Black Hole Week: Black Hole GIFs

Explore how the extreme gravity of two orbiting supermassive black holes distorts our view. In this visualization, disks of bright, hot, churning gas encircle both black holes, shown in red and blue to better track the light source. The red disk orbits the larger black hole, which weighs 200 million times the mass of our Sun, while its smaller blue companion weighs half as much. Zooming into each black hole reveals multiple, increasingly warped images of its partner. Watch to learn more. Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. PowellMusic: "Gravitational Field" from Orbit. Written and produced by Lars Leonhard.Watch this video on the NASA Goddard YouTube channel.Complete transcript available. In this visualization, available in HD and 4K, a binary system containing two supermassive black holes and their accretion disks is initially viewed from above. After about 25 seconds, the camera tips close to the orbital plane to reveal the most dramatic distortions produced by their gravity. The different colors of the accretion disks make it easier to track where light from each black hole turns up. Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell A face-on view of the system highlights the smaller black hole's distorted image (inset) of its bigger companion. To reach the camera, the smaller black hole must bend light from its red companion by 90 degrees. In this secondary image, the accretion disk forms a line, which means we're seeing an edge-on view of the red companion – while also simultaneously seeing it from above. A secondary image of the blue disk can be seen just outside the bright ring of light nearest the larger black hole, too. Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Viewing the system from above and centering the camera on the smaller black hole shows how the secondary image of its partner rotates every orbit. Although subtle, the motion also reveals the non-circular shape of the surrounding rings of light and the inner edge of the blue accretion disk, a distortion produced by the combined effects of gravity and near-lightspeed orbital motion.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell This image shows the warped view of a larger supermassive black hole (red disk) when it passes almost directly behind a companion black hole (blue disk) with half its mass. The gravity of the foreground black hole transforms its partner into a surreal collection of arcs. These distortions play out as light from the accretion disks navigates the tangled fabric of space and time near the black holes.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell This image shows the warped view of a larger supermassive black hole (red disk) when it passes seen almost directly behind a companion black hole (blue disk) with half its mass. The gravity of the foreground black hole transforms its partner into a surreal collection of arcs. Insets highlight areas where one black hole produces a complete but distorted image of the other. Light from the accretion disks produces these self-similar images as it travels through the tangled fabric of space and time near both black holes.High-resolution views of the numbered insets are available below.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Unlabeled version of the image above.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Inset 1 from the compilation above, showing an image of the smaller companion formed near the light ring of the larger black hole.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Inset 2 from the compilation above, showing a highly distorted image of the smaller companion formed by the larger black hole.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Inset 3 from the compilation above, showing even more distorted images of both accretion disks, formed by light deflecting multiple times between the two black holes.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell Inset 4 from the compilation above, showing another warped image of the smaller companion formed by the larger black hole.Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell A pair of orbiting black holes millions of times the Sun’s mass perform a hypnotic dance in this NASA visualization. The movie traces how the black holes distort and redirect light emanating from the maelstrom of hot gas – called an accretion disk – that surrounds each one. Viewed from near the orbital plane, each accretion disk takes on a characteristic warped look. But as one passes in front of the other, the gravity of the foreground black hole transforms its partner into a rapidly changing sequence of arcs. These distortions play out as light from the accretion disks navigates the tangled fabric of space and time near the black holes. The simulated binary contains two supermassive black holes, a larger one with 200 million solar masses and a smaller companion weighing half as much. Astronomers think that in binary systems like this, both black holes could maintain accretion disks for millions of years. The disks have different colors, red and blue, to make it easier to track the light sources, but the choice also reflects reality. Gas orbiting lower-mass black holes experiences stronger effects that produce higher temperatures. For these masses, both accretion disks would actually emit most of their light in the UV, with the blue disk reaching a slightly higher temperature.Visualizations like this help scientists picture the fascinating consequences of extreme gravity’s funhouse mirror. Seen nearly edgewise, the accretion disks look noticeably brighter on one side. Gravitational distortion alters the paths of light coming from different parts of the disks, producing the warped image. The rapid motion of gas near the black hole modifies the disk’s luminosity through a phenomenon called Doppler boosting – an effect of Einstein’s relativity theory that brightens the side rotating toward the viewer and dims the side spinning away. The visualization also shows a more subtle phenomenon called relativistic aberration. The black holes appear smaller as they approach the viewer and larger when moving away.These effects disappear when viewing the system from above, but new features