A bright, dense cluster of hot, massive stars in a galaxy that existed 1.4 billion years after the big bang has been found helping to end the early universe's foggy days during which neutral hydrogen gas was draped across the cosmos, obscuring ultraviolet light from luminous objects.

The cluster was found emitting ultraviolet light in a small but quickly growing galaxy by the Hubble Space Telescope. The presence of this ultraviolet light, and the star-forming history of the cluster producing it, suggests that bursts of star formation contributed to waves of ionizing radiation that gradually cleared out the opaque neutral hydrogen.

In the aftermath of the big bang, the universe was filled with neutral hydrogen gas that is opaque at short wavelengths of light, such as ultraviolet. However, this ultraviolet light was the neutral hydrogen's worst enemy, gradually ionizing the gas across the universe. Once ionized, hydrogen gas cannot absorb ultraviolet light — and so, the cosmos became transparent at those wavelengths.

Because of this, the first billion or so years are called the Epoch of Reionization. It is referred to as "reionization" rather than ionization because, technically, the gas had already been ionized once before during the first 379,000 years after the Big Bang.

While investigating what brought about this epoch, astronomers had identified two chief suspects that could have produced sufficient amounts of ultraviolet light to ionize the neutral hydrogen. One is active supermassive black holes and the other is the first generations of hot, massive stars. The problem is, given that neutral hydrogen is adept at absorbing the ultraviolet light, astronomers have had difficulty tracing that ultraviolet back to its source and identifying which of the two suspects are the main culprit.

In 2023 the James Webb Space Telescope (JWST) made a major breakthrough, finding a galaxy that existed just 900 million years after the Big Bang that was producing enough energy to ionize the neutral gas surrounding it.

Now the Hubble Space Telescope has gone further, detecting ultraviolet light from a galaxy called MXDFz4.4. This ultraviolet light should only be visible if the surrounding gas had already been ionized.

"Observing a galaxy like this was thought to be impossible," said Ilias Goovaerts of the Space Telescope Science Institute (STScI) in Baltimore, who led the discovery, in a statement. "Researchers expected the 'fog' of neutral hydrogen that filled the early universe would be too thick and obscure our view of its ionizing light. Hubble not only spotted that light, but it also helped reveal incredible details about the galaxy's characteristics."

MXDFz4.4 was first identified in the MUSE eXtremely Deep Field (MXDF), with MUSE being the Multi Unit Spectroscopic Explorer on the European Southern Observatory's Very Large Telescope in Chile. The "z4.4" part of its name tells us that the galaxy exists at a redshift of 4.4, meaning that it existed 12.37 billion years ago. As the universe has expanded in the time since then, the ultraviolet light has been redshifted into visible wavelengths that were detected by Hubble.

"Astronomers have found many galaxies that existed at this point in the history of the universe, but we haven't detected ionizing photons from any of them, making MXDFz4.4 one of a kind," said Marc Rafelski, who is the Hubble Deputy Mission Head at STScI.

MXDFz4.4 is 100 times smaller than our Milky Way galaxy but is forming stars ten times faster than our galaxy is. Many of those stars are being born in the tight, luminous cluster producing the ionizing ultraviolet.

The cluster contains "A lot of young, hot, massive stars in a small space [that] do a better job of blasting through opaque gas," said Goovaerts.

Furthermore, by comparing Hubble's observations of MXDFz.4.4 with those of the JWST, which probed for cooler, older stars in the galaxy, Goovaerts and Rafelski's team discovered that the stars in the cluster had formed in bursts, each burst producing fresh quantities of ionizing ultraviolet radiation that helped to clear out more and more of the neutral gas over time. We now see the galaxy about 250 million years after it finished reionizing the surrounding gas. These hot, massive stars in the cluster end their lives after a few million years as supernova explosions, the blast waves and radiation from which can create bubbles in the gas light years across, creating further pathways for ultraviolet light to escape and be detected by Hubble.

The observations seem to nail down the theory that clusters of hot, massive, luminous stars in young galaxies in the early universe played a dominant role in ionizing the universe's neutral gas.

"Hubble's observations of MXDFz4.4 let us test our hypotheses much closer to the Era of Reionization than ever before," said Rafelski. "Finding more galaxies, especially at slightly later cosmic times where larger samples are within reach, would let us refine these measurements and figure out what cleared our view as that era was ending."

The results were published on June 23 in The Astrophysical Journal.

