Thursday, March 28, 2024

SPACE

Curtin research unlocks supernova stardust secrets

CURTIN UNIVERSITY

Curtin University-led research has discovered a rare dust particle trapped in an ancient extra-terrestrial meteorite that was formed by a star other than our sun.

The discovery was made by lead author Dr Nicole Nevill and colleagues during her PhD studies at Curtin, now working at the Lunar and Planetary Science Institute in collaboration with NASA’s Johnson Space Centre.

Meteorites are mostly made up of material that formed in our solar system and can also contain tiny particles which originate from stars born long before our sun.

Clues that these particles, known as presolar grains, are relics from other stars are found by analysing the different types of elements inside them.

Dr Nevill used a technique called atom probe tomography to analyse the particle and reconstruct the chemistry on an atomic scale, accessing the hidden information within.

“These particles are like celestial time capsules, providing a snapshot into the life of their parent star,” Dr Nevill said.

“Material created in our solar system have predictable ratios of isotopes – variants of elements with different numbers of neutrons. The particle that we analysed has a ratio of magnesium isotopes that is distinct from anything in our solar system.

“The results were literally off the charts. The most extreme magnesium isotopic ratio from previous studies of presolar grains was about 1,200. The grain in our study has a value of 3,025, which is the highest ever discovered.

“This exceptionally high isotopic ratio can only be explained by formation in a recently discovered type of star – a hydrogen burning supernova.”

Co-author Dr David Saxey, from the John de Laeter Centre at Curtin said the research is breaking new ground in how we understand the universe, pushing the boundaries of both analytical techniques and astrophysical models.

“The atom probe has given us a whole level of detail that we haven’t been able to access in previous studies,” Dr Saxey said.

“Hydrogen burning supernova is a type of star that has only been discovered recently, around the same time as we were analysing the tiny dust particle. The use of the atom probe in this study, gives a new level of detail helping us understand how these stars formed.”

Co-author Professor Phil Bland, from Curtin’s School of Earth and Planetary Sciences said new discoveries from studying rare particles in meteorites are enabling us to gain insights into cosmic events beyond our solar system.

“It is simply amazing to be able to link atomic-scale measurements in the lab to a recently discovered type of star.”

The research titled “Atomic-scale Element and Isotopic Investigation of 25Mg-rich Stardust from an H-burning Supernova” will appear in the Astrophysical Journal and will be available here once published.

JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4357/ad2996

METHOD OF RESEARCH

Imaging analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Atomic-scale Element and Isotopic Investigation of 25Mg-rich Stardust from an H-burning Supernova

ARTICLE PUBLICATION DATE

27-Mar-2024

ALMA finds new molecular signposts in starburst galaxy

NATIONAL INSTITUTES OF NATURAL SCIENCES

Excerpts from the ALCHEMI atlas of the center of NGC 253 — IMAGE:
THE DIFFERENT COLORS REPRESENT THE DISTRIBUTION OF MOLECULAR GAS (BLUE), SHOCKED REGIONS (RED), RELATIVELY HIGH-DENSITY REGIONS (ORANGE), YOUNG STARBURSTS (YELLOW), DEVELOPED STARBURSTS (MAGENTA), AND MOLECULAR GAS AFFECTED BY COSMIC-RAY IONIZATION (CYAN).
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CREDIT: ALMA (ESO/NAOJ/NRAO), N. HARADA ET AL.

The ALMA radio telescope has detected more than 100 molecular species, including many indicative of different star formation and evolution processes, in a galaxy where stars are forming much more actively than in the Milky Way. This is far more molecules than were found in previous studies. Now the team will try to apply this knowledge to other galaxies.

A team of researchers led by Sergio Martin of the European Southern Observatory/Joint ALMA Observatory, Nanase Harada of the National Astronomical Observatory of Japan, and Jeff Mangum of the National Radio Astronomy Observatory used ALMA (Atacama Large Millimeter/submillimeter Array) to observe the center of a galaxy known as NGC 253. NGC 253 is located about 10 million light-years away in the direction of the constellation Sculptor. NGC 253 is an example of a starburst galaxy, a galaxy where many new stars are forming rapidly. The factors leading to the onset of a starburst are still not well understood.

The birth, evolution, and death of stars change the molecular composition of the surrounding gas. ALMA’s high sensitivity and high resolution allowed astronomers to determine the locations of molecules indicative of the various stages in the life cycle of stars. This survey, dubbed ALCHEMI (ALMA Comprehensive High-resolution Extragalactic Molecular Inventory), found high-density molecular gas that is likely promoting active star formation in this galaxy. The amount of dense gas in the center of NGC 253 turned out to be more than 10 times higher than that in the center of the Milky Way, which could explain why NGC 253 is forming stars about 30 times more efficiently.

The ALCHEMI survey also provided an atlas of 44 molecular species, doubling the number available from previous studies outside the Milky Way. By applying a machine-learning technique to this atlas, the researchers were able to identify which molecules serve as the best signposts to trace the story of star formation from the beginning to the end. This knowledge will help in planning future ALMA observations.

JOURNAL

The Astrophysical Journal Supplement Series

DOI

10.3847/1538-4365/ad1937

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The ALCHEMI Atlas: Principal Component Analysis Reveals Starburst Evolution in NGC 253

New image of the center of our Milky Way: Spiral magnetic fields surround black hole Sagittarius A*

Global astronomy research network EHT analyzes data from another series of observations

GOETHE UNIVERSITY FRANKFURT

The black hole SgrA* — IMAGE:
THE MAGNETIC FIELDS SPIRAL AROUND THE CENTRAL SHADOW OF THE BLACK HOLE.
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CREDIT: EHT COLLABORATION

FRANKFURT. In 2022, scientists of the EHT unveiled the first image of Sgr A* – which is approximately 27,000 light-years away from Earth – revealing that the Milky Way’s supermassive black hole looks remarkably similar to M87’s, even though it is more than a thousand times smaller and less massive. This made scientists wonder whether the two shared common traits outside of their looks. To find out, the team decided to study Sgr A* in polarized light. Previous studies of light around M87* had shown that the magnetic fields around the gigantic black hole allowed it to launch powerful jets of material back into the surrounding environment. Building on this work, the new images revealed that the same may be true for Sgr A*.

Imaging black holes, especially Sgr A*, in polarized light is not easy, because the ionized gas, or plasma, in the vicinity of the black hole orbits it in only a few minutes. Because the particles of the plasma swirl around the magnetic field lines, the magnetic field structures change rapidly during the recording of the radio waves by the EHT. Sophisticated instruments and techniques were required to capture the image the supermassive black hole.

Professor Luciano Rezzolla, theoretical astrophysicist at Goethe University Frankfurt, explains: "Polarized radio waves are influenced by magnetic fields and by studying the degree of polarization of the observed light we can learn how the magnetic fields of the black hole are distributed. However, unlike a standard image, which needs only information on the intensity of the light, creating a polarization map as the one we have just published is considerably harder. Indeed, our polarized image of Sgr A* is the result of a careful comparison between the actual measurements and the hundreds of thousands of possible images we can produce via advanced supercomputer simulations. Similar to the first image of Sgr A*, these polarized images represent an average of all measurements."

Rezzolla’s fellow Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan adds, “Making a polarized image is like opening the book after you have only seen the cover. Because Sgr A* moves around while we try to take its picture, it was difficult to construct even the unpolarized image,” adding that the first image was an average of multiple images due to Sgr A*’s movement. “We were relieved that polarized imaging was even possible. Some models were far too scrambled and turbulent to construct a polarized image, but nature was not so cruel.”

“By imaging polarized light from hot glowing gas near black holes, we are directly inferring the structure and strength of the magnetic fields that thread the flow of gas and matter that the black hole feeds on and ejects,” said Harvard Black Hole Initiative Fellow and project co-lead Angelo Ricarte. “Polarized light teaches us a lot more about the astrophysics, the properties of the gas, and mechanisms that take place as a black hole feeds.”

Sara Issaoun, NASA Hubble Fellowship Program Einstein Fellow at the Center for Astrophysics, Harvard & Smithsonian and co-lead of the project, says “Along with Sgr A* having a strikingly similar polarization structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.”

