Neil Gehrels Swift Observatory

NASA's Neil Gehrels Swift Observatory provides astronomers with a unique tool for exploring many different classes of astronomical phenomena, from gamma-ray bursts and supernovae to spinning neutron stars, outbursts from black holes, and even exoplanets, comets and asteroids. These pages gather together media products associated with Swift news releases.

For more information about the Swift mission, visit its NASA webpage.

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  • Newly Renamed Swift Mission Catches a Comet Slowdown
    2018.01.10
    Observations by NASA's Swift spacecraft, now renamed the Neil Gehrels Swift Observatory after the mission’s late principal investigator, have captured an unprecedented change in the rotation of a comet. Images taken in May 2017 reveal that comet 41P/Tuttle-Giacobini-Kresák — 41P for short — was spinning three times slower than it was in March, when it was observed by the Discovery Channel Telescope at Lowell Observatory in Arizona. The abrupt slowdown is the most dramatic change in a comet's rotation ever seen. Comet 41P orbits the Sun every 5.4 years. As a comet nears the Sun, increased heating causes its surface ice to change directly to a gas, producing jets that launch dust particles and icy grains into space. This material forms an extended atmosphere, called a coma. Ground-based observations established the 41P’s initial rotational period at about 20 hours in early March 2017 and detected its slowdown later the same month. The comet passed 13.2 million miles (21.2 million km) from Earth on April 1, and eight days later made its closest approach to the Sun. Swift's Ultraviolet/Optical Telescope imaged the comet from May 7 to 9, revealing brightness variations associated with material recently ejected into the coma. These slow changes indicated 41P's rotation period had more than doubled, to between 46 and 60 hours. UVOT-based estimates of 41P's water production, coupled with the body's small size, suggest that more than half of its surface area contains sunlight-activated jets. That's a far greater fraction of active real estate than on most comets, which typically support jets over only about 3 percent of their surfaces. Astronomers suspect these active areas are favorably oriented to produce torques that slowed 41P’s spin. Such a slow spin could make the comet's rotation unstable, allowing it to begin tumbling with no fixed rotational axis. This would produce a dramatic change in the comet’s seasonal heating and may result in future outbursts of activity.
  • NASA's Kepler, Swift Missions Harvest ‘Pumpkin’ Stars
    2016.10.27
    Astronomers using observations from NASA's Kepler and Swift missions have discovered a group of rapidly spinning stars that produce X-rays at more than 100 times the peak levels ever seen from the sun. The stars, which spin so fast they've been squashed into pumpkin-like shapes, are thought to be the result of close binary systems where two sun-like stars merge. The 18 stars rotate in just a few days, on average, compared to the sun's nearly one month rotation. Their rapid rotation greatly amplifies the same kind of activity we see on the sun, such as sunspots and solar flares, resulting in enhanced X-ray output. The most extreme member of the group, a K-type orange giant dubbed KSw 71, is more than 10 times larger than the sun, rotates in just 5.5 days, and produces X-ray emission 4,000 times greater than the sun does at solar maximum. These rare stars were found as part of an X-ray survey of the original Kepler field of view. From 2009 to 2013, Kepler measured the brightness of more than 150,000 stars in a single patch of the sky to detect the regular dimming from planets passing in front of their host stars. The mission was immensely successful and continues on as the K2 mission, studying other parts of the sky. Because the original field has been studied so well by Kepler and other missions, it is now one of the best-known parts of the sky. Astronomers decided to observe portions of the field using the X-ray and ultraviolet/optical telescopes on Swift to find X-ray sources that Kepler may have observed in visible light. The Kepler-Swift Active Galaxies and Stars Survey (KSwAGS) found 93 sources, half of which are active galaxies, where a central black hole drives the emissions. The other half are various types of X-ray stars, including the 18 "pumpkin" stars. Forty years ago, Ronald Webbink at the University of Illinois, Urbana-Champaign noted that close binary systems cannot survive once the fuel supply of one star dwindles and it starts to enlarge. The stars coalesce to form a single rapidly spinning star initially residing in a so-called "excretion" disk formed by gas thrown out during the merger. The disk dissipates over the next 100 million years, leaving behind a very active, rapidly spinning star. The KSwAGS pumpkin stars are thought to have shed their disks recently, which means Kepler and Swift have caught them at the end of a very brief evolutionary phase.
  • X-ray Echoes Map a 'Killer' Black Hole
    2016.06.22
    Some 3.9 billion years ago in the heart of a distant galaxy, the tidal pull of a monster black hole shredded a star that wanderd too close. X-rays produced in this event first reached Earth on March 28, 2011, when they were detected by NASA's Swift satellite. Within days, scientists concluded that the outburst, now known as Swift J1644+57, represented both the tidal disruption of a star and the sudden flare-up of a previously inactive black hole. Now astronomers using archival observations from Swift, the European Space Agency's XMM-Newton observatory and the Japan-led Suzaku satellite have identified the reflections of X-ray flares erupting during the event. Led by Erin Kara, a postdoctoral researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland, College Park, the team has used these light echoes, or reverberations, to map the flow of gas near a newly awakened black hole for the first time. Swift J1644+57 is one of only three tidal disruptions that have produced high-energy X-rays, and to date it remains the only event caught at the peak of this emission. While astronomers don't yet understand what causes flares near the black hole, when one occurs they can detect its echo a couple of minutes later as its light washes over structures in the developing accretion disk. The technique, called X-ray reverberation mapping, has been used before to explore stable disks around black holes, but this is time it has been applied to a newly formed disk produced by a tidal disruption. Swift J1644+57's accretion disk was thicker, more turbulent and more chaotic than stable disks, which have had time to settle down into an orderly routine. One surprise is that high-energy X-rays arise from the innermost regions of the disk instead of a narrow jet of accelerated particles, as originally thought. The researchers estimate the black hole has a mass about a million times that of the sun. They expect future improvements in understanding and modeling accretion flows will allow them to measure the black hole's spin using this data.
  • Massive Black Hole Shreds Passing Star
    2015.10.21
    This artist’s rendering illustrates new findings about a star shredded by a black hole. When a star wanders too close to a black hole, intense tidal forces rip the star apart. In these events, called “tidal disruptions,” some of the stellar debris is flung outward at high speed while the rest falls toward the black hole. This causes a distinct X-ray flare that can last for a few years. NASA’s Chandra X-ray Observatory, Swift Gamma-ray Burst Explorer, and ESA/NASA’s XMM-Newton collected different pieces of this astronomical puzzle in a tidal disruption event called ASASSN-14li, which was found in an optical search by the All-Sky Automated Survey for Supernovae (ASAS-SN) in November 2014. The event occurred near a supermassive black hole estimated to weigh a few million times the mass of the sun in the center of PGC 043234, a galaxy that lies about 290 million light-years away. Astronomers hope to find more events like ASASSN-14li to test theoretical models about how black holes affect their environments.
  • NASA Missions Take an Unparalleled Look into Superstar Eta Carinae
    2015.01.07
