NASA's Hubble Finds More Black Holes than Expected in the Early Universe

Supermassive Black Holes in Hubble Ultra Deep Field

This is a new image of the Hubble Ultra Deep Field. The first deep imaging of the field was done with Hubble in 2004. The same survey field was observed again by Hubble several years later, and was then reimaged in 2023. By comparing Hubble Wide Field Camera 3 near-infrared exposures taken in 2009, 2012, and 2023, astronomers found evidence for flickering supermassive black holes in the hearts of early galaxies. One example is seen as a bright object in the inset. Some supermassive black holes do not swallow surrounding material constantly, but in fits and bursts, making their brightness flicker. This can be detected by comparing Hubble Ultra Deep Field frames taken at different epochs. The survey found more black holes than predicted. Credits: Science: NASA, ESA, Matthew Hayes (Stockholm University), Acknowledgment: Steven V.W. Beckwith (UC Berkeley), Garth Illingworth (UC Santa Cruz), Richard Ellis (UCL), Image Processing: Joseph DePasquale (STScI)

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With the help of NASA's Hubble Space Telescope, an international team of researchers led by scientists in the Department of Astronomy at Stockholm University has found more black holes in the early universe than has previously been reported. The new result can help scientists understand how supermassive black holes were created.

Currently, scientists do not have a complete picture of how the first black holes formed not long after the big bang. It is known that supermassive black holes, that can weigh more than a billion suns, exist at the center of several galaxies less than a billion years after the big bang.

"Many of these objects seem to be more massive than we originally thought they could be at such early times — either they formed very massive or they grew extremely quickly," said Alice Young, a PhD student from Stockholm University and co-author of the study published in The Astrophysical Journal Letters.

Black holes play an important role in the lifecycle of all galaxies, but there are major uncertainties in our understanding of how galaxies evolve. In order to gain a complete picture of the link between galaxy and black hole evolution, the researchers used Hubble to survey how many black holes exist among a population of faint galaxies when the universe was just a few percent of its current age.

Initial observations of the survey region were re-photographed by Hubble after several years. This allowed the team to measure variations in the brightness of galaxies. These variations are a telltale sign of black holes. The team identified more black holes than previously found by other methods.

The new observational results suggest that some black holes likely formed by the collapse of massive, pristine stars during the first billion years of cosmic time. These types of stars can only exist at very early times in the universe, because later-generation stars are polluted by the remnants of stars that have already lived and died. Other alternatives for black hole formation include collapsing gas clouds, mergers of stars in massive clusters, and "primordial" black holes that formed (by physically speculative mechanisms) in the first few seconds after the big bang. With this new information about black hole formation, more accurate models of galaxy formation can be constructed.

"The formation mechanism of early black holes is an important part of the puzzle of galaxy evolution," said Matthew Hayes from the Department of Astronomy at Stockholm University and lead author of the study. "Together with models for how black holes grow, galaxy evolution calculations can now be placed on a more physically motivated footing, with an accurate scheme for how black holes came into existence from collapsing massive stars."

Astronomers are also making observations with NASA's James Webb Space Telescope to search for galactic black holes that formed soon after the big bang, to understand how massive they were and where they were located.

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

Source: HubbleSite/News

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About This Release

Credits:

Media Contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Matthew Hayes
Stockholm University, Stockholm, Sweden

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents

• Science Paper: The science paper by Matthew Hayes et al. (ApJL), PDF (1.12 MB)
• NASA's Hubble Portal
• Webb Detects Most Distant Active Supermassive Black Hole to Date
• Hubble Provides First Census of Galaxies Near Cosmic Dawn
• Hubble Reaches the "Undiscovered Country" of Primeval Galaxies
• Hubble's Deepest View of Universe Unveils Never-Before-Seen Galaxies
• ESA/Hubble's Release

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Evaporating Stars, Magnetars, and Bumpy Supernova Light Curves

The Wolf–Rayet star WR 140 as seen by JWST. This image shows the shells of dust created by the interaction of WR 140 with its binary companion. New research shows that the explosion of a Wolf–Rayet star with a binary companion can account for the bumpy light curves of certain supernovae. Credit: NASA, ESA, CSA, STScI, NASA-JPL, Caltech

Artist’s impression of a highly magnetized stellar remnant called a magnetar.
Credit: ESO/L.Calçada; CC BY 4.0

Instead of fading smoothly, some supernova light curves take a bumpy road from brilliance to obscurity. Can unusual binary systems containing a rapidly spinning, wind-emitting magnetar and a stellar companion explain these light curves?

Light Curve Wiggles

When a star explodes, researchers record the light curve from its final moments and attempt to understand its life and death. Certain supernovae show bumps and wiggles in their light curves, the cause of which is not yet agreed upon. Researchers suspect that some of these light-curve bumps crop up when the expanding shock wave of the supernova slams into gas and dust surrounding the star. Other brightness increases might occur when the explosion leaves behind a magnetar — an extremely dense, city-size stellar remnant that spins rapidly and has a strong magnetic field — that injects energy into its surroundings.

In a recent research article, Jin-Ping Zhu (Monash University) and collaborators expanded on the latter possibility, pairing a powerful magnetar with an unlucky companion star to explain bumpy features in the light curves of certain supernovae.

A diagram illustrating the stages of the magnetar–star binary engine model.
Credit: Zhu et al. 2024

What Goes Bump in a Supernova Light Curve

The proposed theory starts with an ordinary star and a massive star in a close binary system. As the massive star evolves, it sheds its outer layers through rapid rotation and fierce winds, exposing its super-hot core and becoming a rare Wolf–Rayet star. As the Wolf–Rayet star continues to evolve, tidal interactions between the stars in the binary system spin the Wolf–Rayet star up to high speeds. It eventually explodes in a core-collapse supernova, leaving behind a rapidly spinning magnetar.

Other models have invoked magnetars to explain bumpy supernova light curves, but this theory goes a step further, giving the companion an important role to play. As the newborn magnetar and the companion star swing around each other on their tight orbits, the magnetar’s powerful particle wind collides with the other star, evaporating some of the unlucky companion. The evaporated stellar material is then heated and accelerated by the magnetar wind, producing a bump in the light curve.