This NASA Hubble Space Telescope image features a galaxy cluster, called CL0016+1609 or MACS J0018.5+1626, that is very bright at X-ray wavelengths and is one of the most extensively studied clusters at X-ray and radio wavelengths. The X-ray observations of this cluster revealed that it is two clusters merging along our line of sight.

Researchers requested time to observe CL0016+1609 with Hubble’s Advanced Camera for Surveys because that data would help them accurately measure the cluster’s dark-matter distribution, which helps them study the merger and the role of CL0016+1609 in the large-scale structure of the universe. Hubble can’t directly see dark matter, but its infrared and visible light observations can detect dark matter’s gravitational lensing effects on the normal matter Hubble observes.

The data in this image also includes observations with Hubble’s Wide Field Camera 3 taken as part of an observing program that obtained the first Hubble infrared images of 46 massive galaxy clusters and looked for distant galaxies gravitationally lensed by these clusters. Called RELICS (Reionization Lensing Cluster Survey), this survey found some 300 high-redshift candidate galaxies lensed by these clusters.

You can see the faint vertical arc of one of these distant galaxies in the image above. Look for it just to the left of the large elliptical galaxies in the center of the image. Another brighter, though shorter arc is visible just above and to the right of the large elliptical galaxies in the center of the image.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov

This NASA Hubble Space Telescope image features a galaxy cluster, called CL0016+1609 or MACS J0018.5+1626, that is very bright at X-ray wavelengths and is one of the most extensively studied clusters at X-ray and radio wavelengths. The X-ray observations of this cluster revealed that it is two clusters merging along our line of sight.

Researchers requested time to observe CL0016+1609 with Hubble’s Advanced Camera for Surveys because that data would help them accurately measure the cluster’s dark-matter distribution, which helps them study the merger and the role of CL0016+1609 in the large-scale structure of the universe. Hubble can’t directly see dark matter, but its infrared and visible light observations can detect dark matter’s gravitational lensing effects on the normal matter Hubble observes.

The data in this image also includes observations with Hubble’s Wide Field Camera 3 taken as part of an observing program that obtained the first Hubble infrared images of 46 massive galaxy clusters and looked for distant galaxies gravitationally lensed by these clusters. Called RELICS (Reionization Lensing Cluster Survey), this survey found some 300 high-redshift candidate galaxies lensed by these clusters.

You can see the faint vertical arc of one of these distant galaxies in the image above. Look for it just to the left of the large elliptical galaxies in the center of the image. Another brighter, though shorter arc is visible just above and to the right of the large elliptical galaxies in the center of the image.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov

The post Hubble Glimpses Merging Galaxy Clusters appeared first on NASA Science.

Researchers using two of humanity’s most powerful observatories — NASA’s James Webb and Hubble Space Telescopes — have definitively shown that Terzan 5 is not a globular star cluster as it was once classified, offering new insight into how galaxies like our own form and evolve over time. A globular star cluster typically has only one ancient star population. New data not only confirms the existence of two distinct populations of stars in Terzan 5, but also provides evidence for two more recent rounds of star formation. Although located within the crowded bulge of our Milky Way, our galaxy’s central, spherical region of older stars, Terzan 5 was massive enough to maintain its separate identity while lighter weight systems spread out and mixed to form the bulge billions of years ago. It’s like a lump in an otherwise well-mixed cake batter.

“Webb’s new near-infrared observations, cross-referenced with Hubble’s archival observations, have given us a much clearer picture of the history of Terzan 5,” said Giorgia Zullo, who led the research and is a PhD student at the University of Bologna in Italy.

These results were presented at a press conference Tuesday at the 248th meeting of the American Astronomical Society in Pasadena, and were published in Astronomy & Astrophysics.

Image: Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)

Four generations of stars

Discovered in 1968 by astronomer Azop Terzan, Terzan 5 resembles a globular cluster in many ways. However, in 2009 this system was discovered to harbor two distinct populations of stars. In 2016 Hubble provided the first estimate of their ages, showing that one formed roughly 12 billion years ago — as the Milky Way itself was assembling — and the other about 5 billion years ago, just before Earth started forming. This pointed to a more complex history than a typical globular cluster.

Studying Terzan 5 is complicated by its location in a region of our galaxy crowded with stars and heavily obscured by dust. This is where Webb stepped in. Its infrared view allowed the research team to peer through the dust and catalog many more stars, and fainter stars, than previous work. By measuring star colors and brightnesses, astronomers can classify them into populations of different ages and chemistries.

