Scientists using NASA's Swift satellite have spotted a stellar flare on a nearby star so powerful that, had it been from our sun, it would have triggered a mass extinction on Earth. The flare was perhaps the most energetic magnetic stellar explosion ever detected.


Image above: This is a real image of a typical solar
flare from our sun, from September 2005, captured in
the X-ray waveband by NASA's TRACE satellite. Note
the bright magnetic loops of matter. The twisting and
reconnecting of these loops initiate the flare. NASA's
Swift satellite detected a similar flare from a star system
called II Pegasi 135 light-years from Earth... except it
was one hundred million times more energetic than
the sun's typical solar flare. Had it been from our sun,
it would have triggered a mass extinction on Earth.
The II Pegasi flare was too distant (fortunately) to
image in detail. Click image to enlarge.
Credit: NASA/LMSAL

The flare was seen in December 2005 on a star slightly less massive than the sun, in a two-star system called II Pegasi in the constellation Pegasus. It was about a hundred million times more energetic than the sun's typical solar flare, releasing energy equivalent to about 50 million trillion atomic bombs.

Fortunately, our sun is now a stable star that doesn't produce such powerful flares. And II Pegasi is at a safe distance of about 135 light-years from Earth.

Yet in detecting this brilliant flare, scientists obtained direct observational evidence that stellar flares on other stars involve particle acceleration, just like on our sun. Rachel Osten of University of Maryland and NASA Goddard Space Flight Center in Greenbelt, Md., presents this finding today at the Cool Stars 14 meeting in Pasadena, Calif.


Image above: This movie shows a solar flare in action, created
from a series of NASA TRACE observations in the X-ray
waveband in April 2002. NASA's Swift satellite detected a similar
flare from a star system called II Pegasi 135 light-years from
Earth... except it was one hundred million times more energetic
than the sun's typical solar flare. Had it been from our sun, it would
have triggered a mass extinction on Earth. The II Pegasi flare was
too distant (fortunately) to image in detail. Click image for movie.
Credit: NASA/GSFC/Scientific Visualization Studio

"The flare was so powerful that, at first, we thought it was a star explosion," said Osten, a Hubble Fellow. "We know much about solar flares on the sun, but these are samples from just one star. This II Pegasi event was our first opportunity to study details of another star's flaring as if it were as close as our sun."

Solar flares on the sun originate in the corona, the outermost part of the sun's atmosphere. The corona's temperature is about two million degrees Fahrenheit, while the sun's surface, called the photosphere, is only about 6,000 degrees. The flare itself is a burst of radiation across much of the electromagnetic spectrum, from low-energy radio waves through high-energy X-rays. The X-ray emission can last up to a few minutes on the sun; on II Pegasi it lasted for several hours.

The flare involves a shower of electrons raining down from the corona onto the photosphere, heating the coronal gas to temperatures usually encountered only deep inside the sun. Scientists think that the twisting and breaking of magnetic field lines lacing through the corona generate the particle acceleration and flaring.


Image above: This animation depicts the initiation of a solar
flare. Magnetic field lines create an arch in the upper atmosphere
of the sun, the corona. Some field lines shoot into space. The
twisting and touching of field lines starts the flare as fields
recombine. Particles, shown in hot white, accelerate down the field
lines into the corona and downward towards the surface of the sun,
not shown here. The white light represents the highest-energy
X-rays, commonly seen by NASA's RHESSI on the sun and now,
for the first time, by NASA's Swift on another star. As particles rain
down on the solar surface (not shown here) the flaring will continue
in lower-energy forms of light.
+ Click for streaming Real Media
+ Click for streaming Windows Media
Credit: NASA

The flaring star in II Pegasi is 0.8 times the mass of the sun; its companion is 0.4 solar masses. The stars are close, only a few stellar radii apart. As a result, tidal forces cause both stars to spin quickly, rotating in step once in 7 days compared to the sun's 28-day rotation period. Fast rotation is conducive to strong stellar flares.

Young stars spin fast and flare more actively, and the early sun likely generated solar flares on par with II Pegasi. Yet II Pegasi could be at least a billion years older than our middle-aged 5-billion-year-old sun. "The tight binary orbit in II Pegasi acts as a fountain of youth, enabling older stars to spin and flare as strongly as young stars," said Steve Drake of NASA Goddard, a co-author with Osten on an upcoming Astrophysical Journal paper.

The key finding in the II Pegasi flare was the detection of higher-energy X-rays. Swift's Burst Alert Telescope usually detects gamma-ray bursts, the most powerful explosions known, which arise from star explosions and star mergers. The II Pegasi flare was energetic enough create a false alarm for a burst detection. Scientists quickly knew this was a different kind of event, however, when the flare overwhelmed Swift's X-ray Telescope, a second instrument.

Higher-energy "hard" X-ray detection in this case is the telltale signal of electron particle acceleration, creating what is called non-thermal X-rays. NASA's RHESSI mission sees this in the sun's solar flares. While lower-energy "soft" X-rays from thermal emission have been seen on other stars, scientists have never seen hard X-rays on any flaring star other than the sun. Because the hard X-rays occur earlier in the flare and are responsible for heating the coronal gas, they reveal unique information about the flare's initial stages.


Image above: This movie shows a massive solar flare from October 2003, captured by
the SOHO satellite. Note the burst of high-speed particles after the flare creating a
snowstorm effect. The stellar flare that Swift detected from a star system called II Pegasi
was millions of times more powerful.
Credit: NASA-ESA/SOHO/EIT

Had the sun flared like II Pegasi, these hard X-rays would have overwhelmed the Earth's protective atmosphere, leading to significant climate change and mass extinction. Ironically, one theory posits that stellar particle outbursts are needed to condition dust to form into planets and perhaps life. The Swift observation demonstrates that such outbursts do occur.

"Swift was built to catch gamma-ray bursts, but we can use its speed to catch supernovae and now stellar flares," said Swift Project Scientist Neil Gehrels of NASA Goddard. "We can't predict when a flare will happen, but Swift can react quickly once it senses an event.