    Eta Carinae is a binary system containing the most luminous and massive star within 10,000 light-years. A long-term study led by astronomers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, combined data from NASA satellites, ground-based observing campaigns and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars' interactions. Located about 7,500 light-years away in the southern constellation of Carina, Eta Carinae comprises two massive stars whose eccentric orbits bring them unusually close every 5.5 years. Both produce powerful gaseous outflows called stellar winds, which enshroud the stars and stymy efforts to directly measure their properties. Astronomers have established that the brighter, cooler primary star has about 90 times the mass of the sun and outshines it by 5 million times. While the properties of its smaller, hotter companion are more contested, Goddard's Ted Gull and his colleagues think the star has about 30 solar masses and emits a million times the sun's light. At closest approach, or periastron, the stars are 140 million miles (225 million kilometers) apart, or about the average distance between Mars and the sun. Astronomers observe dramatic changes in the system during the months before and after periastron. These include X-ray flares, followed by a sudden decline and eventual recovery of X-ray emission; the disappearance and re-emergence of structures near the stars detected at specific wavelengths of visible light; and even a play of light and shadow as the smaller star swings around the primary. During the past 11 years, spanning three periastron passages, the Goddard group has developed a model based on routine observations of the stars using ground-based telescopes and multiple NASA satellites. According to this model, the interaction of the two stellar winds accounts for many of the periodic changes observed in the system. The winds from each star have markedly different properties: thick and slow for the primary, lean and fast for the hotter companion. The primary's wind blows at nearly 1 million mph and is especially dense, carrying away the equivalent mass of our sun every thousand years. By contrast, the companion's wind carries off about 100 times less material than the primary's, but it races outward as much as six times faster. The images and videos on this page include periastron observations from NASA's Rossi X-ray Timing Explorer, the X-Ray Telescope aboard NASA's Swift, the Hubble Space Telescope's STIS instrument, and computer simulations. See the captions for details.
  • Swift: A Decade of Game-Changing Astrophysics
    2014.11.20
    Over the past decade, NASA's Swift Gamma-ray Burst Explorer has proven itself to be one of the most versatile astrophysics missions ever flown. It remains the only satellite capable of precisely locating gamma-ray bursts -- the universe's most powerful explosions -- and monitoring them across a broad range of wavelengths using multiple instruments before they fade from view. "Swift" isn't just a name -- it's a core capability, a part of the spacecraft's DNA. Gamma-ray bursts (GRBs) typically last less than a minute and Swift detects one event about twice a week. Once Swift observes a GRB, it automatically determines the blast's location, broadcasts the position to the astronomical community, and then turns toward the site to investigate with its own sensitive telescopes. In addition to its studies of GRBs, Swift conducts a wide array of observations of other astrophysical phenomena. A flexible planning system enables astronomers to request Swift "target-of-opportunity" (TOO) observations, which can be commanded from the ground in as little as 10 minutes, or set up monitoring programs to observe specific sources at time intervals ranging from minutes to months. The system can schedule up to 75 independent targets a day. Earlier this year, Swift ranked highly in NASA's 2014 Senior Review of Operating Missions and will continue its enormously productive scientific work through at least 2016.
  • Swift Catches Mega Flares from a Mini Star
    2014.09.30
    On April 23, NASA's Swift satellite detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a nearby red dwarf star. The initial blast from this record-setting series of explosions was as much as 10,000 times more powerful than the largest solar flare ever recorded. At its peak, the flare reached temperatures of 360 million degrees Fahrenheit (200 million Celsius), more than 12 times hotter than the center of the sun. The "superflare" came from one of the stars in a close binary system known as DG Canum Venaticorum, or DG CVn for short, located about 60 light-years away. Both stars are dim red dwarfs with masses and sizes about one-third of our sun's. They orbit each other at about three times Earth's average distance from the sun, which is too close for Swift to determine which star erupted. At 5:07 p.m. EDT on April 23, the rising tide of X-rays from DG CVn's superflare triggered Swift's Burst Alert Telescope (BAT). Swift turned to observe the source in greater detail with other instruments and, at the same time, notified astronomers around the globe that a powerful outburst was in progress. For about three minutes after the BAT trigger, the superflare's X-ray brightness was greater than the combined luminosity of both stars at all wavelengths under normal conditions. The largest solar explosions are classified as extraordinary, or X class, solar flares based on their X-ray emission. The biggest flare ever seen from the sun occurred in November 2003 and is rated as X 45. But if the flare on DG CVn were viewed from a planet the same distance as Earth is from the sun and measured the same way, it would have been ranked 10,000 times greater, at about X 100,000. How can a star just a third the size of the sun produce such a giant eruption? The key factor is its rapid spin, a crucial ingredient for amplifying magnetic fields. The flaring star in DG CVn rotates in under a day, about 30 or more times faster than our sun. The sun also rotated much faster in its youth and may well have produced superflares of its own, but, fortunately for us, it no longer appears capable of doing so.
  • Neutron Stars Rip Each Other Apart to Form Black Hole
    2014.05.13
    This supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars colliding, merging and forming a black hole. A neutron star is the compressed core left behind when a star born with between eight and 30 times the sun's mass explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun — equivalent to about half a million Earths — into a ball just 12 miles (20 km) across. As the simulation begins, we view an unequally matched pair of neutron stars weighing 1.4 and 1.7 solar masses. They are separated by only about 11 miles, slightly less distance than their own diameters. Redder colors show regions of progressively lower density. As the stars spiral toward each other, intense tides begin to deform them, possibly cracking their crusts. Neutron stars possess incredible density, but their surfaces are comparatively thin, with densities about a million times greater than gold. Their interiors crush matter to a much greater degree densities rise by 100 million times in their centers. To begin to imagine such mind-boggling densities, consider that a cubic centimeter of neutron star matter outweighs Mount Everest. By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole's event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun. The entire simulation covers only 20 milliseconds. Scientists think neutron star mergers like this produce short gamma-ray bursts (GRBs). Short GRBs last less than two seconds yet unleash as much energy as all the stars in our galaxy produce over one year. The rapidly fading afterglow of these explosions presents a challenge to astronomers. A key element in understanding GRBs is getting instruments on large ground-based telescopes to capture afterglows as soon as possible after the burst. The rapid notification and accurate positions provided by NASA's Swift mission creates a vibrant synergy with ground-based observatories that has led to dramatically improved understanding of GRBs, especially for short bursts.
  • A Trio of Swift Bursts Form A New Class of GRBs
    2013.04.16
    Three unusually long-lasting stellar explosions discovered by NASA's Swift satellite represent a previously unrecognized class of gamma-ray bursts (GRBs). Two international teams of astronomers studying these events conclude that they likely arose from the catastrophic death of supergiant stars hundreds of times larger than the sun.