emerge. Both black holes produce small images of their partners that circle around them each orbit. Looking closely, it’s clear that these images are actually edge-on views. To produce them, light from the black holes must be redirected by 90 degrees, which means we’re observing the black holes from two different perspectives – face on and edge on – at the same time. Zooming into each black hole reveals multiple, increasingly distorted images of its partner.The visualization, created by astrophysicist Jeremy Schnittman at NASA's Goddard Space Flight Center in Greenbelt, Maryland, involved computing the path taken by light rays from the accretion disks as they made their way through the warped space-time around the black holes. On a modern desktop computer, the calculations needed to make the movie frames would have taken about a decade. So Schnittman teamed up with Goddard data scientist Brian P. Powell to use the Discover supercomputer at the NASA Center for Climate Simulation. Using just 2% of Discover’s 129,000 processors, these computations took about a day. Astronomers expect that, one day, they’ll be able to detect gravitational waves – ripples in space-time – produced when two supermassive black holes in a system much like the one Schnittman depicted spiral together and merge. For More InformationSee [https://www.nasa.gov/feature/goddard/2021/new-nasa-visualization-probes-the-light-bending-dance-of-binary-black-holes](https://www.nasa.gov/feature/goddard/2021/new-nasa-visualization-probes-the-light-bending-dance-of-binary-black-holes) Related pages

Watch how a monster black hole ripping apart a star may have launched a ghost particle toward Earth. Astronomers have long predicted that tidal disruption events could produce high-energy neutrinos, nearly massless particles from outside our galaxy traveling close to the speed of light. One recent event, named AT2019dsg, provides the first proof this prediction is true but has challenged scientists’ assumptions of where and when these elusive particles might form during these destructive outbursts. Credit: NASA’s Goddard Space Flight CenterMusic: "Diagnostic Report" from Universal Production MusicComplete transcript available. This animation illustrates what happens when an unlucky star strays too close to a monster black hole. Gravitational forces create intense tides that break the star apart into a stream of gas. The trailing part of the stream escapes the system, while the leading part swings back around, surrounding the black hole with a disk of debris. This cataclysmic phenomenon is called a tidal disruption event.Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR) Eventually, the stellar debris settles into an accretion disk around the black hole, as illustrated here. Gravitational and frictional forces heat the material, producing visible, ultraviolet, and X-ray emissions. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR) The Zwicky Transient Facility, a robotic camera at Caltech’s Palomar Observatory in Southern California, captured this snapshot containing tidal disruption event AT2019dsg (circled) on Oct. 19, 2019. The image was taken during the camera’s follow-up campaign that identified the event as a high-energy neutrino source.This listing includes unmarked versions.Credit: ZTF/Caltech Optical Observatories For only the second time, astronomers have linked an elusive particle called a high-energy neutrino to an object outside our galaxy. Using ground- and space-based facilities, including NASA’s Neil Gehrels Swift Observatory, they traced the neutrino to a black hole tearing apart a star, a rare cataclysmic occurrence called a tidal disruption event.Neutrinos are fundamental particles that far outnumber all the atoms in the universe but rarely interact with other matter. Astrophysicists are particularly interested in high-energy neutrinos, which have energies up to 1,000 times greater than those produced by the most powerful particle colliders on Earth. They think the most extreme events in the universe, like violent galactic outbursts, accelerate particles to nearly the speed of light. Those particles then collide with light or other particles to generate high-energy neutrinos. The first confirmed high-energy neutrino source, announced in 2018, was a type of active galaxy called a blazar. Tidal disruption events occur when an unlucky star strays too close to a black hole. Gravitational forces create intense tides that break the star apart into a stream of gas. The trailing part of the stream escapes the system, while the leading part swings back around, surrounding the black hole with a disk of debris. In some cases, the black hole launches fast-moving particle jets. Scientists hypothesized that tidal disruptions would produce high-energy neutrinos within such particle jets. They also expected the events would produce neutrinos early in their evolution, at peak brightness, whatever the particles’ production process. Tidal disruption event AT2019dsg was discovered on April 9, 2019, by the Zwicky Transient Facility (ZTF), a robotic camera at Caltech’s Palomar Observatory in Southern California. The event occurred over 690 million light-years away in a galaxy called 2MASX J20570298+1412165, located in the constellation Delphinus. As part of a routine follow-up survey of tidal disruptions, scientists requested visible, ultraviolet, and X-ray observations with Swift. They also took X-ray measurements using the European Space Agency’s XMM-Newton satellite and radio measurements with facilities including the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array in Socorro, New Mexico, and the South African Radio Astronomy Observatory's MeerKAT telescope. Peak brightness came and went in May. No clear jet appeared. According to theoretical predictions, AT2019dsg was looking like a poor neutrino candidate. Then, on Oct. 1, 2019, the National Science Foundation’s IceCube Neutrino Observatory at the Amundsen-Scott South Pole Station in Antarctica detected a high-energy neutrino called IC191001A and backtracked along its trajectory to a location in the sky. About seven hours later, ZTF noted that this same patch of sky included AT2019dsg. Astronomers think there is only one chance in 500 that the tidal disruption is not the neutrino’s source. Because the detection came about five months after the event reached peak brightness, it raises questions about when and how these occurrences produce neutrinos. For More InformationSee [https://www.nasa.gov/feature/goddard/2021/nasa-s-swift-helps-tie-neutrino-to-star-shredding-black-hole](https://www.nasa.gov/feature/goddard/2021/nasa-s-swift-helps-tie-neutrino-to-star-shredding-black-hole) Related pages

