two young protostars.

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Rocky planets could form in extreme radiation environment | Digital Trends

Rocky planets could form in extreme radiation environment | Digital Trends

It takes a particular confluence of conditions for rocky planets like Earth to form, as not all stars in the universe are conducive to planet formation. Stars give off ultraviolet light, and the hotter the star burns, the more UV light it gives off. This radiation can be so significant that it prevents planets from forming from nearby dust and gas. However, the James Webb Space Telescope recently investigated a disk around a star thatseems like it could be forming rocky planets, even though nearby massive stars are pumping out huge amounts of radiation.

The disk of material around the star, called a protoplanetary disk, is located in the Lobster Nebula, one of the most extreme environments in our galaxy. This region hosts massive stars that give off so much radiation that they can eat through a disk in as little as a million years, dispersing the material needed for planets to form. But the recently observed disk, named XUE 1, seems to be an exception.

This is an artist’s impression of a young star surrounded by a protoplanetary disk in which planets are forming. ESO

The researchers used James Webb’s Mid-Infrared Instrument (MIRI) to identify water, carbon monoxide, carbon dioxide, hydrogen cyanide, and acetylene in the disk. Those are some of the building blocks for rocky planets and show that the disk is similar to other planet-forming disks, despite the high amount of UV radiation.

“We were surprised and excited because this is the first time that these molecules have been detected under these extreme conditions,” said one of the authors, Lars Cuijpers of Radboud University, in a statement.

The problem for this disk is that there are a number of nearby massive stars, so the disk is being bombarded by UV radiation from several sources. The disk does seem to be a bit smaller than expected, but it still appears that it could be capable of forming rocky planets. That means that rocky planets could form even in very extreme environments, if this particular disk is not an outlier.

“XUE 1 shows us that the conditions to form rocky planets are there, so the next step is to check how common that is,” said lead researcher María Claudia Ramírez-Tannus of the Max Planck Institute for Astronomy. “We will observe other disks in the same region to determine the frequency with which these conditions can be observed.”

The research is published in The Astrophysical Journal.

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Dr. Nergis Mavalvala Helped Detect the First Gravitational Wave. Her Work Doesn’t Stop There

Dr. Nergis Mavalvala Helped Detect the First Gravitational Wave. Her Work Doesn’t Stop There

“Where did all this come from? How did it all get started?”

These are the questions that Dr. Nergis Mavalvala asks about the universe. It’s not the meaning-of-life stuff in the traditional sense, but more of how everything around us came to be. These are the questions we all have, but for Dr. Mavalvala, finding the answers is her life’s work. It’s why she became a physicist.

“I began to understand that these questions are mostly answered outside of our planet, outside of our solar system,” she explains. “It really lies in the universe. And that’s how I got interested in astrophysics.”

As dean of MIT’s School of Science, Dr. Mavalvala has her hands full with her day-to-day responsibilities, but she still has time for her first love: physics.

Black Holes Are More Important Than You Think

“When we look out into the universe, almost all the information we have gathered about the universe over millennia as humans and sentient beings is through light,” Dr. Mavalvala says. But black holes don’t give us light, she points out. That makes them hard to understand. “A black hole is a good example of something that has so much gravity that even light can’t escape its gravitational pull. And how do you study those kinds of objects?”

The answer: gravitational waves.

“About 100 years ago, Einstein gave us a clue to that, which was that there were these objects called gravitational waves, which are essentially waves that are given off by objects because of their gravity,” she explains. “Because they’re really massive and they’re moving, they will cause waves in the spacetime itself.”

It was these ripples in spacetime that drew Dr. Mavalvala in, both the science behind them and the technology that we’d have to build to detect them.

“If we want to answer the question of how our universe came to be and why we see the universe we do today, we have to understand things like black holes,” she says. “They’re important building blocks of the universe. If you want a complete picture of the world around us, then you need to use every messenger that nature provides. Gravitational waves are one such messenger, as is light.”

Detecting Gravitational Waves with LIGO

For much of Dr. Mavalvala’s career, these gravitational waves—ripples in spacetime that result from collisions between massive objects such as black holes—were theoretical.