Mariafelicia De Laurentis, EHT Deputy Project Scientist and professor at the University of Naples Federico II, Italy, also emphasizes the significance of the similarity between the magnetic field structures of M87* and Sgr A*, suggesting universal processes governing black hole feeding and jet launching despite differences in their properties. This finding enhances theoretical models and simulations, refining our understanding of black hole dynamics near the event horizon.

The Event Horizon Telescope Collaboration

The EHT has conducted several observations since 2017 and is scheduled to observe Sgr A* again in April 2024. Each year, the images improve as the EHT incorporates new telescopes, larger bandwidth, and new observing frequencies. Planned expansions for the next decade will enable high-fidelity movies of Sgr A*, may reveal a hidden jet, and could allow astronomers to observe similar polarization features in other black holes. Meanwhile, extending the EHT into space will provide sharper images of black holes than ever before.

The EHT collaboration involves more than 300 researchers from Africa, Asia, Europe, and North and South America. The international collaboration is working to capture the most detailed black hole images ever obtained by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.

The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), the Institut de Radioastronomie Millimetrique (IRAM) 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona AROSubmillimeter Telescope (SMT), the South Pole Telescope (SPT). Since then, the EHT has added the Greenland Telescope (GLT), the IRAM NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.

The EHT consortium consists of 13 stakeholder institutes: the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

JOURNAL

The Astrophysical Journal Letters

DOI

10.3847/2041-8213/ad2df0

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

) EHT collaboration: First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring.

ARTICLE PUBLICATION DATE

27-Mar-2024

Milky Way black hole’s magnetic field mapped for first time

Characteristics of the supermassive black hole at the heart of our galaxy captured in unprecedented detail by international team that includes Waterloo scientists

UNIVERSITY OF WATERLOO

Magnetic field around Sagittarius A* black hole — IMAGE:
THE MAGNETIC FIELDS AROUND THE BLACK HOLE AT THE CENTRE OF THE SGR A* BLACK HOLE AT THE CENTRE OF OUR GALAXY, THE MILKY WAY.
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CREDIT: THE EVENT HORIZON TELESCOPE (EHT) COLLABORATION

Long-held theories on how black holes like the one at the centre of our galaxy, the Milky Way, evolve were proven right this week thanks to research made possible by Canadian scientists.

A team of researchers from the University of Waterloo and Perimeter Institute who are members of the global Event Horizon Telescope (EHT) collaboration, developed a powerful framework called THEMIS that processes the EHT data, generating clear and accurate images that cut through noise and identify what really exists just outside the black hole.

While the first photos of the Sagittarius A* (Sgr A*) black hole were unveiled in 2022, the new images revealed its plasma ring, but also the magnetic field lines that shape and organize it.

“Sgr A* is like a frenetic toddler,” said Dr. Avery Broderick, a professor at the University of Waterloo’s Department of Physics and Astronomy and associate faculty at Perimeter Institute. “We’re seeing for the first time the invisible structure that shepherds the material within the black hole’s disk and drives plasma to the event horizon, helping it to grow.”

THEMIS – led by Broderick and his team – assessed the credibility of any given image of the black hole by providing a reliable statistical method for studying the information Sgr A* sends us from across the galaxy. It also can image black holes like Sgr A* even though they refuse to sit still thanks to swirling plasma, which is constantly churning away over short timescales.

That can be modelled by THEMIS to provide an estimate for the “noise” in the data, which can be averaged out to produce a clear, time-averaged image of Sgr A* in spite of its rapid variability.

The researchers’ results reveal strong polarization patterns in the signals that Sgr A* emits. Polarization – a property describing the orientation of light wave oscillations – is the same principle that sunglasses use to eliminate glare in multiple directions. By measuring the polarization, scientists are able to measure the structure and strength of Sgr A*’s magnetic fields.

“The polarized light we see from Sgr A* is striking,” Broderick said. “Not only is it highly polarized, at three times more polarization than the black hole at the centre of the M87 galaxy, but it’s also highly organized. This new image limits the density of the plasma orbiting Sgr A* and reveals the magnetic fields that govern its fate.”

According to astronomers’ best models of black hole evolution, the magnetic fields in the accretion disk need to be strong enough to push the accreting plasma around. The new results from Sgr A* (and those from its much larger cousin M87* previously) provide the first direct observational evidence to support those models.

This new research marks a milestone in black hole astronomy, helping to tell the story of black hole evolution and bring the unruly core of our galactic neighbourhood into sharp focus.

This research was presented in two papers by the EHT collaboration that will be published on Wednesday, March 27 in The Astrophysical Journal Letters.

Side-by-side comparison of the magnetic fields around the black hole at the centre of the M87 galaxy (left) and the Sgr A* black hole at the centre of our galaxy, the Milky Way.

CREDIT

The Event Horizon Telescope (EHT) collaboration

JOURNAL

The Astrophysical Journal Letters

Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way’s central black hole

CENTER FOR ASTROPHYSICS | HARVARD & SMITHSONIAN

A view of the Milky Way supermassive black hole Sagittarius A* in polarized light. — IMAGE:
THE EVENT HORIZON TELESCOPE (EHT) COLLABORATION, WHO PRODUCED THE FIRST EVER IMAGE OF OUR MILKY WAY BLACK HOLE RELEASED IN 2022, HAS CAPTURED A NEW VIEW OF THE MASSIVE OBJECT AT THE CENTER OF OUR GALAXY: HOW IT LOOKS IN POLARIZED LIGHT. THIS IS THE FIRST TIME ASTRONOMERS HAVE BEEN ABLE TO MEASURE POLARIZATION, A SIGNATURE OF MAGNETIC FIELDS, THIS CLOSE TO THE EDGE OF SAGITTARIUS A*. THIS IMAGE SHOWS THE POLARIZED VIEW OF THE MILKY WAY BLACK HOLE. THE LINES MARK THE ORIENTATION OF POLARIZATION, WHICH IS RELATED TO THE MAGNETIC FIELD AROUND THE SHADOW OF THE BLACK HOLE.
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CREDIT: EHT COLLABORATION

A new image from the Event Horizon Telescope (EHT) collaboration— which includes scientists from the Center for Astrophysics | Harvard & Smithsonian (CfA)— has uncovered strong and organized magnetic fields spiraling from the edge of the supermassive black hole Sagittarius A* (Sgr A*). Seen in polarized light for the first time, this new view of the monster lurking at the heart of the Milky Way Galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the center of the M87 galaxy, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*. The results were published today in The Astrophysical Journal Letters.

Scientists unveiled the first image of Sgr A*— which is approximately 27,000 light-years away from Earth— in 2022, revealing that while the Milky Way’s supermassive black hole is more than a thousand times smaller and less massive than M87’s, it looks remarkably similar. This made scientists wonder whether the two shared common traits outside of their looks. To find out, the team decided to study Sgr A* in polarized light. Previous studies of light around M87* revealed that the magnetic fields around the black hole giant allowed it to launch powerful jets of material back into the surrounding environment. Building on this work, the new images have revealed that the same may be true for Sgr A*.

“What we’re seeing now is that there are strong, twisted, and organized magnetic fields near the black hole at the center of the Milky Way galaxy,” said Sara Issaoun, CfA NASA Hubble Fellowship Program Einstein Fellow, Smithsonian Astrophysical Observatory (SAO) astrophysicist, and co-lead of the project. “Along with Sgr A* having a strikingly similar polarization structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.”

Light is an oscillating, or moving, electromagnetic wave that allows us to see objects. Sometimes, light oscillates in a preferred orientation, and we call it “polarized.” Although polarized light surrounds us, to human eyes it is indistinguishable from “normal” light. In the plasma around these black holes, particles whirling around magnetic field lines impart a polarization pattern perpendicular to the field. This allows astronomers to see in increasingly vivid detail what’s happening in black hole regions and map their magnetic field lines.

But imaging black holes in polarized light isn’t as easy as putting on a pair of polarized sunglasses, and this is particularly true of Sgr A*, which is changing so fast that it doesn’t sit still for pictures. Imaging the supermassive black hole requires sophisticated tools above and beyond those previously used for capturing M87*, a much steadier target. CfA postdoctoral fellow and SAO astrophysicist Paul Tiede said, “It is exciting that we were able to make a polarized image of Sgr A* at all. The first image took months of extensive analysis to understand its dynamical nature and unveil its average structure. Making a polarized image adds on the challenge of the dynamics of the magnetic fields around the black hole. Our models often predicted highly turbulent magnetic fields, making it extremely difficult to construct a polarized image. Fortunately, our black hole is much calmer, making the first image possible.”