Osten's colleagues on this result also include Jack Tueller and Jay Cummings of NASA Goddard; Matteo Perri of the Italian Space Agency; and Alberto Moretti and Stefano Covino of the Italian National Institute for Astrophysics.


Christopher Wanjek
Goddard Space Flight Center

Source: NASA - Swift Mission

Amazing, isn't it? The powers of the celestial realm...

It really puts things into perspective.

Spooky. I postulated on a flare like this being a possible extinction factor in the 'Next Mass Extinction' thread not very long ago. Wasn't certain if it could happen but now...

<ponders lining the house with tin foil to deflect the radiation if this happened>

The press release is reproduced below:

Dec. 20, 2006

Dwayne Brown
Headquarters, Washington
202-358-1726

Susan Hendrix
Goddard Space Flight Center, Greenbelt, Md.
301-286-7745

RELEASE: 06-373

NASA Satellite Discovers New Kind of Black Hole Explosion

GREENBELT, Md. - Scientists using NASA data are studying a newly recognized type of cosmic explosion called a hybrid gamma-ray burst. As with other gamma-ray bursts, this hybrid blast is likely signaling the birth of a new black hole.

It is unclear, however, what kind of object or objects exploded or merged to create the new black hole. The hybrid burst exhibits properties of the two known classes of gamma-ray bursts yet possesses features that remain unexplained.

NASA's Swift first discovered the burst on June 14. Since the Swift finding, more than a dozen telescopes, including the Hubble Space Telescope and large ground-based observatories, have studied the burst.

"We have lots of data on this event, have dedicated lots of observation time, and we just can't figure out what exploded," said Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Md., lead author on one of four reports appearing in this week's edition of the journal Nature. "All the data seem to point to a new but perhaps not so uncommon kind of cosmic explosion."

Gamma-ray bursts represent the most powerful known explosions in the universe. Yet they are random and fleeting, never appearing twice. Scientists have only recently begun to understand their nature.

Such bursts typically fall into one of two categories, long or short. The long bursts last more than two seconds and appear to be from the core collapse of massive stars forming a black hole. Most of these bursts come from the edge of the visible universe. The short bursts, which are under two seconds and often last just a few milliseconds, appear to be the merger of two neutron stars or a neutron star with a black hole, which subsequently creates a new or bigger black hole.

The hybrid burst, called GRB 060614, after the date it was detected, originated from within a galaxy 1.6 billion light years away in the southern constellation Indus. The burst lasted for 102 seconds, placing it soundly in long-burst territory. But the burst lacked the hallmark of a supernova, or star explosion, commonly seen shortly after long bursts. Also, the burst's host galaxy has a low star-formation rate with few massive stars that could produce supernovae and long gamma-ray bursts. "This was close enough to detect a supernova if it existed," said Avishay Gal-Yam of Caltech, Pasadena, Calif., lead author on another Nature report. "Even Hubble didn't see anything."

Certain properties of the burst concerning its brightness and the arrival time of photons of various energies, called the lag-luminosity relationship, suggest that burst behaved more like a short burst (from a merger) than a long burst. Yet no theoretical model of mergers can support a sustained release of gamma-ray energy for 102 seconds. "This is brand new territory; we have no theories to guide us," said Gehrels.

The burst is perhaps not unprecedented. Archived data from the Compton Gamma-Ray Observatory in the 1990s possibly reveal other hybrid "long-short" bursts, but no follow-up observations are available to confirm this. Johan Fynbo of the Niels Bohr Institute in Copenhagen, also lead author on a Nature report, suggests that a burst from May of this year was also long, but had no associated supernova.

Scientists remain divided on whether this was a long-short burst from a merger or a long burst from a star explosion with no supernova. Most conclude, however, that some new process must be at play – either the model of mergers creating second-long bursts needs a major overhaul, or the progenitor star from an explosion is intrinsically different from the kind that make supernovae.

"We siphoned out all the information we could from GRB 060614," said Massimo Della Valle of the Osservatorio Astrofisico di Arcetri in Firenze, Italy, another lead author on a Nature report. "All we can do now is wait for the next nearby hybrid burst."

Swift launched in November 2004. It is a NASA mission in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council, England, and managed by Goddard. Penn State in State College controls science and flight operations. Los Alamos National Laboratory, N.M., provides gamma-ray imaging analysis.

For images and more information on the Internet, visit:

http://www.nasa.gov/swift

- end -

--------------------------------------------------------------------------------

Source: NASA Press Release 06-373

Scientists working with NASA data recently made a discovery that forced them to re-think their theories on gamma-ray bursts – the most powerful cosmic explosions.

Click image to enlarge

Image above: X-ray image of the gamma-ray burst GRB 060614 taken by the XRT instrument on Swift. The burst glowed in X-ray light for more than a week following the gamma-ray burst. This so-called "afterglow" gave an accurate position of the burst on the sky and enabled the deep optical observations made by ground-based observatories and the Hubble Space Telescope.

Credit: NASA/Swift Team

A year ago scientists thought they had figured out the nature of gamma-ray bursts. They signal the birth of black holes and traditionally, fall into one of two categories: long or short. A newly discovered hybrid burst has properties of both known classes of gamma-ray bursts yet possesses features that remain unexplained.

The long bursts are those that last more than two seconds. It is believed that they are ejected by massive stars at the furthest edge of the universe as they collapse to form black holes.

Click image to enlarge

Image above: Image of the host galaxy of GRB 060614 taken with the Hubble Space Telescope. The top panel shows the galaxy on June 27, 2006 with the gamma-ray burst afterglow clearly visible in the circle to the upper right. The bottom panel shows the galaxy on July 15 with the gamma-ray burst afterglow faded away and no light from a supernova detected.

Credit: A. Gal-Yam (Caltech)

Short bursts persist for less than two seconds, with some only lasting a few milliseconds. The cause is thought to be the merger of two neutron stars – or a neutron star and a black hole – to form a new or bigger black hole.

On June 14, 2006, NASA’s Swift satellite presented scientists with a burst that doesn’t fit into either category. At the time of the event, over a dozen telescopes, including the Hubble Space Telescope and several ground-based observatories, collected data and contributed to the study of this burst. Named GRB 060614 (after the date it was detected), this one has qualities of both the long and short bursts.