Webb was able to measure these key properties for every star within the field of view in the sky — both stars within Terzan 5 and unrelated foreground stars. To isolate the stars of Terzan 5, the team relied on the power and longevity of Hubble. The 12-year separation allowed the team to measure very small movements of individual stars, known as proper motions, to determine which stars belong to Terzan 5 and which are part of the Milky Way bulge.

By combining data from both Webb and Hubble, the researchers found strong evidence for two more stellar populations, one that formed 3.8 billion years ago and another only 2.5 billion years ago. They also were able to determine the ages of the previously known stellar populations with unprecedented precision, finding that they formed 12.5 billion and 4.7 billion years ago.

With the previously known two generations of stars, astronomers could not rule out the possibility that Terzan 5 interacted with another object, like a globular cluster or a giant molecular cloud, becoming enriched with new gas and dust that set off a second round of star formation. With four stellar generations, those explanations are ruled out.

Measurements of the stellar composition of Terzan 5 populations made at the W. M. Keck Observatory and European Southern Observatory’s Very Large Telescope also point toward very distinct populations. “Along with the ages of these populations, the cluster preserves a fossil record of progressive enrichment of heavy elements by supernovae,” said co-author R. Michael Rich, a research astronomer at the University of California, Los Angeles.

Terzan 5 formed multiple generations of stars because it was able to retain the necessary raw materials. There is evidence of powerful supernova explosions in Terzan 5 that forged heavier elements that were swept up by subsequent generations of stars. In lighter weight systems, the force of the explosions themselves could have ejected the resulting elements as well as sweeping out leftover gas and dust. The progenitor of Terzan 5 had enough mass to retain those stars’ ejections, allowing new generations of stars to form over billions of years.

‘Bulge fossil fragment’

The results show that Terzan 5 is most likely the remnant of a much more massive stellar system that initially formed 12.5 billion years ago. Terzan 5 is extraordinary because it survived — and never merged or fully “mixed in” with the Milky Way’s bulge. “For some reason, this peculiar clump of stars formed separately from the bulge and was not destroyed as the bulge itself formed,” said Francesco R. Ferraro, a professor at the University of Bologna and principal investigator of the Webb observations. “Terzan 5 is what we now call a bulge fossil fragment because it resembles the primordial clumps that contributed to the formation of the bulge.”

To date, there’s one other known cosmic object like Terzan 5. Liller 1 was the second to be reclassified from a globular star cluster to a bulge fossil fragment. It also contains multiple generations of stars. There may be more objects like it. Between 40 to 50 additional globular clusters that orbit within the bulge will be examined by Ferraro’s team to determine if their stellar populations are all the same, like globular clusters, or have several generations, like bulge fossil fragments. 

Video: Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge

Potential parallels for galaxy formation near, far

Ultimately, this research may improve what we know about how the central bulges of galaxies form over hundreds of millions of years. “Based on observations and in-depth simulations, we think that galaxies in the early universe had huge disks of gas that fragmented into clumps and formed stars. These clumps migrated to the center of the galaxies, and many merged to form their bulges,” said Barbara Lanzoni, a co-author and associate professor at the University of Bologna. For example, Webb has turned up several examples of “clumpy” galaxies that were actively forming when the universe was only a few hundred million years old, like the clumps in the Firefly Sparkle galaxy. “Terzan 5 may provide direct evidence that can help explain how bulges formed in galaxies throughout the universe,” Lanzoni said.

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).

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, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

To learn more about Webb, visit:

https://science.nasa.gov/webb

To learn more about Hubble, visit:

https://science.nasa.gov/hubble

Downloads & Related Information

The following sections contain links to download this article’s images and videos in all available resolutions followed by related information links, media contacts, and if available, research paper and Spanish translation links.

Related Links

Read more: Hubble’s star clusters

Explore more: ViewSpace | Forms of light: the Cluster Omega Centauri

Watch: Globular Clusters, Stellar Pockets

Watch: Sorting the Stars in Omega Centauri

Webb: News | Images | Science | Home Page

Hubble: News | Images | Science | Home Page

Researchers using two of humanity’s most powerful observatories — NASA’s James Webb and Hubble Space Telescopes — have definitively shown that Terzan 5 is not a globular star cluster as it was once classified, offering new insight into how galaxies like our own form and evolve over time. A globular star cluster typically has only one ancient star population. New data not only confirms the existence of two distinct populations of stars in Terzan 5, but also provides evidence for two more recent rounds of star formation. Although located within the crowded bulge of our Milky Way, our galaxy’s central, spherical region of older stars, Terzan 5 was massive enough to maintain its separate identity while lighter weight systems spread out and mixed to form the bulge billions of years ago. It’s like a lump in an otherwise well-mixed cake batter.