    GRBs are the most luminous and mysterious explosions in the universe. The blasts emit surges of gamma rays — the most powerful form of light — as well as X-rays, and they produce afterglows that can be observed at optical and radio energies. Swift, Fermi and other spacecraft detect an average of about one GRB each day.

    Traditionally, astronomers have recognized two GRB types, short and long, based on the duration of the gamma-ray signal. Short bursts last two seconds or less and are thought to represent a merger of compact objects in a binary system, with the most likely suspects being neutron stars and black holes. Long GRBs may last anywhere from several seconds to several minutes, with typical durations falling between 20 and 50 seconds. These events are thought to be associated with the collapse of a star several times the sun's mass and the resulting birth of a new black hole.

    Both scenarios give rise to powerful jets that propel matter at nearly the speed of light in opposite directions. As they interact with matter in and around the star, the jets produce a spike of high-energy light.

    A detailed study of GRB 111209A, which erupted on Dec. 9, 2011, and continued to produce high-energy emission for an astonishing seven hours, making it by far the longest-duration GRB ever recorded.

    Another event, GRB 101225A, exploded on Christmas Day in 2010 and produced high-energy emission for at least two hours. Subsequently nicknamed the "Christmas burst," the event's distance was unknown, which led two teams to arrive at radically different physical interpretations. One group concluded the blast was caused by an asteroid or comet falling onto a neutron star within our own galaxy. Another team determined that the burst was the outcome of a merger event in an exotic binary system located some 3.5 billion light-years away.

    Using the Gemini North Telescope in Hawaii, a team led by Andrew Levan at the University of Warwick in Coventry, England, obtained a spectrum of the faint galaxy that hosted the Christmas burst. This enabled the scientists to identify emission lines of oxygen and hydrogen and determine how much these lines were displaced to lower energies compared to their appearance in a laboratory. This difference, known to astronomers as a redshift, places the burst some 7 billion light-years away.

    Levan and his colleagues also examined 111209A and the more recent burst 121027A, which exploded on Oct. 27, 2012. All show similar X-ray, ultraviolet and optical emission and all arose from the central regions of compact galaxies that were actively forming stars. The astronomers conclude that all three GRBs constitute a hitherto unrecognized group of "ultra-long" bursts.

    To account for the normal class of long GRBs, astronomers envision a star similar to the size sun's size but with many times its mass. The mass must be high enough for the star to undergo an energy crisis, with its core ultimately running out of fuel and collapsing under its own weight to form a black hole. Some of the matter falling onto the nascent black hole becomes redirected into powerful jets that drill through the star, creating the gamma-ray spike, but because this burst is short-lived, the star must be comparatively small.

    Because ultra-long GRBs persist for periods up to 100 times greater than long GRBs, they require a stellar source of correspondingly greater physical size. Both groups suggest that the likely candidate is a supergiant, a star with about 20 times the sun's mass that still retains its deep hydrogen atmosphere, making it hundreds of times the sun's diameter.

  • X-ray Satellites Monitor the Clashing Winds of a Colossal Binary
    2012.10.12
    One of the nearest and richest OB associations in our galaxy is Cygnus OB2, which is located about 4,700 light-years away and hosts some 3,000 hot stars, including about 100 in the O class. Weighing in at more than a dozen times the sun's mass and sporting surface temperatures five to ten times hotter, these ginormous blue-white stars blast their surroundings with intense ultraviolet light and powerful outflows called stellar winds.

    Two of these stars can be found in the intriguing binary system known as Cygnus OB2 #9. In 2011, NASA's Swift satellite, the European Space Agency's XMM-Newton observatory and several ground-based facilities took part in a campaign to monitor the system as the giant stars raced toward their closest approach. The observations are giving astronomers a more detailed picture of the stars, their orbits and the interaction of their stellar winds.

    An O-type star is so luminous that the pressure of its starlight actually drives material from its surface, creating particle outflows with speeds of several million miles an hour. Put two of these humongous stars in the same system and their winds can collide during all or part of the orbit, creating both radio emission and X-rays.

    In 2008, research showed that Cygnus OB2 #9 emitted radio signals that varied every 2.355 years. In parallel, Yael Naz

  • X-Ray Nova Reveals a New Black Hole in Our Galaxy
    2012.10.05
    On Sept. 16, NASA's Swift satellite detected a rising tide of high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, announced the presence of a previously unknown stellar-mass black hole.

    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.

    Named Swift J1745-26 after the coordinates of its sky position, the nova is located a few degrees from the center of our galaxy toward the constellation Sagittarius. While astronomers do not know its precise distance, they think the object resides about 20,000 to 30,000 light-years away in the galaxy's inner region. The pattern of X-rays from the nova signals that the central object is a black hole.

    Ground-based observatories detected infrared and radio emissions, but thick clouds of obscuring dust have prevented astronomers from catching Swift J1745-26 in visible light.

    The black hole must be a member of a low-mass X-ray binary (LMXB) system, which includes a normal, sun-like star. A stream of gas flows from the normal star and enters into a storage disk around the black hole. In most LMXBs, the gas in the disk spirals inward, heats up as it heads toward the black hole, and produces a steady stream of X-rays.

    But under certain conditions, stable flow within the disk depends on the rate of matter flowing into it from the companion star. At certain rates, the disk fails to maintain a steady internal flow and instead flips between two dramatically different conditions — a cooler, less ionized state where gas simply collects in the outer portion of the disk like water behind a dam, and a hotter, more ionized state that sends a tidal wave of gas surging toward the center.

    This phenomenon, called the thermal-viscous limit cycle, helps astronomers explain transient outbursts across a wide range of systems, from protoplanetary disks around young stars, to dwarf novae - where the central object is a white dwarf star - and even bright emission from supermassive black holes in the hearts of distant galaxies.

  • Hubble, Swift Detect First-ever Changes in an Exoplanet Atmosphere
    2012.06.28
    An international team of astronomers using data from NASA's Hubble Space Telescope has detected significant changes in the atmosphere of a planet located beyond our solar system. The scientists conclude the atmospheric variations occurred in response to a powerful eruption on the planet's host star, an event observed by NASA's Swift satellite.

    The exoplanet is HD 189733b, a gas giant similar to Jupiter, but about 14 percent larger and more massive. The planet circles its star at a distance of only 3 million miles, or about 30 times closer than Earth's distance from the sun, and completes an orbit every 2.2 days. Its star, named HD 189733A, is about 80 percent the size and mass of our sun.

    Astronomers classify the planet as a "hot Jupiter." Previous Hubble observations show that the planet's deep atmosphere reaches a temperature of about 1,900 degrees Fahrenheit (1,030 C).

    HD 189733b periodically passes across, or transits, its parent star, and these events give astronomers an opportunity to probe its atmosphere and environment. In a previous study, a group led by Lecavelier des Etangs used Hubble to show that hydrogen gas was escaping from the planet's upper atmosphere. The finding made HD 189733b only the second-known "evaporating" exoplanet at the time.

    The system is just 63 light-years away, so close that its star can be seen with binoculars near the famous Dumbbell Nebula. This makes HD 189733b an ideal target for studying the processes that drive atmospheric escape.

    When HD 189733b transits its star, some of the star's light passes through the planet's atmosphere. This interaction imprints information on the composition and motion of the planet's atmosphere into the star's light.

    In April 2010, the researchers observed a single transit using Hubble's Space Telescope Imaging Spectrograph (STIS), but they detected no trace of the planet's atmosphere. Follow-up STIS observations in September 2011 showed a surprising reversal, with striking evidence that a plume of gas was streaming away from the exoplanet.

    The researchers determined that at least 1,000 tons of gas was leaving the planet's atmosphere every second. The hydrogen atoms were racing away at speeds greater than 300,000 mph.

    Because X-rays and extreme ultraviolet starlight heat the planet's atmosphere and likely drive its escape, the team also monitored the star with Swift's X-ray Telescope (XRT). On Sept. 7, 2011, just eight hours before Hubble was scheduled to observe the transit, Swift was monitoring the star when it unleashed a powerful flare. It brightened by 3.6 times in X-rays, a spike occurring atop emission levels that already were greater than the sun's. Astronomers estimate that HD 189733b encountered about 3 million times as many X-rays as Earth receives from a solar flare at the threshold of the X class.