The existence of this hybrid, coming from 1.6 billion light years away in the constellation Indus, suggests that the black hole birth happened in a different way from other known bursts. The hybrid lasted for 102 seconds, a long burst property. But long bursts are usually followed by a supernova, or star explosion. GRB 060614 had no associated supernova, and is in fact in a galaxy with very few stars that could produce either a supernova or a long burst.

The collapsing star scenario that is one of the leading contenders as the cause of gamma-ray bursts. This artist's concept of the collapsar model shows the center of a dying star collapsing minutes before the star implodes and emits a gamma-ray burst that is seen across the universe. Many scientists say longer bursts (more than four seconds in duration) are caused by massive star explosions.

Click image to view animation
Credit: NASA/Dana Berry, Skyworks Digital

No current scientific models can explain the existence of this hybrid burst. Most scientists believe something new may be responsible. Are stars that produce hybrid bursts inherently different from the kind that make supernovae? “This is brand new territory; we have no theories to guide us,” said Dr. Neil Gehrels of NASA GSFC.

The burst is perhaps not unprecedented. Archived data from the Compton Gamma-ray Observatory in the 1990s possibly reveal other hybrid "long-short" bursts, but no follow-up observations are available to confirm this. Johan Fynbo of the Niels Bohr Institute in Copenhagen, also lead author on a Nature report, suggests that a burst from May of this year was also long, but had no associated supernova.

Gamma-ray bursts are common, yet random, and fleeting events that have mystified astronomers since their discovery in the late 1960s. Shorter bursts (less than two seconds in duration) are thought to be caused by mergers of binary systems with black holes or neutron stars.

Click image to view animation
Credit: NASA/Dana Berry, Skyworks Digital

Scientists remain divided on whether this was a long-short burst from a merger or a long burst from a star explosion with no supernova. Most conclude, however, that some new process must be at play – either the model of mergers creating second-long bursts needs a major overhaul, or the progenitor star from an explosion is intrinsically different from the kind that make supernovae.

Earlier hybrid bursts may have been detected by other telescopes. NASA’s orbiting Compton Gamma-Ray Observatory, for example, has data from the 1990s that hint at hybrids, but are insufficient to confirm them. At this point, Swift has the best instruments ever designed to study gamma-ray bursts. Dr. Johan Fynbo of the Niels Bohr Institute in Copenhagen suggests that a burst detected by Swift just nine days earlier may also have been a hybrid, though data on GRB 060605 is less complete.

NASA's Swift satellite successfully launched on November 20, 2004, from the Cape Canaveral Air Force Station, Fla. The satellite pinpoints the location of distant yet fleeting explosions that appear to signal the births of black holes. When a GRB occurs, the BAT will be the first of Swift's instruments to detect it. The BAT feeds the gamma ray burst's position to the Swift spacecraft's attitude control system so the spacecraft can slew bringing the GRB into the XRT and UVOT's fields-of-view.

Click image to view animation
Credit: NASA/Chris Meaney

But even good Swift data aren’t enough to answer the questions without more information. “We have lots of data on this, have dedicated lots of observation time, and we just can’t figure out what exploded or merged,” said Dr. Gehrels.

So scientists must lie in wait for the next hybrid burst, ready to pounce on any new clues as to what kind of stars could produce this energetic surprise.

Swift was launched in November 2004 as a NASA mission in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council in England; it is managed by NASA GSFC. Penn State controls science and flight operations, and the Los Alamos National Laboratory provides gamma-ray imaging analysis.

Related Link:

+ Hybrid GRB 060614: A Long Gamma-Ray Burst Without a Supernova

Beth Barbier
Goddard Space Flight Center

Source: NASA - Swift Mission

In a series of landmark observations gathered over a period of four months, NASA's Swift satellite has challenged some of astronomers' fundamental ideas about gamma-ray bursts (GRBs), which are among the most extreme events in our universe. GRBs are the explosive deaths of very massive stars, some of which eject jets that can release in a matter of seconds the same amount of energy that the sun will radiate over its 10-billion-year lifetime.


Image above: The core of a massive star in a distant galaxy
collapses, ending its life -- though there is little effect visible at the
surface. Deep inside, twin beams of matter and energy begin to
blast their way outward.
Credit for caption: Phil Plait SSU NASA E/PO;
Images: Aurore Simonnet SSU NASA E/PO

When GRB jets slam into nearby interstellar gas, the resulting collision generates an intense afterglow that can radiate brightly in X-rays and other wavelengths for several weeks. Swift, however, has monitored a GRB whose afterglow remained visible for more than 125 days in the satellite's X-ray Telescope (XRT).

Swift's Burst Alert Telescope (BAT) detected the GRB in the constellation Pictor on July 29, 2006. The XRT picked up GRB 060729 (named for its date of detection) 124 seconds after BAT's detection. Normally, the XRT monitors an afterglow for a week or two until it fades to near invisibility. But for the July 29 burst, the afterglow started off so bright and faded so slowly that the XRT could regularly monitor it for months, and the instrument was still able to detect it in late November. The burst's distance from Earth (it was much closer than many GRBs) was also a factor in XRT's ability to monitor the afterglow for such an extended period.


Image above: Within seconds, the beams have eaten their way
out of the star, and observers at Earth see it as a gamma-ray burst,
GRB 060729A.
Credit for caption: Phil Plait SSU NASA E/PO;
Images: Aurore Simonnet SSU NASA E/PO

The slow fading of the X-ray afterglow has several important ramifications for our understanding of GRBs. "It requires a larger energy injection than what we normally see in bursts, and may require continuous energy input from the central engine," says astronomer Dirk Grupe of Penn State University, University Park, Penn., and lead author of an international team that reports these results in an upcoming issue of the Astrophysical Journal.

One possibility is that the GRB's central engine was a magnetar — a neutron star with an ultra-powerful magnetic field. The magnetar's magnetic field acts like a brake, forcing the star's rotation rate to spin-down rapidly. The energy of this spin-down can be converted into magnetic energy that is continuously injected into the initial blast wave that triggered the GRB. Calculations by paper coauthor Xiang-Yu Wang of Penn State show that this energy could power the observed X-ray afterglow and keep it shining for months.