“I got started with LIGO when I was a graduate student at MIT in the early 1990s,” Dr. Mavalvala says, referring to the Laser Interferometer Gravitational-Wave Observatory in the US. “The team of people who were working on it were seen as sort of a ragtag team of dreamers.” Her PhD adviser, Nobel laureate Dr. Rainer Weiss, was one of the founders of the project, but many of her graduate school colleagues warned her not to pursue this path. At the time, there was still some debate about whether gravitational waves even existed. “It was sort of a maverick science,” she explains. “And I have to say, in some ways, that was part of the draw, to be part of something so improbable.”

Starquakes Might Solve the Mysteries of Stellar Magnetism

Starquakes Might Solve the Mysteries of Stellar Magnetism

That was a surprise—and a possible indication that something crucial was missing in those models: magnetism.

Stellar Symmetry

Last year, Gang Li, an asteroseismologist now at KU Leuven, went digging through Kepler’s giants. He was searching for a mixed-mode signal that recorded the magnetic field in the core of a red giant. “Astonishingly, I actually found a few instances of this phenomenon,” he said.

Typically, mixed-mode oscillations in red giants occur almost rhythmically, producing a symmetric signal. Bugnet and others had predicted that magnetic fields would break that symmetry, but no one was able to make that tricky observation—until Li’s team.

Li and his colleagues found a giant trio that exhibited the predicted asymmetries, and they calculated that each star’s magnetic field was up to “2,000 times the strength of a typical fridge magnet”—strong, but consistent with predictions.

However, one of the three red giants surprised them: Its mixed-mode signal was backward. “We were a bit puzzled,” said Sébastien Deheuvels, a study author and an astrophysicist at Toulouse. Deheuvels thinks this result suggests that the star’s magnetic field is tipped on its side, meaning that the technique could determine the orientation of magnetic fields, which is crucial for updating models of stellar evolution.

A second study, led by Deheuvels, used mixed-mode asteroseismology to detect magnetic fields in the cores of 11 red giants. Here, the team explored how those fields affected the properties of g-modes—which, Deheuvels noted, may provide a way to move beyond red giants and detect magnetic fields in stars that don’t show those rare asymmetries. But first “we want to find the number of red giants that show this behavior and compare them to different scenarios for the formation of these magnetic fields,” Deheuvels said.

Not Just a Number

Using starquakes to investigate the interiors of stars kicked off a “renaissance” in stellar evolution, said Conny Aerts, an astrophysicist at KU Leuven.

The renaissance has far-reaching implications for our understanding of stars and of our place in the cosmos. So far, we know the exact age of just one star—our sun—which scientists determined based on the chemical composition of meteorites that formed during the birth of the solar system. For every other star in the universe, we only have estimated ages based on rotation and mass. Add internal magnetism, and you have a way to estimate stellar ages with more precision.

Super high energy particle falls to Earth, source a mystery | Digital Trends

Super high energy particle falls to Earth, source a mystery | Digital Trends

Researchers have detected one of the highest-energy particles ever falling to Earth. Cosmic rays are high-energy particles that come from sources in space such as the sun, but this recent detection is more powerful than anything that can be explained by known sources in our galaxy or even beyond. The particle had an energy of 2.4 x 1020eV, which is millions of times the energy of the particles produced in a particle collider.

Artist’s illustration of ultra-high-energy cosmic ray astronomy to clarify extremely energetic phenomena. Osaka Metropolitan University/Kyoto University/Ryuunosuke Takeshige

The detection was made in May 2021 using a facility called the Telescope Array, located near Salt Lake City in Utah. It has 500 surface detectors which are spread over 300 square miles of desert, designed to detect cosmic ray events. It has observed more than 30 ultra-high-energy cosmic rays since 2007, but this was the most powerful one detected so far.

It is the second most powerful cosmic ray ever detected, only beaten out by one detected in 1991 which was named the Oh-My-God particle. The strange thing about these events is that the researchers have no idea where they are coming from.

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“The particles are so high energy, they shouldn’t be affected by galactic and extra-galactic magnetic fields. You should be able to point to where they come from in the sky,” said one of the researchers, John Matthews of the University of Utah, in a statement. “But in the case of the Oh-My-God particle and this new particle, you trace its trajectory to its source and there’s nothing high energy enough to have produced it. That’s the mystery of this—what the heck is going on?”

