Astronomers

Astronomers Discover the Brightest Known Object in the Universe, Shining 500 Trillion Times as Bright as the Sun

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The quasar—a glowing, active core of a galaxy—has a black hole at its center that consumes more than a sun’s-worth of mass each day

An artist's rendering of a fiery galactic core swirling around a black hole at its cennter
An artist’s rendering of the quasar that set the record for the universe’s brightest object, with its black hole at its center.

Astronomers have found the brightest known object in the universe—a glowing core of a galaxy, called a quasar, located 12 billion light-years away.

Quasars, as a whole, are the brightest objects in the cosmos, each consisting of a supermassive black hole that’s actively devouring an orbiting disc of gas and dust. But the black hole in this record-setting quasar is gobbling up more than a sun’s-worth of mass every day, making it the fastest growing black hole scientists have ever seen, according to a statement from the European Space Agency (ESA).

The gargantuan object stretches about seven light-years across, and it puts our sun’s luminosity to shame—the quasar shines more than 500 trillion times brighter than the star in our solar system, the researchers reported Monday in the journal Nature Astronomy.

“This quasar is the most violent place that we know in the universe,” Christian Wolf, lead author of the new study and an astrophysicist at Australian National University, tells Marcia Dunn of the Associated Press (AP).

“It is a surprise that it has remained unknown until today, when we already know about a million less impressive quasars,” study co-author Christopher Onken, an astronomer at Australian National University, says in the statement. “It has literally been staring us in the face until now.”

Supermassive black holes, which are at the heart of every quasar, grow by pulling stars and gas clouds into a ring of orbiting material called an accretion disc and swallowing them up. The matter circling the black hole rubs together, creating friction that releases glowing heat that can be seen from far away.

Researchers unknowingly spotted the ultra-bright quasar, officially called J059-4351, in images taken in 1980 by the Schmidt Southern Sky Survey, a telescope in Australia—but at first, they mistakenly identified it as a star. Typically, astronomers find quasars using machine-learning models trained to survey large areas of the sky for objects that look like known quasars in existing data. This makes it harder to spot unusually bright quasars that are unlike anything seen before.

But last year, the study authors determined the object was in fact a quasar using a telescope at the Siding Spring Observatory in Australia. They followed up with data from the Very Large Telescope in Chile to determine the quasar was the brightest ever seen.

“The exciting thing about this quasar is that it was hiding in plain sight and was misclassified as a star previously,” Priyamvada Natarajan, an astrophysicist at Yale University who did not contribute to the findings, tells the AP.

Around the quasar, the accretion disk is 15,000 times the length between the sun and Neptune, per the ESA, and its black hole weighs about the same as 17 billion suns.

The black hole in the quasar is ravenous, consuming an amount of material equivalent to as much as 413 suns each year, according to New Scientist’s Alex Wilkins. As a result, the disc glows brightly as it releases unfathomable amounts of energy.

“It looks like a gigantic and magnetic storm cell with temperatures of 10,000 degrees Celsius, lightning everywhere and winds blowing so fast they would go around Earth in a second,” Wolf tells the Guardian’s Tory Shepherd.

Because the accretion disc spans such a long distance, it could be possible for future researchers to accurately measure the mass of the black hole at the center, Christine Done, a physicist studying black holes at Durham University in England who was not involved in the research, tells New Scientist.

“This is big enough and bright enough that we could resolve it with our current instruments,” Done says to the publication. “We could have a much more direct measure of the black hole mass in this monster, and that’s what I did get quite excited about.”

The light from the quasar took about 12 billion years—the majority of the history of the universe—to reach us. Its black hole would have stopped growing long ago, Wolf writes in the Conversation. Since much of the gas that once floated freely around the cosmos has consolidated into stars that travel on long orbits around black holes, these massive objects no longer have as much material to feed on as they did in the early universe.

Astronomers Caught Dark Matter in the Cosmic Web, Revealing an Unseen Universe

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We finally got a glimpse at the galactic glue holding everything together.

shape

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  • Researchers just detected dark matter on the cosmic web for the first time.
  • Using a technique known as gravitational lensing, the team was able to detect the presence of dark matter even though we can’t see it, further confirming a long-held theory about the superstructure of our universe.
  • Hopefully, the discovery will be able to teach us more about how our universe evolved.