Text-on-screen explainer of the above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC)Complete transcript available. This visualization shows gravitational waves emitted by two black holes (black spheres) of nearly equal mass as they spiral together and merge. Yellow structures near the black holes illustrate the strong curvature of space-time in the region. Orange ripples represent distortions of space-time caused by the rapidly orbiting masses. These distortions spread out and weaken, ultimately becoming gravitational waves (purple). The merger timescale depends on the masses of the black holes. For a system containing black holes with about 30 times the sun’s mass, similar to the one detected by LIGO in 2015, the orbital period at the start of the movie is just 65 milliseconds, with the black holes moving at about 15 percent the speed of light. Space-time distortions radiate away orbital energy and cause the binary to contract quickly. As the two black holes near each other, they merge into a single black hole that settles into its "ringdown" phase, where the final gravitational waves are emitted. For the 2015 LIGO detection, these events played out in little more than a quarter of a second. This simulation was performed on the Pleiades supercomputer at NASA's Ames Research Center. At maximum resolution this visualization is 8192x8192 pixels in size.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Animated gif of early stage of the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Animated gif of final stage of the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Still frame from the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Still frame from the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Still frame from the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Final still frame from the visualization described above.Credit: NASA/Bernard J. Kelly (Goddard and Univ. of Maryland Baltimore County), Chris Henze (Ames) and Tim Sandstrom (CSC Government Solutions LLC) Related pages

Watch how X-ray echoes, mapped by NASA’s Neutron star Interior Composition Explorer (NICER) revealed changes to the corona of black hole MAXI J1820+070.Credit: NASA’s Goddard Space Flight CenterMusic: "Superluminal" from Killer TracksComplete transcript available. X-ray light echoes reveal changes to the accretion disk and corona of a black hole in this animation. Over time, the echoes get closer and closer together, indicating that the corona is compacting. Credit: NASA’s Goddard Space Flight Center In this illustration of a newly discovered black hole named MAXI J1820+070, a black hole pulls material off a neighboring star and into an accretion disk. Above the disk is a region of subatomic particles called the corona. Credit: Aurore Simonnet and NASA’s Goddard Space Flight Center An animated version of the illustration above.Credit: Aurore Simonnet and NASA’s Goddard Space Flight Center The NICER instrument installed on the International Space Station, as captured by a high-definition external camera on Oct. 22, 2018. Credit: NASA The Neil Gehrels Swift Observatory took this image of MAXI J1820+070 on March 11, 2018, using its X-Ray Telescope. Credit: NASA/Swift Animated GIF showing waves of X-rays from the corona echoing off the accretion disk like the sonar we use to explore the ocean floor. These echoes tell us about the size and shape of the disk and corona. Credit: NASA's Goddard Space Flight Center Animated GIF showing the anatomy of MAXI J1820+070.Credit: NASA's Goddard Space Flight Center Animated GIF illustrating how iron atoms in the disk absorb X-rays from the corona and then re-emit them. Gravitational distortion of space-time stretches the wavelengths of the X-rays, reducing their energy. The farther from the black hole they are, the less the light is affected.Credit: NASA's Goddard Space Flight Center Scientists have mapped the environment surrounding a black hole that is 10 times the mass of the Sun using NASA’s Neutron star Interior Composition Explorer (NICER) payload aboard the International Space Station. NICER detected X-ray light from a recently discovered black hole, called MAXI J1820+070 (J1820 for short), as it consumed material from a companion star. Waves of X-rays formed "light echoes" that reflected off the swirling gas near the black hole and revealed changes in the environment’s size and shape. A black hole can siphon gas from a nearby star and into a ring of material called an accretion disk that glows in X-rays. Above this disk is the corona, a region of subatomic particles that glows in higher-energy X-rays. Astrophysicists want to better understand how the inner edge of the accretion disk and the corona change in size and shape as a black hole accretes material from its companion star. If they can understand how and why these changes occur in stellar-mass black holes over a period of weeks, they could shed light on how supermassive black holes evolve over millions of years and how they affect the galaxies in which they reside. One method used to chart those changes is called X-ray reverberation mapping, which uses X-ray reflections in much the same way sonar uses sound waves to map undersea terrain. From 10,000 light-years away, the scientists estimated that the corona contracted vertically from roughly 100 to 10 miles — that’s like seeing something the size of a blueberry shrink to something the size of a poppy seed at the distance of Pluto. For More InformationSee [https://umdrightnow.umd.edu/news/nicer-view-black-hole-gives-new-insight-source-dramatic-x-ray-flashes](https://umdrightnow.umd.edu/news/nicer-view-black-hole-gives-new-insight-source-dramatic-x-ray-flashes) Related pages