Even a big event like a supernova would be nowhere near powerful enough to produce particles like this, and the particle seemed to come from an empty area of space on the edge of the Milky Way called the Local Void. “These events seem like they’re coming from completely different places in the sky. It’s not like there’s one mysterious source,” said another of the researchers, John Belz. “It could be defects in the structure of spacetime, colliding cosmic strings. I mean, I’m just spit-balling crazy ideas that people are coming up with because there’s not a conventional explanation.”

The researchers hope to use upcoming facilities like an expansion to the Telescope Array to find and study more of these events and learn about their possible source. “It’s a real mystery,” said Belz.

The research is published in the journal Science.

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Stunning James Webb image shows the heart of our Milky Way | Digital Trends

Stunning James Webb image shows the heart of our Milky Way | Digital Trends

A new image from the James Webb Space Telescope shows the heart of our galaxy, in a region close to the supermassive black hole at the center of the Milky Way, Sagittarius A*. The image shows a star-forming region where filaments of dust and gas are clumping together to give birth to new baby stars.

The image was captured using Webb’s NIRCam instrument, a camera that looks in the near-infrared portion of the electromagnetic spectrum with shorter wavelengths shown in blue and cyan and longer wavelengths shown in yellow and red.

The full view of the NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) instrument reveals a 50 light-years-wide portion of the Milky Way’s dense center. An estimated 500,000 stars shine in this image of the Sagittarius C (Sgr C) region, along with some as-yet-unidentified features. NASA, ESA, CSA, STScI, S. Crowe (UVA)

This region is called Sagittarius C, and is located around 300 light-years away from the supermassive black hole Sagittarius A*. For reference, Earth is located much further away from the galactic center, at a distance of around 26,000 light years from Sagittarius A*.

There are thought to be as many as 500,000 stars in the Sagittarius C region, including many young protostars, some of which will go on to become main-sequence stars like our sun. As stars form, they give off powerful stellar winds which blow away nearby material and prevent more stars from forming very close to them.

These outflows are illuminated in the infrared wavelength, and the cyan-colored patches in the image are created by ionized gas. The young stars give off a great deal of energy, which ionizes the hydrogen gas around them and makes them glow in the infrared.

However, there are actually even more stars in this area than can be seen in the image. The pockets of darkness scattered throughout the image aren’t blank but are dense clouds that are dark in the infrared, including a large dense area in the heart of the region.

There are still some surprises to be found in the image too, with some features that scientists need to study in more depth. “Researchers say they have only begun to dig into the wealth of unprecedented high-resolution data that Webb has provided on this region, and many features bear detailed study,” Webb scientists write. “This includes the rose-colored clouds on the right side of the image, which have never been seen in such detail.”

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Why can’t we measure how fast the universe is expanding? | Digital Trends

Why can’t we measure how fast the universe is expanding? | Digital Trends

A view of thousands of galaxies in the galaxy cluster MACS0416, combining data from the James Webb Space Telescope and the Hubble Space Telescope. NASA

Something very strange is going on in the universe. The science of cosmology, which studies the universe on a grand scale, is in a state of crisis. Over the last century, scientists have found mountains of evidence that the universe is expanding over time, as they observed that the further away from Earth a galaxy is, the faster it is moving away from us.

The problem is that no one is sure how fast this expansion is happening. Two different ways of measuring this value, called the Hubble constant, produce two different results. The last decades have seen the best theories and experiments that humanity can come up with struggle to explain how this could be so.

Usually, when there’s a discrepancy like this, newer technologies enable more accurate experimental data which helps to solve the mystery. But in the case of this puzzle, called the Hubble tension, the more we learn, the harder it is to explain the discrepancy.

The cosmological distance ladder

When the Hubble Space Telescope was launched in 1990, one of its main aims was to investigate the expansion of the universe. The debate over the rate of this expansion was raging, and scientists were keen to pin down an answer more precisely — because this information was crucial to understanding the age of the universe, and at this time that age could have been as little as 8 billion years old or as much as 20 billion years.

By the late 2000s, scientists had honed in on a figure by looking at stars that brightened in a particular rhythm, called Cepheid variables, and a particular type of supernova called Type Ia supernovae. Both of these objects have a predictable level of brightness, which means they can be used to measure distance — Cephids for closer galaxies and Type Ia supernovae for more distant ones — so they are used as “standard candles” for astronomical measurements.