Image above: The outer envelope of the star explodes outward,
causing a supernova.
Credit for caption: Phil Plait SSU NASA E/PO;
Images: Aurore Simonnet SSU NASA E/PO

A burst observed on January 10, 2007, also suggests that magnetars power some GRBs. GRB 070110's X-ray afterglow remained nearly constant in brightness for 5 hours, then faded rapidly more than tenfold. In another paper submitted to the Astrophysical Journal, an international group led by Eleonora Troja of the INAF—IASF of Palermo, Italy, proposes that a magnetar best explains these observations.

"People have thought for a long time that GRBs are black holes being born, but scientists are now thinking of other possibilities," says Swift principal investigator Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Md., a co-author on both studies.


Image above: Deep at the heart of this event, the core has shrunk
into a fantastically dense magnetar, a neutron star possessing a
magnetic field trillions or even quadrillions of times stronger than
Earth's. The magnetism is what powers the long glow of X-rays
seen by Earthbound scientists.

Another surprising result from GRB 060729 is that the X-ray afterglow displayed no sharp decrease in brightness over the 125-day period that it was detected by the XRT. Using widely accepted theory, Grupe and his colleagues conclude that the angle of the GRB's jet must have been at least 28 degrees wide. In contrast, most GRB jets are thought to have very narrow opening angles of only about 5 degrees. "The much wider opening angle seen in GRB 060729 suggests a much larger energy release than we typically see in GRBs," says Grupe.


Bob Naeye
Goddard Space Flight Center

Source: NASA/GSFC - News

Using NASA’s Swift satellite, astronomers have discovered that energetic flares seen after gamma-ray bursts (GRBs) are not just hiccups, they appear to be a continuation of the burst itself.


Image above: The X-ray Telescope on NASA's Swift satellite captured the intensity of a bright X-flare from
GRB 060714. The elongated blue and gray regions are an artifact of the image processing (left). After the flare,
(right) the GRB's X-ray emission faded considerably, revealing a faint afterglow.
Click image to enlarge.
Credit: NASA / Swift / XRT Science Team

GRBs release in seconds the same amount of energy our Sun will emit over its expected 10 billion-year lifetime. The staggering energy of a long-duration GRB (lasting more than a few seconds) comes from the core of a massive star collapsing to form a black hole or neutron star. In current theory, inrushing gas forms a disk around the central object. Magnetic fields channel some of that material into two jets moving at near-light speed. Collisions between shells of ejected material within the jet trigger the actual GRB.

Early in the mission, Swift’s X-ray Telescope (XRT) discovered that the initial pulse of gamma-rays, known as prompt emission, is often followed minutes to hours later by short-lived but powerful X-ray flares. The flares suggested — but did not prove — that GRB central engines remain active long after the prompt emission.


Image above: This artwork depicts the central engine of a gamma-
ray burst. A powerful jet of radiation and fast-moving particles
blasts its way out of the central region of a dying star. The jet is
presumably powered by material spiraling into a black hole or
neutron star. Multiple episodes of infall provides fuel for the engine,
leading to the burst and
later X-ray flares.
Credit: NASA / SkyWorks Digital.

After analyzing GRB 060714, named for its detection date of July 14, 2006, Hans Krimm of Universities Space Research Association, Columbia, Md. and NASA’s Goddard Space Flight Center in Greenbelt, Md., and eight colleagues, have demonstrated that X-ray flares are indeed a continuation of the prompt emission, showing that GRB central engines are active much longer than previously thought.

Swift’s Burst Alert Telescope (BAT) picked up the initial GRB in the constellation Libra. Then, from about 70 to 200 seconds after the initial burst, the BAT and XRT registered five flares. Each flare exhibited rapid and large-scale variability in intensity, but the overall energy steadily diminished from flare to flare. Moreover, the peak photon energy of each flare “softened” by progressing from gamma-rays to X-rays (from higher to lower energy).

The prompt gamma-ray emission and the subsequent X-ray flares appear to form a continuously connected and evolving succession of events. “This pattern points to a continuous injection of energy from the central engine, perhaps fueled by sporadic infall of material onto a black hole. The black hole just keeps gobbling up gas and the engine keeps spewing out energy,” says Krimm, whose paper is scheduled for publication in the August 10 Astrophysical Journal.

Swift's Burst Alert Telescope, and then its Xray Telescope, picked up the prompt emission of GRB 060714, and then several flares.



Image above: Swift's Burst Alert Telescope, and then its X-ray Telescope, picked up the prompt emission
of GRB 060714, and then several flares. The outbursts gradually decreased in total energy, showing that the
XRT flares were related to the prompt emission. The BAT data appears in black, and the XRT data appears
in red. Even though the X-ray brightness of the first XRT flare was less than the next two flares, it was more
energetic, since its X-ray photons had higher energy.
+ Click to see image without labels.
Credit: NASA / Swift / Hans Krimm.

The rapid and large-scale variability of the X-ray flares argues strongly against the idea that they come from jets sweeping up the surrounding gas. Since the observed emission comes from a wide region, the afterglow should vary smoothly with time. Nobody has come up with a viable explanation for why the surrounding material would be so lumpy to lead to such rapid variability. "This particular GRB had a series of flares over a wide range in time that were bright enough that we could study their properties in detail,” says study coauthor Jonathan Granot of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, Stanford, Calif. “It clearly shows a gradual evolution with time in the properties of the flares within the same GRB, while in other GRBs there are typically only one or two flares that are bright enough to be studied in detail, making it very hard to reach a similar conclusion." "This is a very important result," adds Swift principal investigator and study coauthor Neil Gehrels of NASA Goddard. "By chance, if you look at enough bursts you’ll find the one that opens the door. GRB 060714 shows that everything happening in the first few minutes is driven by the central engine."

Swift is managed by NASA’s Goddard Space Flight Center and was built and is operated in collaboration with Penn State University, the Los Alamos National Laboratory, and General Dynamics in the US; the University of Leicester and Mullard Space Sciences Laboratory in the UK; Brera Observatory and the Italian Space Agency in Italy; plus partners in Germany and Japan.