“Webb’s new near-infrared observations, cross-referenced with Hubble’s archival observations, have given us a much clearer picture of the history of Terzan 5,” said Giorgia Zullo, who led the research and is a PhD student at the University of Bologna in Italy.

These results were presented at a press conference Tuesday at the 248th meeting of the American Astronomical Society in Pasadena, and were published in Astronomy & Astrophysics.

Image: Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)

Four generations of stars

Discovered in 1968 by astronomer Azop Terzan, Terzan 5 resembles a globular cluster in many ways. However, in 2009 this system was discovered to harbor two distinct populations of stars. In 2016 Hubble provided the first estimate of their ages, showing that one formed roughly 12 billion years ago — as the Milky Way itself was assembling — and the other about 5 billion years ago, just before Earth started forming. This pointed to a more complex history than a typical globular cluster.

Studying Terzan 5 is complicated by its location in a region of our galaxy crowded with stars and heavily obscured by dust. This is where Webb stepped in. Its infrared view allowed the research team to peer through the dust and catalog many more stars, and fainter stars, than previous work. By measuring star colors and brightnesses, astronomers can classify them into populations of different ages and chemistries.

Webb was able to measure these key properties for every star within the field of view in the sky — both stars within Terzan 5 and unrelated foreground stars. To isolate the stars of Terzan 5, the team relied on the power and longevity of Hubble. The 12-year separation allowed the team to measure very small movements of individual stars, known as proper motions, to determine which stars belong to Terzan 5 and which are part of the Milky Way bulge.

By combining data from both Webb and Hubble, the researchers found strong evidence for two more stellar populations, one that formed 3.8 billion years ago and another only 2.5 billion years ago. They also were able to determine the ages of the previously known stellar populations with unprecedented precision, finding that they formed 12.5 billion and 4.7 billion years ago.

With the previously known two generations of stars, astronomers could not rule out the possibility that Terzan 5 interacted with another object, like a globular cluster or a giant molecular cloud, becoming enriched with new gas and dust that set off a second round of star formation. With four stellar generations, those explanations are ruled out.

Measurements of the stellar composition of Terzan 5 populations made at the W. M. Keck Observatory and European Southern Observatory’s Very Large Telescope also point toward very distinct populations. “Along with the ages of these populations, the cluster preserves a fossil record of progressive enrichment of heavy elements by supernovae,” said co-author R. Michael Rich, a research astronomer at the University of California, Los Angeles.

Terzan 5 formed multiple generations of stars because it was able to retain the necessary raw materials. There is evidence of powerful supernova explosions in Terzan 5 that forged heavier elements that were swept up by subsequent generations of stars. In lighter weight systems, the force of the explosions themselves could have ejected the resulting elements as well as sweeping out leftover gas and dust. The progenitor of Terzan 5 had enough mass to retain those stars’ ejections, allowing new generations of stars to form over billions of years.

‘Bulge fossil fragment’

The results show that Terzan 5 is most likely the remnant of a much more massive stellar system that initially formed 12.5 billion years ago. Terzan 5 is extraordinary because it survived — and never merged or fully “mixed in” with the Milky Way’s bulge. “For some reason, this peculiar clump of stars formed separately from the bulge and was not destroyed as the bulge itself formed,” said Francesco R. Ferraro, a professor at the University of Bologna and principal investigator of the Webb observations. “Terzan 5 is what we now call a bulge fossil fragment because it resembles the primordial clumps that contributed to the formation of the bulge.”

To date, there’s one other known cosmic object like Terzan 5. Liller 1 was the second to be reclassified from a globular star cluster to a bulge fossil fragment. It also contains multiple generations of stars. There may be more objects like it. Between 40 to 50 additional globular clusters that orbit within the bulge will be examined by Ferraro’s team to determine if their stellar populations are all the same, like globular clusters, or have several generations, like bulge fossil fragments. 

Video: Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge

Potential parallels for galaxy formation near, far

Ultimately, this research may improve what we know about how the central bulges of galaxies form over hundreds of millions of years. “Based on observations and in-depth simulations, we think that galaxies in the early universe had huge disks of gas that fragmented into clumps and formed stars. These clumps migrated to the center of the galaxies, and many merged to form their bulges,” said Barbara Lanzoni, a co-author and associate professor at the University of Bologna. For example, Webb has turned up several examples of “clumpy” galaxies that were actively forming when the universe was only a few hundred million years old, like the clumps in the Firefly Sparkle galaxy. “Terzan 5 may provide direct evidence that can help explain how bulges formed in galaxies throughout the universe,” Lanzoni said.