This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J, a Type Ia supernova, in the galaxy M82.
This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J, a Type Ia supernova, in the galaxy M82. NASA, ESA, A. Goobar (Stockholm University), and the Hubble Heritage Team (STScI/AURA)

With these accurate distance measurements, the value Hubble scientists came up with for the expansion of the universe was 72 kilometers per second per megaparsec. That’s a measurement of the amount of expansion by time by distance, because the further away from us galaxies are, the faster they are moving. A parsec is 3.26 light-years, and a megaparsec is one million parsecs. So if we look at a galaxy 3.26 million light-years away, it will be moving away from us at around 70 kilometers per second, or around 150,000 mph.

That measurement was an enormous scientific step forward, but it still had a potential error of around 10%. Subsequent research managed to chip away at reducing this error, honing in on a recent figure of 73.2km/s/Mpc with an error rate of under 2%, but they were bumping up against the physical limitations of the telescope.

A new telescope in the toolkit

While one group of astronomers was busy with data from the Hubble Space Telescope, another was looking in quite a different place, by examining the Cosmic Microwave Background, or CMB. This is the leftover energy remaining from the Big Bang and it’s seen everywhere as a constant very slight background hum. When calculating the Hubble constant based on this data, researchers found quite a different figure: 67 km/s/Mpc. That difference might seem small, but it’s stubborn: The more accurately each group made its measurements, the more entrenched the divide seemed.

A scientist examines the mirrors on the James Webb Space Telescope.
A scientist examines the mirrors on the James Webb Space Telescope. Chris Gunn / NASA

But when the James Webb Space Telescope was launched in 2021, researchers had a new and even more accurate tool for their measurements. A group of researchers including Richard Anderson of the Swiss Federal Institute of Technology Lausanne got to work double-checking Hubble’s measurements using this new technology. Perhaps the Hubble Space Telescope’s measurements had been inaccurate due to the limitations of the telescope, which might explain the different figures, and this new tool could help to show if that was the case.

The advantage James Webb has over Hubble in this context is greater spatial resolution when looking at Cephids. “Previously, when you had lower resolution you needed to statistically correct for the light of sources that blend together,” Anderson explained to Digital Trends. And this statistical correction introduced a nugget of doubt into the Hubble data. Perhaps the rate of expansion measured by Hubble was inaccurate, some argued, because the statistical tools used for this correction were inaccurate.

With the better spatial resolution of new Webb data, though, that statistical correction is much smaller. “So if you don’t have to correct so much, you add less error, and your measurement becomes more precise,” Anderson said. Not only does the Webb data agree with the previous Hubble measurements, but it increases the precision of that measurement too.

The evidence is in, and it’s clear: Hubble’s measurements of the rate of expansion are correct. Of course, nothing this complex can be proved beyond any shadow of doubt, but the measurements are as accurate as we can practically make them.

A sticky problem

So if the Hubble telescope data is correct, maybe the problem is with the other measurement. Maybe it’s the Cosmic Microwave Background data that is wrong?

That’s tough too, however. Because just as researchers were refining the figure from Hubble data, so too the CMB researchers were making their own figure more and more accurate. The biggest step forward in this field was the launch of the European Space Agency’s Planck space observatory in 2009. This mission was specifically designed to measure the CMB and it acquired the most accurate data yet of the small variations in temperature across the CMB. That’s important because although the CMB is at a consistent temperature almost everywhere, there are tiny variations in this temperature of 1 part in 100,000.

An artist's rendition shows ESA's Planck Space Observatory.
An artist’s rendition shows ESA’s Planck Space Observatory. ESA

As small as these temperature variations are, they are important because they represent variations that were present when the universe was forming. Looking at the variations as they exist now, researchers can roll back the clock to understand what the universe must have looked like in its earliest stages.

When researchers use this Planck data to estimate the expansion of the universe, based on our understanding of the universe as it existed when it was young, they honed in on a figure for the constant of 67.4 km/s/Mpc with an error of less than 1%. There’s no crossover between the uncertainties of the two figures anymore — they’re both solid, and they don’t agree.

A history of expansion

Scientists have been studying the CMB since the 1960s, and in that time the research has progressed to a degree of precision that makes its specialists confident in their findings. When it comes to modeling the inflation of the universe in its early stages, they have gotten about as accurate as possible according to Jamie Bock of Caltech, PI for NASA’s upcoming SPHEREx mission to investigate the CMB.