Gas glows brightly in this computer simulation of supermassive black holes only 40 orbits from merging. Models like this may eventually help scientists pinpoint real examples of these powerful binary systems. Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018Music: "Games Show Sphere 01" from Killer TracksWatch this video on the NASA Goddard YouTube channel.Complete transcript available. Same as above, without text overlay.Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018 Same as above, trimmed and formated for Instagram. No text overlay.Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018 This animated gif rotates a frozen version of the simulation through 360 degrees as viewed from the plane of the disk.Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018 This animated gif rotates a frozen version of the simulation through 180 degrees and then back, from directly above to directly below the plane of the disk.Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018 This 360-degree video places the viewer between two circling supermassive black holes around 18.6 million miles (30 million kilometers) apart with an orbital period of 46 minutes. The simulation shows how the black holes distort the starry background and capture light, producing black hole silhouettes. A distinctive feature called a photon ring outlines the black holes. The entire system has a mass about 1 million times the Sun’s.Credit: NASA’s Goddard Space Flight Center/Scott Noble; background, ESA/Gaia/DPAC Watch this video on the NASA Goddard YouTube channel. This 360-degree video places the viewer between two circling supermassive black holes around 18.6 million miles (30 million kilometers) apart with an orbital period of 46 minutes. The simulation shows how the black holes distort the starry background and capture light, producing black hole silhouettes. A distinctive feature called a photon ring outlines the black holes. The entire system would have around 1 million times the Sun’s mass. The background is a view of the entire sky as observed by the NASA's Wide-field Infrared Survey Explorer (WISE).Credit: NASA’s Goddard Space Flight Center/Scott Noble; background, NASA/JPL-Caltech/UCLA A new model is bringing scientists a step closer to understanding the kinds of light signals produced when two supermassive black holes, which are millions to billions of times the mass of the Sun, spiral toward a collision. For the first time, a new computer simulation that fully incorporates the physical effects of Einstein’s general theory of relativity shows that gas in such systems will glow predominantly in ultraviolet and X-ray light. The new simulation shows three orbits of a pair of supermassive black holes only 40 orbits from merging. The models reveal the light emitted at this stage of the process may be dominated by UV light with some high-energy X-rays, similar to what’s seen in any galaxy with a well-fed supermassive black hole. Three regions of light-emitting gas glow as the black holes merge, all connected by streams of hot gas: a large ring encircling the entire system, called the circumbinary disk, and two smaller ones around each black hole, called mini disks. All these objects emit predominantly UV light. When gas flows into a mini disk at a high rate, the disk’s UV light interacts with each black hole’s corona, a region of high-energy subatomic particles above and below the disk. This interaction produces X-rays. When the accretion rate is lower, UV light dims relative to the X-rays. Based on the simulation, which ran on the National Center for Supercomputing Applications’ Blue Waters supercomputer at the University of Illinois at Urbana-Champaign, the researchers expect X-rays emitted by a near-merger will be brighter and more variable than X-rays seen from single supermassive black holes. The pace of the changes links to both the orbital speed of gas located at the inner edge of the circumbinary disk as well as that of the merging black holes. For More InformationSee [http://www.nasa.gov/feature/goddard/2018/new-simulation-sheds-light-on-spiraling-supermassive-black-holes](http://www.nasa.gov/feature/goddard/2018/new-simulation-sheds-light-on-spiraling-supermassive-black-holes) Related pages

This animation captures phenomena observed over the course of nine days following the neutron star merger known as GW170817, detected on Aug. 17, 2017. They include gravitational waves (pale arcs), a near-light-speed jet that produced gamma rays (magenta), expanding debris from a kilonova that produced ultraviolet (violet), optical and infrared (blue-white to red) emission, and, once the jet directed toward us expanded into our view from Earth, X-rays (blue). Credit: NASA's Goddard Space Flight Center/CI LabMusic: "Exploding Skies" from Killer TracksWatch this video on the NASA Goddard YouTube channel.Complete transcript available. Doomed neutron stars whirl toward their demise in this illustration. Gravitational waves (pale arcs) bleed away orbital energy, causing the stars to move closer together and merge. As the stars collide, some of the debris blasts away in particle jets moving at nearly the speed of light, producing a brief burst of gamma rays. Credit: NASA's Goddard Space Flight Center/CI Lab This illustration shows the hot, dense, expanding cloud of debris stripped from the neutron stars just before they collided. This cloud produces the kilonova's visible and infrared light. Within this neutron-rich debris, large quantities of some of the universe's heaviest elements were forged, including hundreds of Earth masses of gold and platinum. Credit: NASA's Goddard Space Flight Center/CI Lab After the neutron stars merged, the remains of the jets that produced the gamma-ray burst continue expanding into space, as shown in this illustration. After nine days, the jet directed toward us had spread laterally enough that observers could detect its X-ray emission.Credit: NASA's Goddard Space Flight Center/CI Lab This animation shows the shrinking orbit and explosive merging of two neutron stars, immediately followed by the eruption of powerful jets (orange) and then expanding shock waves where the jets plow into surrounding material (pink structures at the tip of each jet). The animation then shows the kilonova, the neutron-rich debris of the