For a long time, we thought the universe might be totally random. Galaxies flung hither and yon, black holes swirling at their centers, and everything from nebulae to nothingness scattered in between. Infinite space, infinite time—no pattern.

But in the 1970s, we found out we were wrong about that. It turns out that the universe has a pattern after all, and it’s one we are able to map. All of that pattern is built on the back of what is now known as the cosmic web. It’s mostly made up of galaxies, gas, and dark matter, and it crisscrosses the universe in a beautiful, spider-like pattern.

And recently, scientists made a huge discovery about this universal super-structure. For the first time ever, researchers were able to indirectly “see” the dark matter threads hanging from the strings of the web. The team published a paper detailing their findings in the journal Nature Astronomy.

How do astronomers know the age of the planets and stars?

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How old are the stars and planets that light up our universe? Age is more than just a number in the world of astrophysics; it unravels the history, evolution, and potential for life in faraway worlds. Yet, determining the age of these celestial objects is more complex than you might think.

Imagine trying to guess the age of a person who remains visually unchanged from childhood to old age – that’s the kind of challenge scientists face when studying objects in space. This article delves into the ingenious methods and tools astronomers employ to decode the chronology of the cosmos.

By Adam Burgasser – Professor of Astronomy & Astrophysics, University of California, San Diego

Measuring the ages of planets and stars helps scientists understand when they formed and how they change – and, in the case of planets, if life has had time to have evolved on them.

Unfortunately, age is hard to measure for objects in space.

Stars like the Sun maintain the same brightness, temperature and size for billions of years. Planet properties like temperature are often set by the star they orbit rather than their own age and evolution.

Determining the age of a star or planet can be as hard as guessing the age of a person who looks exactly the same from childhood to retirement.

SUSSING OUT A STAR’S AGE

Fortunately, stars change subtly in brightness and color over time. With very accurate measurements, astronomers can compare these measurements of a star to mathematical models that predict what happens to stars as they get older and estimate an age from there.

Stars don’t just glow, they also spin. Over time, their spinning slows down, similar to how a spinning wheel slows down when it encounters friction. By comparing the spin speeds of stars of different ages, astronomers have been able to create mathematical relationships for the ages of stars, a method known as gyrochronology.

Researchers estimate the Sun is 4.58 billion years old

A star’s spin also generates a strong magnetic field and produces magnetic activity, such as stellar flares – powerful bursts of energy and light that occur on stars’ surfaces. A steady decline in magnetic activity from a star can also help estimate its age.

A more advanced method for determining the ages of stars is called asteroseismology, or star shaking. Astronomers study vibrations on the surfaces of stars caused by waves that travel through their interiors. Young stars have different vibrational patterns than old stars. By using this method, astronomers have estimated the Sun to be 4.58 billion years old.

PIECING TOGETHER A PLANET’S AGE

In the solar system, radionuclides are the key to dating planets. These are special atoms that slowly release energy over a long period of time. As natural clocks, radionuclides help scientists determine the ages of all kinds of things, from rocks to bones and pottery.

Using this method, scientists have determined that the oldest known meteorite is 4.57 billion years old, almost identical to the Sun’s asteroseismology measurement of 4.58 billion years. The oldest known rocks on Earth have slightly younger ages of 4.40 billion years. Similarly, soil brought back from the Moon during the Apollo missions had radionuclide ages of up to 4.6 billion years.

Craters on the surface of the moon

Although studying radionuclides is a powerful method for measuring the ages of planets, it usually requires having a rock in hand. Typically, astronomers only have a picture of a planet to go by. Astronomers often determine the ages of rocky space objects like Mars or the Moon by counting their craters. Older surfaces have more craters than younger surfaces. However, erosion from water, wind, cosmic rays and lava flow from volcanoes can wipe away evidence of earlier impacts.

Aging techniques don’t work for giant planets like Jupiter that have deeply buried surfaces. However, astronomers can estimate their ages by counting craters on their moons or studying the distribution of certain classes of meteorites scattered by them, which are consistent with radionuclide and cratering methods for rocky planets.

