NASA’s Neil Gehrels Swift Observatory captured an “orphan” black hole lighting up as it devoured a star on the outskirts of a faraway galaxy. These phenomena are rare to begin with, and none had ever before been seen so far outside of a galaxy’s core.

“We were looking for these star-shredding events as a way to find otherwise invisible supermassive black holes wandering away from the galactic cores where they usually reside,” said Robert Stein, a research fellow at The University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “With this discovery, which is one of just a couple that have been confirmed so far, we’ve validated a new technique and can use it to hunt for more.”

A paper describing the results, led by Stein, was published Monday in The Astrophysical Journal Letters.

Researchers saw an ultrabright flare unleashed by a star being torn apart by extreme gravitational forces after drifting too close to a monster black hole — a phenomenon called a tidal disruption event. The black hole behind the blast weighs in at about a million times the Sun’s mass. Its existence was first flagged in November 2025 as an unusual brightening in a galaxy about 750 million light-years away by ZTF (Zwicky Transient Facility), a survey conducted by the Palomar Observatory in Southern California.

“Out of the half million flashes ZTF detects each night, our new artificial intelligence algorithm automatically recognized a flare that looked a lot like a tidal disruption event, despite its unusual location in the outskirts of a galaxy,” Stein said. For a few months, the tidal disruption event outshone its entire host galaxy in ultraviolet wavelengths, temporarily radiating with the light of about 10 billion suns.

Other telescopes, including the SOAR (Southern Astrophysical Research) telescope in Chile, followed up on the ZTF source to look at the event’s spectrum, which revealed features supporting that it was likely a tidal disruption event. Astronomers then used NASA’s Swift to look at wavelengths they can’t detect with ground-based telescopes to uncover new information. For example, Swift’s UVOT (Ultraviolet/Optical Telescope) took the blip’s temperature and found that it had quite a fever at about 54,000 degrees Fahrenheit (30,000 degrees Celsius).

“The combination of all this data helped us rule out other explanations and confidently say it’s a tidal disruption event, despite its strange location,” said Jonathan Carney, a doctoral student at the University of North Carolina at Chapel Hill, who took the first spectra that supported the flare’s interpretation as a tidal disruption event.

Hidden heavyweights

Nearly every galaxy in the universe is anchored by a supermassive black hole sitting right in the center. About once every 100,000 years, a star will drift too close to this invisible heavyweight and trigger a tidal disruption event.

While they’re rather rare in any given galaxy, scientists scour millions of galaxies for them. Each year, astronomical surveys typically spot about 30 tidal disruption events occurring somewhere in the universe.

Prior to 2024, they’d only been seen in galaxy cores. That’s partly because astronomers mainly looked for them there; after all, it’s where all the known supermassive black holes were, and you can’t get a tidal disruption event without one (the gravitational pull of lighter black holes isn’t strong enough).

Then scientists saw the telltale signs of a star being shredded 2,600 light-years from the center of its host galaxy. That inspired more astronomers to look beyond galaxy cores for similar events, and now a team has identified one more than 30,000 light-years away from a galaxy’s center.

Oddball origin story

So how did the newfound black hole become so off-kilter?

“It must have originated in a galaxy’s center, but not the one it’s in the outskirts of now,” Stein said. “We think the host galaxy’s supermassive black hole is still at its core, but the one eating the star could have started off in a small galaxy that merged with the big one we see today.”

The researchers have outlined two possibilities. Three or more galaxies may have merged together, and the gravitational tug-of-war between their central supermassive black holes may have flung the lightest black hole out to the galaxy’s edge.

Or a dwarf galaxy could be midway through a merger. As the dwarf’s stars fell into the larger galaxy, one may have passed too close to the dwarf’s supermassive black hole.

“Further discoveries could reveal the origin of this apparent ‘orphan’ black hole,” Stein said. “The key science question we want to answer is: How common are wandering black holes?”