“The microwave background is very close to hitting cosmological limits on those measures,” Bock said. “In other words, you can’t build a better experiment. You’re just limited on how much of the universe you can see.”

An artist's rendition of NASA's SPHEREx space mission.
An artist’s rendition of NASA’s SPHEREx space mission. NASA

SPHEREx will be a space-based mission that won’t take direct measurements of the Hubble constant. But it will help researchers learn about the history of the universe’s expansion, by investigating a period of the early universe called inflation when the universe expanded rapidly. In this very early period, the universe was much, much smaller, hotter, and denser, and that affected the way in which it expanded. Over its lifetime, the most significant driving factors of the universe’s expansion have changed as it has grown, cooled, and become less dense. We know that today, a hypothesized form of energy called dark energy is the main force pushing the universe to expand. But at other times in the universe’s history, other factors such as the presence of dark matter have been more significant.

“The trajectory of the universe is set by the type of matter and energy that are dominant at that time,” Bock explained. Dark energy, for example, “has only started to dominate the expansion of the universe in the latter half of the age of the universe. Prior to that, it would have been dark matter that would drive the evolution of the universe.”

One popular theory for the difference in the two measurements is that dark energy could be the culprit. Perhaps there was more dark energy in the early universe than is currently believed, which would make it expand faster. We might learn more about this possibility with new missions like ESA’s Euclid, which launched recently and aims to map a huge chunk of the universe in 3D to study dark matter and dark energy.

A thermometer for our understanding of the universe

You can think of the two values of the Hubble constant as measuring from the universe as we see it now, called the late universe, compared to measuring from the universe as it was when it was young, called the early universe. When the two different rates were calculated using less accurate methods, it was possible that the two could actually be in agreement but just appeared further apart due to overlapping errors.

But as scientists have reduced these errors down and down, that explanation can’t work anymore. Either one of the measurements is wrong — always possible, but increasingly unlikely given the mountain of data on each — or there’s something fundamental about the universe that we just don’t understand yet.

“The thermometer tells us that we have a fever.”

“What we have here is like a thermometer of how good our understanding is of the cosmos at this time,” Anderson said. “And I think the thermometer tells us that we have a fever, and we have a problem.”

And bear in mind, the Hubble constant isn’t a minor issue. It’s a fundamental measurement, arguably the most important number in cosmology. And the more accurate our measurements of it get, the more the mystery deepens.

Searching for independent verification

This is another way of measuring the universe as we see it now, and that’s by looking at gravitational waves. When massive enough objects collide, such as two black holes merging, the enormous forces create ripples in spacetime called gravitational waves, which can be detected from billions of light-years away.

These ripples can be detected on Earth by specialized facilities like LIGO (the Laser Interferometer Gravitational-Wave Observatory) and can be used to determine how far away a source is, which means they can theoretically be used to measure the rate of expansion as well.

An aerial view shows the Laser Interferometer Gravitational-Wave Observatory.
Laser Interferometer Gravitational-Wave Observatory The Virgo collaboration/CCO 1.0

This is a late universe measurement, but it’s also completely independent of the Cephids and supernovas used in other research. That means that if measurements of the expansion rate appear similar based on gravitational wave data, we could be even more confident that the higher figure is correct — and if they don’t, then we’d know better where the problem is.

The advantage of using gravitational waves for this type of measurement is that the signature is very clean — “the only thing that affects it is very heavy masses,” said gravitational wave expert Stefan Ballmer of Syracuse University. And when black holes merge, their dynamic behavior is very consistent, no matter their size. That makes them ideal standard candles for measuring distances — “about as good as it gets,” according to Ballmer.

So measuring distance with gravitational waves is relatively simple. The challenge with using these measurements for calculating the expansion rate is finding the velocity. With supernovas, it’s easy to know the redshift (which gives you the velocity) but hard to know the absolute brightness (which gives you the distance). Whereas with gravitational waves it’s easy to know the distance but hard to know the velocity.

One way of approaching the velocity issue is to look for mergers happening in nearby galaxies, and then use the known redshift of those galaxies for your gravitational wave velocity. This only works when you can find the source of gravitational waves and pinpoint it to somewhere close by.

But in the future, once scientists observe enough of these gravitational wave events, they’ll be able to build up a picture of what the average event looks like and use that information to calculate the expansion rate on a large scale.