We cannot yet directly measure the ages of planets outside our solar system with current technology.

HOW ACCURATE ARE THESE ESTIMATES?

Our own solar system provides the best check for accuracy, since astronomers can compare the radionuclide ages of rocks on the Earth, Moon, or asteroids to the asteroseismology age of the Sun, and these match very well.

Stars in clusters like the Pleiades or Omega Centauri are believed to have all formed at roughly the same time, so age estimates for individual stars in these clusters should be the same. In some stars, astronomers can detect radionuclides like uranium – a heavy metal found in rocks and soil – in their atmospheres, which have been used to check the ages from other methods.

Astronomers believe planets are roughly the same age as their host stars, so improving methods to determine a star’s age helps determine a planet’s age as well. By studying subtle clues, it’s possible to make an educated guess of the age of an otherwise steadfast star.

Shattering Galactic Beliefs: Astronomers Uncover Surprising Magnetic Field Structures in Milky Way

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Researchers have mapped the magnetic fields in a Milky Way spiral arm, discovering significant variations from previous galactic models. This groundbreaking study, leveraging advanced telescopes and the Gaia satellite, shows that galactic magnetic fields, particularly in the Sagittarius arm, are more complex and influential in star formation than previously thought, offering new insights into the evolution of galaxies.

A team of astronomers including those from the University of Tokyo created the first-ever map of magnetic field structures within a spiral arm of our Milky Way galaxy. Earlier research provided only a broad overview of galactic magnetic fields. However, this novel study uncovers that the magnetic fields within the galaxy’s spiral arms deviate markedly from this broad overview, displaying a significant tilt from the galactic average. These discoveries indicate that magnetic fields have a substantial influence on regions where stars are formed, implying their role in the formation of our solar system.

It might come as a surprise to some that magnetic fields can exist on scales larger than a planet. Most of our daily experience with magnetic fields involves either sticking things to our refrigerator, or perhaps using a compass to point north. The latter shows the existence of magnetic fields generated by our planet. Our sun also creates a vast magnetic field, and this can affect phenomena like solar flares. But magnetic fields that span the galaxy are almost too large to comprehend, and yet they likely have a role in the formation of stars and planets.

New Insights into the Milky Way’s Magnetic Structure

“Until now, all observations of magnetic fields within the Milky Way led to a very limited model that was uniform all over and largely matched the disc shape of the galaxy itself,” said Assistant Professor Yasuo Doi from the Department of Earth Science and Astronomy. “Thanks in part to telescope facilities at Hiroshima University capable of measuring polarized light to help us ascertain magnetic signatures, and the Gaia satellite launched by the European Space Agency in 2013, which specialized in measuring the distances to stars, we are able to build a better model with finer details in three dimensions. We focused on a specific area, the Sagittarius arm of our spiral galaxy (we are in the neighboring Orion arm), and found the dominant magnetic field there breaks away from the plane of the galaxy significantly.”

The white lines superimposed on this image of the Sagittarius arm of the Milky Way show the polarization, or orientation, of light. This correlates with the orientation of local magnetic field lines. Combined, this information builds a detailed map of the magnetic field in that arm of the galaxy. Credit: 2023 Doi et al.

Rethinking Galactic Magnetic Field Models

Previous models and observations could only imagine a smooth and largely homogeneous magnetic field in our galaxy; whereas the new data show that although magnetic field lines in the spiral arms do roughly align with the galaxy at large, at small scales the lines are actually spread out across a range of distances due to various astrophysical phenomena such as supernovae and stellar winds.

The galactic magnetic fields are also incredibly weak, around 100,000 times weaker than Earth’s own magnetic field. Despite this, however, over long time spans, gas and dust in interstellar space are accelerated by these fields which explains the presence of some stellar nurseries — star-forming regions — that cannot be explained by gravity alone. This finding implies further mapping of the magnetic fields within our galaxy could help better explain the nature and evolution of the Milky Way and other galaxies too.