Related Link:

+ NASA's Swift website


Bob Naeye
Goddard Space Flight Center

Source: NASA/GSFC - News

In just the past six weeks, two supernovae have flared up in an obscure galaxy in the constellation Hercules. Never before have astronomers observed two of these powerful stellar explosions occurring in the same galaxy so close together in time.

Image above: Supernova 2007ck (left) is a Type II event, and Supernova 2007co (right) is a Type Ia event. The image is a combination of red, green, and blue pictures taken on June 9 and 12 by the Ultraviolet/Optical Telescope on NASA’s Swift satellite, which was designed primarily to study another type of stellar explosion – gamma ray bursts.
Click image to enlarge.
Credit: Stefan Immler NASA/GSFC, Swift Science Team

The galaxy, known as MCG +05-43-16, is 380 million light-years from Earth. Until this year, astronomers had never sighted a supernova popping off in this stellar congregation. A supernova is an extremely energetic and life-ending explosion of a star.

Making the event even more unusual is the fact that the two supernovae belong to different types. Supernova 2007ck is a Type II event – which is triggered when the core of a massive star runs out of nuclear fuel and collapses gravitationally, producing a shock wave that blows the star to smithereens. Supernova 2007ck was first observed on May 19.

In contrast, Supernova 2007co is a Type Ia event, which occurs when a white dwarf star accretes so much material from a binary companion star that it blows up like a giant thermonuclear bomb. It was discovered on June 4, 2007. A white dwarf is the exposed core of a star after it has ejected its atmosphere; it’s approximately the size of Earth but with the mass of our Sun.

"Most galaxies have a supernova every 25 to 100 years, so it’s remarkable to have a galaxy with two supernovae discovered just 16 days apart," says Stefan Immler of NASA’s Goddard Space Flight Center. In 2006 Immler used NASA’s Swift satellite to image two supernovae in the elliptical galaxy NGC 1316, but both of those explosions were Type Ia events, and they were discovered six months apart.

The simultaneous appearance of two supernovae in one galaxy is an extremely rare occurrence, but it’s merely a coincidence and does not imply anything unusual about MCG +05-43-16. Because the two supernovae are tens of thousands of light-years from each other, and because light travels at a finite speed, astronomers in the galaxy itself, or in a different galaxy, might record the two supernovae exploding thousands of years apart.


Robert Naeye
Goddard Space Flight Center

Source: NASA/GSFC - News

An international team of astronomers using NASA’s Swift satellite and the Japanese/U.S. Suzaku X-ray observatory has discovered a new class of active galactic nuclei (AGN).

By now, you’d think that astronomers would have found all the different classes of AGN — extraordinarily energetic cores of galaxies powered by accreting supermassive black holes. AGN such as quasars, blazars, and Seyfert galaxies are among the most luminous objects in our Universe, often pouring out the energy of billions of stars from a region no larger than our solar system.


Image above: In the newly discovered type of AGN, the disk and torus
surrounding the black hole are so deeply obscured by gas and dust that no
visible light escapes, making them very difficult to detect. This illustration
shows the scene from a more distant perspective than does the other image.
Click on image for high-res version.
Image credit: Aurore Simonnet, Sonoma State University

But by using Swift and Suzaku, the team has discovered that a relatively common class of AGN has escaped detection…until now. These objects are so heavily shrouded in gas and dust that virtually no light gets out.

"This is an important discovery because it will help us better understand why some supermassive black holes shine and others don’t," says astronomer and team member Jack Tueller of NASA’s Goddard Space Flight Center in Greenbelt, Md.

Evidence for this new type of AGN began surfacing over the past two years. Using Swift’s Burst Alert Telescope (BAT), a team led by Tueller has found several hundred relatively nearby AGNs that were previously missed because their visible and ultraviolet light was smothered by gas and dust. The BAT was able to detect high-energy X-rays from these heavily blanketed AGNs because, unlike visible light, high-energy X-rays can punch through thick gas and dust.


Image above: This illustration shows the different features of an active galactic nucleus (AGN), and how our
viewing angle determines what type of AGN we observe. The extreme luminosity of an AGN is powered by a
supermassive black hole at the center. Some AGN have jets, while others do not.
Click on image for high-res version.
Image credit: Aurore Simonnet, Sonoma State University

To follow up on this discovery, Yoshihiro Ueda of Kyoto University, Japan, Tueller, and a team of Japanese and American astronomers targeted two of these AGNs with Suzaku. They were hoping to determine whether these heavily obscured AGNs are basically the same type of objects as other AGN, or whether they are fundamentally different. The AGNs reside in the galaxies ESO 005-G004 and ESO 297-G018, which are about 80 million and 350 million light-years from Earth, respectively.

Suzaku covers a broader range of X-ray energies than BAT, so astronomers expected Suzaku to see X-rays across a wide swath of the X-ray spectum. But despite Suzaku’s high sensitivity, it detected very few low- or medium-energy X-rays from these two AGN, which explains why previous X-ray AGN surveys missed them.

According to popular models, AGNs are surrounded by a donut-shaped ring of material, which partially obscures our view of the black hole. Our viewing angle with respect to the donut determines what type of object we see. But team member Richard Mushotzky, also at NASA Goddard, thinks these newly discovered AGN are completely surrounded by a shell of obscuring material. "We can see visible light from other types of AGN because there is scattered light," says Mushotzky. "But in these two galaxies, all the light coming from the nucleus is totally blocked."


Image above: The images from the Digitized Sky Survey show the two galaxies targeted by Suzaku that have
a heavily shrouded active nucleus: ESO 005-G004 (left) and ESO 297-G018 (right). Both galaxies have a spiral
structure.
Image credit: DSS/UK Schmidt Telescope/AAT Board.

Another possibility is that these AGN have little gas in their vicinity. In other AGN, the gas scatters light at other wavelengths, which makes the AGN visible even if they are shrouded in obscuring material.

"Our results imply that there must be a large number of yet unrecognized obscured AGNs in the local universe," says Ueda.