explosion (depicted by the expanding and flattened blue spheres) powered by the decay of newly forged radioactive elements. The jets emit gamma rays, the shock wave glows in X-rays and the kilonova produces ultraviolet light.Credit: NASA's Goddard Space Flight Center/CI LabMusic: "Exploding Skies" from Killer TracksComplete transcript available. This animation shows the shrinking orbit and explosive merging of two neutron stars, immediately followed by the eruption of powerful jets (orange) and then expanding shock waves where the jets plow into surrounding material (pink structures at the tip of each jet). The animation then shows the kilonova, the neutron-rich debris of the explosion (depicted by the expanding and flattened blue spheres) powered by the decay of newly forged radioactive elements. The jets emit gamma rays, the shock wave glows in X-rays and the kilonova produces ultraviolet light. This version is the raw 3840x2160, 60 fps animation and includes frames for download.Credit: NASA's Goddard Space Flight Center/CI Lab On Aug. 17, gravitational waves from merging neutron stars reached Earth. Just 1.7 seconds after that, NASA's Fermi saw a gamma-ray burst from the same event. Now that astronomers can combined what we can “see” (light) and what we can “hear” (gravitational waves) from the same event, our ability to understand these extreme cosmic phenomena is greatly enhanced. Credit: NASA's Goddard Space Flight Center On Aug. 17, gravitational waves from merging neutron stars reached Earth. Just 1.7 seconds after that, NASA's Fermi saw a gamma-ray burst from the same event. Now that astronomers can combined what we can “see” (light) and what we can “hear” (gravitational waves) from the same event, our ability to understand these extreme cosmic phenomena is greatly enhanced. Still Image. Credit: NASA's Goddard Space Flight Center Illustration of two merging neutron stars. The rippling space-time grid represents gravitational waves that travel out from the collision, while the narrow beams show the burst of gamma rays that are shot out just seconds after the gravitational waves. Swirling clouds of material ejected from the merging stars are also depicted—these clouds glow with visible and other wavelengths of light.Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet NASA's Fermi Gamma-ray Space Telescope detected a gamma-ray burst just 1.7 seconds after gravitational waves from a neutron star merger rattled Earth, confirming a long-held association. Fermi's Gamma-ray Burst Monitor, which detected the burst, sees all of the sky not blocked by Earth. Credit: NASA's Goddard Space Flight Center On August 17, 2017, the Laser Interferometer Gravitational-wave Observatory detected gravitational waves from a neutron star collision. Within 12 hours, observatories had identified the source of the event within the galaxy NGC 4993, shown in this Hubble Space Telescope image, and located an associated stellar flare called a kilonova (box). Inset: Hubble observed the kilonova fade over the course of six days.Credit: NASA and ESA On August 17, 2017, the Laser Interferometer Gravitational-wave Observatory detected gravitational waves from a neutron star collision. Within 12 hours, observatories had identified the source of the event within the galaxy NGC 4993, shown in this Hubble Space Telescope image, and located an associated stellar flare called a kilonova. Hubble observed that flare of light fade over the course of six days. Credit: NASA and ESA Swift’s Ultraviolet/Optical Telescope imaged the kilonova produced by merging neutron stars in the galaxy NGC 4993 (box) on Aug. 18, 2017, about 15 hours after gravitational waves and the gamma-ray burst were detected. The source was unexpectedly bright in ultraviolet light. It faded rapidly and was undetectable in UV when Swift looked again on Aug. 29. This false-color composite combines images taken through three ultraviolet filters. Inset: Magnified views of the galaxy. Credit: NASA/Swift Swift's Ultraviolet/Optical Telescope imaged the kilonova produced by merging neutron stars in the galaxy NGC 4993 (box) on Aug. 18, 2017. The source was unexpectedly bright in ultraviolet light. This false-color composite combines images taken through three ultraviolet filters. Inset: A magnified view of the galaxy. Credit: NASA/Swift Swift's Ultraviolet/Optical Telescope imaged the kilonova produced by merging neutron stars in the galaxy NGC 4993 (box) on Aug. 18, 2017. The source was unexpectedly bright in ultraviolet light. This false-color composite combines images taken through three ultraviolet filters. Inset: A magnified view of the galaxy. No Labels.Credit: NASA/Swift The kilonova's ultraviolet light had faded completely when Swift observed the source on Aug. 29, 2017. This false-color composite combines images taken through three ultraviolet filters. Inset: A magnified view of the galaxy. Credit: NASA/Swift The kilonova's ultraviolet light had faded completely when Swift observed the source on Aug. 29, 2017. This false-color composite combines images taken through three ultraviolet filters. Inset: A magnified view of the galaxy. No Labels. Credit: NASA/Swift The kilonova associated with GW170817 (box) was observed by NASA's Hubble Space Telescope and Chandra X-ray Observatory. Hubble detected optical and infrared light from the hot expanding debris. The merging neutron stars produced gravitational waves and launched jets that produced a gamma-ray burst. Nine days later, Chandra detected the X-ray afterglow emitted by the jet directed toward Earth after it had spread into our line of sight. Credit: NASA/CXC/E. Troja On Aug. 26, 2017, NASA's Chandra X-ray Observatory first detected X-rays from the source of the neutron star collision known as GW170817. Earlier observations did not see X-ray emission. The crash produced jets that immediately emitted a gamma-ray burst and continued on into space. Nine days later, Chandra detected the X-ray afterglow emitted by the jet directed toward Earth after it had spread into our line of sight. Labels. Credit: NASA/CXC/E. Troja On Aug. 26, 2017, NASA's Chandra X-ray Observatory first detected X-rays from the source of the neutron star collision known as GW170817. Earlier observations