Astronomers Just Found the Closest Black Hole to Earth. Until Now, It Was Invisible

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This black hole is ten times as massive as the sun and is 1,600 light years away—three times closer than the previous record holder.

black hole, artwork

  • Astronomers have located the closest stellar-mass black hole to Earth ever discovered.
  • Because this black hole isn’t feeding on matter and shooting out radiation, making it pretty much invisible, scientists had to take a different approach to find it.
  • A star orbiting the black hole exhibited a “wobble,” which helped them locate the black hole-star binary system Gaia BH1.

What would you get if you took the solar system and put a black hole where the sun is and placed the sun where Earth sits? The answer is something like the newly discovered black hole-star binary system Gaia BH1, which contains the closest stellar-mass black hole to Earth ever discovered and a star orbiting it at an incredible 223,000 miles per hour.

“That’s because while the black hole is about ten times the mass of the sun, the star that orbits it is very similar to the sun and has an orbital period of about half a year,” Kareem El-Badry, an astrophysicist at the Center for Astrophysics at the Harvard/Smithsonian Center for Astrophysics and the Max Planck Institute for Astronomy, tells Popular Mechanics. This similarity to the solar system extends to the separation between the black hole and its companion star, which is about one-and-a-half times the separation between Earth and the sun.

New research on this first unambiguous detection of a stellar-mass black hole in the Milky Way—which, notably, isn’t feeding on matter and blasting out radiation—was published in the journal Monthly Notices of the Royal Astronomical Society in November. Astronomers describe these non-feeding black holes as dormant, and they’re tough to spot because any light that comes too close to them is trapped behind a light-capturing boundary called the event horizon, yielding them invisible.

That means even though there are estimated to be millions of stellar-mass black holes, with masses between three and ten times that of the sun, the few that have been detected thus far have been snacking on material from a companion star. When this stellar matter falls toward a black hole, it’s superheated. That causes it to emit powerful radiation that can be used to detect the feeding black hole. So, how did scientists manage to find a black hole without an appetite?

Detecting a Wobble

To discover this dormant black hole in the absence of such emissions, El-Badry and his team used the effect that the black hole has on the star that orbits it to infer its presence.

Looking through data from the Gaia space telescope, which has been creating a 3D map of the Milky Way since 2013, the astronomers saw that the star in Gaia BH1 was demonstrating a tell-tale “wobble.”

“Gaia is very precisely measuring the positions of all the stars in the sky relative to a fixed background at different times, so one of the things you can do with that data is look for stars that are wobbling,” El-Badry says. “What we learned about this system is the star is wobbling more than you would expect for any star with a normal companion.”

Concluding the gravitational influence of a massive compact object caused the wobble, the astronomers performed follow-up observations with the Gemini Multi-Object Spectrograph instrument on the Gemini North Telescope

This allowed them to measure the rapid velocity of the companion star as it orbits the black hole, and confirmed the masses of the two objects, cementing the theory that the central object of Gaia BH1 is a stellar-mass black hole.

“When we look with images and spectra, we don’t see anything else there that’s luminous, so we can rule out basically all possibilities that aren’t a black hole,” El-Badry says. “We don’t actually detect the black hole at all. We just see an enormous source of mass contributing no light.”

This newly discovered black hole of Gaia BH1 won’t always be dormant or invisible, however.

Ending the Fast

El-Badry says that when the orbiting star reaches the end of its hydrogen-burning phase, its core will collapse and its outer layers will puff out. That will allow the central black hole to start stripping away this swelled outer material from its companion, which it will begin to feed on, heating it and making its presence known with luminous emissions.

“Gaia BH1 is very stable for now, but it is doomed,” El-Badry adds. “The black hole will eventually be something like a million times as bright as the sun whereas now it’s basically totally dark.”

The black hole in Gaia BH1 once experienced a red supergiant phase itself and this represents a mystery for astronomers. This is because to leave the black hole detected today, the progenitor star must have possessed around 20 times the mass of the sun. At that size during the red supergiant phase, the black hole’s outer layers should have swelled up to where the sun-like star orbits it today.

That means it’s difficult to explain how the companion star survived so close to the birthing process of the black hole without being irrevocably changed or swallowed entirely. And that means Gaia BH1 could change how we think about the evolution of binary systems.

“The Gaia BH1 system is not really one that we would have predicted to exist,” El-Badry says.