Example of multi-band light curves for a supernova that is well fit by the authors’ model.
Adapted from Zhu et al. 2024

A Fitting Theory

That’s the theory — how does it compare to observations? Zhu and collaborators applied their magnetar–star binary engine model to the light curves of supernovae with a single bump after maximum brightness. They found that the model generally fits the observations well, with the best-fitting results implying that a significant chunk — about 25–60% — of the companion star gets evaporated.

Zhu and collaborators suspect that their model may apply to light curves with multiple bumps, as well. If the companion star remains bound to the magnetar after the supernova explosion but is kicked into a new, highly eccentric orbit, a bump could be created each time the stars draw close to one another on their orbits.

The team notes that there isn’t yet firm observational or theoretical evidence that rapidly rotating massive stars leave behind magnetars, and it’s not clear whether a magnetar embedded within a supernova remnant can sustain a magnetar wind, as is required here. Future work may shore up the needed evidence, and in the meantime, this work provides a new way to interpret bumpy light curves.

By Kerry Hensley

Citation

“Bumpy Superluminous Supernovae Powered by a Magnetar–Star Binary Engine,” Jin-Ping Zhu et al 2024 ApJL 970 L42.
doi:10.3847/2041-8213/ad63a8

Source: American Astronomical Society/AAS-Nova

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The light of knowledge

NGC 1449

A spiral galaxy, tilted at an angle, with irregularly-shaped arms. It appears large and close-up. The centre glows in a yellowish colour, while the disc around it is a bluer colour, due to light from older and newer stars. Dark reddish threads of dust cover the galaxy, and there are many large, shining pink spots in the disc, where stars are forming. Credit: ESA/Hubble & NASA, F. Belfiore, W. Yuan, J. Lee and the PHANGS-HST Team, A. Riess, K. Takáts, D. de Martin & M. Zamani (ESA/Hubble)

The magnificent galaxy featured in this Hubble Picture of the Week is NGC 1559. It is a barred spiral galaxy located in the constellation Reticulum near the Large Magellanic Cloud, but much more distant at approximately 35 million light-years from Earth. Hubble last visited this object in 2018. The brilliant light captured in this image offers a wealth of information, which thanks to Hubble can be put to use by both scientists and the public.

This picture is composed of a whopping ten different images taken by the Hubble Space Telescope, each filtered to collect light from a specific wavelength or range of wavelengths. It spans Hubble’s sensitivity to light, from ultraviolet around 275 nanometres through blue, green and red to near-infrared at 1600 nanometres. This allows information about many different astrophysical processes in the galaxy to be recorded: a notable example is the red 656-nanometre filter used here. Hydrogen atoms which get ionised can emit light at this particular wavelength, called H-alpha emission. New stars forming in a molecular cloud, made mostly of hydrogen gas, emit copious amounts of ultraviolet light which is absorbed by the cloud, but which ionises it and causes it to glow with this H-alpha light. Therefore, filtering to detect only this light provides a reliable means to detect areas of star formation (called H II regions), shown in this image by the bright red and pink colours of the blossoming patches filling NGC 1559’s spiral arms.

These ten images come from six different observing programmes with Hubble, running from 2009 all the way up to the present year. These programmes were led by teams of astronomers from around the world with a variety of scientific goals, ranging from studying ionised gas and star formation, to following up on a supernova, to tracking variable stars as a contribution to calculating the Hubble constant. The data from all of these observations live on in the Hubble archive, available for anyone to use — not only for new science, but also to create spectacular images like this one! This image of NGC 1559, then, is a reminder of the incredible opportunities that the Hubble Space Telescope has provided and continues to provide.

Besides Hubble’s observations, astronomers are using the NASA/ESA/CSA James Webb Space Telescope to research this galaxy in even greater depth. This Webb image from February showcases the galaxy in near- and mid-infrared light.

Source: ESA/Hubble/potw

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NASA's Hubble, Chandra Find Supermassive Black Hole Duo

A Pair of Merging Black Holes (Artist's Concept)

This is an artist's depiction of a pair of active black holes at the heart of two merging galaxies. They are both surrounded by an accretion disk of hot gas. Some of the material is ejected along the spin axis of each black hole. Confined by powerful magnetic fields, the jets blaze across space at nearly the speed of light as devastating beams of energy. Credits: Artwork: NASA, ESA, Joseph Olmsted (STScI)

Black Hole Pair Embedded in Middle of Active Galaxy MCG-03-34-064

A Hubble Space Telescope visible-light image of the galaxy MCG-03-34-064. Hubble's sharp view reveals three distinct bright spots embedded in a white ellipse at the galaxy's center (expanded in an inset image at upper right). Two of these bright spots are the source of strong X-ray emission, a telltale sign that they are supermassive black holes. The black holes shine brightly because they are converting infalling matter into energy, and blaze across space as active galactic nuclei. Their separation is about 300 light-years. The third spot is a blob of bright gas. The blue streak pointing to the 5 o'clock position may be a jet fired from one of the black holes. The black hole pair is a result of a merger between two galaxies that will eventually collide. Images

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Like two Sumo wrestlers squaring off, the closest confirmed pair of supermassive black holes have been observed in tight proximity. These are located approximately 300 light-years apart and were detected using NASA's Hubble Space Telescope and the Chandra X-ray Observatory. These black holes, buried deep within a pair of colliding galaxies, are fueled by infalling gas and dust, causing them to shine brightly as active galactic nuclei (AGN).

This AGN pair is the closest one detected in the local universe using multiwavelength (visible and X-ray light) observations. While several dozen "dual" black holes have been found before, their separations are typically much greater than what was discovered in the gas-rich galaxy MCG-03-34-64. Astronomers using radio telescopes have observed one pair of binary black holes in even closer proximity than in MCG-03-34-64, but without confirmation in other wavelengths.