  • Swift Captures Flyby of Asteroid 2005 YU55
    2011.11.11
    As asteroid 2005 YU55 swept past Earth in the early morning hours of Wednesday, Nov. 9, telescopes aboard NASA's Swift satellite joined professional and amateur astronomers around the globe in monitoring the fast-moving space rock. The unique ultraviolet data will aid scientists in understanding the asteroid's surface composition.

    The challenge with 2005 YU55 was its rapid motion across the sky, which was much too fast for Swift to track. Instead, the team trained the spacecraft's optics at two locations along the asteroid's predicted path and let it streak through the field. The first exposure began a few hours after the asteroid's closest approach and fastest sky motion — near 9 p.m. EST on Nov. 8 — but failed to detect it.

    Six hours later, around 3 a.m. EST on Nov. 9, Swift began an exposure that captured the asteroid sweeping through the Great Square of the constellation Pegasus. The 11th- magnitude rock was then 333,000 miles away and moving at 24,300 mph, about an hour from its closest approach to the Moon.

    That exposure gave the Swift team more than a streak through the stars. "A novel feature of Swift is the ability to go into a mode tracking the arrival of every photon captured by the instrument. With that information, we can reconstruct the asteroid as a point source moving through the Ultraviolet/Optical Telescope's field of view," said Neil Gehrels, lead scientist for Swift at NASA's Goddard Space Flight Center in Greenbelt, Md.

    The 27-minute-long image was effectively sliced into short 10-second-long exposures, which then were combined into a movie. This allows scientists to study short-term brightness variations caused by the object's rotation.

    The result is a movie of 2005 YU55 at ultraviolet wavelengths unobtainable from ground-based telescopes. For planetary scientists, this movie is a treasure trove of data that will help them better understand how this asteroid is put together, information that may help make predictions of its motion more secure for centuries to come.

    The press release on NASA.gov is here.

  • NASA's Swift Satellite Spots Black Hole Devouring A Star
    2011.08.24
    In late March 2011, NASA's Swift satellite alerted astronomers to intense and unusual high-energy flares from a new source in the constellation Draco. They soon realized that the source, which is now known as Swift J1644+57, was the result of a truly extraordinary event — the awakening of a distant galaxy's dormant black hole as it shredded and consumed a star. The galaxy is so far away that the radiation from the blast has traveled 3.9 billion years before reaching Earth.

    Most galaxies, including our own, possess a central supersized black hole weighing millions of times the sun's mass. According to the new studies, the black hole in the galaxy hosting Swift J1644+57 may be twice the mass of the four-million-solar-mass black hole lurking at the center of our own Milky Way galaxy. As a star falls toward a black hole, it is ripped apart by intense tides. The gas is corralled into a disk that swirls around the black hole and becomes rapidly heated to temperatures of millions of degrees.

    The innermost gas in the disk spirals toward the black hole, where rapid motion and magnetism creates dual, oppositely directed "funnels" through which some particles may escape. Particle jets driving matter at velocities greater than 80-90 percent the speed of light form along the black hole's spin axis. In the case of Swift J1644+57, one of these jets happened to point straight at Earth.

    Theoretical studies of tidally disrupted stars suggested that they would appear as flares at optical and ultraviolet energies. The brightness and energy of a black hole's jet is greatly enhanced when viewed head-on. The phenomenon, called relativistic beaming, explains why Swift J1644+57 was seen at X-ray energies and appeared so strikingly luminous.

    When first detected on March 28, the flares were initially assumed to signal a gamma-ray burst, one of the nearly daily short blasts of high-energy radiation often associated with the death of a massive star and the birth of a black hole in the distant universe. But as the emission continued to brighten and flare, astronomers realized that the most plausible explanation was the tidal disruption of a sun-like star seen as beamed emission.

  • Nearby Galaxy Boasts Two Monster Black Holes, Both Active
    2011.06.10
    A study using NASA's Swift satellite and the Chandra X-ray Observatory has found a second supersized black hole at the heart of an unusual nearby galaxy already known to be sporting one.

    The galaxy, which is known as Markarian 739 or NGC 3758, lies 425 million light-years away toward the constellation Leo. Only about 11,000 light-years separate the two cores, each of which contains a black hole gorging on infalling gas.

    Astronomers refer to galaxy centers exhibiting such intense emission as active galactic nuclei (AGN). Yet as common as monster black holes are, only about one percent of them are currently powerful AGN. Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years.

    Many scientists think that disruptive events like galaxy collisions trigger AGN to switch on by sending large amounts of gas toward the black hole. As the gas spirals inward, it becomes extremely hot and radiates huge amounts of energy.

  • Swift and Hubble Probe an Asteroid Crash
    2011.04.28
    Late last year, astronomers noticed that an asteroid named Scheila had unexpectedly brightened and it was sporting short-lived plumes. Data from NASA's Swift satellite and Hubble Space Telescope show that these changes likely occurred after Scheila was struck by a much smaller asteroid.

    On Dec. 11, 2010, images from the University of Arizona's Catalina Sky Survey, a project of NASA's Near Earth Object Observations Program, revealed the Scheila to be twice as bright as expected and immersed in a faint comet-like glow. Looking through the survey's archived images, astronomers inferred the outburst began between Nov. 11 and Dec. 3.

    Three days after the outburst was announced, Swift's Ultraviolet/Optical Telescope (UVOT) captured multiple images and a spectrum of the asteroid. Ultraviolet sunlight breaks up the gas molecules surrounding comets; water, for example, is transformed into hydroxyl (OH) and hydrogen (H). But none of the emissions most commonly identified in comets — such as hydroxyl or cyanogen (CN) — show up in the UVOT spectrum. The absence of gas around Scheila led the Swift team to reject scenarios where exposed ice accounted for the activity.

    Images show the asteroid was flanked in the north by a bright dust plume and in the south by a fainter one. The dual plumes formed as small dust particles excavated by the impact were pushed away from the asteroid by sunlight. Hubble observed the asteroid's fading dust cloud on Dec. 27, 2010, and Jan. 4, 2011.

    The two teams found the observations were best explained by a collision with a small asteroid impacting Scheila's surface at an angle of less than 30 degrees, leaving a crater 1,000 feet across. Laboratory experiments show a more direct strike probably wouldn't have produced two distinct dust plumes. The researchers estimated the crash ejected more than 660,000 tons of dust—equivalent to nearly twice the mass of the Empire State Building.

    For the collision animation go to #10759.

  • When Neutron Stars Collide
    2011.04.07
    Armed with state-of-the-art supercomputer models, scientists have shown that colliding neutron stars can produce the energetic jet required for a gamma-ray burst. Earlier simulations demonstrated that mergers could make black holes. Others had shown that the high-speed particle jets needed to make a gamma-ray burst would continue if placed in the swirling wreckage of a recent merger.

    Now, the simulations reveal the middle step of the process—how the merging stars' magnetic field organizes itself into outwardly directed components capable of forming a jet. The Damiana supercomputer at Germany's Max Planck Institute for Gravitational Physics needed six weeks to reveal the details of a process that unfolds in just 35 thousandths of a second—less than the blink of an eye.

    For the researchers' website, with more video and stills of their simulations, go here.