The Black Hole Police

For El-Badry, the discovery of the closest black hole to Earth is particularly pleasing. This is because the astrophysicist has inadvertently become part of a crew of researchers that are more accustomed to debunking local stellar-mass black holes. This has led to them being affectionately called the “black hole police” in astronomy circles.

“I didn’t get into the game planning to ‘debunk’ black holes, I was just looking for them and just happened to find different interpretations for black holes others had suggested,” El-Badry explains. “It’s definitely exciting to find one and be able to study it. It feels good to be on the other side of the coin.”

El-Badry expects this discovery will be scrutinized as closely as he and his colleagues have looked at other suspected black holes, but is confident that the nature of Gaia BH1 will just be confirmed by follow-ups. In fact, El-Badry points out that a separate paper authored by a separate research team has reached very similar conclusions regarding Gaia BH1

The system’s central object could still lose its status as the closest stellar-mass black hole to Earth, however. If the technique El-Badry and the team used to find it is successfully adapted to search for other similar systems containing black holes in the Milky Way, it could lead to the discovery of some that are even closer to home.

“The satellite Gaia that provided the data we used to make this discovery is continuing to take data, and the longer it takes data, the more accurate or the more useful data becomes for this kind of detection,” El-Badry says. “We estimate that in the Milky Way there are something like 40,000 of these normal-star-plus-black-hole binaries and by the end of its mission in five years, Gaia will find dozens of these.”

“Of course, that means there are many more that Gaia won’t find, but are still out there,” he concludes.

How do astronomers know the age of the planets and stars?

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How old are the stars and planets that light up our universe? Age is more than just a number in the world of astrophysics; it unravels the history, evolution, and potential for life in faraway worlds. Yet, determining the age of these celestial objects is more complex than you might think.

Imagine trying to guess the age of a person who remains visually unchanged from childhood to old age – that’s the kind of challenge scientists face when studying objects in space. This article delves into the ingenious methods and tools astronomers employ to decode the chronology of the cosmos.

By Adam Burgasser – Professor of Astronomy & Astrophysics, University of California, San Diego

Measuring the ages of planets and stars helps scientists understand when they formed and how they change – and, in the case of planets, if life has had time to have evolved on them.

Unfortunately, age is hard to measure for objects in space.

Stars like the Sun maintain the same brightness, temperature and size for billions of years. Planet properties like temperature are often set by the star they orbit rather than their own age and evolution.

Determining the age of a star or planet can be as hard as guessing the age of a person who looks exactly the same from childhood to retirement.

SUSSING OUT A STAR’S AGE

Fortunately, stars change subtly in brightness and color over time. With very accurate measurements, astronomers can compare these measurements of a star to mathematical models that predict what happens to stars as they get older and estimate an age from there.

Stars don’t just glow, they also spin. Over time, their spinning slows down, similar to how a spinning wheel slows down when it encounters friction. By comparing the spin speeds of stars of different ages, astronomers have been able to create mathematical relationships for the ages of stars, a method known as gyrochronology.

Researchers estimate the Sun is 4.58 billion years old

A star’s spin also generates a strong magnetic field and produces magnetic activity, such as stellar flares – powerful bursts of energy and light that occur on stars’ surfaces. A steady decline in magnetic activity from a star can also help estimate its age.

A more advanced method for determining the ages of stars is called asteroseismology, or star shaking. Astronomers study vibrations on the surfaces of stars caused by waves that travel through their interiors. Young stars have different vibrational patterns than old stars. By using this method, astronomers have estimated the Sun to be 4.58 billion years old.

PIECING TOGETHER A PLANET’S AGE

In the solar system, radionuclides are the key to dating planets. These are special atoms that slowly release energy over a long period of time. As natural clocks, radionuclides help scientists determine the ages of all kinds of things, from rocks to bones and pottery.

Using this method, scientists have determined that the oldest known meteorite is 4.57 billion years old, almost identical to the Sun’s asteroseismology measurement of 4.58 billion years. The oldest known rocks on Earth have slightly younger ages of 4.40 billion years. Similarly, soil brought back from the Moon during the Apollo missions had radionuclide ages of up to 4.6 billion years.