AGN binaries like this were likely more common in the early universe when galaxy mergers were more frequent. This discovery provides a unique close-up look at a nearby example, located about 800 million light-years away.

The discovery was serendipitous. Hubble's high-resolution imaging revealed three optical diffraction spikes nested inside the host galaxy, indicating a large concentration of glowing oxygen gas within a very small area. "We were not expecting to see something like this," said Anna Trindade Falcão of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, lead author of the paper published today in The Astrophysical Journal. "This view is not a common occurrence in the nearby universe, and told us there's something else going on inside the galaxy."

Diffraction spikes are imaging artifacts caused when light from a very small region in space bends around the mirror inside telescopes.

Falcão's team then examined the same galaxy in X-rays light using the Chandra observatory to drill into what's going on. "When we looked at MCG-03-34-64 in the X-ray band, we saw two separated, powerful sources of high-energy emission coincident with the bright optical points of light seen with Hubble. We put these pieces together and concluded that we were likely looking at two closely spaced supermassive black holes," said Falcão.

To support their interpretation, the researchers used archival radio data from the Karl G. Jansky Very Large Array near Socorro, New Mexico. The energetic black hole duo also emits powerful radio waves. "When you see bright light in optical, X-rays, and radio wavelengths, a lot of things can be ruled out, leaving the conclusion these can only be explained as close black holes. When you put all the pieces together it gives you the picture of the AGN duo," said Falcão.

The third source of bright light seen by Hubble is of unknown origin, and more data is needed to understand it. That might be gas that is shocked by energy from a jet of ultra high-speed plasma fired from one of the black holes, like a stream of water from a garden hose blasting into a pile of sand.

"We wouldn't be able to see all of these intricacies without Hubble's amazing resolution," said Falcão.

The two supermassive black holes were once at the core of their respective host galaxies. A merger between the galaxies brought the black holes into close proximity. They will continue to spiral closer together until they eventually merge – in perhaps 100 million years – rattling the fabric of space and time as gravitational waves.

The National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected gravitational waves from dozens of mergers between stellar-mass black holes. But the longer wavelengths resulting from a supermassive black hole merger are beyond LIGO's capabilities. The next-generation gravitational wave detector, called the LISA (Laser Interferometer Space Antenna) mission, will consist of three detectors in space, separated by millions of miles, to capture these longer wavelength gravitational waves from deep space. ESA (European Space Agency) is leading this mission, partnering with NASA and other participating institutions, with a planned launch in the mid-2030s.

NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge, Massachusetts and flight operations from Burlington, Massachusetts. Northrop Grumman Space Technologies in Redondo Beach, California was the prime contractor for the spacecraft.

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

Source: HubbleSite/News

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About This Release

Credits:

Media Contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Anna Trindade Falcão
Center for Astrophysics | Harvard & Smithsonian, Cambridge, Massachusetts

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents

• Science Paper: The science paper by Anna Trindade Falcão (ApJ), PDF (1004.37 KB)
• NASA's Hubble Portal
• Chandra X-ray Center's Release
• NASA Goddard's Video (on YouTube)

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NASA's Webb Peers into the Extreme Outer Galaxy

Digel Cloud 2S

NASA’s James Webb Space Telescope observed the outskirts of our Milky Way galaxy. Known as the Extreme Outer Galaxy, this region is located more than 58,000 light-years from the Galactic Center.

To learn more about how a local environment affects the star formation process within it, a team of scientists directed the telescope’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) toward a total of four star-forming areas within Digel Clouds 1 and 2: 1A, 1B, 2N, and 2S.

In the case of Cloud 2S, shown here, Webb revealed a luminous main cluster that contains newly formed stars. Several of these young stars are emitting extended jets of material from their poles. To the main cluster’s top right is a sub-cluster of stars, a feature that scientists previously suspected to exist but has now been confirmed with Webb. Additionally, the telescope revealed a deep sea of background galaxies and red nebulous structures that are being carved away by winds and radiation from nearby stars.

Compass Image of Digel Cloud 2S

Annotated image of Digel Cloud 2S captured by Webb's NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument), with compass arrows, a scale bar, color key, and graphic overlays for reference.

The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).

The scale bar is labeled in light-years and arcseconds. One light-year is equal to about 5.88 trillion miles or 9.46 trillion kilometers. One arcsecond is equal to 1/3600 of one degree of arc. (The full Moon has an angular diameter of about 0.5 degrees.) The actual size of an object that covers one arcsecond on the sky depends on its distance from the telescope.

This image shows invisible near- and mid-infrared wavelengths of light that have been translated into visible-light colors. The color key shows which NIRCam and MIRI filters were used when collecting the light. The color of each filter name is the visible light color used to represent the infrared light that passes through that filter.

In the main cluster are five white arrows, which highlight the paths of five protostar jets. To learn more about how a local environment affects the star formation process within it, a team of scientists directed the telescope’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) toward a total of four star-forming areas within Digel Clouds 1 and 2: 1A, 1B, 2N, and 2S.

In the case of Cloud 2S, shown here, Webb revealed a luminous main cluster that contains newly formed stars. Several of these young stars are emitting extended jets of material from their poles. To the main cluster’s top right is a sub-cluster of stars, a feature that scientists previously suspected to exist but has now been confirmed with Webb. Additionally, the telescope revealed a deep sea of background galaxies and red nebulous structures that are being carved away by winds and radiation from nearby stars. Credits: Image: NASA, ESA, CSA, STScI, Michael Ressler (NASA-JPL)

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Astronomers have directed NASA’s James Webb Space Telescope to examine the outskirts of our Milky Way galaxy. Scientists call this region the Extreme Outer Galaxy due to its location more than 58,000 light-years away from the Galactic Center. (For comparison, Earth is approximately 26,000 light-years from the center.)

A team of scientists used Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) to image select regions within two molecular clouds known as Digel Clouds 1 and 2. With its high degree of sensitivity and sharp resolution, the Webb data resolved these areas, which are hosts to star clusters undergoing bursts of star formation, in unprecedented detail. Details of this data include components of the clusters such as very young (Class 0) protostars, outflows and jets, and distinctive nebular structures.