  • NASA's Swift Finds 'Missing' Active Galaxies
    2011.01.20
    Most large galaxies contain a giant central black hole. In an active galaxy, matter falling toward the supermassive black hole powers high-energy emissions so intense that two classes of active galaxies, quasars and blazars, rank as the most luminous objects in the universe. Thick clouds of dust and gas near the central black hole screens out ultraviolet, optical and low-energy (or soft) X-ray light. Although there are many different types of active galaxy, astronomers explain the different observed properties based on how the galaxy angles into our line of sight. We view the brightest ones nearly face on, but as the angle increases, the surrounding ring of gas and dust absorbs increasing amounts of the black hole's emissions.
  • A Flickering X-ray Candle
    2011.01.12
    The Crab Nebula, created by a supernova seen nearly a thousand years ago, is one of the sky's most famous "star wrecks." For decades, most astronomers have regarded it as the steadiest beacon at X-ray energies, but data from orbiting observatories show unexpected variations, showing astronomers their hard X-ray "standard candle" isn't as steady as they once thought. From 1999 to 2008, the Crab brightened and faded by as much as 3.5 percent a year, and since 2008, it has faded by 7 percent. The Gamma-ray Burst Monitor on NASA's Fermi satellite first detected the decline, and Fermi's Large Area Telescope also spotted two gamma-ray flares at even higher energies. Scientists think the X-rays reveal processes deep within the nebula, in a region powered by a rapidly spinning neutron star — the core of the star that blew up. But figuring out exactly where the Crab's X-rays are changing over the long term will require a new generation of X-ray telescopes.
  • Swift's 500 Gamma-ray Bursts
    2010.04.19
    On April 13, 2010, NASA's Swift Gamma-ray Burst Explorer satellite discovered its 500th burst. Swift's main job is to quickly localize each gamma-ray burst (GRB), report its position so that others can immediately conduct follow-up observations, and then study the burst using its X-ray and Ultraviolet/Optical telescopes. The plots and videos below illustrate Swift's first 500 GRBs.

    For more on the story, see the feature "NASA's Swift Catches 500th Gamma-ray Burst".

    This page has been updated with a new version of this animation highlighting Swift's detection of the most distant gamma-ray burst ever seen—13.14 billion light years.

  • Swift's UV portrait of the Andromeda Galaxy
    2009.09.16
    NASA's Swift satellite has acquired the highest-resolution view of the neighboring spiral galaxy M31. Also known as the Andromeda Galaxy, M31 is the largest and closest such galaxy to our own. It's more than 220,000 light-years across and lies 2.5 million light-years away in the constellation Andromeda. Between May 25 and July 26, 2008, Swift's Ultraviolet/Optical Telescope (UVOT) acquired 330 images of M31 at wavelengths of 192.8, 224.6, and 260 nanometers. The images represent a total exposure time of 24 hours. Some 20,000 ultraviolet sources are visible in the image, including M32, a small galaxy in orbit around M31. Dense clusters of hot, young, blue stars sparkle in the disk beyond the galaxy's smooth, redder central bulge. Star clusters are especially plentiful along a ring about 150,000 light-years across.
  • GLASTCast Episode 3 - Swift and GLAST
    2008.08.05
    NASA's GLAST mission is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

    What's the difference between the Swift and GLAST satellites? Both missions look at gamma-ray bursts (GRBs), but in different ways. Swift can rapidly and precisely determine the locations of GRBs and observe their afterglows at X-ray, ultraviolet, and optical wavelengths. GLAST will provide exquisite observations of the burst over the gamma ray spectrum, giving scientists their first complete view of the total energy released in these extraordinary events. Beyond GRB science, GLAST is a multipurpose observatory that will study a broad range of cosmic phenomena. Swift is also a multipurpose observatory, but was built primarily to study GRBs.

    Interviews with (in order of appearance):

    David Thompson - GLAST Deputy Project Scientist, NASA Goddard

    Charles "Chip" Meegan - GLAST Burst Monitor (GBM) Principal Investigator, NASA Marshall

    Lynn Cominsky - GLAST Astrophysicist and Education and Public Outreach Lead, Sonoma State University

    Neil Gehrels - GLAST Deputy Project Scientist, NASA Goddard

    Steve Ritz - GLAST Project Scientist, NASA Goddard

    Alan Marscher - Professor of Astronomy, Boston University

Science Topics

Stills/Graphics

  • Swift - Print Still Images - Wallpaper
    2008.07.24
    From the animation series - a few high resolution JPEG images
  • Swift Millionth Image Mosaic
    2018.08.21
    The Ultraviolet/Optical Telescope (UVOT) aboard the Neil Gehrels Swift Observatory captured its millionth image on May 13, 2018. It took an image of an active galaxy called 2MASX J16110570+0234002, which scientists think exhibited some unusual behavior. A mosaic, created using images UVOT has taken since Swift launched in 2004, celebrates this major milestone for the mission. UVOT monitors the optical and ultraviolet afterglow of gamma-ray bursts, the most powerful explosions in the universe. Swift’s two other instruments observe these bursts in X-rays and gamma rays. The explosions only last for a few seconds, but Swift can autonomously respond to a burst detection within 1-2 minutes and bring the event into view for follow up observations. Swift was renamed in January 2018 to honor the late Neil Gehrels, who served as the mission’s principle investigator. Imagery for this mosaic came from here and here.
  • NASA's Swift Catches its 1,000th Gamma-ray Burst
    2015.11.06
    NASA's Swift spacecraft has detected its 1,000th gamma-ray burst (GRB). GRBs are the most powerful explosions in the universe, typically associated with the collapse of a massive star and the birth of a black hole. A GRB is a fleeting blast of high-energy light, often lasting a minute or less, occurring somewhere in the sky every couple of days. Scientists are looking for exceptional bursts that offer the deepest insights into the extreme physical processes at work. Shortly before 6:41 p.m. EDT on Oct. 27, Swift's Burst Alert Telescope detected GRB 1,000 as a sudden pulse of gamma rays arising from a location toward the constellation Eridanus. Astronomers dubbed the event GRB 151027B, after the detection date and the fact that it was the second burst of the day. Swift automatically determined its location, broadcast the position to astronomers around the world, and turned to investigate the source with its own sensitive X-ray, ultraviolet and optical telescopes. Astronomers classify GRBs by their duration. Like GRB 151027B, roughly 90 percent of bursts are of the "long" variety, where the gamma-ray pulse lasts more than two seconds. They are believed to occur in a massive star whose core has run out of fuel and collapsed into a black hole. As matter falls toward the newly formed black hole, it launches jets of subatomic particles that move out through the star's outer layers at nearly the speed of light. When the particle jets reach the stellar surface, they emit gamma rays, the most energetic form of light. In many cases, the star is later seen to explode as a supernova.
  • Infographic: NASA's Swift Gamma-ray Burst Explorer
    2015.08.03
    Click download button to select from a range of sizes.