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).

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, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

To learn more about Webb, visit:

https://science.nasa.gov/webb

To learn more about Hubble, visit:

https://science.nasa.gov/hubble

Downloads & Related Information

The following sections contain links to download this article’s images and videos in all available resolutions followed by related information links, media contacts, and if available, research paper and Spanish translation links.

Related Links

Read more: Hubble’s star clusters

Explore more: ViewSpace | Forms of light: the Cluster Omega Centauri

Watch: Globular Clusters, Stellar Pockets

Watch: Sorting the Stars in Omega Centauri

Webb: News | Images | Science | Home Page

Hubble: News | Images | Science | Home Page

The post NASA Webb, Hubble Reveal History of Relic of Milky Way’s Formation appeared first on NASA Science.

The aftermath of a supernova, a stellar explosion, is usually a slowly fading cloud of hot gas. So when astronomers pointed NASA’s Chandra X-ray Observatory at the nearby galaxy Messier 83 (M83), they did not expect to find a population of supernova remnants, or the debris from these explosions, showing dramatic changes in their brightness. The new results were presented at the American Astronomical Society meeting in Pasadena, California, and published in The Astrophysical Journal.

The galaxy M83, located about 15 million light-years from Earth, is forming stars at a high rate. Researchers analyzed 14 years of Chandra data of the galaxy, spanning 2000 to 2014.

Using this extensive set of data, the researchers caught surprising variations in the X-ray brightness of sources previously identified as supernova remnants. The researchers expected supernova remnants older than a century or so to fade gradually in X-rays, but not change dramatically in brightness.

The team found that roughly half of the 22 X-ray sources associated with supernova remnants in their sample showed changes in X-ray brightness over the 14-year span of observations — a result that was completely unexpected.

“We knew that individual X-ray sources could vary dramatically,” said Andrea Prestwich, of the Catholic University of America who led the study. “But finding that so many supernova remnants were behaving this way was a real surprise. Something unusual is going on in these objects. Pinpointing the cause remains a challenge, as M83’s distance limits the detail we can observe.”

One of the 22 variable supernova remnants has a straightforward explanation: SN 1957D, the debris from a supernova first observed nearly 70 years ago, is ramming into material surrounding the explosion site, producing the observed X-ray flares. But this cannot explain the rest of the sample. There is no evidence to suggest that all 22 remnants were formed within the last century. Something else must be driving the variability.

The most likely explanation is that the team has uncovered a population of stellar survivors stars that lived through their partner’s destruction in a supernova explosion. In this scenario, each variable X-ray source began as a pair of massive stars orbiting each other. The more massive star collapsed and exploded as a supernova, leaving behind a black hole or ultra-dense neutron star. Its companion survived.

“It may be that this galaxy contains a collection of supernova remnants where one massive star survives the supernova and becomes locked into an orbit with a black hole or neutron star,” said co-author Michael McCollough of the Center for Astrophysics | Harvard & Smithsonian (CfA). “The neutron star or black hole can then start pulling material from the massive star’s surface.”

That infalling material is superheated by the intense gravitational pull, producing the X-rays Chandra detects. These types of systems, known as high-mass X-ray binaries (HMXBs), are among the most variable X-ray sources in the universe. Researchers say they may be the cause of the variations seen in M83’s supernova remnants.

Astronomers have known about HMXBs for decades, but the difference with this group in M83 is their connection to supernova remnants. Previously, only a handful of supernova remnants associated with HMXBs had been identified across observations of all galaxies. It is unprecedented to find more than 20 strong candidates in just one galaxy.

The authors found that the variable supernova remnants are in regions with higher concentrations of massive stars than in other parts of the galaxy, increasing the chances of a link between the remnants and HMXBs.

There is another possible explanation: Instead of pulling in material from a companion star, the black hole or neutron star may be recapturing some of the material blasted outward by the original explosion.

“This could be an example of cosmic recycling, where debris from the explosion falls back onto the very object the supernova created,” said co-author Roy Kilgard of Wesleyan University. “And it’s quite possible that both explanations are at play — different sources in our sample may have different origins.”

These results are not unique to M83. A follow-up study of the nearby star-forming galaxy M51 by Zoe Hoiland of Vassar College and Kilgard has uncovered a similar population of variable X-ray sources associated with supernova remnants, suggesting that such systems may be a feature of galaxies undergoing vigorous star formation.