In fact, these objects might comprise about 20 percent of point sources comprising the X-ray background, a glow of X-ray radiation that pervades our Universe. NASA’s Chandra X-ray Observatory has found that this background is actually produced by huge numbers of AGNs, but Chandra was unable to identify the nature of all the sources.

By missing this new class, previous AGN surveys were heavily biased, and thus gave an incomplete picture of how supermassive black holes and their host galaxies have evolved over cosmic history. "We think these black holes have played a crucial role in controlling the formation of galaxies, and they control the flow of matter into clusters," says Tueller. "You can’t understand the universe without understanding giant black holes and what they’re doing. To complete our understanding we must have an unbiased sample."

The discovery paper will appear in the August 1st issue of the Astrophysical Journal Letters.

More information about Swift can be found at http://swift.gsfc.nasa.gov, and about Suzaku can be found at http://suzaku.gsfc.nasa.gov.

Robert Naeye
NASA Goddard Space Flight Center

Source: NASA/GSFC - News

The Penn State University, Eberly College of Science press release is reproduced below:

20 August 2007 —Using NASA's Swift satellite, McGill University and Penn State University astronomers have identified an object that is likely one of the closest neutron stars to Earth -- and possibly the closest.

The object, located in the constellation Ursa Minor, is nicknamed Calvera, after the villain in the movie "The Magnificent Seven." If confirmed, it would be only the eighth known "isolated neutron star" -- meaning a neutron star that does not have an associated supernova remnant, binary companion, or radio pulsations. "The seven previously known isolated neutron stars are known collectively as 'The Magnificent Seven' within the community and so the name Calvera is a bit of an inside joke on our part," says co-discoverer Derek Fox of Penn State. A paper describing the research will be published in the Astrophysical Journal.


Credit: Casey Reed, courtesy of Penn State
Artist's illustration of an "isolated neutron star"
-- a neutron star that does not have an associated
supernova remnant, binary companion, or radio
pulsations.

The object, located in the constellation Ursa Minor, is nicknamed Calvera, after the villain in the movie "The Magnificent Seven." If confirmed, it would be only the eighth known "isolated neutron star" -- meaning a neutron star that does not have an associated supernova remnant, binary companion, or radio pulsations. "The seven previously known isolated neutron stars are known collectively as 'The Magnificent Seven' within the community and so the name Calvera is a bit of an inside joke on our part," says co-discoverer Derek Fox of Penn State. A paper describing the research will be published in the Astrophysical Journal.

First author Robert Rutledge of McGill University in Montreal, Quebec, originally called attention to the source. He compared a catalog of 18,000 X-ray sources from the German-American ROSAT satellite, which operated from 1990 to 1999, with catalogs of objects that appear in visible light, infrared light, and radio waves. He realized that the ROSAT source known as 1RXS J141256.0+792204 did not appear to have a counterpart at any other wavelength.

The group aimed Swift at the object in August 2006. Swift's X-ray Telescope showed that the source was still there, and emitting about the same amount of X-ray energy as it had during the ROSAT era. The Swift observations enabled the group to pinpoint the object's position more accurately, and showed that it was not associated with any known object.

"The Swift observation of this source is what got the show going," says paper coauthor and Penn State undergraduate Andrew Shevchuk. "As soon as I saw the data, I knew Calvera was a great neutron-star candidate."

The team next targeted Calvera with the 8.1-meter Gemini North Telescope in Hawaii. These observations, along with a short observation by NASA's Chandra X-ray Observatory, showed that the object is not associated with any optical counterpart down to a very faint magnitude. Chandra's sharper X-ray vision sees the object as point-like, consistent with the neutron-star interpretation.

According to Rutledge, there are no widely accepted alternate theories for objects like Calvera that are bright in X-rays and faint in visible light. Exactly which type of neutron star it is, however, remains a mystery. As Rutledge says, "Either Calvera is an unusual example of a known type of neutron star, or it is some new type of neutron star, the first of its kind."

Calvera's location high above the plane of our Milky Way Galaxy is part of its mystery. In all likelihood, the neutron star is the remnant of a star that lived in our galaxy's starry disk before exploding as a supernova. In order to reach its current position, it had to wander some distance out of the disk. But exactly how far? "The best guess is that it is still close to its birthplace, and therefore close to Earth," says Rutledge. If this interpretation is correct, the object is 250 to 1,000 light-years away. This would make Calvera one of the closest known neutron stars -- possibly the closest.

"Because it is so bright, and probably close to Earth, it is a promising target for many types of observations," says Fox. Indeed, to clear up the mysteries surrounding Calvera the team will be taking a longer observation with Chandra to see if the source pulsates in X-rays, and to measure its spectrum. They also joined a group using a radio telescope to search for radio pulsations, which were not seen.

Calvera could represent the tip of the iceberg for isolated neutron stars. "There could easily be dozens," says Fox. "The key point is that until our Swift survey, no one was able to refine the X-ray positions of large numbers of ROSAT sources to the point where it became clear which ROSAT sources were 'missing' their optical counterparts."



CONTACTS:
Derek Fox: (+1)814-863-4989, dfox@astro.psu.edu
Robert Rutledge: (+1)514-398-6509, rutledge@physics.mcgill.ca
Barbara K. Kennedy (Penn State PIO): (+1)814-863-4682, science@psu.edu
Mark Shainblum (McGill PIO): (+1)514-398-2189, mark.shainblum@mcgill.ca
Lynn Cominsky (Swift PIO): (+1)707-664-2655, lynnc@universe.sonoma.edu

Source: PSU Press Release

Awesome. I hope it's a new kind of neutron star.



Theres must be so many things nearby Earth in space we haven't detected yet.

Using NASA’s Swift and Rossi X-ray Timing Explorer (RXTE) satellites, astronomers have discovered one of the most bizarre planet-mass objects ever found.