Scientists are excited to have images of both supermassive black holes in polarized light because these images, and the data that come with them, provide new ways to compare and contrast black holes of different sizes and masses. As technology improves, the images are likely to reveal even more secrets of black holes and their similarities or differences.

Michi Bauböck, postdoctoral researcher at the University of Illinois Urbana-Champaign, said, “M87* and Sgr A* are different in a few important ways: M87* is much bigger, and it’s pulling in matter from its surroundings at a much faster rate. So, we might have expected that the magnetic fields also look very different. But in this case, they turned out to be quite similar, which may mean that this structure is common to all black holes. A better understanding of the magnetic fields near black holes helps us answer several open questions—from how jets are formed and launched to what powers the bright flares we see in infrared and X-ray light.”

The CfA is leading several major initiatives to sharply enhance the EHT over the next decade. The next-generation EHT (ngEHT) project is undertaking a transformative upgrade of the EHT, aiming to bring multiple new radio dishes online, enable simultaneous multi-color observations, and increase the overall sensitivity of the array. The ngEHT expansion will enable the array to make real-time movies of supermassive black holes on event horizon scales. These movies will resolve detailed structure and dynamics near the event horizon, bringing into focus “strong-field” gravity features predicted by General Relativity as well as the interplay of accretion and relativistic jet-launching that sculpts large-scale structures in the Universe. Meanwhile, the Black Hole Explorer (BHEX) mission concept will extend the EHT into space, producing the sharpest images in the history of astronomy. BHEX will enable the detection and imaging of the “photon ring” – a sharp ring feature formed by strongly lensed emission around black holes. The properties of a black hole are imprinted on the size and shape of the photon ring, revealing masses and spins for dozens of black holes, in turn showing how these strange objects grow and interact with their host galaxies.

Additional Information

This research was presented in two papers by the EHT collaboration published today in The Astrophysical Journal Letters: "First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring" (doi: 10.3847/2041-8213/ad2df0) and "First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring" (doi: 10.3847/2041-8213/ad2df1).

The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder Experiment (APEX), the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), the South Pole Telescope (SPT).

Since then, the EHT has added the Greenland Telescope (GLT), which is operated by ASIAA and the CfA, the NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.

At left, the supermassive black hole at the center of the Milky Way Galaxy, Sagittarius A*, is seen in polarized light, the visible lines indicating the orientation of polarization, which is related to the magnetic field around the shadow of the black hole. At center, the polarized emission from the center of the Milky Way, as captured by SOFIA. At back right, the Planck Collaboration mapped polarized emission from dust across the Milky Way.

CREDIT

S. Issaoun, EHT Collaboration

Seen here in polarized light, this side-by-side image of the supermassive black holes M87* and Sagittarius A* indicates to scientists that these beasts have similar magnetic field structures. This is significant because it suggests that the physical processes that govern how a black hole feeds and launches a jet may be universal features amongst supermassive black holes.

CREDIT

EHT Collaboration

About the Event Horizon Telescope (EHT)

The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Center for Astrophysics | Harvard & Smithsonian.

About the Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask—and ultimately answer—humanity's greatest unresolved questions about the nature of the universe. The Center for Astrophysics is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.

JOURNAL

The Astrophysical Journal Letters

DOI

10.3847/2041-8213/ad2df0

ARTICLE TITLE

First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring

ARTICLE PUBLICATION DATE

27-Mar-2024

Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way’s central black hole

ESO

A new image from the Event Horizon Telescope (EHT) collaboration has uncovered strong and organised magnetic fields spiraling from the edge of the supermassive black hole Sagittarius A* (Sgr A*). Seen in polarised light for the first time, this new view of the monster lurking at the heart of the Milky Way galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the centre of the M87 galaxy, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*. The results were published today in The Astrophysical Journal Letters.

In 2022 scientists unveiled the first image of Sgr A* at press conferences around the world, including at the European Southern Observatory (ESO). While the Milky Way’s supermassive black hole, which is roughly 27 000 light-years away from Earth, is more than a thousand times smaller and less massive than M87’s, the first-ever black hole imaged, the observations revealed that the two look remarkably similar. This made scientists wonder whether the two shared common traits outside of their looks. To find out, the team decided to study Sgr A* in polarised light. Previous studies of light around the M87 black hole (M87*) revealed that the magnetic fields around it allowed the black hole to launch powerful jets of material back into the surrounding environment. Building on this work, the new images have revealed that the same may be true for Sgr A*.

“What we’re seeing now is that there are strong, twisted, and organised magnetic fields near the black hole at the centre of the Milky Way galaxy,” said Sara Issaoun, NASA Hubble Fellowship Program Einstein Fellow at the Center for Astrophysics | Harvard & Smithsonian, US, and co-lead of the project. “Along with Sgr A* having a strikingly similar polarisation structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.”

Light is an oscillating, or moving, electromagnetic wave that allows us to see objects. Sometimes, light oscillates in a preferred orientation, and we call it ‘polarised’. Although polarised light surrounds us, to human eyes it is indistinguishable from ‘normal’ light. In the plasma around these black holes, particles whirling around magnetic field lines impart a polarisation pattern perpendicular to the field. This allows astronomers to see in increasingly vivid detail what’s happening in black hole regions and map their magnetic field lines.

“By imaging polarised light from hot glowing gas near black holes, we are directly inferring the structure and strength of the magnetic fields that thread the flow of gas and matter that the black hole feeds on and ejects,” said Harvard Black Hole Initiative Fellow and project co-lead Angelo Ricarte. “Polarised light teaches us a lot more about the astrophysics, the properties of the gas, and mechanisms that take place as a black hole feeds.”

But imaging black holes in polarised light isn’t as easy as putting on a pair of polarised sunglasses, and this is particularly true of Sgr A*, which is changing so fast that it doesn’t sit still for pictures. Imaging the supermassive black hole requires sophisticated tools above and beyond those previously used for capturing M87*, a much steadier target. EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei said, “Because Sgr A* moves around while we try to take its picture, it was difficult to construct even the unpolarised image,” adding that the first image was an average of multiple images owing to Sgr A*’s movement. “We were relieved that polarised imaging was even possible. Some models were far too scrambled and turbulent to construct a polarised image, but Nature was not so cruel.”

Mariafelicia De Laurentis, EHT Deputy Project Scientist and professor at the University of Naples Federico II, Italy, said, “With a sample of two black holes — with very different masses and very different host galaxies — it’s important to determine what they agree and disagree on. Since both are pointing us toward strong magnetic fields, it suggests that this may be a universal and perhaps fundamental feature of these kinds of systems. One of the similarities between these two black holes might be a jet, but while we’ve imaged a very obvious one in M87*, we’ve yet to find one in Sgr A*.”

To observe Sgr A*, the collaboration linked eight telescopes around the world to create a virtual Earth-sized telescope, the EHT. The Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, and the ESO-hosted Atacama Pathfinder Experiment (APEX), both in northern Chile, were part of the network that made the observations, conducted in 2017.

"As the largest and most powerful of the telescopes in the EHT, ALMA played a key role in making this image possible,” says ESO’s María Díaz Trigo, European ALMA Programme Scientist. “ALMA is now planning an ‘extreme makeover’, the Wideband Sensitivity Upgrade, which will make ALMA even more sensitive and keep it a fundamental player in future EHT observations of Sgr A* and other black holes."

The EHT has conducted several observations since 2017 and is scheduled to observe Sgr A* again in April 2024. Each year, the images improve as the EHT incorporates new telescopes, larger bandwidth, and new observing frequencies. Planned expansions for the next decade will enable high-fidelity movies of Sgr A*, may reveal a hidden jet, and could allow astronomers to observe similar polarisation features in other black holes. Meanwhile, extending the EHT into space would provide sharper images of black holes than ever before.