The Chandra data for M83 began with single observations in 2000 and 2001, followed by 10 observations from 2010 to 2011 and another observation in 2014.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Visual Description

This release features a composite image of the nearby galaxy Messier 83, and short timelapse videos of two curious supernova remnants hidden inside.

In the composite image, Messier 83, or M83, is shown to have a spiral structure, viewed straight on. At the center is a brilliant white and yellow pool of light. From that light, spiral arms of hot pink cloud corkscrew out in wide, sweeping arches. The galaxy is covered in a faint grey haze, and flecked with red, green, blue, white, and yellow dots.

In an annotated version of the composite image, two tiny dots to our lower right of center are highlighted by white circles. These are two of the supernova remnants being considered by researchers. Each is examined further in a separate timelapse video.

Over a 14-year period from 2000 to 2014, astronomers pointed NASA’s X-ray observatory at the M83 galaxy. They discovered that about half of the X-ray sources believed to be supernova remnants, the aftermath of stellar explosions, were exhibiting dramatic changes in brightness. This result was entirely unexpected.

Those changes in brightness are highlighted in the timelapse videos. In each video, a series of static images flashes by, focused on one of the two X-ray sources once believed to be supernova remnants. In the videos, the X-ray sources appear as bright blue blobs with glowing cores. But in each image, taken months or years apart, the shapes change, as does the intensity of the blue color, and the brightness of the core. By presenting the substantively different images of the same objects one after another in quick succession, short timelapse videos are created.

The most likely explanation for the changes in brightness is that the team has uncovered a population of stellar survivors, stars that lived through an orbiting partner’s destruction in a supernova explosion. Material is being pulled from the surviving star onto the black hole or neutron star that formed in the supernova, a process known to cause rapid changes in X-ray brightness.

Read more from NASA’s Chandra X-ray Observatory

To learn more about NASA’s Chandra mission, visit:

https://science.nasa.gov/chandra

https://chandra.si.edu

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Joel Wallace
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
joel.w.wallace@nasa.gov

The aftermath of a supernova, a stellar explosion, is usually a slowly fading cloud of hot gas. So when astronomers pointed NASA’s Chandra X-ray Observatory at the nearby galaxy Messier 83 (M83), they did not expect to find a population of supernova remnants, or the debris from these explosions, showing dramatic changes in their brightness. The new results were presented at the American Astronomical Society meeting in Pasadena, California, and published in The Astrophysical Journal.

The galaxy M83, located about 15 million light-years from Earth, is forming stars at a high rate. Researchers analyzed 14 years of Chandra data of the galaxy, spanning 2000 to 2014.

Using this extensive set of data, the researchers caught surprising variations in the X-ray brightness of sources previously identified as supernova remnants. The researchers expected supernova remnants older than a century or so to fade gradually in X-rays, but not change dramatically in brightness.

The team found that roughly half of the 22 X-ray sources associated with supernova remnants in their sample showed changes in X-ray brightness over the 14-year span of observations — a result that was completely unexpected.

“We knew that individual X-ray sources could vary dramatically,” said Andrea Prestwich, of the Catholic University of America who led the study. “But finding that so many supernova remnants were behaving this way was a real surprise. Something unusual is going on in these objects. Pinpointing the cause remains a challenge, as M83’s distance limits the detail we can observe.”

One of the 22 variable supernova remnants has a straightforward explanation: SN 1957D, the debris from a supernova first observed nearly 70 years ago, is ramming into material surrounding the explosion site, producing the observed X-ray flares. But this cannot explain the rest of the sample. There is no evidence to suggest that all 22 remnants were formed within the last century. Something else must be driving the variability.

The most likely explanation is that the team has uncovered a population of stellar survivors stars that lived through their partner’s destruction in a supernova explosion. In this scenario, each variable X-ray source began as a pair of massive stars orbiting each other. The more massive star collapsed and exploded as a supernova, leaving behind a black hole or ultra-dense neutron star. Its companion survived.

“It may be that this galaxy contains a collection of supernova remnants where one massive star survives the supernova and becomes locked into an orbit with a black hole or neutron star,” said co-author Michael McCollough of the Center for Astrophysics | Harvard & Smithsonian (CfA). “The neutron star or black hole can then start pulling material from the massive star’s surface.”

That infalling material is superheated by the intense gravitational pull, producing the X-rays Chandra detects. These types of systems, known as high-mass X-ray binaries (HMXBs), are among the most variable X-ray sources in the universe. Researchers say they may be the cause of the variations seen in M83’s supernova remnants.