    Credit: NASA's Goddard Space Flight Center

  • X-ray Echoes Create a Black Hole Bull's-eye
    2015.07.09
    What looks like a shooting target is actually an image of nested rings of X-ray light centered on an erupting black hole. On June 15, NASA's Swift satellite detected the start of a new outburst from V404 Cygni, where a black hole and a sun-like star orbit each other. Since then, astronomers around the world have been monitoring the ongoing light show. On June 30, a team led by Andrew Beardmore at the University of Leicester, U.K., imaged the system using the X-ray Telescope aboard Swift, revealing a series concentric rings extending about one-third the apparent size of a full moon. A movie made by combining additional observations acquired on July 2 and 4 shows the expansion and gradual fading of the rings. Astronomers say the rings result from an "echo" of X-ray light. The black hole's flares emit X-rays in all directions. Dust layers reflect some of these X-rays back to us, but the light travels a longer distance and reaches us slightly later than light traveling a more direct path. The time delay creates the light echo, forming rings that expand with time. Detailed analysis of the expanding rings shows that they all originate from a large flare that occurred on June 26 at 1:40 p.m. EDT. There are multiple rings because there are multiple reflecting dust layers between 4,000 and 7,000 light-years away from us. Regular monitoring of the rings and how they change as the eruption continues will allow astronomers to better understand their nature. V404 Cygni is located about 8,000 light-years away. Every couple of decades the black hole fires up in an outburst of high-energy light. Its previous eruption ended in 1989. The investigating team includes scientists from the Universities of Leicester, Southampton, and Oxford in the U.K., the University of Alberta in Canada, and the European Space Agency in Spain.
  • Fermi Finds Hints of Starquakes in Magnetar 'Storm'
    2014.10.21
    Astronomers analyzing data acquired by NASA's Fermi Gamma-ray Space Telescope during a rapid-fire "storm" of high-energy blasts in 2009 have discovered underlying signals related to seismic waves rippling throughout the host neutron star. The burst storm came from SGR J1550−5418, a neutron star with a super-strong magnetic field, also known as a magnetar. Located about 15,000 light-years away in the constellation Norma, the magnetar was quiet until October 2008, when it entered a period of eruptive activity that ended in April 2009. At times, the object produced hundreds of bursts in as little as 20 minutes, and the most intense explosions emitted more total energy than the sun does in 20 years. High-energy instruments on many spacecraft, including NASA's Swift and Rossi X-ray Timing Explorer, detected hundreds of gamma-ray and X-ray blasts. An examination of 263 individual bursts detected by Fermi's Gamma-ray Burst Monitor confirms vibrations in the frequency ranges previously only seen in rare giant flares from magnetars. Astronomers suspect these are twisting oscillations of the star where the crust and the core, bound by the magnetic field, vibrate together. In addition, a single burst showed an oscillation at a frequency never seen before and which scientists still do not understand. While there are many efforts to describe the interiors of neutron stars, scientists lack enough observational detail to choose between differing models. Neutron stars reach densities far beyond the reach of laboratories and their interiors may exceed the density of an atomic nucleus by as much as 10 times. Knowing more about how bursts shake up these stars will give theorists an important new window into understanding their internal structure. Magnetar Burst with Torsional WavesMagnetar Burst Unlabled still of Fermi here
  • Swift Catches X-ray Activity at the
    Galaxy's Center
    2014.01.08
    A seven-year campaign to monitor the center of our galaxy with NASA's Swift spacecraft has provided astronomers with a unique bounty, more than doubling the number of bright X-ray flares observed from our galaxy's central black hole and leading to the discovery of a rare type of neutron star.

    The innermost region of our galaxy lies 26,000 light-years away in the direction of the constellation Sagittarius. At the center of it all lurks Sgr A* (pronounced "saj a-star"), a behemoth black hole containing 4 million times the sun's mass.

    Sgr A* regularly produces bright X-ray flares today, but astronomers know it was much more active in the past.

    To better understand its long-term behavior, the Swift team began regular observations of the galactic center in February 2006. Every few days, the spacecraft turns toward the inmost galaxy and takes a 17-minute-long "snapshot" with its X-Ray Telescope (XRT).

    Swift's XRT has now detected six bright flares, during which the black hole's X-ray emission brightened by up to 150 times for a couple of hours. These new detections, in addition to four found by other spacecraft, enabled astronomers to estimate that similar flares occur every five to 10 days.

    The Swift XRT team is on the lookout for the first sign that a small cold gas cloud named G2, which is swinging near Sgr A*, has begun emitting X-rays. This is expected to start sometime in spring 2014. The event will unfold for years and may fuel strong activity from the monster black hole.

    The monitoring campaign has already yielded one important discovery: SGR J1745-29, an object called a magnetar. This subclass of neutron star has a magnetic field thousands of times stronger than normal; so far, only 26 magnetars are known. A magnetar orbiting Sgr A* may allow scientists to explore important properties of the black hole and test predictions of Einstein’s theory of general relativity.

  • NASA's Swift Catches an Anti-glitch from a Neutron Star
    2013.05.29
    Using observations by NASA's Swift satellite, an international team of astronomers has identified an abrupt slowdown in the rotation of a neutron star. The discovery holds important clues for understanding some of the densest matter in the universe.

    While astronomers have witnessed hundreds of events, called glitches, associated with sudden increases in the spin of neutron stars, the sudden spin-down caught them off guard.

    A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. It's the closest thing to a black hole that astronomers can observe directly, compressing half a million times Earth's mass into a ball roughly the size of Manhattan Island. Matter within a neutron star is so dense that a teaspoonful would weigh about a billion tons on Earth.

    Neutron stars possess two other important traits. They spin rapidly, ranging from a few rpm to as many as 43,000, comparable to the blades of a kitchen blender, and they boast magnetic fields a trillion times stronger than Earth's.

    About two dozen neutron stars occasionally produce high-energy explosions that astronomers say require magnetic fields thousands of times stronger than expected. These exceptional objects, called magnetars, are routinely monitored by a McGill team led by Kaspi using Swift's X-Ray Telescope.

  • NASA Swift Provides the Best-Ever UV View of the Nearest Galaxies
    2013.06.03
    Astronomers at NASA's Goddard Space Flight Center in Greenbelt, Md., and the Pennsylvania State University in University Park, Pa., have used NASA's Swift satellite to create the most detailed surveys of the Large and Small Magellanic Clouds, the two closest major galaxies, in ultraviolet light.

    Thousands of images were assembled into seamless portraits of the main body of each galaxy to produce the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths. The project was proposed by Stefan Immler, an astronomer at Goddard.

    The Large and Small Magellanic Clouds, or LMC and SMC for short, lie about 163,000 and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy.

    Compared to the Milky Way, the LMC has about one-tenth its physical size and only 1 percent of its mass. The SMC is only half the size of the LMC and contains about two-thirds of its mass.

    The new images reveal about a million ultraviolet sources within the LMC and about 250,000 in the SMC.

    Viewing in the ultraviolet allows astronomers to suppress the light of normal stars like the sun, which are not very bright at these higher energies, and provide a clearer picture of the hottest stars and star-formation regions.

    Only Swift's Ultraviolet/Optical Telescope, or UVOT, is capable of producing such high-resolution wide-field multi-color surveys in the ultraviolet. The LMC and SMC images range from 1,600 to 3,300 angstroms, UV wavelengths largely blocked by Earth's atmosphere.

    The Large and Small Magellanic Clouds are readily visible from the Southern Hemisphere as faint, glowing patches in the night sky. The galaxies are named after Ferdinand Magellan, the Portuguese explorer who in 1519 led an expedition to sail around the world. He and his crew were among the first Europeans to sight the objects.

  • A Trio of Swift Bursts Form A New Class of GRBs
    2013.04.16
    Three unusually long-lasting stellar explosions discovered by NASA's Swift satellite represent a previously unrecognized class of gamma-ray bursts (GRBs). Two international teams of astronomers studying these events conclude that they likely arose from the catastrophic death of supergiant stars hundreds of times larger than the sun.