More information

This research was presented in two papers by the EHT collaboration published today in The Astrophysical Journal Letters: "First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring" and "First Sagittarius A* Event Horizon Telescope Results. VIII.: Physical interpretation of the polarized ring"

The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), the Institut de Radioastronomie Millimetrique (IRAM) 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), and the South Pole Telescope (SPT). Since then, the EHT has added the Greenland Telescope (GLT), the IRAM NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Next mission to space station carries research on vision loss treatments and earth-viewing technology

Cartilage repair, retinal gene therapies, neurological disease treatments, and technology testing on external platforms among investigations flying on NASA’s SpaceX CRS-30

INTERNATIONAL SPACE STATION U.S. NATIONAL LABORATORY

NASA's SpaceX CRS-30 Launches to Space Station Today — IMAGE:
NEXT MISSION TO INTERNATIONAL SPACE STATION PACKED WITH R&D SLATED TO LAUNCH THIS AFTERNOON FROM CAPE CANAVERAL SPACE FORCE STATION IN FLORIDA.
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CREDIT: NASA

CAPE CANAVERAL (FL), March 21, 2024 – The next resupply mission to the International Space Station (ISS) will carry more than 40 payloads sponsored by the ISS National Laboratory®, including in-space production applications projects, technology demonstrations, life science experiments, and student-led inquiries. These investigations, launching on SpaceX’s 30th Commercial Resupply Services (CRS) mission, funded by NASA, aim to improve life on Earth through space-based research and foster a sustainable economy in low Earth orbit (LEO).

Below highlights a sample of those payloads, and findings could lead to advances in technology for future spaceflight and the development of novel therapeutics for use both on Earth and in space.

Redwire Corporation is partnering with pharmaceutical company Eli Lilly & Company and Butler University for two investigations leveraging Redwire’s Pharmaceutical In-space Laboratory (PIL-BOX), a platform to crystallize organic molecules in microgravity. Results from this research could lead to improved therapeutics to treat an array of conditions. This research continues Eli Lilly’s space journey, as the company has launched a variety of investigations to the orbiting laboratory over the years for the benefit of patient care on Earth.
A collaboration between Boeing and CSIRO (an Australian government agency responsible for scientific research) will test the ability of a Multi-Resolution Scanner to create 3D maps of the space station. To do this, the project will use Astrobee, an autonomous free-flying robotic system on station. This scanner technology could be useful in future exploration efforts and in remote environments for manufacturing and maintenance tasks, such as identifying leaks or checking for damage to systems.
The National Stem Cell Foundation will continue to examine the mechanisms behind neuroinflammation, a common feature of neurodegenerative diseases. To carry out this study, the research team created 3D brain models derived from induced pluripotent stem cells of patients with Alzheimer’s and Parkinson’s diseases as well as primary progressive multiple sclerosis.
Airbus U.S. Space & Defense is launching an enhancement to the station’s Bartolomeo platform. Called ArgUS, the external mechanical platform has added capabilities for hosting payloads in LEO. Once ArgUS is installed, it will host multiple payloads on this mission, including SpaceTV-1, an optical video system designed to livestream high-definition views of Earth and the space station.
A project from the University of Connecticut will examine the feasibility of producing Janus base nanomaterials in microgravity that could help repair cartilage and reduce joint inflammation. Through this project, researchers aim to advance in-space manufacturing concepts for these materials, which could significantly improve patient care for orthopedic injuries and degenerative joint diseases like arthritis, as there is currently no way to repair damaged cartilage.

Additionally, two investigations flying on NASA’s SpaceX CRS-30 mission were selected through the Technology in Space Prize, funded by Boeing and the Center for the Advancement of Science in Space™ (CASIS™), manager of the ISS National Lab, as part of the MassChallenge startup accelerator program.

An investigation from biopharmaceutical company Oculogenex will use the space station to test a novel gene therapy to prevent and possibly even reverse vision loss from age-related macular degeneration (AMD). Findings will help advance the company’s therapeutic, which can potentially treat AMD-related symptoms in millions of Americans.
A project from biomedical startup Encapsulate aims to leverage the microgravity environment of the space station to validate an automated tumor-on-a-chip system that grows patient-derived cancer cells to test chemotherapy drugs. The company seeks to use precision diagnostics for personalized cancer treatments.

SpaceX’s Falcon 9 rocket will launch these investigations and more no earlier than Thursday, March 21, 2024, at 4:55 p.m. EDT from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida.

Researchers briefed media on select payloads during a recent webinar, and the recording can be viewed on our launch page.

Download a high-resolution photo for the release: NASA’s SpaceX CRS-29 Mission

Long-period oscillations control the Sun’s differential rotation

High-latitude long-period oscillations provide a feedback mechanism that limits the Sun’s pole-to-equator differential rotation.

MAX PLANCK INSTITUTE FOR SOLAR SYSTEM RESEARCH

The Sun’s differential rotation pattern has puzzled scientists for decades: while the poles rotate with a period of approximately 34 days, mid-latitudes rotate faster and the equatorial region requires only approximately 24 days for a full rotation. In addition, in past years advances in helioseismology, i.e. probing the solar interior with the help of solar acoustic waves, have established that this rotational profile is nearly constant throughout the entire convection zone. This layer of the Sun stretches from a depth of approximately 200 000 kilometers to the visible solar surface and is home to violent upheavals of hot plasma which play a crucial role in driving solar magnetism and activity.

While theoretical models have long postulated a slight temperature difference between solar poles and equator to maintain the Sun’s rotational pattern, it has proven notoriously difficult to measure. After all, observations have to “look through” the background of the Sun’s deep interior which measures up to million degrees in temperature. However, as the researchers from MPS show, it is now possible to determine the temperature difference from the observations of the long-period oscillations of the Sun.

In their analysis of observational data obtained by the Helioseismic and Magnetic Imager (HMI) onboard NASA’s Solar Dynamics Observatory from 2017 to 2021, the scientists turned to global solar oscillations with long periods that can be discerned as swirling motions at the solar surface. Scientists from MPS reported their discovery of these inertial oscillations three years ago. Among these observed modes, the high-latitude modes with velocities of up to 70 km per hour, proved to be especially influential.

To study the nonlinear nature of these high-latitude oscillations, a set of three-dimensional numerical simulations was conducted. In their simulations, the high-latitude oscillations carry heat from the solar poles to the equator, which limits the temperature difference between the Sun’s poles and the equator to less than seven degrees. “This very small temperature difference between the poles and the equator controls the angular momentum balance in the Sun and thus is an important feedback mechanism for the Sun’s global dynamics” says MPS Director Prof. Dr. Laurent Gizon.

In their simulations, the researchers for the first time described the crucial processes in a fully three-dimensional model. Former endeavors had been limited to two-dimensional approaches that assumed the symmetry about the Sun’s rotation axis. “Matching the nonlinear simulations to the observations allowed us to understand the physics of the long-period oscillations and their role in controlling the Sun’s differential rotation”, says MPS postdoc and the lead author of the study, Dr. Yuto Bekki.

The solar high-latitude oscillations are driven by a temperature gradient in a similar way to extratropical cyclones on the Earth. The physics is similar, though the details are different: “In the Sun, the solar pole is about seven degrees hotter than equator and this is enough to drive flows of about 70 kilometers per hour over a large fraction of the Sun. The process is somewhat similar to the driving of cyclones”, says MPS scientist Dr. Robert Cameron.

Probing the physics of the Sun’s deep interior is difficult. This study is important as it shows that the long-period oscillations of the Sun are not only useful probes of the solar interior, but that they play an active role in the way the Sun works. Future work, which will be carried out in the context of the ERC Synergy Grant WHOLESUN and the DFG Collaborative Research Center 1456 Mathematics of Experiments, will be aimed at better understanding the role of these oscillations and their diagnostic potential.

JOURNAL

Science Advances

DOI

10.1126/sciadv.adk5643

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The Sun’s differential rotation is controlled by high-latitude baroclinically unstable inertial modes

ARTICLE PUBLICATION DATE

27-Mar-2024

Persistent hiccups in a far-off galaxy draw astronomers to new black hole behavior

New analysis reveals a tiny black hole repeatedly punching through a larger black hole’s disk of gas

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

At the heart of a far-off galaxy, a supermassive black hole appears to have had a case of the hiccups.

Astronomers from MIT, Italy, the Czech Republic, and elsewhere have found that a previously quiet black hole, which sits at the center of a galaxy about 800 million light years away, has suddenly erupted, giving off plumes of gas every 8.5 days before settling back to its normal, quiet state.