Astronomers have known about HMXBs for decades, but the difference with this group in M83 is their connection to supernova remnants. Previously, only a handful of supernova remnants associated with HMXBs had been identified across observations of all galaxies. It is unprecedented to find more than 20 strong candidates in just one galaxy.

The authors found that the variable supernova remnants are in regions with higher concentrations of massive stars than in other parts of the galaxy, increasing the chances of a link between the remnants and HMXBs.

There is another possible explanation: Instead of pulling in material from a companion star, the black hole or neutron star may be recapturing some of the material blasted outward by the original explosion.

“This could be an example of cosmic recycling, where debris from the explosion falls back onto the very object the supernova created,” said co-author Roy Kilgard of Wesleyan University. “And it’s quite possible that both explanations are at play — different sources in our sample may have different origins.”

These results are not unique to M83. A follow-up study of the nearby star-forming galaxy M51 by Zoe Hoiland of Vassar College and Kilgard has uncovered a similar population of variable X-ray sources associated with supernova remnants, suggesting that such systems may be a feature of galaxies undergoing vigorous star formation.

The Chandra data for M83 began with single observations in 2000 and 2001, followed by 10 observations from 2010 to 2011 and another observation in 2014.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Visual Description

This release features a composite image of the nearby galaxy Messier 83, and short timelapse videos of two curious supernova remnants hidden inside.

In the composite image, Messier 83, or M83, is shown to have a spiral structure, viewed straight on. At the center is a brilliant white and yellow pool of light. From that light, spiral arms of hot pink cloud corkscrew out in wide, sweeping arches. The galaxy is covered in a faint grey haze, and flecked with red, green, blue, white, and yellow dots.

In an annotated version of the composite image, two tiny dots to our lower right of center are highlighted by white circles. These are two of the supernova remnants being considered by researchers. Each is examined further in a separate timelapse video.

Over a 14-year period from 2000 to 2014, astronomers pointed NASA’s X-ray observatory at the M83 galaxy. They discovered that about half of the X-ray sources believed to be supernova remnants, the aftermath of stellar explosions, were exhibiting dramatic changes in brightness. This result was entirely unexpected.

Those changes in brightness are highlighted in the timelapse videos. In each video, a series of static images flashes by, focused on one of the two X-ray sources once believed to be supernova remnants. In the videos, the X-ray sources appear as bright blue blobs with glowing cores. But in each image, taken months or years apart, the shapes change, as does the intensity of the blue color, and the brightness of the core. By presenting the substantively different images of the same objects one after another in quick succession, short timelapse videos are created.

The most likely explanation for the changes in brightness is that the team has uncovered a population of stellar survivors, stars that lived through an orbiting partner’s destruction in a supernova explosion. Material is being pulled from the surviving star onto the black hole or neutron star that formed in the supernova, a process known to cause rapid changes in X-ray brightness.

Read more from NASA’s Chandra X-ray Observatory

To learn more about NASA’s Chandra mission, visit:

https://science.nasa.gov/chandra

https://chandra.si.edu

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Joel Wallace
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
joel.w.wallace@nasa.gov

The post NASA’s Chandra Finds Unexpected Fireworks in Aftermath of Stellar Explosions appeared first on NASA Science.

This faint galaxy is hard to look away from.

This March 20, 2026, image of Messier 64, or the Black Eye Galaxy, is a composite view from NASA’s Hubble Space Telescope and James Webb Space Telescope. It shows Messier 64 captured at near- and mid-infrared wavelengths by Webb, while Hubble’s image shows the galaxy in ultraviolet, visible, and near-infrared light.

Messier 64 is characterized by its bizarre internal motion. The gas in the outer regions of this spiral galaxy is rotating in the opposite direction from the gas and stars in its inner regions. This strange behavior may be the result of a merger between M64 and a satellite galaxy over a billion years ago.

Image credit: NASA, CSA, ESA, F. Belfiore (European Southern Observatory – Germany), J. Lee (Space Telescope Science Institute), A. Leroy (The Ohio State University), and D. Thilker (The Johns Hopkins University); Processing: Gladys Kober (NASA/Catholic University of America)

The post Black Eye Galaxy appeared first on NASA Science.

This March 20, 2026, image of Messier 64, or the Black Eye Galaxy, is a composite view from NASA’s Hubble Space Telescope and James Webb Space Telescope. It shows Messier 64 captured at near- and mid-infrared wavelengths by Webb, while Hubble’s image shows the galaxy in ultraviolet, visible, and near-infrared light.