These Webb observations, which came from telescope time allocated to Mike Ressler of NASA’s Jet Propulsion Laboratory in California, are enabling scientists to study star formation in the outer Milky Way in the same depth of detail as observations of star formation in our own solar neighborhood.

“In the past, we knew about these star forming regions but were not able to delve into their properties,” said Natsuko Izumi of Gifu University and the National Astronomical Observatory of Japan, lead author of the study. “The Webb data builds upon what we have incrementally gathered over the years from prior observations with different telescopes and observatories. We can get very powerful and impressive images of these clouds with Webb. In the case of Digel Cloud 2, I did not expect to see such active star formation and spectacular jets.”

Stars in the Making

Although the Digel Clouds are within our galaxy, they are relatively poor in elements heavier than hydrogen and helium. This composition makes them similar to dwarf galaxies and our own Milky Way in its early history. Therefore, the team took the opportunity to use Webb to capture the activity occurring in four clusters of young stars within Digel Clouds 1 and 2: 1A, 1B, 2N, and 2S.

For Cloud 2S, Webb captured the main cluster containing young, newly formed stars. This dense area is quite active as several stars are emitting extended jets of material along their poles. Additionally, while scientists previously suspected a sub-cluster might be present within the cloud, Webb’s imaging capabilities confirmed its existence for the first time.

“We know from studying other nearby star-forming regions that as stars form during their early life phase, they start emitting jets of material at their poles,” said Ressler, second author of the study and principal investigator of the observing program. “What was fascinating and astounding to me from the Webb data is that there are multiple jets shooting out in all different directions from this cluster of stars. It’s a little bit like a firecracker, where you see things shooting this way and that.”

The Saga of Stars

The Webb imagery skims the surface of the Extreme Outer Galaxy and the Digel Clouds, and is just a starting point for the team. They intend to revisit this outpost in the Milky Way to find answers to a variety of current mysteries, including the relative abundance of stars of various masses within Extreme Outer Galaxy star clusters. This measurement can help astronomers understand how a particular environment can influence different types of stars during their formation.

“I’m interested in continuing to study how star formation is occurring in these regions. By combining data from different observatories and telescopes, we can examine each stage in the evolution process,” said Izumi. “We also plan to investigate circumstellar disks within the Extreme Outer Galaxy. We still don’t know why their lifetimes are shorter than in star-forming regions much closer to us. And of course, I’d like to understand the kinematics of the jets we detected in Cloud 2S.”

Though the story of star formation is complex and some chapters are still shrouded in mystery, Webb is gathering clues and helping astronomers unravel this intricate tale.

These findings have been published in the Astronomical Journal.

The observations were taken as part of Guaranteed Time Observation program 1237.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

Source: NASA's James Webb Space Telescope/News

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About This Release

Credits:

Media Contact:

Abigail Major
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

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Jellyfish Galaxies: NGC 3312 & NGC 3314

Jellyfish Galaxies: NGC 3312 & NGC 3314

Detail ： Low Res. (198 KB) / Mid. Res. (2.5 MB) / High Res. (10.6 MB)

NGC 3312 (above center) and NGC 3314 (below center) are jellyfish galaxies in the Hydra Galaxy Cluster. Both galaxies have filamentary structures toward the lower right that resemble jellyfish’s tentacles. These structures were formed while the disk gas of the galaxies was stripped away by the intense gas pressure of the intergalactic gas as they moved. There may not be any other images like this, featuring two rare jellyfish galaxies in a single field of view.

NGC 3314 is a pair of galaxies (NGC 3314a and NGC 3314b) located at different distances. They overlap in the same line of sight from Earth and do not gravitationally interact. The foreground face-on galaxy (NGC 3314a) is the jellyfish galaxy, and the background inclined galaxy (NGC 3314b) does not have a tentacle-like structure.

Distance from Earth: About 194 million light-years (NGC 3312), 117 million light-years (NGC 3314a), 140 million light-years (NGC 3314b)

Instrument: Hyper Suprime-Cam (HSC)

Source: Subaru Telescope/Press Release

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How hyper-accreting black holes shape their environment with anisotropic winds

Fig.1: Radio image of W50 nebula (see http://snrcat.physics.umanitoba.ca/SNRrecord.php?id=G039.7m02.0 and https://ui.adsabs.harvard.edu/abs/1998AJ....116.1842D/abstract for detailed description). The central bright spot is a hyperaccreting source SS433. The radio nebula (W50), features a quasi-spherical part (indicated by the dashed circle) and two extensions.

Fig. 2: Sketch of the W50 model as a combination of isotropic and “polar” winds coming from an accreting black hole. The central region represents a combination of an isotropic wind and a more collimated polar wind aligned with the orbital axis of the binary system. The isotropic wind passes through a termination shock, which converts its kinetic energy into heat, and after that, its increased pressure and density re-collimate in turn the polar wind. The resulting recollimation shocks are capable of accelerating particles to extremely high energies giving rise to the high-energy synchrotron emission from the axial flow.

Fig.3: Slices of gas density obtained in numerical simulations for different wind configurations. In response to changes in the density contrast between the wind components and/or the wind velocities, the morphology of the nebula changes too. W50 morphology is best reproduced by the two central plots.

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Among many X-ray sources in our Galaxy, the one called SS 433 (as an entry number 433 in the catalog of Halpha emitters by Stephenson & Sanduleak 1977) is especially famous and peculiar. It is likely powered by a black hole in a massive binary system. The accretion rate on this black hole from its companion star is hundreds of times higher than the critical value known as the Eddington limit (when the pressure of produced radiation becomes so great that it can eject matter and form powerful “winds” of the accretion disk). The new model discusses the impact of such winds on the surrounding interstellar medium. In particular, this wind can inflate the giant W50 nebula, encompassing SS 433 and spanning tens of parsecs in size. A similar situation may occur for rapidly growing massive black holes at the dawn of the Universe, galaxies with extreme nucleus activity and star formation rates during the “Cosmic Noon” (when the Universe was about 2-3 billion years old), or in the most extreme ultraluminous X-ray sources in normal star-forming galaxies today.