The periodic hiccups are a new behavior that has not been observed in black holes until now. The scientists believe the most likely explanation for the outbursts stems from a second, smaller black hole that is zinging around the central, supermassive black hole and slinging material out from the larger black hole’s disk of gas every 8.5 days.

The team’s findings, which will be published in the journal Science Advances, challenge the conventional picture of black hole accretion disks, which scientists had assumed are relatively uniform disks of gas that rotate around a central black hole. The new results suggest that accretion disks may be more varied in their contents, possibly containing other black holes, and even entire stars.

“We thought we knew a lot about black holes, but this is telling us there are a lot more things they can do,” says study author Dheeraj “DJ” Pasham, a research scientist in MIT’s Kavli Institute for Astrophysics and Space Research. “We think there will be many more systems like this, and we just need to take more data to find them.”

The study’s MIT co-authors include postdoc Peter Kosec, graduate student Megan Masterson, Associate Professor Erin Kara, Principal Research Scientist Ronald Remillard, and former research scientist Michael Fausnaugh, along with collaborators from multiple institutions, including the Tor Vergata University of Rome, the Astronomical Institute of the Czech Academy of Sciences, and Masaryk University in the Czech Republic.

“Use it or lose it”

The team’s findings grew out of an automated detection by ASAS-SN (the All Sky Automated Survey for SuperNovae), a network of 20 robotic telescopes situated in various locations across the northern and southern hemispheres. The telescopes automatically survey the entire sky once a day for signs of supernovae and other transient phenomena.

In December of 2020, the survey spotted a burst of light in a galaxy about 800 million light years away. That particular part of the sky had been relatively quiet and dark until the telescopes’ detection, when the galaxy suddenly brightened by a factor of 1,000. Pasham, who happened to see the detection reported in a community alert, chose to focus in on the flare with NASA’s NICER (the Neutron star Interior Composition Explorer), an X-ray telescope aboard the International Space Station that continuously monitors the sky for X-ray bursts that could signal activity from neutron stars, black holes, and other extreme gravitational phenomena. The timing was fortuitous, as it was getting toward the end of Pasham’s year-long period during which he had permission to point, or “trigger” the telescope.

“It was either use it or lose it, and it turned out to be my luckiest break,” he says.

He trained NICER to observe the far-off galaxy as it continued to flare. The outburst lasted for about four months before petering out. During that time, NICER took measurements of the galaxy’s X-ray emissions on a daily, high-cadence basis. When Pasham looked closely at the data, he noticed a curious pattern within the four-month flare: subtle dips, in a very narrow band of X-rays, that seemed to reappear every 8.5 days.

It seemed that the galaxy’s burst of energy periodically dipped every 8.5 days. The signal is similar to what astronomers see when an orbiting planet crosses in front of its host star, briefly blocking the star’s light. But no star would be able to block a flare from an entire galaxy.

“I was scratching my head as to what this means because this pattern doesn’t fit anything that we know about these systems,” Pasham recalls.

Punch it

As he was looking for an explanation to the periodic dips, Pasham came across a recent paper by theoretical physicists in the Czech Republic. The theorists had separately worked out that it would be possible, in theory, for a galaxy’s central supermassive black hole to host a second, much smaller black hole. That smaller black hole could orbit at an angle from its larger companion’s accretion disk.

As the theorists proposed, the secondary would periodically punch through the primary black hole’s disk as it orbits. In the process, it would release a plume of gas , like a bee flying through a cloud of pollen. Powerful magnetic fields, to the north and south of the black hole, could then slingshot the plume up and out of the disk. Each time the smaller black hole punches through the disk, it would eject another plume, in a regular, periodic pattern. If that plume happened to point in the direction of an observing telescope, it might observe the plume as a dip in the galaxy’s overall energy, briefly blocking the disk’s light every so often.

“I was super excited by this theory, and I immediately emailed them to say, ‘I think we’re observing exactly what your theory predicted,’” Pasham says.

He and the Czech scientists teamed up to test the idea, with simulations that incorporated NICER’s observations of the original outburst, and the regular, 8.5-day dips. What they found supports the theory: The observed outburst was likely a signal of a second, smaller black hole, orbiting a central supermassive black hole, and periodically puncturing its disk.

Specifically, the team found that the galaxy was relatively quiet prior to the December 2020 detection. The team estimates the galaxy’s central supermassive black hole is as massive as 50 million suns. Prior to the outburst, the black hole may have had a faint, diffuse accretion disk rotating around it, as a second, smaller black hole, measuring 100 to 10,000 solar masses, was orbiting in relative obscurity.

The researchers suspect that, in December 2020, a third object — likely a nearby star — swung too close to the system and was shredded to pieces by the supermassive black hole’s immense gravity — an event that astronomers know as a “tidal disruption event.” The sudden influx of stellar material momentarily brightened the black hole’s accretion disk as the star’s debris swirled into the black hole. Over four months, the black hole feasted on the stellar debris as the second black hole continued orbiting. As it punched through the disk, it ejected a much larger plume than it normally would, which happened to eject straight out toward NICER’s scope.

The team carried out numerous simulations to test the periodic dips. The most likely explanation, they conclude, is a new kind of David-and-Goliath system — a tiny, intermediate-mass black hole, zipping around a supermassive black hole.

“This is a different beast,” Pasham says. “It doesn’t fit anything that we know about these systems. We’re seeing evidence of objects going in and through the disk, at different angles, which challenges the traditional picture of a simple gaseous disk around black holes. We think there is a huge population of these systems out there.”

“This is a brilliant example of how to use the debris from a disrupted star to illuminate the interior of a galactic nucleus which would otherwise remain dark. It is akin to using fluorescent dye to find a leak in a pipe,” says Richard Saxton, an X-ray astronomer from the European Space Astronomy Centre (ESAC) in Madrid, Spain, who was not involved in the study. “This result shows that very close super-massive black hole binaries could be common in galactic nuclei, which is a very exciting development for future gravitational wave detectors.”

This research was supported in part NASA.

###

Written by Jennifer Chu, MIT News

JOURNAL

Science Advances

DOI

10.1126/sciadv.adj8898

ARTICLE TITLE

A Case for a Binary Black Hole System Revealed via Quasi-Periodic Outflows

ARTICLE PUBLICATION DATE

27-Mar-2024

U-M astronomers conduct first search for forming planets with new space telescope

UNIVERSITY OF MICHIGAN

Images

Planets form in disks of dust and gas called protoplanetary disks that whirl around a central protostar during its final assembly.

Although several dozens of such disks have been imaged, just two planets have been caught in the act of forming so far. Now, astronomers are aiming the powerful instruments aboard the James Webb Space Telescope at protoplanetary disks to try to find early clues about the ways in which planets form, and how these planets influence their natal disk.

A trio of studies led by the University of Michigan, University of Arizona and University of Victoria combined JWST's images with prior observations made by the Hubble Space Telescope and the Atacama Large Millimeter Array, or ALMA, in Chile. Based on the ancillary observations, the team used JWST to observe protoplanetary disks HL Tau, SAO 206462 and MWC 758 in hopes of detecting any planets that might be forming.

In the papers, published in The Astronomical Journal, the researchers pieced together previously unseen interactions between the planet-forming disk and the envelope of gas and dust surrounding the young stars at the center of the protoplanetary disks.

To catch a planet

The U-M study, led by U-M astronomer Gabriele Cugno, aimed JWST at a disk surrounding a protostar called SAO 206462. There, the researchers potentially found a planet candidate in the act of forming in a protoplanetary disk—but it wasn't the planet they expected to find.

"Several simulations suggest that the planet should be within the disk, massive, large, hot, and bright. But we didn't find it. This means that either the planet is much colder than we think, or it may be obscured by some material that prevents us from seeing it," said Cugno, also a co-author on all three papers. "What we have found is a different planet candidate, but we cannot tell with 100% certainty whether it's a planet or a faint background star or galaxy contaminating our image. Future observations will help us understand exactly what we are looking at."

Astronomers have observed the disk in the past, notably with the Hubble Space Telescope, the Subaru Telescope, the Very Large Telescope and ALMA. These observations show a disk composed of two strong spirals, which are likely launched by a forming planet. The planet the U-M team expected to find is a type called a gas giant, planets composed mainly of hydrogen and helium, similar to Jupiter in our own solar system.