The next generation of facilities 

For that, though, we’ll need hundreds of data points on gravitational wave events, compared to the handful we have now. This is a very new area of research, and our ability to detect gravitational waves is still limited to a small number of facilities. Currently, the uncertainties of the expansion rate measured using gravitational waves are still larger than the two other methods.

“Right now, our signal lies right in the middle between the two other results,” Ballmer said.

Artist's conception shows two merging black holes similar to those detected by LIGO.
Artist’s conception shows two merging black holes similar to those detected by LIGO. LIGO/Caltech/MIT

However, that could change in the future. With the next generation of gravitational wave detectors, being planned for construction in the next decades, these measurements could become more and more accurate.

The deepening of this puzzle might be a source of frustration, but it’s also given an impetus for new and better experiments as scientists from a wide range of fields tackle one of the great questions about the universe as we see it.

“The only way to really know is to make the experiment better,” Ballmer said. “That’s the world we live in.”

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Astronomers discover how tiny dwarf galaxies form fossils | Digital Trends

Astronomers discover how tiny dwarf galaxies form fossils | Digital Trends

Galaxies come in many different shapes and sizes, including those considerably smaller than our Milky Way. These smaller galaxies, called dwarf galaxies, can have as few as 1,000 stars, compared to the several hundred billion in our galaxy. And when these dwarf galaxies age and begin to erode away, they can transform into an even smaller and more dense shape, called an ultra-compact dwarf galaxy.

The Gemini North telescope has recently been studying more than 100 of these eroding dwarf galaxies, seeing how they lose their outer stars and gas to become ultra-compact dwarf galaxies or UCDs.

This illustration shows a dwarf galaxy in the throes of transitioning to an ultra-compact dwarf galaxy as it’s stripped of its outer layers of stars and gas by a nearby larger galaxy. Ultra-compact dwarf galaxies are among the densest stellar groupings in the Universe. Being more compact than other galaxies with similar mass, but larger than star clusters — the objects they most closely resemble — these mystifying objects have defied classification. The missing piece to this puzzle has been a lack of sufficient transitional, or intermediate objects to study. A new galaxy survey, however, fills in these missing pieces to show that many of these enigmatic objects are likely formed from the destruction of dwarf galaxies. NOIRLab/NSF/AURA/M. Zamani

“Our results provide the most complete picture of the origin of this mysterious class of galaxy that was discovered nearly 25 years ago,” said one of the researchers, NOIRLab astronomer Eric Peng in a statement. “Here we show that 106 small galaxies in the Virgo cluster have sizes between normal dwarf galaxies and UCDs, revealing a continuum that fills the ‘size gap’ between star clusters and galaxies.”

While astronomers did predict that dwarf galaxies could become UCDs, they hadn’t observed many cases of one transforming into the other. So this study looked for these “missing links” to see how this transition occurred. They found that these in-between galaxies were most often located near larger galaxies, which stripped away stars and gas from the small dwarf galaxies to leave a UCD behind.

“Once we analyzed the Gemini observations and eliminated all the background contamination, we could see that these transition galaxies existed almost exclusively near the largest galaxies. We immediately knew that environmental transformation had to be important,” explained lead author Kaixiang Wang of Peking University.

These objects were spotted using data from sky surveys, which was followed up using observations from Gemini North. That allowed the researchers to pick out the small dwarf galaxies from the many background galaxies visible in the sky.

“It’s exciting that we can finally see this transformation in action,” said Peng. “It tells us that many of these UCDs are visible fossil remnants of ancient dwarf galaxies in galaxy clusters, and our results suggest that there are likely many more low-mass remnants to be found.”

The research is published in the journal Nature.

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Webb and Hubble image the Christmas Tree Galaxy Cluster | Digital Trends

Webb and Hubble image the Christmas Tree Galaxy Cluster | Digital Trends

Different telescopes work at different wavelengths, meaning they can observe different objects in the sky — and when data from various telescopes is combined, it can make for stunning views that would be impossible to get from any one instrument. That’s the case with a beautiful new image of a cluster of thousands of galaxies that combines data from both the Hubble Space Telescope and the James Webb Space Telescope to create a stunning and colorful view.