Craters on the surface of the moon

Although studying radionuclides is a powerful method for measuring the ages of planets, it usually requires having a rock in hand. Typically, astronomers only have a picture of a planet to go by. Astronomers often determine the ages of rocky space objects like Mars or the Moon by counting their craters. Older surfaces have more craters than younger surfaces. However, erosion from water, wind, cosmic rays and lava flow from volcanoes can wipe away evidence of earlier impacts.

Aging techniques don’t work for giant planets like Jupiter that have deeply buried surfaces. However, astronomers can estimate their ages by counting craters on their moons or studying the distribution of certain classes of meteorites scattered by them, which are consistent with radionuclide and cratering methods for rocky planets.

We cannot yet directly measure the ages of planets outside our solar system with current technology.

HOW ACCURATE ARE THESE ESTIMATES?

Our own solar system provides the best check for accuracy, since astronomers can compare the radionuclide ages of rocks on the Earth, Moon, or asteroids to the asteroseismology age of the Sun, and these match very well.

Stars in clusters like the Pleiades or Omega Centauri are believed to have all formed at roughly the same time, so age estimates for individual stars in these clusters should be the same. In some stars, astronomers can detect radionuclides like uranium – a heavy metal found in rocks and soil – in their atmospheres, which have been used to check the ages from other methods.

Astronomers believe planets are roughly the same age as their host stars, so improving methods to determine a star’s age helps determine a planet’s age as well. By studying subtle clues, it’s possible to make an educated guess of the age of an otherwise steadfast star.

Astronomers Puzzled by Galaxy With No Stars

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It could be a never before seen part of the cosmos.

The Big Empty

Astronomers have accidentally found an entire galaxy that appears to have plenty of gas — but no visible stars to speak of.

Their findings, which were presented this week at the annual meeting of the American Astronomy Society, may seem paradoxical on their face, but the discovery could provide a rare, possibly never-before-seen insight that challenges our understanding of how stars and galaxies are formed.

The eerily empty object, called J0613+52, is located 270 million light years away, according to a Big Think writeup on the discovery, and at the very least appears to be a low-surface brightness galaxy (LSB).

As the name suggests, an LSB is significantly less bright than other glimmering objects that populate the night sky because the gasses it contains are so spread out that few stars are formed.

Still, this classification holds that such a galaxy would at least have some stars, and J0613+52, with seemingly none at all, could be something even more rare and elusive: a dark, primordial galaxy.

“This could be our first discovery of a nearby galaxy made up of primordial gas,” Karen O’Neil, a senior scientist of the Green Bank Observatory, said in a statement about the research.

Gassy Galaxy

O’Neil and her team stumbled on the object thanks to a fortuitous error made while studying LSBs. Basically, they realized there was a discrepancy in the data between two telescopes they were using, which led to them double-checking where they were looking at.

“The [Green Bank Telescope] was accidentally pointed to the wrong coordinates and found this object,” O’Neil said.

Not only did they find that the galaxy was lacking stars despite being rich in gas — they believe it contains between one and two billion solar masses of hydrogen — it was also extremely isolated.

“It’s too far from other galaxies for them to help trigger star formation through any encounters,” O’Neil said. “J0613+52 appears to be both undisturbed and underdeveloped.”

That last part — “undisturbed and underdeveloped” — is key. It would suggest that over the billions of years of its existence, the “dark” galaxy has remained stable to an unparalleled degree, with no significant gravitational interactions occurring that would lead to gas clumping together to form stars, and no nearby galaxies to intrude on its near-perfect equilibrium.

In other words, it’s an uncannily preserved relic of the early years of the cosmos, so perfect that it almost defies understanding.

Future observations will have to bear out these findings. As Big Think notes, astronomers will likely follow up by searching for heavy metals that indicate the presence of stars. If none are found, it’ll be strong evidence in favor of J0613+52 indeed being the fabled dark galaxy that has for so long eluded detection.