"The problem is, whatever we're trying to detect is hundreds of thousands, if not millions of times fainter than the star," Cugno said. "That's like trying to detect a little light bulb next to a lighthouse."

To peer more closely into the disk, the team used an instrument on JWST called NIRCam. NIRCam detects infrared light, and the astronomers used the instrument employing a technique called angular differential imaging. This technique can be used to detect both the thermal radiation of the planet, as the team has done to detect the planet candidate, and specific emission lines associated with material falling onto the planet and hitting its surface with high velocity.

"When material falls onto the planet, it shocks at the surface and gives off an emission line at specific wavelengths," Cugno said. "We use a set of narrow-band filters to try to detect this accretion. This has been done before from the ground at optical wavelengths, but this is the first time it's been done in the infrared with JWST."

Imaging the 'raw material' of planets

The University of Victoria paper, led by astronomy student Camryn Mullin, describes images of the disk surrounding the young star HL Tau.

"HL Tau is the youngest system in our survey, and still surrounded by a dense inflow of dust and gas falling onto the disk," said Mullin, a co-author of all three studies. "We were amazed by the level of detail with which we could see this surrounding material with JWST, but unfortunately, it obscures any signals from potential planets. "

HL Tau’s disk is known for having several solar-system scale rings and gaps which could harbor planets.

"While there is a ton of evidence for ongoing planet formation, HL Tau is too young with too much intervening dust to see the planets directly," said Jarron Leisenring, the principal investigator of the observing campaign searching for forming planets and astronomer at the University of Arizona Steward Observatory. "We have already begun looking at other young systems with known planets to help form a more complete picture."

However, to the team's surprise, JWST revealed unexpected details of a different feature: the proto-stellar envelope, which is essentially a dense inflow of dust and gas surrounding the young star that is just beginning to coalesce, according to Leisenring. Under the influence of gravity, material from the interstellar medium falls inward onto the star and the disk, where it serves as the raw material for planets and their precursors.

The UArizona study, led by Kevin Wagner, a NASA Hubble/Sagan Fellow at UArizona Steward Observatory, examined the protoplanetary disk of MWC 758. Similar to SAO 206462, previous observations by the UArizona-led team revealed spiral arms forming in the disk, hinting at a massive planet orbiting its host star.

While no new planets were detected in the disk during the most recent observations, the sensitivity is groundbreaking, the researchers say, as it allows them to place the most stringent constraints yet on the suspected planets. For one, the results rule out the existence of additional planets in the outer regions of the MWC 758, consistent with a single giant planet driving the spiral arms.

"The lack of planets detected in all three systems tells us that the planets causing the gaps and spiral arms either are too close to their host stars or too faint to be seen with JWST," said Wagner, a co-author of all three studies. "If the latter is true, it tells us that they're of relatively low mass, low temperature, enshrouded in dust, or some combination of the three—as is likely the case in MWC 758."

The search for forming planets continues

Catching planets in the act of forming is important because astronomers can glean information not only about the formation process, but how chemical elements get distributed throughout a planetary system.

"Only about 15 percent of stars like the sun have planets like Jupiter. It's really important to understand how they form and evolve, and to refine our theories," said U-M Michael Meyer, U-M astronomer and coauthor of all three studies. "Some astronomers think that these gas giant planets regulate the delivery of water to rocky planets forming in the inner parts of the disks."

Knowing how these disks are shaped by gas giants will help astronomers ultimately understand the properties and evolution of protoplanetary disks that later give rise to rocky, Earth-like planets, said Meyer.

"Basically in every disk we have observed with high enough resolution and sensitivity, we have seen large structures like gaps, rings and, in the case of SAO 206462, spirals," Cugno said. "Most if not all of these structures can be explained by forming planets interacting with the disk material, but other explanations that do not involve the presence of giant planets exist.

If we manage to finally see these planets, we can connect some of the structures with forming companions and relate formation processes to the properties of other systems at much later stages. We can finally connect the dots and understand how planets and planetary systems evolve as a whole."

Studies:

JWST/NIRCam Imaging of Young Stellar Objects. I. Constraints on Planets Exterior to the Spiral Disk Around MWC 758 (DOI: 10.3847/1538-3881/ad11d5)

JWST/NIRCam Imaging of Young Stellar Objects. II. Deep Constraints on Giant Planets and a Planet Candidate Outside of the Spiral Disk Around SAO 206462 (DOI: 10.3847/1538-3881/ad1ffc)

JWST/NIRCam Imaging of Young Stellar Objects III. Detailed Imaging of the Nebular Environment Around the HL Tau Disk (DOI: 10.3847/1538-3881/ad2de9)

JOURNAL

The Astronomical Journal

Scientists propose a new way to search for dark matter

DOE/SLAC NATIONAL ACCELERATOR LABORATORY

Ever since its discovery, dark matter has remained invisible to scientists, despite the launch of multiple ultra-sensitive particle detector experiments around the world over several decades.

Now, physicists at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory are proposing a new way to look for dark matter using quantum devices, which might be naturally tuned to detect what researchers call thermalized dark matter.

Most dark matter experiments hunt for galactic dark matter, which rockets into Earth directly from space, but another kind might have been hanging around Earth for years, said SLAC physicist Rebecca Leane, who was an author on the new study.

“Dark matter goes into the Earth, bounces around a lot, and eventually just gets trapped by the gravitational field of the Earth,” Leane said, bringing it into an equilibrium scientists refer to as thermalized. Over time, this thermalized dark matter builds up to a higher density than the few loose, galactic particles, meaning that it could be more likely to hit a detector. Unfortunately, thermalized dark matter moves much more slowly than galactic dark matter, meaning it would impart far less energy than galactic dark matter – likely too little for traditional detectors to see.

With that in mind, Leane and SLAC postdoctoral fellow Anirban Das reached out to Noah Kurinsky, a staff scientist at SLAC and leader of a new lab focused on detecting dark matter with quantum sensors, who had been thinking about a puzzle: Even when superconductors are cooled to absolute zero, removing all of the energy out of the system and creating a stable quantum state, somehow energy reenters and disrupts the quantum state.

Typically, scientists assume that's because of imperfect cooling systems or some source of heat in the environment, said Kurinksy. But there could be another reason, he said: “What if we actually have a perfectly cold system, and the reason we can’t cool it down effectively is because it’s constantly being bombarded by dark matter?”

Das, Kurinsky, and Leane wondered whether superconducting quantum devices could be redesigned as thermalized dark matter detectors. According to their calculations, the minimum energy needed to activate a quantum sensor is low enough – around one thousandth of an electron volt – that it could detect low-energy galactic dark matter as well as thermalized dark matter particles hanging around Earth.

Of course, that doesn't mean that dark matter is to blame for disrupted quantum devices – only that it is possible. The next step, Leane and Kurinsky said, is to figure out if and how they can turn sensitive quantum devices into dark matter detectors.

With that, there are a few things to consider. For starters, maybe there is a better material to make the device out of. “We were looking at aluminum to start with, and that's just because that's probably the best characterized material that's been used for detectors so far,” said Leane. “But it could turn out that for the sort of mass range we're looking at, and the sort of detector we want to use, maybe there's a better material.”

There’s also a possibility that thermalized dark matter wouldn’t interact with a quantum device the same way galactic dark matter is suspected to interact with direct detection devices, Leane said. “In this study, we were just thinking about a simple case for dark matter coming in and bouncing straight off the detector, but it could do a lot of other things.” For example, other particles could interact with dark matter that change the way the particles in the detector are distributed.

“This is one of the great things about being at SLAC,” Leane says. “We really have quite a diverse range of groups working on a lot of different science, and I feel like this project is a really nice synergy of the research at SLAC.”

The research was funded by the DOE Office of Science.