The answer may soon be within reach. “Pointed science observations with Swift’s UVOT and XRT (X-Ray Telescope) instruments are temporarily suspended as the mission awaits an orbit boost, which is planned for this summer,” said co-author S. Bradley Cenko, Swift’s principal investigator at NASA Goddard. The spacecraft, whose primary mission ran from 2004 to 2006, is slowly sinking toward Earth due to atmospheric drag after more than 20 years of observations of the changing universe. Nudging it to a higher orbit could extend its lifetime even longer. “Once it resumes normal operations, Swift could continue searching for more examples of out-of-place black holes.”

In the coming years, scientists will use the new technique to search for disintegrating stars in observations from the newly operational Vera C. Rubin Observatory, jointly funded by the U.S. Department of Energy and National Science Foundation, in Chile and NASA’s upcoming Nancy Grace Roman Space Telescope.

“Rubin’s wide, deep surveys will reveal a much larger sample of tidal disruption events than current observatories are capable of collecting, including ones that are off-center,” Carney said. “And Roman’s space-based surveys will extend the current search zone by seeing ones that are farther away, looking back through 9 billion years of cosmic history.” Adding their observations to Swift’s and those from ground-based observatories will bring astronomers closer than ever before to completing a census of the universe’s behemoth black holes.

To learn more about the Swift mission, visit:

https://nasa.gov/swift

By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Media contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-1940

Lee esta nota de prensa en español aquí.

How do black holes at the center of galaxies form and grow over time? To answer this question, scientists need to detect and study supermassive black holes at great distances, which existed much earlier in the universe’s history. New research suggests NASA’s Nancy Grace Roman Space Telescope, which is on track to launch Aug. 30, 2026, will be able to detect these distant, ancient black holes that existed up to 11 billion years ago.

Black holes are best studied by looking for the light emitted from their accretion disk — the matter that swirls around them before being consumed. Lighter supermassive black holes are challenging to observe because they tend to be less luminous due to less accretion. But occasionally, they shred and consume an entire star, brightening to outshine their entire host galaxy — known as a tidal disruption event (TDE). By characterizing that population of early supermassive black holes and how they evolve and grow for billions of years, Roman will provide clues to the ultimate origin of these behemoths.

“The Roman Space Telescope is going to be transformative for transient science,” said lead author Mitchell Karmen of the Johns Hopkins University, a graduate student and National Science Foundation Graduate Research Fellow. “Thanks to Roman’s high sensitivity, we can find multiple tidal disruption events out to greater distances and earlier cosmic times than ever before.”

A paper about this research published Tuesday in The Astrophysical Journal.

Shredding Stars

Roman’s High-Latitude Time-Doman Survey, one of three core community surveys, is particularly well suited to find and study TDEs in the early universe. This survey will cover about 18 square degrees on the sky, an area equivalent to 90 full moons, at a regular cadence. By revisiting the same regions repeatedly, astronomers can find large numbers of transient events like TDEs.

Tidal disruption events are phenomena unique to lighter supermassive black holes. Heftier black holes weighing more than 1 billion Suns will swallow incoming stars whole. But lighter black holes of about 100,000 to 100 million Suns can shred a star before consuming it, creating a beacon that brightens over a couple of weeks before gradually fading away.

The rate of TDEs fluctuates over cosmic time. Previous work predicted that the rate of TDEs would decrease with increasing distance because most young black holes were too light to generate a TDE. However, this new research takes into account numerous factors that evolve over time, like the frequency of galaxy (and hence black hole) mergers as well as the number of stars within the core of each galaxy and how closely packed they are.

Karmen and his colleagues modeled these and other effects to predict how many tidal disruption events Roman could observe, as well as other observatories like the ground-based National Science Foundation-Department of Energy Vera C. Rubin Observatory and NASA’s James Webb Space Telescope. The team forecasts that astronomers will see the rate of TDEs increase as Roman probes greater distances and earlier times until “cosmic noon,” about 11 to 12 billion years ago when star formation peaked throughout the universe, before decreasing again.

Complementary Observations

Roman will observe near-infrared wavelengths of light. Light from distant TDEs becomes stretched to longer wavelengths by the expansion of the universe, a phenomenon known as cosmological redshift. As a result, Roman is inherently optimized to detect TDEs whose light traveled anywhere from 8 billion to 11 billion years to reach us.

The Rubin Observatory also will scan large swaths of the sky and pick up many new TDEs. However, it will observe visible light, which limits it to closer TDEs than Roman.