Astronomers discover new Be/X-ray binary system

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by Tomasz Nowakowski , Phys.org UKIDSS J-band finding chart for 4XMM J182531.5–144036. The red circle is centered on the XMM-Newton detected position, with a radius of 1′′ equal to the positional error. The white circle is centered on the Chandra detected position and has a radius of 0.6′′ equal to its positional error. Credit: arXiv (2024). DOI: 10.48550/arxiv.2401.02468

Astronomers from the Open University in Milton Keynes, UK and elsewhere report the detection of a new Be/X-ray binary. The newfound system, designated 4XMM J182531.5–144036, exhibits persistent X-ray emission. The finding was detailed in a paper published January 4 on the pre-print server arXiv.

X-ray binaries are composed of a normal star or a white dwarf transferring mass onto a compact neutron star or a black hole. Based on the mass of the companion star, astronomers divide them into low-mass X-ray binaries (LMXBs) and high-mass X-ray binaries (HMXBs).

Be/X-ray binaries (Be/XRBs) are the largest subgroup of HMXBs. These systems consist of Be stars and, usually, neutron stars, including pulsars. Observations have found that most of these systems showcase weak persistent X-ray emission that is interrupted by outbursts lasting several weeks.

4XMM J182531.5–144036 was initially detected as a hard X-ray source in April 2008 with ESA’s XMM-Newton satellite. Given that its nature remains undisclosed, a team of astronomers led by Open University’s Andrew Mason Jr. has analyzed the available data from XMM-Newton, NASA’s Chadra spacecraft, Very Large Telescope (VLT) and UKIDSS (UKIRT Infrared Deep Sky Survey) Galactic Plane Survey, in order to investigate this source.

The study found that the position of 4XMM J182531.5–144036 is coincident with an infrared object exhibiting a near-infrared excess when compared to the spectra of early B-type dwarf or giant stars. This object also displays a strong hydrogen emission line. The researchers noted that these properties are characteristic for Be stars.

Furthermore, coherent X-ray pulsation of 4XMM J182531.5–144036 was detected, with a period of 781 seconds. The presence of such a pulsation is typical for BeXRB pulsars. The astronomers added that the X-ray pulse profile is asymmetric, which is seen in X-ray pulsars and it can provide information about the magnetic field structure of the neutron star.

According to the paper, the X-ray pulsation is seen with the same profile in widely separated XMM-Newton and Chandra observations. This indicates that the X-ray emission is likely persistent.

When it comes to the orbital period of 4XMM J182531.5–144036, the researchers calculate that it is within the range of 250–500 days. The orbit of the system was found to have a low eccentricity.

“We therefore conclude that 4XMM J182531.5–144036 is a newly identified persistent, long period, Be/X-ray binary,” the authors of the study wrote.

The astronomers estimate that the distance to 4XMM J182531.5–144036 is between 3,300 and 23,00 light years. However, they noted that the system is too faint to be detected by ESA’s Gaia satellite so no independent distance estimate is available.

Astronomers Puzzled by Galaxy With No Stars

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It could be a never before seen part of the cosmos.

The Big Empty

Astronomers have accidentally found an entire galaxy that appears to have plenty of gas — but no visible stars to speak of.

Their findings, which were presented this week at the annual meeting of the American Astronomy Society, may seem paradoxical on their face, but the discovery could provide a rare, possibly never-before-seen insight that challenges our understanding of how stars and galaxies are formed.

The eerily empty object, called J0613+52, is located 270 million light years away, according to a Big Think writeup on the discovery, and at the very least appears to be a low-surface brightness galaxy (LSB).

As the name suggests, an LSB is significantly less bright than other glimmering objects that populate the night sky because the gasses it contains are so spread out that few stars are formed.

Still, this classification holds that such a galaxy would at least have some stars, and J0613+52, with seemingly none at all, could be something even more rare and elusive: a dark, primordial galaxy.

“This could be our first discovery of a nearby galaxy made up of primordial gas,” Karen O’Neil, a senior scientist of the Green Bank Observatory, said in a statement about the research.

Gassy Galaxy

O’Neil and her team stumbled on the object thanks to a fortuitous error made while studying LSBs. Basically, they realized there was a discrepancy in the data between two telescopes they were using, which led to them double-checking where they were looking at.

“The [Green Bank Telescope] was accidentally pointed to the wrong coordinates and found this object,” O’Neil said.