Image above: In this artist depiction of the SWIFT J1756.9-2508
system, the foreground object is the planet-mass object. The pulsar,
located at the upper right, is tidally distorting the companion into a
teardrop-shaped object, and ripping gas from it. This material flows
in a stream toward the pulsar and forms a disk around it. Eventually,
enough gas builds up in the disk to produce an outburst bright
enough to make the system visible from Earth.
Click on image to enlarge.
Credit: Aurore Simonnet/Sonoma State University

The object’s minimum mass is only about 7 times the mass of Jupiter. But instead of orbiting a normal star, this low-mass body orbits a rapidly spinning pulsar. It orbits the pulsar every 54.7 minutes at an average distance of only about 230,000 miles (slightly less than the Earth-Moon distance).

"This object is merely the skeleton of a star," says co-discoverer Craig Markwardt of NASA’s Goddard Space Flight Center in Greenbelt, Md. "The pulsar has eaten away the star’s outer envelope, and all the remains is its helium-rich core."

Hans Krimm of NASA Goddard discovered the system on June 7, when Swift’s Burst Alert Telescope picked up an outburst of X rays and gamma rays in the direction of the galactic center. The source was named SWIFT J1756.9-2508 for its sky coordinates in the constellation Sagittarius.

RXTE began observing SWIFT J1756.9 on June 13 with its Proportional Counter Array (PCA). After analyzing the PCA data, Markwardt realized that the object was pulsing in X rays 182.07 times per second, which told him that it was a rapidly spinning pulsar. These so-called millisecond pulsars are neutron stars that spin hundreds of times per second, faster than a kitchen blender. Normally, the spin rate of neutron stars slows down as they age, but much like we can pull a string to “spin up” a top, gas spiraling onto a neutron star from its companion can maintain or even increase its fast spin.


Image above: The low-mass companion in SWIFT J1756.9-2508
may have a mass just a few times greater than Jupiter, but up close,
it would probably look nothing like a planet. The object is probably
dominated by helium gas. Even though it is much larger than the
pulsar, the pulsar is at least 100 times more massive.
Click on image to enlarge.
Credit: Aurore Simonnet/Sonoma State University

In the case of SWIFT J1756.9-2508, Markwardt detected subtle modulations in the X-ray timing data that revealed a low-mass companion tugging the pulsar toward and away from Earth. His calculations show that the companion has a minimum mass about 7 times that of Jupiter. Because we don’t know the orbital inclination of the system, the companion’s actual mass is unknown, but it is extremely unlikely to exceed 30 Jupiters.

MIT astronomers led by Deepto Chakrabarty also observed the system with RXTE, before it faded to invisibility on June 21. Chakrabarty’s group reached identical conclusions, and the two teams have coauthored a paper that has been accepted for publication in the Astrophysical Journal Letters.

The system is only the eighth millisecond pulsar that is observed to be accreting mass from a companion. Only one other such system has a pulsar companion with such a low mass. The companion in this system, XTE J1807-294, also has a minimum mass of about 7 Jupiters. "Given that we don’t know the exact mass of either companion, ours could be the smallest," says Krimm.

The system probably formed several billion years ago, when it consisted of a very massive star and a smaller star with perhaps 1 to 3 solar masses. The more massive star evolved quickly and exploded as a supernova, leaving behind the neutron star. The smaller star eventually started to puff up en route to becoming a red giant, and the two objects became embedded in the extended stellar envelope. This drained orbital energy, causing the two stars to draw ever nearer, while simultaneously ejecting the envelope.

Today, the two objects are so close to each other than the neutron star’s powerful gravity produces a tidal bulge on its companion, siphoning off gas that flows into a disk that surrounds the neutron star. The flow eventually becomes unstable and dumps large quantities of gas onto the neutron star, causing an outburst like the one observed in June.


Image above: The orbital separation of the two members in SWIFT
J1756.9-2508 is remarkably similar to the Earth-Moon distance, but the
bodies themselves are totally different in their physical nature.
Credit: Aurore Simonnet/Sonoma State University

Evolution models by Christopher Deloye of Northwestern University suggest that the low-mass companion is helium dominated. "Despite its extremely low mass, the companion isn’t considered a planet because of its formation," says Deloye. "It’s essentially a white dwarf that has been whittled down to a planetary mass."

After billions of years, little remains of the companion star, and it remains unclear whether it will survive. "It’s been taking a beating, but that’s part of nature," adds Krimm.

With an estimated distance of roughly 25,000 light-years, the system is normally too faint to be detected at any wavelength, and is only visible during an outburst. SWIFT J1756.9 has never been seen to erupt until this June, so as Markwardt points out, "We don't know how long it will slumber before it wakes up again."


Bob Naeye
Goddard Space Flight Center

Source: NASA/GSFC - News

When a shot is fired, one expects to see a person with a gun. In the same way, whenever a giant star explodes, astronomers expect to see a galaxy of stars surrounding the site of the blast. This comes right out of basic astronomy, since almost all stars in our universe belong to galaxies.


The robotic Palomar 60-inch telescope imaged
the afterglow of GRB 070125 on January 26, 2007.
Right: An image taken of the same field on
February 16 with the 10-meter Keck I telescope
reveals no trace of an afterglow, or a host galaxy.
The white cross in this zoom-in view marks the
GRB’s location. The two nearest galaxies, and their
distances, are marked with arrows.
Credit: B. Cenko, et al. and the W. M. Keck Observatory.
> Click for larger image.
> Click for unlabeled version of the image.

When a shot is fired, one expects to see a person with a gun. In the same way, whenever a giant star explodes, astronomers expect to see a galaxy of stars surrounding the site of the blast. This comes right out of basic astronomy, since almost all stars in our universe belong to galaxies.

But a stellar explosion seen last January has shocked astronomers because when they looked for the star’s parent galaxy, they saw nothing at all. The explosion took place in the middle of nowhere, far away from any detectable galaxy. The astronomers saw no hint of a galaxy even though they looked for one with the world’s largest telescope: the giant Keck I telescope in Hawaii.

"Here we have this very bright burst, yet it's surrounded by darkness on all sides," says Brad Cenko, an astronomer at the California Institute of Technology (Caltech) in Pasadena, Calif. Cenko is the leader of the team that made this discovery. The team includes astronomers from both Caltech and Penn State University.