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from NASA’s James Webb Space Telescope with visible-light data from NASA’s Hubble Space Telescope. To make the image, the shortest wavelengths of light were color-coded blue, the longest wavelengths red, and intermediate wavelengths green. The resulting wavelength coverage, from 0.4 to 5 microns, reveals a vivid landscape of galaxies that could be described as one of the most colorful views of the universe ever created. NASA, ESA, CSA, STScI, Jose M. Diego (IFCA), Jordan C. J. D’Silva (UWA), Anton M. Koekemoer (STScI), Jake Summers (ASU), Rogier Windhorst (ASU), Haojing Yan (University of Missouri)

Hubble looks in the optical wavelength, like the human eye, and the galaxies that it detected are mostly shown in blue and cyan. James Webb, however, looks beyond the range of human vision in the infrared wavelength, and the galaxies it viewed are shown mostly in yellow and red. There’s some crossover in the green parts of the image, which represent portions of the spectrum visible to both telescopes.

The huge MACS0416 cluster is actually a pair of galaxy clusters that are in the process of colliding, and which will eventually form one enormous cluster. This cluster was studied by Hubble over the last decade to look for some of the furthest galaxies that had been detected at that time — work that has now been taken up by Webb.

“We are building on Hubble’s legacy by pushing to greater distances and fainter objects,” said lead researcher Rogier Windhorst of Arizona State University in a statement.

In addition to producing a stunning image, the Webb data is also helping to investigate objects that change their brightness over time, called transients. These could be supernovae events, when a star comes to the end of its life and explodes in a large, bright event that quickly dims, or they could be other types of object such as stars or galaxies that are briefly magnified due to the effect of gravitational lensing. There were 14 of these transient objects identified in the image.

“We’re calling MACS0416 the Christmas Tree Galaxy Cluster, both because it’s so colorful and because of these flickering lights we find within it. We can see transients everywhere,” said fellow researcher Haojing Yan of the University of Missouri.

Two papers describing the research are published in Astronomy & Astrophysics and are forthcoming in The Astrophysical Journal.

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Supermassive black hole is oldest even seen in X-rays | Digital Trends

Supermassive black hole is oldest even seen in X-rays | Digital Trends

Astronomers recently discovered the most distant black hole ever observed in the X-ray wavelength, and it has some unusual properties that could help uncover the mysteries of how the largest black holes form.

Within the center of most galaxies lies a supermassive black hole, which is hundreds of thousands or even millions or billions of times the mass of our sun. These huge black holes are thought to be related to the way in which galaxies form, but this relationship isn’t clear — and how exactly supermassive black holes grow so massive is also an open question.

The recently discovered black hole, in the galaxy UHZ1 located an incredible 13.2 billion light-years away, is a young one and its mass is currently similar to that of the galaxy in which it resides. It is visible thanks to the gravitational lensing effect of the galaxy cluster Abell 2744, shown below, which has such huge mass that it bends spacetime and magnifies the distant galaxy to make it observable. It was located using the James Webb Space Telescope and then observed using then Chandra X-Ray Observatory.

Astronomers found the most distant black hole ever detected in X-rays, in a galaxy dubbed UHZ1, using the Chandra and Webb telescopes. This composite image shows the galaxy cluster Abell 2744 that UHZ1 is located behind, in X-rays from Chandra (purple) and infrared data from Webb (red, green, blue). Credits: X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand

“We needed Webb to find this remarkably distant galaxy and Chandra to find its supermassive black hole,” said lead author of the research, Akos Bogdan of the Center for Astrophysics | Harvard & Smithsonian, in a statement. “We also took advantage of a cosmic magnifying glass that boosted the amount of light we detected.”

This black hole seems to have been born massive, which allowed it to reach a large mass even at a young age. “There are physical limits on how quickly black holes can grow once they’ve formed, but ones that are born more massive have a head start. It’s like planting a sapling, which takes less time to grow into a full-size tree than if you started with only a seed,” explained another of the researchers, Andy Goulding of Princeton University.

The black hole is located within a pocket of superheated gas that is giving off X-rays, suggesting that it could have formed from the collapse of a cloud of gas. “We think that this is the first detection of an ‘Outsize Black Hole’ and the best evidence yet obtained that some black holes form from massive clouds of gas,” said fellow researcher Priyamvada Natarajan of Yale University. “For the first time, we are seeing a brief stage where a supermassive black hole weighs about as much as the stars in its galaxy, before it falls behind.”

The research is published in the journal Nature Astronomy, with other results published in Astrophysical Journal Letters.

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