Not only did they find that the galaxy was lacking stars despite being rich in gas — they believe it contains between one and two billion solar masses of hydrogen — it was also extremely isolated.

“It’s too far from other galaxies for them to help trigger star formation through any encounters,” O’Neil said. “J0613+52 appears to be both undisturbed and underdeveloped.”

That last part — “undisturbed and underdeveloped” — is key. It would suggest that over the billions of years of its existence, the “dark” galaxy has remained stable to an unparalleled degree, with no significant gravitational interactions occurring that would lead to gas clumping together to form stars, and no nearby galaxies to intrude on its near-perfect equilibrium.

In other words, it’s an uncannily preserved relic of the early years of the cosmos, so perfect that it almost defies understanding.

Future observations will have to bear out these findings. As Big Think notes, astronomers will likely follow up by searching for heavy metals that indicate the presence of stars. If none are found, it’ll be strong evidence in favor of J0613+52 indeed being the fabled dark galaxy that has for so long eluded detection.

Astronomers Reveal the Most Detailed Radio Image Yet of the Milky Way’s Galactic Plane

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askap parkes telescopes radio image galactic plane supernova remnants

Two major astronomy research programs, called EMU and PEGASUS, have joined forces to resolve one of the mysteries of our Milky Way: where are all the supernova remnants?

A supernova remnant is an expanding cloud of gas and dust marking the last phase in the life of a star, after it has exploded as a supernova. But the number of supernova remnants we have detected so far with radio telescopes is too low. Models predict five times as many, so where are the missing ones?

We have combined observations from two of Australia’s world-leading radio telescopes, the ASKAP radio telescope and the Parkes radio telescope, Murriyang, to answer this question.

The Gas Between the Stars

https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=1743639e-9560-11ed-b5bd-6595d9b17862

The new image reveals thin tendrils and clumpy clouds associated with hydrogen gas filling the space between the stars. We can see sites where new stars are forming, as well as supernova remnants.

In just this small patch, only about 1 percent of the whole Milky Way, we have discovered more than 20 new possible supernova remnants where only 7 were previously known.

These discoveries were led by PhD student Brianna Ball from Canada’s University of Alberta, working with her supervisor, Roland Kothes of the National Research Council of Canada, who prepared the image. These new discoveries suggest we are close to accounting for the missing remnants.

So why can we see them now when we couldn’t before?

The Power of Joining Forces

I lead the Evolutionary Map of the Universe or EMU program, an ambitious project with ASKAP to make the best radio atlas of the southern hemisphere.

EMU will measure about 40 million new distant galaxies and supermassive black holes to help us understand how galaxies have changed over the history of the universe.

Early EMU data have already led to the discovery of odd radio circles (or “ORCs”), and revealed rare oddities like the “Dancing Ghosts.”

For any telescope, the resolution of its images depends on the size of its aperture. Interferometers like ASKAP simulate the aperture of a much larger telescope. With 36 relatively small dishes (each 12m in diameter) but a 6km distance connecting the farthest of these, ASKAP mimics a single telescope with a 6km wide dish.

That gives ASKAP a good resolution, but comes at the expense of missing radio emission on the largest scales. In the comparison above, the ASKAP image alone appears too skeletal.

To recover that missing information, we turned to a companion project called PEGASUS, led by Ettore Carretti of Italy’s National Institute of Astrophysics.

PEGASUS uses the 64m diameter Parkes/Murriyang telescope (one of the largest single-dish radio telescopes in the world) to map the sky.

Even with such a large dish, Parkes has rather limited resolution. By combining the information from both Parkes and ASKAP, each fills in the gaps of the other to give us the best fidelity image of this region of our Milky Way galaxy. This combination reveals the radio emission on all scales to help uncover the missing supernova remnants.

Linking the datasets from EMU and PEGASUS will allow us to reveal more hidden gems. In the next few years we will have an unprecedented view of almost the entire Milky Way, about a hundred times larger than this initial image, but with the same level of detail and sensitivity.

We estimate there may be up to 1,500 or more new supernova remnants yet to discover. Solving the puzzle of these missing remnants will open new windows into the history of our Milky Way.