The research by Karmen’s team finds that Rubin will detect thousands to tens of thousands of TDEs per year. While Roman is expected to find up to 100 TDEs per year, those black holes will be much more distant, within the realm of cosmic history that is most important for distinguishing among black hole origin scenarios.

“Just by counting the number of TDEs as a function of redshift, you can put meaningful constraints on the population of million-solar-mass black holes,” said co-author Suvi Gezari, an associate professor of astronomy at the University of Maryland. “Roman will be transformative in that it can probe tidal disruption events out to greater distances, so you can look at how the rate of TDEs evolves over time.”

Origins of supermassive black holes

Astronomers have observed truly gargantuan black holes very early in the history of the universe — so early that theories struggle to explain how they could have become so large, so quickly. They must have started smaller and grown over time, but how much smaller?

One theory, known as “light seeds,” begins with black holes that are created from the deaths of massive stars. Such black holes might weigh up to a few hundred times our Sun. These black holes then would merge over time, as well as consume surrounding gas at an astonishing rate. In this scenario, every young galaxy would be expected to have a massive black hole at its center.

A second theory, known as “heavy seeds,” suggests that a black hole could be born with a much higher mass, up to a million times our Sun, through a process such as the direct collapse of a gas cloud. This process should be less common, though, which would result in supermassive black holes being much rarer in early galaxies.

“Tidal disruption events help us probe the population of light supermassive black holes, which can help us discriminate between these models,” Karmen said.

Ultimately, Roman’s tally of tidal disruption events will help researchers trace global effects that impact the black hole population over time.

Once Roman and Rubin begin regular science operations, the team looks forward to comparing their forecasts to the actual detections those observatories make.

“Just like Webb has transformed our understanding of distant, high-redshift galaxies, Roman is poised to transform our understanding of high-redshift transients,” Gezari said.

The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory in Southern California; Caltech/IPAC in Pasadena, California; the Space Telescope Science Institute in Baltimore; and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.

By Christine Pulliam
Space Telescope Science Institute, Baltimore, Md.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-1940

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NASA’s Chandra Reveals ‘Red, White, Blue’ Universe for US 250th

In celebration of the 250th birthday of the United States, NASA has unveiled four cosmic images from its Chandra X-ray Observatory rendered in red, white, and blue that represent the wonders of the universe the agency explores. The images are accompanied by a trio of new sonifications – a technique that translates astronomical data into sounds.

The image set begins with Cassiopeia A in the top panel, where X-rays from Chandra (represented in blue and purple) have been combined with an infrared image from NASA’s James Webb Space Telescope (red and white). Chandra’s X-ray vision reveals the blast wave that tore through the star, as well as elements in the debris field like iron, calcium, and oxygen. Webb’s infrared data also shows the expanding shell of material from the explosion and cosmic dust throughout the remnant.

 In the bottom row, the first image on the left is the nebula NGC 3603, which contains a massive cluster of stars and is located in the Milky Way Galaxy. This new composite image contains Chandra’s X-ray data (red and white) and shows diffuse emissions near the galaxy’s center along with point-like X-ray sources throughout the middle of the image. Optical, infrared, and ultraviolet light from NASA’s Hubble Space Telescope (red-orange, green, blue, and yellow) reveal stars in the center of the image and dust and gas toward the bottom. The combined layering of the colors makes this nebula and the stars forming within it appear primarily red, white, and blue, with X-rays showing the sparkling lights of young stars.

The middle panel of the bottom row is a new look at the galaxy NGC 4736, also known as Messier 94. In this image, X-rays of different wavelengths from Chandra (red, orange, and blue) are layered with a visible light image from astrophotographers using their telescopes on the ground (red, green, and blue). Messier 94 is a spiral galaxy with a bright inner ring around it, called a starburst ring, where new stars are forming, perhaps fueled by gas driven in the unique oval-shaped structure seen here.

The final image in this red, white, and blue quartet features ZwCl 0024+1652. This is a distant galaxy cluster in which astronomers have found evidence for dark matter by using specially processed data from Hubble (blue). Another image from Hubble reveals the individual galaxies in the cluster (appearing as yellow and white). X-ray data from Chandra shows the enormous reservoir of superheated gas that pervades this galaxy cluster (red) with much more mass than all the galaxies taken together.