did not see X-ray emission. The crash produced jets that immediately emitted a gamma-ray burst and continued on into space. Nine days later, Chandra detected the X-ray afterglow emitted by the jet directed toward Earth after it had spread into our line of sight. Credit: NASA/CXC/E. Troja The first sign of the Aug. 17, 2017, neutron star merger was a brief burst of gamma-rays seen by NASA's Fermi Gamma-ray Space Telescope (top). Shortly after, LIGO scientists reported detecting gravitational waves that arrived 1.7 seconds before the Fermi burst (middle). A short time later, scientists analyzing gamma-ray data from the European Space Agency's INTEGRAL spacecraft also reported seeing the burst (bottom). Credit: NASA's Goddard Space Flight Center, Caltech/MIT/LIGO Lab and ESA The first sign of the Aug. 17, 2017, neutron star merger was a brief burst of gamma-rays seen by NASA's Fermi Gamma-ray Space Telescope (top). Shortly after, LIGO scientists reported detecting gravitational waves that arrived 1.7 seconds before the Fermi burst (middle). A short time later, scientists analyzing gamma-ray data from the European Space Agency's INTEGRAL spacecraft also reported seeing the burst (bottom). With reporting time labels.Credit: NASA's Goddard Space Flight Center, Caltech/MIT/LIGO Lab and ESA On Aug. 17, 2017, gravitational waves from a neutron star merger produced a signal detected by LIGO. 1.7 seconds later, a brief burst of gamma-rays was seen by NASA's Fermi Gamma-ray Space Telescope (top). This video contains the actual sound of the LIGO detection. Credit: NASA's Goddard Space Flight Center, Caltech/MIT/LIGO Lab Gamma-ray bursts come from jets moving near the speed of light. How bright the burst appears depends on how we view the jet — brightest when we look straight directly down the barrel and dimmer at wider angles. This is a likely explanation for the faintness of the gamma-ray burst associated with GW170817. Since it was one-tenth as far away as similar bursts at known distances, if we viewed directly into the jet it would have appeared much brighter.Credit: NASA's Goddard Space Flight Center Additional still from animation. Doomed neutron stars whirl toward their demise in this illustration. Gravitational waves (pale arcs) bleed away orbital energy, causing the stars to move closer together and merge. Credit: NASA's Goddard Space Flight Center/CI Lab Additional still from animation. As neutron stars collide, some of the debris blasts away in particle jets moving at nearly the speed of light, producing a brief burst of gamma rays. Credit: NASA's Goddard Space Flight Center/CI Lab Additional still from animation. This illustration shows the hot, dense, expanding cloud of debris stripped from the neutron stars just before they collided. This cloud produces the kilonova's visible and infrared light. Within this neutron-rich debris, large quantities of some of the universe's heaviest elements were forged, including hundreds of Earth masses of gold and platinum. Credit: NASA's Goddard Space Flight Center/CI Lab Additional still from animation. After the neutron stars merged, the remains of the jets that produced the gamma-ray burst continue expanding into space, as shown in this illustration. After nine days, the jet directed toward us had spread laterally enough that observers could detect its X-ray emission.Credit: NASA's Goddard Space Flight Center/CI Lab For the first time, NASA scientists have detected light tied to a gravitational-wave event, thanks to two merging neutron stars in the galaxy NGC 4993, located about 130 million light-years from Earth in the constellation Hydra. Shortly after 8:41 a.m. EDT on Aug. 17, NASA's Fermi Gamma-ray Space Telescope picked up a pulse of high-energy light from a powerful explosion, which was immediately reported to astronomers around the globe as a short gamma-ray burst. The scientists at the National Science Foundation’s Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves dubbed GW170817 from a pair of smashing stars tied to the gamma-ray burst, encouraging astronomers to look for the aftermath of the explosion. Shortly thereafter, the burst was detected as part of a follow-up analysis by ESA’s (European Space Agency’s) INTEGRAL satellite.NASA's Swift, Hubble, Chandra and Spitzer missions, along with dozens of ground-based observatories, including the NASA-funded Pan-STARRS survey, later captured the fading glow of the blast's expanding debris. Neutron stars are the crushed, leftover cores of massive stars that previously exploded as supernovas long ago. The merging stars likely had masses between 10 and 60 percent greater than that of our Sun, but they were no wider than Washington, D.C. The pair whirled around each other hundreds of times a second, producing gravitational waves at the same frequency. As they drew closer and orbited faster, the stars eventually broke apart and merged, producing both a gamma-ray burst and a rarely seen flare-up called a "kilonova."Neutron star mergers produce a wide variety of light because the objects form a maelstrom of hot debris when they collide. Merging black holes -- the types of events LIGO and its European counterpart, Virgo, have previously seen -- very likely consume any matter around them long before they crash, so we don't expect the same kind of light show.Within hours of the initial Fermi detection, LIGO and the Virgo detector at the European Gravitational Observatory near Pisa, Italy, greatly refined the event's position in the sky with additional analysis of gravitational wave data. Ground-based observatories then quickly located a new optical and infrared source -- the kilonova -- in NGC 4993. To Fermi, this appeared to be a typical short gamma-ray burst, but it occurred less than one-tenth as far away as any other short burst with a known distance, making it among the faintest known. Astronomers are still trying to figure out why this burst is so odd, and how this event relates to the more luminous gamma-ray bursts seen at much greater distances. NASA’s Swift, Hubble and Spitzer missions followed the evolution of the kilonova to better understand the composition of this slower-moving material, while Chandra searched for X-rays associated with the remains of the ultra-fast jet. For More InformationSee [https://www.nasa.gov/press-release/nasa-missions-catch-first-light-from-a-gravitational-wave-event](https://www.nasa.gov/press-release/nasa-missions-catch-first-light-from-a-gravitational-wave-event) Related pages