By now, millions of X-ray sources are known throughout the sky. The names of several dozen of them are known to almost all astronomers and astrophysicists. Among them is the microquasar SS433 in our Galaxy, a unique object in all parts of the electromagnetic spectrum from radio waves to ultra-high-energy photons. Since the late 1970s, it was known that this microquasar ejects narrow jets of matter, the speed of which is approximately a quarter of the speed of light, and the direction strictly periodically changes in time like a precessing top! Although such a picture was predicted and considered in pioneering works on accretion theory (Shakura & Sunyaev 1973), and since its discovery, several thousand works have been devoted to the study of this source, there are still no generally accepted answers to numerous questions about the structure of the super-Eddington flow of matter onto a black hole and the mechanism for launching the jets.

Similarly impressive and puzzling is the radio nebula W50 surrounding SS433 (Fig.1), the origin of which also remains open. Its shape has made another name popular - “Manatee Nebula”. The formation of a close binary system of a massive star + a black hole is preceded by a supernova explosion, which accompanies the formation of a black hole. It is usually believed that the quasi-spherical part of the nebula was created by the expanding shell of the supernova. As for the elongated parts of W50, there is no generally accepted model, but it is often assumed that a certain role is played by those very narrow precessing sub-relativistic jets of matter, although global traces of their deceleration and violent interaction with the environment have not yet been found.

A completely different explanation was recently proposed. Given the gigantic accretion rate onto a black hole, most of the matter should be ejected by radiation pressure, forming a powerful wind with a speed of thousands and even tens of thousands of kilometers per second. The work suggests that this wind is anisotropic, and the entire W50 nebula was created just by the action of such a profiled wind. In this model, the density of the kinetic energy flux in the wind is higher in the direction perpendicular to the plane of the accretion disk and is almost the same in other directions. This explains the shape of the nebula - in the directions where the wind power is higher, the nebula has a more elongated shape (Fig. 2).

It is remarkable that this assumption also explains the mysterious structures inside the nebula observed at high energies, from keV to TeV. Moreover, the magnetohydrodynamic structure of the anisotropic wind indicates the possibility of efficient acceleration of relativistic cosmic ray protons with petaelectronvolt energies. It is well known how jets of matter behave when interacting with the environment. In astrophysical conditions, such jets arise near supermassive black holes, as well as stellar-mass black holes. When the density of matter in the jets becomes much less than the density of the surrounding gas, shock waves arise that can focus the jets and allow them to propagate over large distances. In the case of SS433, the isotropic part of the wind plays the role of the “environment” for the more collimated part of the wind. It focuses and heats the axial part of the wind, remaining invisible to the observer. As a result, at a large distance from the compact source, a bright structure in the X-ray and TeV range appears “out of nowhere”. Depending on the density/velocity contrast between the isotropic and “polar” winds, the morphology of the nebula can change the aspect ratio and its inner structure, but the recollimation shocks are almost always present (Fig.3).

If we extrapolate this model to other sources in which the regime of very fast accretion onto a compact object is realized, then we can expect that conditions for effective acceleration of particles in the anisotropic wind can naturally arise in them. As a result, a noticeable share of the released accretion energy is converted into cosmic rays and also stored in a hot multiphase cocoon inside the nebula. The total energy released at this stage of the source's life turns out to be greater than the energy of the explosion of the parent supernova.

Source: Max Planck Institute for Astrophysics/All News

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Author:

Ildar Khabibullin (LMU)

and

Eugene Churazov
Scientific Staff
2219
echurazov@mpa-garching.mpg.de

Original Publication

Eugene Churazov, Ildar Khabibullin, Andrey Bykov

Minimalist model of the W50/SS433 extended X-ray jet: Anisotropic wind with recollimation shocks
DOI 10.1051/0004-6361/202449343

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Astronomers track bubbles on star’s surface in most detailed video yet

PR Image eso2412a
Detailed images of the surface of the star R Doradus

PR Image eso2412b
Detailed images of the surface of the star R Doradus (no annotations)

PR Image eso2412c
The star R Doradus in the constellation Dorado

PR Image eso2412d
Wide-field view of the region of the sky around the R Doradus star

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Videos

PR Video eso2412a
Most detailed video yet of bubbles on a star’s surface

PR Video eso2412b
Zooming in on the R Doradus star

PR Video eso2412c
Stellar bubbles captured by ALMA | ESO News

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For the first time, astronomers have captured images of a star other than the Sun in enough detail to track the motion of bubbling gas on its surface. The images of the star, R Doradus, were obtained with the Atacama Large Millimeter/submillimeter Array (ALMA), a telescope co-owned by the European Southern Observatory (ESO), in July and August 2023. They show giant, hot bubbles of gas, 75 times the size of the Sun, appearing on the surface and sinking back into the star’s interior faster than expected.

“This is the first time the bubbling surface of a real star can be shown in such a way,“ [1] says Wouter Vlemmings, a professor at Chalmers University of Technology, Sweden, and lead author of the study published today in Nature. “We had never expected the data to be of such high quality that we could see so many details of the convection on the stellar surface.”

Stars produce energy in their cores through nuclear fusion. This energy can be carried out towards the star’s surface in huge, hot bubbles of gas, which then cool down and sink — like a lava lamp. This mixing motion, known as convection, distributes the heavy elements formed in the core, such as carbon and nitrogen, throughout the star. It is also thought to be responsible for the stellar winds that carry these elements out into the cosmos to build new stars and planets.

Convection motions had never been tracked in detail in stars other than the Sun, until now. By using ALMA, the team were able to obtain high-resolution images of the surface of R Doradus over the course of a month. R Doradus is a red giant star, with a diameter roughly 350 times that of the Sun, located about 180 light-years away from Earth in the constellation Dorado. Its large size and proximity to Earth make it an ideal target for detailed observations. Furthermore, its mass is similar to that of the Sun, meaning R Doradus is likely fairly similar to how our Sun will look like in five billion years, once it becomes a red giant.