New sonifications of the three images along the bottom row of this mosaic are also available, allowing listeners to experience data through sound.

The translation of NGC 3603 into sound begins with a left to right scan, where the brightnesses of the sources once again dictate volume. Chandra’s observations of compact sources sprinkled throughout the galaxy are heard as piano notes, while the diffuse X-ray emission is mapped to a range of audio frequencies. The Hubble optical data is played as sustained tones and acoustic guitar harmonics.

In the sonification of NGC 4736, the radar-like scan moves clockwise, and the brightness of the sources dictates the volume of the sounds. X-rays from Chandra have been turned into wind-like sounds that follow the shape of the X-ray emission. Neutron stars and stellar-mass black holes (known as “compact sources”) detected by Chandra are mapped to pitched tones on a glass marimba. Optical data from ground-based observations is mapped to musically pitched tones, creating a low drone, while stars and background galaxies are heard as a soft piano.

For ZwCl 0024+1652, the sonification begins as a circle on the outside of the image and moves inward. The volume is linked to the brightness of the data, reaching one peak as the circle passes over the dark matter detected by inference from Hubble optical observations and another as it reaches the core. The background stars are heard as a swelling glockenspiel-like sound, and the galaxies are played on a piano. Chandra’s X-rays, which dominate the center of the galaxy cluster and reveal superheated gas, are represented by airy synthesizer notes.

The sonification program is led by the Chandra X-ray Center (CXC) and included as part of NASA’s Universe of Learning program. The collaboration was driven by visualization scientist Kimberly Arcand, (CXC), Matt Russo, astrophysicist; and Andrew Santaguida, musician, SYSTEM Sounds project; along with Christine Malec, consultant. Previously released sonifications of data from Cassiopeia A can be found at chandra.si.edu/sound.

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.

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

https://nasa.gov/chandra

Visual Description

In celebration of the 250th birthday of the United States, this release includes a series of images featuring four wonders of the universe, rendered in red, white, and blue. The images contain X-ray data from the Chandra X-ray Observatory, optical and infrared data from the Hubble Space Telescope and the James Webb Space Telescope, as well as ground-based telescopes.

The main image set features composite images of the four individual objects; Cassiopeia A, NGC 3603, M94/NGC 4736, and ZwCl 0024+1652.

Cassiopeia A occupies the top panel of the frame, significantly larger than the other images in the set. The cloudy blast-wave of the supernova remnant is ring-like in shape, streaked with veins of iron, calcium, and oxygen. Here, presented in red, white, and blue, the remnant resembles an electrified donut, crackling with marbled veins of strawberry and blueberry icing.

At our lower left of the image set is the nebula NCG 3603, which contains a massive cluster of stars on the other side of the Milky Way galaxy. Here, a tight cluster of neon red and white stars packs the center of the image, dissipating as it reaches the outer edges of the panel. Sweeping in at the lower corners of the image are hazy blue clouds resembling sheets of gauze.

Centered at the bottom of the image set is the galaxy NGC 4736, also known as Messier 94 (M94). Here, the spiral galaxy is seen face on, with concentric pale violet cloud rings flecked with scores of stars in white, pale blue, soft red, and golden yellow. The inner ring of the galaxy is bright, and rosy yellow in color. This is a starburst ring, where new stars are forming.

At our bottom right of the image set is the distant galaxy cluster ZwCl 0024+1652. The image is packed with streaks and specks in golden yellow and brilliant white. Upon close inspection, each streak and speck is revealed to be an individual galaxy, some with discernible spiral shapes. At the center of the image is a round pool of bright red light, surrounded by royal blue haze. The red light represents X-ray observations by Chandra, which reveal an enormous reservoir of superheated gas pervading the cluster. The blue haze represents specially-processed data from Hubble, suggesting evidence of dark matter.

This release also includes new sonifications of the three images presented in the bottom row of this data set, allowing listeners to experience the data through sound.

Read more from NASA’s Chandra X-ray Observatory

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

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