Messier 64 is characterized by its bizarre internal motion. The gas in the outer regions of this spiral galaxy is rotating in the opposite direction from the gas and stars in its inner regions. This strange behavior may be the result of a merger between M64 and a satellite galaxy over a billion years ago.

Image credit: NASA, CSA, ESA, F. Belfiore (European Southern Observatory – Germany), J. Lee (Space Telescope Science Institute), A. Leroy (The Ohio State University), and D. Thilker (The Johns Hopkins University); Processing: Gladys Kober (NASA/Catholic University of America)

Looking somewhat like a swarm of bees returning to their hive, this NASA Hubble Space Telescope image features the galaxy cluster MACS0329-0211. Galaxy clusters like MACS0329-0211 are important signposts in the story of how the structure of the universe evolved, and are the ultimate telescopic lenses, placing gravitationally lensed galaxies from the earliest stages of the universe into our view.

Zoom into this galaxy swarm and you will find large, oval-shaped elliptical galaxies, and thin spiral and lenticular galaxies viewed from the edge. We can also see the full, face-on view of spiral galaxies and their curving spiral arms. The image’s upper-right quadrant holds faint arcs of distant galaxies gravitationally lensed by the cluster’s massive gravity. The largest of these arcs appears above the bright oval shape of a giant elliptical galaxy. Closer inspection of the image’s center reveals several bright-white intersecting curves that appear as a distorted figure eight. This may be another distant galaxy whose light was magnified and distorted by this massive cluster’s gravity.

Hubble looked at MACS0329-0211 as part of an observing program of X-ray bright galaxy clusters. Researchers used Hubble’s two main cameras, the Advanced Camera for Surveys and its Wide Field Camera 3, to gather data visible and infrared light from the cluster. Hubble’s ability to see such a broad spectrum of light makes it a valuable tool in understanding the very nature of these galaxy clusters.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov

Looking somewhat like a swarm of bees returning to their hive, this NASA Hubble Space Telescope image features the galaxy cluster MACS0329-0211. Galaxy clusters like MACS0329-0211 are important signposts in the story of how the structure of the universe evolved, and are the ultimate telescopic lenses, placing gravitationally lensed galaxies from the earliest stages of the universe into our view.

Zoom into this galaxy swarm and you will find large, oval-shaped elliptical galaxies, and thin spiral and lenticular galaxies viewed from the edge. We can also see the full, face-on view of spiral galaxies and their curving spiral arms. The image’s upper-right quadrant holds faint arcs of distant galaxies gravitationally lensed by the cluster’s massive gravity. The largest of these arcs appears above the bright oval shape of a giant elliptical galaxy. Closer inspection of the image’s center reveals several bright-white intersecting curves that appear as a distorted figure eight. This may be another distant galaxy whose light was magnified and distorted by this massive cluster’s gravity.

Hubble looked at MACS0329-0211 as part of an observing program of X-ray bright galaxy clusters. Researchers used Hubble’s two main cameras, the Advanced Camera for Surveys and its Wide Field Camera 3, to gather data visible and infrared light from the cluster. Hubble’s ability to see such a broad spectrum of light makes it a valuable tool in understanding the very nature of these galaxy clusters.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov

The post Hubble Sees Swarm of Galaxies appeared first on NASA Science.

A dark void once dismissed as cosmic dust may be a far more fascinating dance of black holes.

A spectacular spiral galaxy known as M88 is traveling toward the crowded heart of the Virgo Cluster, where powerful forces are already beginning to reshape its future. A striking new image from the NASA/ESA Hubble Space Telescope highlights Messier 88 (M88), a spiral galaxy that is in the midst of a cosmic journey spanning hundreds [...]

Many "Moon Landing Hoax" proponents dismiss any pictures from NASA which clearly show Apollo Moon landing sites, taken by the lunar orbiter spacecraft. Also we have clear images from India’s ISRO lunar orbiter. But we can’t resolve the Apollo Lunar Module descent stages with Earth-based telescopes because of the limitations of the physics involved.

Tom Akers and Joe Tanner are finally in the same class.

The two veteran space shuttle crew members were inducted into the US Astronaut Hall of Fame together on May 16. They could also have been in the same NASA astronaut selection group, too, had history played out a little differently.

In 1984, Tanner reported to the Johnson Space Center (JSC) to fly as an instructor pilot and then applied for the next class of astronaut candidates.

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