    GRBs are the most luminous and mysterious explosions in the universe. The blasts emit surges of gamma rays — the most powerful form of light — as well as X-rays, and they produce afterglows that can be observed at optical and radio energies. Swift, Fermi and other spacecraft detect an average of about one GRB each day.

    Traditionally, astronomers have recognized two GRB types, short and long, based on the duration of the gamma-ray signal. Short bursts last two seconds or less and are thought to represent a merger of compact objects in a binary system, with the most likely suspects being neutron stars and black holes. Long GRBs may last anywhere from several seconds to several minutes, with typical durations falling between 20 and 50 seconds. These events are thought to be associated with the collapse of a star several times the sun's mass and the resulting birth of a new black hole.

    Both scenarios give rise to powerful jets that propel matter at nearly the speed of light in opposite directions. As they interact with matter in and around the star, the jets produce a spike of high-energy light.

    A detailed study of GRB 111209A, which erupted on Dec. 9, 2011, and continued to produce high-energy emission for an astonishing seven hours, making it by far the longest-duration GRB ever recorded.

    Another event, GRB 101225A, exploded on Christmas Day in 2010 and produced high-energy emission for at least two hours. Subsequently nicknamed the "Christmas burst," the event's distance was unknown, which led two teams to arrive at radically different physical interpretations. One group concluded the blast was caused by an asteroid or comet falling onto a neutron star within our own galaxy. Another team determined that the burst was the outcome of a merger event in an exotic binary system located some 3.5 billion light-years away.

    Using the Gemini North Telescope in Hawaii, a team led by Andrew Levan at the University of Warwick in Coventry, England, obtained a spectrum of the faint galaxy that hosted the Christmas burst. This enabled the scientists to identify emission lines of oxygen and hydrogen and determine how much these lines were displaced to lower energies compared to their appearance in a laboratory. This difference, known to astronomers as a redshift, places the burst some 7 billion light-years away.

    Levan and his colleagues also examined 111209A and the more recent burst 121027A, which exploded on Oct. 27, 2012. All show similar X-ray, ultraviolet and optical emission and all arose from the central regions of compact galaxies that were actively forming stars. The astronomers conclude that all three GRBs constitute a hitherto unrecognized group of "ultra-long" bursts.

    To account for the normal class of long GRBs, astronomers envision a star similar to the size sun's size but with many times its mass. The mass must be high enough for the star to undergo an energy crisis, with its core ultimately running out of fuel and collapsing under its own weight to form a black hole. Some of the matter falling onto the nascent black hole becomes redirected into powerful jets that drill through the star, creating the gamma-ray spike, but because this burst is short-lived, the star must be comparatively small.

    Because ultra-long GRBs persist for periods up to 100 times greater than long GRBs, they require a stellar source of correspondingly greater physical size. Both groups suggest that the likely candidate is a supergiant, a star with about 20 times the sun's mass that still retains its deep hydrogen atmosphere, making it hundreds of times the sun's diameter.

  • Central Engine Supernova
    2010.01.27
    In March 2009, NASA's Swift observed the supernova SN 2009bb in the spiral galaxy NGC 3278. The explosion is apparent in visible light, but not at ultraviolet and X-ray energies, and satellites recorded no gamma-ray burst. Nevertheless, particle jets reaching 85 percent the speed of light accompanied the explosion. Astronomers believe these jets are powered by a "central engine" — likely a newborn black hole at the star's center, a scenario that also fits most gamma-ray bursts.
  • NASA's Swift Images SN 2014J in M82
    2014.01.24
    An exceptionally close stellar explosion discovered on Jan. 21 has become the focus of observatories around and above the globe, including several NASA spacecraft. The blast, designated SN 2014J, occurred in the galaxy M82 and lies only about 12 million light-years away. This makes it the nearest optical supernova in two decades and potentially the closest type Ia supernova to occur during the life of currently operating space missions.

    As befits its moniker, Swift was the first to take a look. On Jan. 22, just a day after the explosion was discovered, Swift's Ultraviolet/Optical Telescope (UVOT) captured the supernova and its host galaxy.

    A type Ia supernova represents the total destruction of a white dwarf star by one of two possible scenarios. In one, the white dwarf orbits a normal star, pulls a stream of matter from it, and gains mass until it reaches a critical threshold and explodes. In the other, the blast arises when two white dwarfs in a binary system eventually spiral inward and collide.

    Either way, the explosion produces a superheated shell of plasma that expands outward into space at tens of millions of miles an hour. Short-lived radioactive elements formed during the blast keep the shell hot as it expands. The interplay between the shell's size, transparency and radioactive heating determines when the supernova reaches peak brightness. Astronomers expect SN 2014J to continue brightening into the first week of February, by which time it may be visible in binoculars.

    M82, also known as the Cigar Galaxy, is located in the constellation Ursa Major and is a popular target for small telescopes. M82 is undergoing a powerful episode of star formation that makes it many times brighter than our own Milky Way galaxy and accounts for its unusual and photogenic appearance.

  • NASA's Fermi, Swift See 'Shockingly Bright' Gamma-ray Burst
    2013.05.03
    A record-setting blast of gamma rays from a dying star in a distant galaxy has wowed astronomers around the world. The eruption, which is classified as a gamma-ray burst, or GRB, and designated GRB 130427A, produced the highest-energy light ever detected from such an event.

    The GRB lasted so long that a record number of telescopes on the ground were able to catch it while space-based observations were still ongoing.

    Just after 3:47 a.m. EDT on Saturday, April 27, Fermi's Gamma-ray Burst Monitor (GBM) triggered on an eruption of high-energy light in the constellation Leo. The burst occurred as NASA's Swift satellite was slewing between targets, which delayed its Burst Alert Telescope's detection by less than a minute.

    Fermi's Large Area Telescope (LAT) recorded one gamma ray with an energy of at least 94 billion electron volts (GeV), or some 35 billion times the energy of visible light, and about three times greater than the LAT's previous record. The GeV emission from the burst lasted for hours, and it remained detectable by the LAT for the better part of a day, setting a new record for the longest gamma-ray emission from a GRB.

    The burst subsequently was detected in optical, infrared and radio wavelengths by ground-based observatories, based on the rapid accurate position from Swift. Astronomers quickly learned that the GRB was located about 3.6 billion light-years away, which for these events is relatively close.

    Gamma-ray bursts are the universe's most luminous explosions. Astronomers think most occur when massive stars run out of nuclear fuel and collapse under their own weight. As the core collapses into a black hole, jets of material shoot outward at nearly the speed of light.

    The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star and generate bright afterglows that fade with time.

    If the GRB is near enough, astronomers usually discover a supernova at the site a week or so after the outburst.

    This GRB is in the closest 5 percent of bursts, so ground-based observatories are monitoring its location in hopes of finding an underlying supernova.