JOURNAL

Physical Review Letters

DOI

10.1103/PhysRevLett.132.121801

ARTICLE TITLE

Dark Matter Induced Power in Quantum Devices

ARTICLE PUBLICATION DATE

27-Mar-2024

‘Cosmic Cannibals’ expel jets into space at 40% speed of light

For the first time, astronomers have measured the speed of fast-moving jets in space, crucial to star formation and the distribution of elements needed for life

UNIVERSITY OF WARWICK

VIDEO:

[IMAGE DESCRIPTION: IN THE FOREGROUND, AT THE CENTRE RIGHT, THERE IS A VERY BRIGHT WHITE BALL, REPRESENTING THE NEUTRON STAR. WHITE/PURPLE FILAMENTS ARE STREAMING OUT FROM ITS POLAR REGION. THE BALL IS SURROUNDED BY A HAZY WHITE LARGER SPHERE, THE CORONA, AND FURTHER OUT BY A DISK WITH CONCENTRIC BANDS OF DIFFERENT COLOURS, GOING FROM WHITE IN THE INNER DISK TO ORANGE IN THE MIDDLE AND TO RED-MAGENTA IN THE OUTER REGION. AN ORANGE BAND CONNECTS THE OUTER PART OF THE DISK TO A LARGE YELLOW-ORANGE-RED SECTION OF A SPHERE IN THE TOP LEFT CORNER. THIS REPRESENTS THE STAR COMPANION OF THE NEUTRON STAR, THAT IS FEEDING THE DISK AROUND THE BRIGHT WHITE SPHERICAL BODY.]view more

CREDIT: CREDIT: ESA. AKNOWLEDGMENTS: D. FUTSELAAR AND N. DEGENAAR, UNIVERSITY OF AMSTERDAM. WORK PERFORMED BY ATG MEDIALAB UNDER CONTRACT WITH ESA LICENSE: ESA STANDARD LICENCE

Astronomers including those at the University of Warwick, have observed jets of matter being expelled into space at more than one-third the speed of light.
These jets play an important role in the universe, from forming stars to transporting elements deep into space.
Jets are produced by many different astronomical objects but studying them is hard, as they are so energetic.
This study forms a blueprint for future research into many areas of the cosmos.

For the first time, astronomers have measured the speed of fast-moving jets in space, crucial to star formation and the distribution of elements needed for life.

The jets of matter, expelled by stars deemed ‘cosmic cannibals’, were measured to travel at over one-third of the speed of light – thanks to a groundbreaking new experiment published in Nature today.

The study sheds new light on these violent processes, making clever use of runaway nuclear explosions on the surface of stars.

Co-Author Jakob van den Eijnden, Warwick Prize Fellow at the Department of Physics, University of Warwick, said: “The explosions occurred on neutron stars, which are incredibly dense and notorious for their enormous gravitational pull that makes them swallow gas from their surroundings – a gravitational pull that is only surpassed by black holes.

“The material, mostly hydrogen from a nearby star that orbits around, swirls towards the collapsed star, falling like snow across its surface. As more and more material rains down, the gravitational field compresses it until a runaway nuclear explosion is initiated. This explosion impacts the jets, that are also shot out from the infalling material and eject particles into space at very high speed.”

The team devised a way of measuring the speed and properties of the jets by comparing X-ray and radio signals picked up by the Australia Telescope Compact Array (owned and operated by CSIRO, Australia’s national science agency) and the European Space Agency’s (ESA’s) Integral satellite.

Co-Author Thomas Russell, National Institute for Astrophysics, INAF, Palermo, Italy, said: “This gave us a perfect experiment. We had a very brief short-lived impulse of extra material that gets shot into the jet and that we can track as it moves down the jet to learn about its speed.”

Jakob van den Eijnden added: “These explosion occur every couple of hours, but you can't predict exactly when they will happen. So you have to stare at the telescope observations for a long time, and hope you catch a couple of bursts. Over three days of observations we saw 10 explosions and jets lighting up.”

The jets travelled around 114,000 kilometres per second, an incredible 35-40% the speed of light.

This was the first time astronomers had been able to anticipate and directly watch how a certain amount of gas got channelled into a jet and accelerated into space.

Co-Author Nathalie Degenaar, University of Amsterdam, the Netherlands, continued: “Based on previous data, we thought the explosion would destroy the location where the jet was being launched. But we saw exactly the opposite: a strong input into the jet rather than a disruption.”

The researchers believe the mass and rotation of neutron stars and black holes also impacts the jets.

Having now shown this research is possible, this study will form the blueprint for future experiments into neutron stars and their jets. Jets can also be produced by cataclysmic events such as supernova explosions and gamma-ray bursts. The new results will have wide applicability in many studies of the cosmos.

Read the paper here: https://www.nature.com/articles/s41586-024-07133-5

Notes to editors

Radio emission was collected using the Australia Telescope Compact Array, owned and operated by CSIRO, Australia’s national science agency, and X-rays from The European Space Agency’s Integral satellite.

Scientific paper

Thermonuclear explosions on neutron stars reveal the speed of their jets. By: Thomas D. Russell, Nathalie Degenaar, Jakob van den Eijnden, Thomas Maccarone, Alexandra J. Tetarenko, Celia Sánchez-Fernández, James C.A. Miller-Jones, Erik Kuulkers & Melania Del Santo. In: Nature, <date> 2024. Original: <link>. Preprint: <link>

“Thermonuclear explosions on neutron stars reveal the speed and feeding of their jets” is published in Nature. DOI: 10.1038/s41586-024-07133-5

JOURNAL

Nature

DOI

10.1038/s41586-024-07133-5

NRL’s Sungrazer Project discovers 5000th comet

NAVAL RESEARCH LABORATORY

WASHINGTON – WASHINGTON - On March 25, the U.S. Naval Research Laboratory’s (NRL) Sungrazer Project reached a remarkable milestone – the discovery of its 5,000th comet in data from the joint European Space Agency – National Aeronautics and Space Administration (ESA-NASA) Solar and Heliospheric Observatory (SOHO).

The Sungrazer Project is a NASA-funded citizen science program operating from NRL for over 20 years, and enables volunteers from anywhere in the world to submit reports of suspected new near-Sun and “sungrazing” comets in NASA and ESA heliophysics imaging data.

Almost all of the project’s 5,000 discoveries have been made in images returned by NRL’s Large Angle Spectrometric Coronagraph (LASCO) telescope which has operated continuously aboard the SOHO satellite since 1995.

LASCO is a coronagraph telescope, designed to return visible-light images of the solar corona and near-Sun region, to aid in the study of solar eruptions and outflows. However, the high-sensitivity of the instrument has also led to an unanticipated wealth of observations of previously unknown comets as they pass extremely close to the Sun and begin vaporizing. Due to their proximity to the Sun, these comets are invisible from Earth, and can only be seen by specialized instrumentation like LASCO.

“When LASCO was launched, no one had any idea that it would turn out to be the most prolific discoverer in history,” said NRL researcher Karl Battams, Ph.D., the principal investigator of LASCO and the Sungrazer Project. “The amount of data and science returned has just been beyond our wildest dreams.”

The 5,000th discovery was made by amateur astronomer Hanjie Tan from Guangzhou, China, who is currently an astronomy Ph.D. student in Prague, Czech Republic. Tan has been participating in the Sungrazer Project since he was 13 years old, making him one of the project’s youngest comet discoverers. He spotted the images from LASCO’s C2 camera. Unlike most of SOHO’s comets, it very probably survived its passage by the Sun. It will have passed approximately 8.2 million kilometers (5.1 million miles) from the Sun – this is slightly farther from the Sun than the current orbit of NASA’s Parker Solar Probe, which carries NRL’s WISPR imaging instrument.

SOHO-5000 is a small, short-period comet belonging to the so-called ‘Marsden group’ of comets, named for the late Dr. Brian Marsden who first recognized the group. The Marsden group was not known to exist until SOHO (LASCO) discovered it. The group is believed to be an ancient descendants of the Near-Sun comet 96P/Machholz, which NRL’s LASCO observes every 5.3 years. Only approximately 75 of SOHO’s 5,000 comets belong to this comet group.

The crowd-sourced discovery of comets in SOHO/LASCO observations has led to a wealth of new science regarding the compositional properties of comets, their photometric behavior, and their physical properties, as well as orbital evolution and fragmentation. Studies of these comets also aids our understanding of the Sun, allowing scientists to study the way the comets and their tails react to, and interact with the extreme near-Sun region, including the Sun’s magnetic fields and outflows. LASCO is one of the most impactful heliophysics instruments in history, currently providing critical realtime imagery of solar eruptions that can lead to potentially disruptive space weather events.