“Convection creates the beautiful granular structure seen on the surface of our Sun, but it is hard to see on other stars,” adds Theo Khouri, a researcher at Chalmers who is a co-author of the study. “With ALMA, we have now been able to not only directly see convective granules  — with a size 75 times the size of our Sun! — but also measure how fast they move for the first time.”

The granules of R Doradus appear to move on a one-month cycle, which is faster than scientists expected based on how convection works in the Sun. “We don’t yet know what is the reason for the difference. It seems that convection changes as a star gets older in ways that we don't yet understand,” says Vlemmings. Observations like those now made of R Doradus are helping us to understand how stars like the Sun behave, even when they grow as cool, big and bubbly as R Doradus is.

“It is spectacular that we can now directly image the details on the surface of stars so far away, and observe physics that until now was mostly only observable in our Sun,” concludes Behzad Bojnodi Arbab, a PhD student at Chalmers who was also involved in the study.

Source: ESO/News

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Notes

[1] Convection bubbles have been previously observed in detail on the surface of stars, including with the PIONIER instrument on ESO's Very Large Telescope Interferometer. But the new ALMA observations track the motion of the bubbles in a way that was not possible before.

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More information

This research was presented in a paper entitled “One month convection timescale on the surface of a giant evolved star” to appear in Nature (doi:10.1038/s41586-024-07836-9).

The team is composed of W. Vlemmings (Chalmers University of Technology, Sweden [Chalmers]), T. Khouri (Chalmers), B. Bojnordi (Chalmers), E. De Beck (Chalmers), and M. Maercker (Chalmers).

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.

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.

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Contacts

Wouter Vlemmings
Chalmers University of Technology
Gothenburg, Sweden
Tel: +46 31 772 63 54
Email: wouter.vlemmings@chalmers.se

Theo Kouri
Chalmers University of Technology
Gothenburg, Sweden
Tel: +46 31 772 6022
Email: theo.khouri@chalmers.se

Behzad Bojnodi Arbab
Chalmers University of Technology
Gothenburg, Sweden
Email: bojnordi@chalmers.se

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: press@eso.org

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Solution to a cosmic mystery—the eccentric orbits of trans-Neptunian objects

Simulation snapshots of model A1.
Credit: Nature Astronomy (2024).
DOI: 10.1038/s41550-024-02349-x

New evidence suggests that billions of years ago, a star may have passed very close to our solar system. As a result, thousands of smaller celestial bodies in the outer solar system outside Neptune's orbit were deflected into highly inclined trajectories around the sun. It is possible that some of them were captured by the planets Jupiter and Saturn as moons.

These findings come from a team of astrophysicists from Forschungszentrum Jülich and Leiden University in the Netherlands. They were published in two studies in the journals Nature Astronomy and The Astrophysical Journal Letters.

When we think of our solar system, we usually assume that it ends at the outermost known planet, Neptune. "However, several thousand celestial bodies are known to move beyond the orbit of Neptune," explains Susanne Pfalzner, astrophysicist at Forschungszentrum Jülich.

It is even suspected that there are tens of thousands of objects with a diameter of more than 100 kilometers. "Surprisingly, many of these so-called trans-Neptunian objects move on eccentric orbits that are inclined relative to the common orbital plane of the planets in the solar system."

Together with her Jülich colleague Amith Govind and Simon Portegies Zwart from Leiden University, Susanne Pfalzner has used more than 3,000 computer simulations to investigate a possible cause of the unusual orbits: could another star have caused the strange orbits of trans-Neptunian objects?

The three astrophysicists found that a distinctive, close flyby of another star can explain the inclined and eccentric orbits of the known trans-Neptunian celestial bodies. "Even the orbits of very distant objects can be deduced, such as that of the dwarf planet Sedna in the outermost reaches of the solar system, which was discovered in 2003.

"And also objects that move in orbits almost perpendicular to the planetary orbits," says Susanne Pfalzner. Such a flyby can even explain the orbits of 2008 KV42 and 2011 KT19—the two celestial bodies that move in the opposite direction to the planets.

Saturn's moon Phoebe is a prime example of the unusual properties of irregular moons. Like many others, it orbits Saturn in the opposite direction. Credit: NASA / JPL

"The best match for today's outer solar system that we found with our simulations is a star that was slightly lighter than our sun—about 0.8 solar masses," explains Pfalzner's colleague Amith Govind. "This star flew past our sun at a distance of around 16.5 billion kilometers. That's about 110 times the distance between Earth and the sun, a little less than four times the distance of the outermost planet Neptune."

However, the scientists' most surprising realization was that the flyby of an alien star billions of years ago could also provide a natural explanation for phenomena closer to home. Susanne Pfalzner and her colleagues found that in their simulations, some trans-Neptunian objects were hurled into our solar system—into the region of the outer giant planets Jupiter, Saturn, Uranus and Neptune.

"Some of these objects could have been captured by the giant planets as moons," says Simon Portegies Zwart from Leiden University. "This would explain why the outer planets of our solar system have two different types of moons."

In contrast to the regular moons, which orbit close to the planet on circular orbits, the irregular moons orbit the planet at a greater distance on inclined, elongated orbits. Until now, there was no explanation for this phenomenon.

"The beauty of this model lies in its simplicity," says Pfalzner. "It answers several open questions about our solar system with just a single cause."

Source: Phys.org

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More information: Susanne Pfalzner et al, Trajectory of the stellar flyby that shaped the outer Solar System, Nature Astronomy (2024). DOI: 10.1038/s41550-024-02349-x

Susanne Pfalzner et al, Irregular Moons Possibly Injected from the Outer Solar System by a Stellar Flyby, The Astrophysical Journal Letters (2024). DOI: 10.3847/2041-8213/ad63a6

Journal information: Astrophysical Journal Letters , Nature Astronomy

Provided By Forschungszentrum Juelich

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Explore further

• Impact of a stellar intruder on our solar system

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Complex Composition: The Origins of J1010+2358

A massive young star IRS 4 heats and warps the nebula Sharpless 2-106
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Once thought to be a pure descendant of one the universe’s first stars, new research on star J1010+2358 uncovers a more complex history.