This video introduces a new computer simulation exploring the connection between two of the most elusive phenomena in the universe, black holes and dark matter. In the visualization, dark matter particles are gray spheres attached to shaded trails representing their motion. Redder trails indicate particles more strongly affected by the black hole's gravitation and closer to its event horizon (black sphere at center, mostly hidden by trails). The ergosphere, where all matter and light must follow the black hole's spin, is shown in teal. Watch this video on the NASA Goddard YouTube channel.Credit: NASA's Goddard Space Flight CenterFor complete transcript, click here. The image layers multiple frames from the visualization to increase the number of dark matter particles. The particles are shown as gray spheres attached to shaded trails representing their motion. Redder trails indicate particles more strongly affected by the black hole's gravitation and closer to its event horizon (black sphere at center, mostly hidden by trails). The ergosphere, where all matter and light must follow the black hole's spin, is shown in teal. Credit: NASA Goddard Scientific Visualization Studio This image shows the gamma-ray signal produced in the computer simulation by annihilations of dark matter particles. Lighter colors indicate higher energies. The highest-energy gamma rays originate from the center of the crescent-shaped region at left, closest to the black hole's equator and event horizon. The gamma rays with the greatest chances of escape are produced on the side of the black hole that spins toward us. Such lopsided emission is typical for a rotating black hole.Credit: NASA Goddard/Jeremy Schnittman Same as above but aligned with the visualization image below.Credit: NASA Goddard/Jeremy Schnittman A single frame of the visulization previously described. The image is registered with the simulated gamma-ray image above. Credit: NASA Goddard Scientific Visualization Studio A new computer simulation tracking dark matter particles in the extreme gravity of a black hole shows that strong, potentially observable gamma-ray light can be produced. Detecting this emission would provide astronomers with a new tool for understanding both black holes and the nature of dark matter, an elusive substance accounting for most of the mass of the universe that neither reflects, absorbs nor emits light. Jeremy Schnittman, an astrophysicist at NASA's Goddard Space Flight Center, developed a computer simulation to follow the orbits of hundreds of millions of dark matter particles, as well as the gamma rays produced when they collide, in the vicinity of a black hole. He found that some gamma rays escaped with energies far exceeding what had been previously regarded as theoretical limits. In the simulation, dark matter takes the form of Weakly Interacting Massive Particles, or WIMPS, now widely regarded as the leading candidate class. In this model, WIMPs that crash into other WIMPs mutually annihilate and convert into gamma rays, the most energetic form of light. But these collisions are extremely rare under normal circumstances. Over the past few years, theorists have turned to black holes as dark matter concentrators, where WIMPs can be forced together in a way that increases both the rate and energies of collisions. The concept is a variant of the Penrose process, first identified in 1969 by British astrophysicist Sir Roger Penrose as a mechanism for extracting energy from a spinning black hole. The faster it spins, the greater the potential energy gain.In this process, all of the action takes place outside the black hole's event horizon, the boundary beyond which nothing can escape, in a flattened region called the ergosphere. Within the ergosphere, the black hole's rotation drags space-time along with it and everything is forced to move in the same direction at nearly speed of light. This creates a natural laboratory more extreme than any possible on Earth. Previous work indicated that the maximum gamma-ray energy from the collisional version of the Penrose process was only about 1.3 times the rest mass of the annihilating particles. In addition, only a small portion of high-energy gamma rays managed to escape the ergosphere. These results suggested that a conclusive annihilation signal might never be seen from a supermassive black hole. However, earlier work made simplifying assumptions about the locations of the highest-energy collisions. Schnittman's model instead tracks the positions and properties of hundreds of millions of randomly distributed particles as they collide and annihilate near a black hole. The new model reveals processes that produce gamma rays with much higher energies, as well as a better likelihood of escape and detection, than ever thought possible. He identified previously unrecognized trajectories where collisions produce gamma rays with a peak energy 14 times the rest mass of the annihilating particles. The simulation tells astronomers that there is an astrophysically interesting signal they may be able to detect as gamma-ray telescopes improve. For More InformationSee [http://www.nasa.gov/feature/nasa-simulation-suggests-black-holes-may-make-ideal-dark-matter-labs](http://www.nasa.gov/feature/nasa-simulation-suggests-black-holes-may-make-ideal-dark-matter-labs) Related pages