The SOHO project is reaching the end of its planned lifetime. It was originally a two-year mission, and has now stretched to nearly 30 years. It is currently scheduled to cease operations at the end of 2025. “It will be truly sad when the SOHO mission finally ends,” said Battams, “but the discoveries that it has made over nearly the past 30 years have completely revolutionized heliophysics and comet science, so we have so very much to thank SOHO for.”

About the U.S. Naval Research Laboratory

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

For more information, contact NRL Corporate Communications at (202) 480-3746 or nrlpao@us.navy.mil.

WISPR team images turbulence within solar transients for the first time

NAVAL RESEARCH LABORATORY

WASHINGTON — The Wide-field Imager for Parker Solar Probe (WISPR) Science Team, led by the U.S. Naval Research Laboratory (NRL), captured the development of turbulence as a Coronal Mass Ejection (CME) interacted with the ambient solar wind in the circumsolar space. This discovery is reported in the Astrophysical Journal.

Taking advantage of its unique location inside the Sun’s atmosphere, the NRL-built WISPR telescope on NASA’s Parker Solar Probe (PSP) mission, operated by the Johns Hopkins University Applied Physics Laboratory (JHUAPL), captured in unparalleled detail the interaction between a CME and the background ambient solar wind. To the surprise of the WISPR team, images from one of the telescopes showed what seemed like turbulent eddies, so-called Kelvin-Helmholtz instabilities (KHI). Such structures have been imaged in the terrestrial atmosphere as trains of crescent wave-like clouds and are the results of strong wind shear between the upper and lower levels of the cloud. This phenomenon, while rarely imaged, is thought to occur regularly at the interface of fluid flows when the right conditions arise.

“We never anticipated that KHI structures could develop to large enough scales to be imaged in visible light CME images in the heliosphere when we designed the instrument,” said Angelos Vourlidas, Ph.D., JHUAPL and WISPR Project Scientist. “These fine detail observations show the power of the WISPR high sensitivity detector combined with the close-up vantage point afforded by Parker Solar Probe’s unique sun-encounter orbit,” said Mark Linton, Ph.D., head, NRL Heliophysics Theory and Modeling Section and Principal Investigator for the WISPR instrument.

The KHI structures were detected by the keen eye of an early career member of the WISPR team, Evangelos Paouris, Ph.D., George Mason University. Paouris, and his WISPR colleagues, undertook a thorough investigation to verify that the structures were indeed KHI waves. The results not only report an extremely rare phenomenon, even at Earth, but also open a new window of investigation with important consequences for the civilian and Department of Defense (DOD) communities.

“The turbulence that gives rise to KHI plays a fundamental role in regulating the dynamics of CMEs flowing through the ambient solar wind. Hence, understanding turbulence is key in achieving a deeper understanding of CME evolution and kinematics,” said Paouris. By extension, this knowledge will lead to more accurate forecasting of the arrival of CMEs in Earth’s vicinity and their effects on civilian and DOD space assets, thus safeguarding society and the warfighter.

“The direct imaging of extraordinary ephemeral phenomena like KHI with WISPR/PSP is a discovery that opens a new window to better understand CME propagation and their interaction with the ambient solar wind,” Paouris said.

WISPR is the only imaging instrument aboard the NASA Parker Solar Probe mission. The instrument, designed, developed and led by NRL, records visible-light images of the solar corona and solar outflow in two overlapping cameras that together observe more than 100-degrees angular width from the Sun. This NASA mission travels closer to the Sun than any other mission. PSP uses a series of Venus flyby’s to gradually reduce its perihelion from 36 solar radii in 2018 to 9.5 in 2025. The mission is approaching its 19th perihelion on March 30, 2024 at a distance of 11.5 solar radii from Sun center.

By observing the data the team found the Kelvin-Helmholtz instability is excited at the boundary between the CME and the ambient wind, as the two are flowing at distinctly different velocities. The resulting vortex-like structures are analyzed with respect to what the Kelvin-Helmholtz instability predicts, and inferences are presented about what the local magnetic field strength and density must be to allow such an instability in this environment.

About the U.S. Naval Research Laboratory

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

For more information, contact NRL Corporate Communications at (202) 480-3746 or nrlpao@us.navy.mil.

Illustration of Parker Solar Probe approaching the Sun. Credit: NASA/Johns Hopkins APL/Steve Gribben

CREDIT

NASA/Johns Hopkins APL/Steve Gribben

JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4357/ad2208

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

First Direct Imaging of a Kelvin–Helmholtz Instability by PSP/WISPR

ARTICLE PUBLICATION DATE

27-Mar-2024

Distant ‘space snowman’ unlocks mystery of how some dormant deep space objects become ‘ice bombs’

A new study on how comets evolve reveals that deep space objects like Kuiper Belt Object 486958 Arrokoth may be time capsules containing ancient ices from billions of years ago

BROWN UNIVERSITY

PROVIDENCE, R.I. [Brown University] — A new study is shaking up what scientists thought they knew about distant objects in the far reaches of the solar system, starting with an object called the space snowman.

Researchers from Brown University and the SETI Institute found that the double-lobed object, which is officially named Kuiper Belt Object 486958 Arrokoth and resembles a snowman, may have ancient ices stored deep within it from when the object first formed billions of years ago. But that’s just the beginning of their findings.

Using a new model they developed to study how comets evolve, the researchers suggest this feat of perseverance isn’t unique to Arrokoth but that many objects from the Kuiper Belt — which lies at the outermost regions of the solar system and dates back to the early formation of the solar system around 4.6 billion years ago — may also contain the ancient ices they formed with.

“We’ve shown here in our work, with a rather simple mathematical model, that you can keep these primitive ices locked deep within the interiors of these objects for really long times,” said Sam Birch, a planetary scientist at Brown and one of the paper’s co-authors. “Most of our community had thought that these ices should be long lost, but we think now that may not be the case.”

Birch describes the work in the journal Icarus with co-author Orkan Umurhan, a senior research scientist at the SETI Institute.

Until now, scientists had a hard time figuring out what happens to ices on these space rocks over time. The study challenges widely used thermal evolutionary models that have failed to account for the longevity of ices that are as temperature sensitive as carbon monoxide. The model the researchers created for the study accounts for this change and suggests that the highly volatile ices in these objects stick around much longer than was previously thought.

“We are basically saying that Arrokoth is so super cold that for more ice to sublimate — or go directly from solid to a gas, skipping the liquid phase within it — that the gas it sublimates into first has to have travel outwards through its porous, sponge-like interior,” Birch said. “The trick is that to move the gas, you also have to sublimate the ice, so what you get is a domino effect: it gets colder within Arrokoth, less ice sublimates, less gas moves, it gets even colder, and so on. Eventually, everything just effectively shuts off, and you’re left with an object full of gas that is just slowly trickling out.”

The work suggests that Kuiper Belt objects can act as dormant "ice bombs," preserving volatile gases within their interiors for billions of years until orbital shifts bring them closer to the sun and the heat makes them unstable. This new idea could help explain why these icy objects from the Kuiper Belt erupt so violently when they first get closer to the sun. All of a sudden, the cold gas inside them rapidly gets pressurized and these objects evolve into comets.

"The key thing is that we corrected a deep error in the physical model people had been assuming for decades for these very cold and old objects," said Umurhan, Birch’s co-author on the paper. "This study could be the initial mover for reevaluating the comet interior evolution and activity theory."

Altogether, the study challenges existing predictions and opens up new avenues for understanding the nature of comets and their origins. Birch and Umurhan are co-investigators in NASA’s Comet Astrobiology Exploration Sample Return (CAESAR) mission to acquire at least 80 grams of surface material from the comet 67P/Churyumov-Gerasimenko and return it to Earth for analysis.

The results from this study could help guide CAESAR’s exploration and sampling strategies, helping to deepen our understanding of cometary evolution and activity.

“There may well be massive reservoirs of these primitive materials locked away in small bodies all across the outer solar system — materials that are just waiting to erupt for us to observe them or sit in deep freeze until we can retrieve them and bring them home to Earth,” Birch said.

JOURNAL

Icarus

DOI

10.1016/j.icarus.2024.116027

METHOD OF RESEARCH

Computational simulation/modeling

ARTICLE TITLE

Retention of CO ice and gas within 486958 Arrokoth

Thursday, March 28, 2024

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