The First Stars and Their Violent Ends

During the universe’s debut into star formation, only hydrogen, helium, and some lithium existed. Without metals (i.e., elements heavier than helium) to efficiently cool the gas, the first generation of stars, called Population III stars, likely formed with much higher masses than any subsequent generation. Based on theoretical modeling, Pop III stars may have had masses hundreds of times the mass of the Sun; however, their true mass distribution is still under investigation.

Some of the most massive Pop III stars likely ended their lives in pair-instability supernovae (PISNe), a type of supernova so energetic and violent it completely rips the star apart, leaving behind no stellar remnant. Metals that formed inside these stars and within their explosions are released into the interstellar medium, creating a newly enriched cosmic soup that fuels the next generation of star formation. Finding stars born out of PISN material, and particularly descendants whose chemical signatures trace back to a single Pop III star, is no simple task, but this detection would provide powerful information about the first stars in the universe.

Measured chemical abundance pattern of J1010+2358 (red stars). Multiple model predictions are overlaid; the dashed gray line shows a 100% 260-solar-mass PISN contribution, indicating an ill fit to the data. Credit: Skúladóttir et al. 2024

Likely Origins of J1010+2358

How, then, did J1010+2358 obtain its interesting chemical composition? Through applying theoretical models for various progenitor combinations, Skúladóttir’s team found a best fit where the star’s metals come from a combination of a 13-solar-mass second-generation star that underwent a core-collapse supernova and a 39-solar-mass Pop III core-collapse supernova. They considered multiple scenarios with the star obtaining some of its metals from a 260-solar-mass PISN, but all plausible fits have PISN contributions too low to further characterize the mass distribution of first-generation stars.

Measuring Chemical Abundances

With a low metallicity and unique chemical abundance pattern, the star J1010+2358 was initially suggested to have been formed from the gaseous remains of a single 260-solar-mass Pop III star. However, more recent analysis suggests that the star’s origins are more ambiguous, perhaps obtaining only 10% of its metals from such a PISN.

To more confidently determine J1010+2358’s ancestry, a team led by Ása Skúladóttir (University of Florence) used the Ultraviolet and Visible Echelle Spectrograph on the European Southern Observatory’s 8.2-meter Very Large Telescope to derive a more detailed abundance pattern of the star. They found the carbon and aluminum abundances to be significantly higher than predicted for pure PISN descendants. The team also remeasured a number of other elements, and the results further signal that J1010+2358 is not a descendant of a single, massive Pop III star as previously claimed.

Quality of fit results for J1010+2358 containing two progenitors, with one being a PISN of a given mass and fraction of metal contribution and the other being a 13-solar-mass second-generation star that underwent a core-collapse supernova. Values 2 and below are best quality fits and most plausible progenitor scenarios. Click to enlarge. Credit: Skúladóttir et al. 2024

Likely Origins of J1010+2358

How, then, did J1010+2358 obtain its interesting chemical composition? Through applying theoretical models for various progenitor combinations, Skúladóttir’s team found a best fit where the star’s metals come from a combination of a 13-solar-mass second-generation star that underwent a core-collapse supernova and a 39-solar-mass Pop III core-collapse supernova. They considered multiple scenarios with the star obtaining some of its metals from a 260-solar-mass PISN, but all plausible fits have PISN contributions too low to further characterize the mass distribution of first-generation stars.

Stars have complex histories stored within their chemical DNA, and the difficulty of identifying a star with a single first-generation predecessor underscores the importance of careful chemical abundance analyses. Although J1010+2358 is likely not a true PISN descendant, the lessons learned through this star will be critical in the quest to uncover the properties of the universe’s first stars, and upcoming high-resolution spectroscopic surveys may reveal more promising candidates in the near future.

By Lexi Gault

Source: American Astronomical Society/AAS-Nova

Citation

“On the Pair-instability Supernova Origin of J1010+2358,” Ása Skúladóttir et al 2024 ApJL 968 L23.
doi:10.3847/2041-8213/ad4b1a

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Editor’s Note: Lexi Gault is a fourth-year graduate student at Indiana University who was recently selected as the 2024–2025 AAS Media Fellow. We’re excited to welcome Lexi to the team and look forward to featuring her writing on AAS Nova regularly!

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Cloudy with a chance of explosions

NGC 5668

A spiral galaxy, seen up close and face-on. It is coloured yellow and glowing brightly at the oval-shaped centre, showing older and cooler stars, and it becomes bluer out to the edge of the disc where the stars are younger and hotter. It has a number of somewhat patchy spiral arms curling around, with sparkling areas where stars form. The black background can just be seen at the corners. Credit: ESA/Hubble & NASA, C. Kilpatrick

The subject of this Hubble Picture of the Week is a spiral galaxy in the constellation Virgo named NGC 5668. It is relatively near to us at 90 million light-years from Earth and quite accessible for astronomers to study with both space- and ground-based telescopes. At first blush, it doesn’t seem like a remarkable galaxy. It is around 90 000 light-years across, similar in size and mass to our own Milky Way galaxy, and its orientation nearly face-on to us shows open spiral arms made of cloudy, irregular patches.

One noticeable difference between the Milky Way galaxy and NGC 5668 is that this galaxy is forming new stars 60% more quickly. This fact belies a galaxy with churning clouds and flows of gas, inclement weather that forms excellent conditions for the formation of new stars! Two main drivers of star formation have been identified by astronomers. Firstly, this high-quality Hubble snapshot reveals a bar at the centre; it might look more like a slight oval shape than a real bar, but it appears to have impacted the galaxy’s star formation rate, as central bars do in many spiral galaxies. Secondly, high-velocity clouds of hydrogen gas have been tracked moving vertically between the disc of the galaxy and the spherical, faint halo which surrounds it. These can be produced by the strong stellar winds of hot, massive stars, and they contribute gas to new star-forming regions.