This animation of supercomputer data takes you to the inner zone of the accretion disk of a stellar-mass black hole. Gas heated to 20 million degrees F as it spirals toward the black hole glows in low-energy, or soft, X-rays. Just before the gas plunges to the center, its orbital motion is approaching the speed of light. X-rays up to hundreds of times more powerful ("harder") than those in the disk arise from the corona, a region of tenuous and much hotter gas around the disk. Coronal temperatures reach billions of degrees. The event horizon is the boundary where all trajectories, including those of light, must go inward. Nothing, not even light, can pass outward across the event horizon and escape the black hole.Music: "Lost in Space" by Lars Leonhard, courtesy of artist.For complete transcript, click here. This animation of supercomputer data shows low-energy (soft) X-ray emission from the inner accretion disk of a stellar-mass black hole. Infalling gas is compressed and heated to millions of degrees as it swirls toward the inner edge of the disk, where the orbital speed approaches the speed of light. Magnetic fields threading through the gas are dramatically amplified. They affect the motion of the ionized gas, resulting in complex, turbulent motion. The left side of the disk appears brighter than the right because the energy of light emitted by gas approaching us (left) is increased by the Doppler shift, while the energy of light emitted in gas moving away from us (right) is decreased. We view the scene from a perspective 45 degrees above the accretion disk.Credit: NASA's Goddard Space Flight Center/J. Schnittman, J. Krolik (JHU) and S. Noble (RIT) This animation of supercomputer data shows high-energy (hard) X-rays radiated from the corona region above the accretion disk of a stellar-mass black hole. The corona is a tenuous gas above and below the disk with temperatures reaching billions of degrees. The contrast between the left and right sides of the image, caused by the Doppler shift, is much less pronounced than in the disk movie. This is because the random motions of particles in the corona are as fast as their orbital speed, which reduces the contrast. Particles in the corona scatter soft X-rays from the disk and give them an energy boost, resulting in hard X-ray emission. We view the corona from a perspective 45 degrees above the plane of the accretion disk.Credit: NASA's Goddard Space Flight Center/J. Schnittman, J. Krolik (JHU) and S. Noble (RIT) This animation of supercomputer data shows both low-energy X-rays (red) from the inner accretion disk and high-energy X-rays (blue) from the inner corona of a stellar-mass black hole. Particles in the corona scatter soft X-rays from the disk and give them an energy boost, resulting in hard X-ray emission. We view the scene from a perspective 45 degrees above the plane of the accretion disk.Credit: NASA's Goddard Space Flight Center/J. Schnittman, J. Krolik (JHU) and S. Noble (RIT) This annotated image labels several features in the simulation, including the event horizon of the black hole. This illustration shows the approximate relationships between the black hole, its accretion disk (red), and the viewpoint and field of view of the simulation. This illustration shows the paths of soft X-rays (arrows) from the underside of the accretion disk that form rings seen near the black hole in the simulation. This illustration shows the approximate relationships between the black hole, its accretion disk and the corona region (blue). The arrows show a soft X-ray (red) traveling into the corona and striking a particle moving near the speed of light. The collision scatters the light and boosts it to much higher energy, making it a hard X-ray. This process is known as inverse Compton scattering. This animation illustrates inverse Compton scattering. In the corona region above a black hole's accretion disk, electrons and other particles move at appreciable fractions of the speed of light. When a low-energy X-ray (red) from the disk travels through this region, it may collide with one of the fast-moving particles (in this case, an electron). The impact scatters the light while simultaneously boosting its energy into the hard X-ray (blue) regime. A new study by astronomers at NASA, Johns Hopkins University and the Rochester Institute of Technology confirms long-held suspicions about how stellar-mass black holes produce their highest-energy light. By analyzing a supercomputer simulation of gas flowing into a black hole, the team finds they can reproduce a range of important X-ray features long observed in active black holes. Jeremy Schnittman, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md., led the research.Black holes are the densest objects known. Stellar black holes form when massive stars run out of fuel and collapse, crushing up to 20 times the sun's mass into compact objects less than 75 miles (120 kilometers) wide. Gas falling toward a black hole initially orbits around it and then accumulates into a flattened disk. The gas stored in this disk gradually spirals inward and becomes greatly compressed and heated as it nears the center, ultimately reaching temperatures up to 20 million degrees Fahrenheit (12 million C), or some 2,000 times hotter than the sun's surface. It glows brightly in low-energy, or soft, X-rays.For more than 40 years, however, observations show that black holes also produce considerable amounts of "hard" X-rays, light with energy tens to hundreds of times greater than soft X-rays. This higher-energy light implies the presence of correspondingly hotter gas, with temperatures reaching billions of degrees. The new study involves a detailed computer simulation that simultaneously tracked the fluid, electrical and magnetic properties of the gas while also taking into account Einstein's theory of relativity. Using this data, the scientists developed tools to track how X-rays were emitted, absorbed, and scattered in and around the disk. The study demonstrates for the first time a direct connection between magnetic turbulence in the disk, the formation of a billion-degree corona above and below the disk, and the production of hard X-rays around an actively "feeding" black hole.Watch this video on YouTube. For More InformationSee [http://www.nasa.gov/topics/universe/features/black-hole-study.html](http://www.nasa.gov/topics/universe/features/black-hole-study.html) Related pages

Artist's interpretation of Swift J1745-26, a newly discovered black hole with a flaring accretion disk. Additional still from animation An X-ray nova is a short-lived X-ray source that appears suddenly, reaches its emission peak in a few days and then fades out over a period of months. The outburst arises when a torrent of stored gas suddenly rushes toward one of the most compact objects known, either a neutron star or a black hole. Related pages