  • Swift Probes Exotic Object: 'Kicked' Black Hole or Mega Star?
    2014.11.19
    An international team of researchers analyzing decades of observations from many facilities, including NASA's Swift satellite, has discovered an unusual source in a galaxy some 90 million light-years away. The object's curious properties make it a good match for a supermassive black hole ejected from its home galaxy after merging with another giant black hole. An alternative explanation for the source, called SDSS1133, is just as intriguing. It may be the remains of a massive star called a luminous blue variable (LBV) that exploded as a supernova. These stars undergo episodic eruptions that cast large amounts of mass into space long before their final blast. Interpreted in this way, SDSS1133 would represent the longest period of LBV eruptions ever observed, followed by a terminal supernova explosion in 2001. Whatever SDSS1133 is, it's persistent. The team was able to detect it in astronomical surveys dating back more than 60 years. The mystery object is part of the dwarf galaxy Markarian 177, located in the bowl of the Big Dipper, a well-known star pattern within the constellation Ursa Major. Although supermassive black holes usually occupy galactic centers, SDSS1133 is located at least 2,600 light-years from its host galaxy's core. In June 2013, the researchers obtained high-resolution near-infrared images of the object using the 10-meter Keck II telescope at the W. M. Keck Observatory in Hawaii. They reveal the emitting region of SDSS1133 is less than 40 light-years across and that the center of Markarian 177 shows evidence of intense star formation and other features indicating a recent disturbance.
  • Swift's UV portrait of the Andromeda Galaxy
    2009.09.16
    NASA's Swift satellite has acquired the highest-resolution view of the neighboring spiral galaxy M31. Also known as the Andromeda Galaxy, M31 is the largest and closest such galaxy to our own. It's more than 220,000 light-years across and lies 2.5 million light-years away in the constellation Andromeda. Between May 25 and July 26, 2008, Swift's Ultraviolet/Optical Telescope (UVOT) acquired 330 images of M31 at wavelengths of 192.8, 224.6, and 260 nanometers. The images represent a total exposure time of 24 hours. Some 20,000 ultraviolet sources are visible in the image, including M32, a small galaxy in orbit around M31. Dense clusters of hot, young, blue stars sparkle in the disk beyond the galaxy's smooth, redder central bulge. Star clusters are especially plentiful along a ring about 150,000 light-years across.
  • Soft Gamma-Ray Repeater Light Echoes Captured by Swift Satellite
    2009.02.10
    The X-Ray Telescope (XRT) aboard NASA's Swift satellite captured light echoes from a soft-gamma-ray repeater. These stellar remnants, which are thought to be highly magnetized neutron stars called magnetars, occasionally belt out a series of X- and gamma-ray flares. On Jan. 22, 2009, an object known as SGR J1550-5418 began its second and most intense round of outbursts since October 2008. In the following days, Swift's XRT captured what appears to be an expanding halo as X-rays from the brightest bursts scatter off of intervening dust. Multiple rings form as the X-rays interact with different dust clouds. Closer clouds produce larger rings. Both the rings and their apparent expansion are an effect of light's finite speed and the longer path the scattered light must travel. They will be studied to make a more reliable measurement of the distance to the source and to the dust clouds.

Presentation Resources

  • Briefing Materials: NASA Missions Explore Record-Setting Cosmic Blast
    2013.11.21
    On Thursday, Nov. 21, 2013, NASA held a media teleconference to discuss new findings related to a brilliant gamma-ray burst detected on April 27. Audio of the teleconference is available for download
  • X-ray Telescopes Find Black Hole May Be a Neutrino Factory
    2015.01.15
    The supermassive black hole at the center of the Milky Way, seen in this image from NASA's Chandra X-ray Observatory, may be producing mysterious particles called neutrinos, as described in our latest press release. Neutrinos are tiny particles that have virtually no mass and carry no electric charge. Unlike light or charged particles, neutrinos can emerge from deep within their sources and travel across the Universe without being absorbed by intervening matter or, in the case of charged particles, deflected by magnetic fields. Using three NASA X-ray telescopes, Chandra, Swift, and NuSTAR, scientists have found evidence for one such cosmic source for high-energy neutrinos: the 4-million-solar-mass black hole at the center of our Galaxy called Sagittarius A* (Sgr A*, for short). After comparing the arrival of high-energy neutrinos at the underground facility in Antarctica, called IceCube, with outbursts from Sgr A*, a team of researchers found a correlation. This Chandra image shows the region around Sgr A* in low, medium, and high-energy X-rays that have been colored red, green, and blue respectively. Sgr A* is located within the white area in the center of the image. The blue and orange plumes around that area may be the remains of outbursts from Sgr A* that occurred millions of years ago. The flares that are possibly associated with the IceCube neutrinos involve just the Sgr A* X-ray source.

Live Events

  • Astrophysics Live Shot 10.17.2017
    2017.10.13
    An exciting discovery out of NASA’s Goddard Space Flight Center! The bling in your ring is a product of the most violent kind of explosion in the universe.

    Suggested Anchor Intro:
    Yesterday scientists announced another giant discovery in the physics world. This time, it involves the most powerful explosion in the universe, head-banging stars and a cosmic gold rush. We have NASA scientist *NAME* here to give us a bite-sized astrophysics lesson.

    While observing a galaxy 130 million light-years away, NASA scientists became the first to see a gamma-ray burst caused by two neutron stars smashing into each other. Join some of these brilliant minds from 6:00-11:30 a.m. ET on Tuesday, Oct. 17, for a bite-sized astrophysics lesson about an exciting discovery: many precious metals on Earth are remnants of these stellar collisions. This particular explosion produced 500 times the mass of Earth in platinum and 200 times the mass of Earth in gold.

    Gamma-ray bursts are the most powerful explosions in the cosmos. Most occur when a massive star collapses under its own weight as it nears the end of its life. For decades scientists have suspected these bursts might also come from something else: collisions between neutron stars, the smallest and densest stars known to exist — they were right. Black holes merge darkly, but neutron stars do so with a splash. Matter is packed so tightly in neutron stars that a sugar cube-sized amount of material would weigh as much as Mount Everest. So, as it turns out, a neutron star merger can fuel the creation of precious metals and scatter them across the universe — precisely how gold, platinum and dozens of other elements arrived at Earth.

    We now know that a neutron star merger is powerful enough to cause ripples in space-time, just as a rock thrown into a pond creates ripples in the water. The discovery of these gravitational waves earned three physicists a 2017 Nobel Prize. This neutron star collision marks the first time scientists have been able to pinpoint exactly where gravitational waves originated. This discovery brings remarkable new insights into the physics behind the most powerful explosions in the universe — and a reminder that we're surrounded by the stuff of stars.

    Suggested Questions:
    1. Walk us through this incredible discovery. What did you see?
    2. So, the gold in my ring is stardust? How did these heavy metals get to Earth?
    3. This isn't the first time you've seen an explosion like this. Why is this one so special?
    4. The science community is pretty excited about gravitational waves. What are they?
    5. Where can we learn more?

    Location: NASA's Goddard Space Flight Center/Greenbelt, Maryland

    Scientists:
    Dr. Brad Cenko / NASA Astrophysicist, Goddard Space Flight Center
    Dr. Paul Hertz / Director, Astrophysics Science Division, NASA Headquarters
    Dr. Julie McEnery / NASA Astrophysicist, Goddard Space Flight Center

    To book a window contact: 
 Micheala Sosby / micheala.m.sosby@nasa.gov / 301-286-8199

  • NASM 2015: Our Violent Universe
    2015.11.23
    On September 23, 2015, NASA held a special event at the Smithsonian National Air and Space Museum. “Our Violent Universe” put a spotlight on the latest high energy astrophysics research coming out of NASA, highlighting key missions such as Swift, Fermi, Chandra, NuSTAR, and Hubble. NASA scientists who are leaders in this field gave presentations on some of the most exciting events in our universe, including black holes, supernovae, and gamma ray bursts. NASA does an annual presentation at the Smithsonian National Air and Space Museum to share the latest science from the agency.