The enhanced star formation rate in NGC 5668 comes with a corresponding abundance of supernova explosions. Three have been spotted in the galaxy, in 1952, 1954 and 2004. In this image, Hubble was used to examine the surroundings of the Type II SN 2004G, seeking to study the kinds of stars that end their lives as this kind of supernova.

Source: ESA/Hubble/potw

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Dancing Galaxies Make a Monster at the Cosmic Dawn

The interacting galaxies observed by the ALMA radio telescope at the Cosmic Dawn. This image shows the distribution of ionized carbon gas, which reflects the overall distribution and motion of interstellar matter. It is clearly visible that the two galaxies are interacting, and are connected by a structure between them. The two crosses in the image indicate the positions of the low-luminosity quasars discovered by the Subaru Telescope. Credit: T.Izumi et al.

An artist’s impression of the interacting galaxies is based on the current observation results. The illustration depicts how the interaction between the galaxies gradually triggers star formation activity and the growth of the supermassive black holes at their centers. Credit: T.Izumi et al.

Credit: T.Izumi et al.

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Using the combined power of the Subaru Telescope and the ALMA radio telescope, astronomers have discovered a system where two distant galaxies, located 12.8 billion light-years away, are in the process of merging. These galaxies, hosting faint quasars at their centers, could be the ancestors of the brightest and most massive quasars in the early Universe, shedding light on the mysterious processes that trigger the explosive growth of supermassive black holes.

Astronomical observations to date have discovered several supermassive black holes with masses exceeding a billion times that of the Sun in the early Universe when it was less than a billion years old. These objects, known as high-luminosity quasars, shine brighter than an entire galaxy when they consume vast amounts of interstellar matter. Galaxies hosting these quasars often experience a burst of star formation, producing hundreds to thousands of times the mass of our Sun in new stars every year. What triggers and sustains such rapid growth of supermassive black holes and starburst activity?

A leading hypothesis is the mergers of gas-rich galaxies. Scientists think that when gas-rich galaxies merge, some of the gas gets compressed to form a large number of stars, while some of it flows into the galaxy's center, fueling the growth of the central black hole. To better understand galaxy/black hole formation in the early Universe, we need detailed investigations of the probable ancestors of high-luminosity quasars: galaxies and black holes in the pre-merger stage. However, research on such ancestors has long been stagnant because they are not yet bright, high-luminosity quasars (before merging), making them extraordinarily faint and difficult to detect.

To overcome this challenge, a research team led by Associate Professor Yoshiki Matsuoka of Ehime University analyzed large-scale survey data taken with the Subaru Telescope's Hyper Suprime-Cam, which boasts a vast field of view. Utilizing the Subaru Telescope's high light-gathering power, this survey is significantly more sensitive than other large-scale surveys, enabling astronomers to detect fainter objects. As a result, the team discovered a system with two very faint quasars (about 10 to 100 times fainter than high-luminosity quasars of the same era) side by side.

Located approximately 12.8 billion light-years away, corresponding to the "Cosmic Dawn" era when the Universe was only 900 million years old, this is the most distant record of such "pair quasars." Due to their faintness, scientists thought these objects were in the pre-merger stage before the rapid growth of the supermassive black holes. However, observations with the Subaru Telescope could only provide information about the central supermassive black holes, leaving unanswered whether the host galaxies were destined to merge and eventually grow into high-luminosity quasars.

As a next step, a research team led by Associate Professor Takuma Izumi of the National Astronomical Observatory of Japan conducted observations of the host galaxies of these pair quasars using the ALMA radio telescope. The results obtained during Director's Discretionary Time were astonishing. The distribution of interstellar matter observed (two host galaxies and the structure bridging them: Figure 1) and the nature of their motion indicated that these galaxies were interacting. They are undoubtedly on the path to merging into a single galaxy shortly. Furthermore, calculations from the observational data revealed that the total gas mass in these galaxies (around 100 billion times the mass of the Sun) is comparable to or even more significant than the gas masses of the host galaxies of most high-luminosity quasars, whose nuclei are extraordinarily bright. With this tremendous amount of material, post-merger explosive star formation and fueling of the supermassive black holes should be easily triggered and sustained. Therefore, these findings represent a significant achievement in identifying the ancestors of high-luminosity quasars—the brightest celestial objects in the early Universe—and starburst galaxies from multiple perspectives, including galaxy structure, motion, and the amount of interstellar matter.

Commenting on this discovery, Associate Professor Takuma Izumi, who led the research, expresses his excitement: "When we first observed the interaction between these two galaxies, it was like watching a dance, with the black holes at their centers having started their growth. It was truly beautiful." He also looked forward to future research, saying, "With the combined power of the Subaru Telescope and ALMA, we have begun to unveil the nature of the central engines (supermassive black holes), as well as the gas in the host galaxies. However, the properties of the stars in the host galaxies remain unknown. Using the James Webb Space Telescope, which is currently operational, we could learn about the stellar properties of these objects. As these are the long-sought ancestors of high-luminosity quasars, which should serve as a precious cosmic laboratory, I hope to deepen our understanding of their nature and evolution through various observations in the future."

Source: ALMA (Atacama Large Millimeter/submillimeter Array);Press Release

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Additional Information

Izumi et al. "Merging Gas-rich Galaxies that Harbor Low-luminosity Twin Quasars at z = 6.05: A Promising Progenitor of the Most Luminous Quasars" in The Astrophysical Journal, DOI: 10.3847/1538-4357/ad57c6.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (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 ALMA's construction, commissioning, and operation.

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Contacts:

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago - Chile
Phone: +56 2 2467 6519
Cel: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Yuichi Matsuda
ALMA EA-ARC Staff Member
NAOJ
Email: yuichi.matsuda@nao.ac.jp

Juan Carlos Muñoz Mateos
ESO Media Officer
Garching bei München, Germany
Phone: +49 89 3200 6176
Email: press@eso.org

Jill Malusky
Public Information Officer
NRAO
Phone: +1 304-456-2236
Email: jmalusky@nrao.edu

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