The explosion belongs to a class of events know as gamma-ray bursts, or GRBs for short. GRBs are triggered when a very heavy star can no longer produce energy. The core of the star implodes to form a black hole — a region of space where gravity is so strong that nothing, not even light, can escape. The black hole spins very fast, producing intense magnetic fields. As inrushing gas from the star spirals toward the black hole, the magnetic fields fling some of the material away from the black hole in two powerful jets. These jets produce the GRB.

Several spacecraft detected the explosion on January 25, 2007. Observations by NASA's Swift satellite pinpointed the explosion, named GRB 070125 for its detection date, to a region of sky in the constellation Gemini. It was one of the brightest bursts of the year, and the Caltech/Penn State team moved quickly to observe the burst’s location with large telescopes on the ground.

Using the team's robotic 60-inch telescope at Palomar Observatory in Calif., the astronomers discovered that the burst had a bright afterglow that was fading fast. They observed the afterglow in detail with two of the world's largest telescopes, the Gemini North telescope and the Keck I telescope, both near the summit of Hawaii's Mauna Kea.


A recent galaxy collision produced the long tail
in the Tadpole Galaxy. If GRB 070125 exploded
in a similar tail, only Hubble could detect the tail.
Credit: NASA, H. Ford, et al.
> Click for larger image
> Click for print resolution version.

What came next was a total surprise. Contrary to experience with more than a hundred previous GRBs, The Gemini and Keck observations saw no trace of a galaxy at the burst’s location. "A Keck image could have revealed a very small, faint galaxy at that distance," says team member Derek Fox of Penn State.

So why didn’t the team see a galaxy? One possibility is that the star formed in the outskirts of two galaxies that are colliding. Hubble Space Telescope images of colliding galaxies show that many of them have long star tails that are produced by the gravity of the two galaxies. These tails are very faint, and would not show up in Keck images at the burst’s measured distance from Earth. If this idea is correct, it should be possible to detect the tail by taking a long exposure with Hubble. "That's definitely our next stop," says Cenko.

"Many Swift discoveries have left astronomers scratching their heads in befuddlement," adds Swift lead scientist Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Md. "But this discovery of a long GRB with no host galaxy is one of the most perplexing of all."

Robert Naeye
NASA Goddard Space Flight Center

Source: NASA - Universe

J.D. Harrington
Headquarters, Washington
202-358-5241
j.d.harrington@nasa.gov

Robert Naeye / Rob Gutro
Goddard Space Flight Center, Greenbelt, Md.
301-286-4453

Release No. 08-86

WASHINGTON - A powerful stellar explosion detected March 19 by NASA's Swift satellite has shattered the record for the most distant object that could be seen with the naked eye.


The extremely luminous afterglow of GRB 080319B
was imaged by Swift's X-ray Telescope (left) and
Optical/Ultraviolet Telescope (right). This was by
far the brightest gamma-ray burst afterglow ever
seen.
Credit: NASA/Swift/Stefan Immler, et al.
> Larger image

The explosion was a gamma ray burst. Most gamma ray bursts occur when massive stars run out of nuclear fuel. Their cores collapse to form black holes or neutron stars, releasing an intense burst of high-energy gamma rays and ejecting particle jets that rip through space at nearly the speed of light like turbocharged cosmic blowtorches. When the jets plow into surrounding interstellar clouds, they heat the gas, often generating bright afterglows. Gamma ray bursts are the most luminous explosions in the universe since the big bang.

"This burst was a whopper," said Swift principal investigator Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Md. "It blows away every gamma ray burst we've seen so far."

Swift's Burst Alert Telescope picked up the burst at 2:12 a.m. EDT, March 19, and pinpointed the coordinates in the constellation Boötes. Telescopes in space and on the ground quickly moved to observe the afterglow. The burst is named GRB 080319B, because it was the second gamma ray burst detected that day.

Swift's other two instruments, the X-ray Telescope and the Ultraviolet/Optical Telescope, also observed brilliant afterglows. Several ground-based telescopes saw the afterglow brighten to visual magnitudes between 5 and 6 in the logarithmic magnitude scale used by astronomers. The brighter an object is, the lower its magnitude number. From a dark location in the countryside, people with normal vision can see stars slightly fainter than magnitude 6. That means the afterglow would have been dim, but visible to the naked eye.


GRB 080319B's optical afterglow appears in the
center of this image from Pi of the Sky, a Polish
group that monitors the sky for afterglows and
other short-lived sources.
Credit: Pi of the Sky
> Larger image
> View animation at Pi in the Sky's Web site

Later that evening, the Very Large Telescope in Chile and the Hobby-Eberly Telescope in Texas measured the burst's redshift at 0.94. A redshift is a measure of the distance to an object. A redshift of 0.94 translates into a distance of 7.5 billion light years, meaning the explosion took place 7.5 billion years ago, a time when the universe was less than half its current age and Earth had yet to form. This is more than halfway across the visible universe.

"No other known object or type of explosion could be seen by the naked eye at such an immense distance," said Swift science team member Stephen Holland of Goddard. "If someone just happened to be looking at the right place at the right time, they saw the most distant object ever seen by human eyes without optical aid."

GRB 080319B's optical afterglow was 2.5 million times more luminous than the most luminous supernova ever recorded, making it the most intrinsically bright object ever observed by humans in the universe. The most distant previous object that could have been seen by the naked eye is the nearby galaxy M33, a relatively short 2.9 million light-years from Earth.

Analysis of GRB 080319B is just getting underway, so astronomers don't know why this burst and its afterglow were so bright. One possibility is the burst was more energetic than others, perhaps because of the mass, spin, or magnetic field of the progenitor star or its jet. Or perhaps it concentrated its energy in a narrow jet that was aimed directly at Earth.

GRB 080319B was one of four bursts that Swift detected, a Swift record for one day. "Coincidentally, the passing of Arthur C. Clarke seems to have set the universe ablaze with gamma ray bursts," said Swift science team member Judith Racusin of Penn State University in University Park, Pa.

Swift is managed by Goddard. It was built and is being operated in collaboration with Penn State, the Los Alamos National Laboratory, and General Dynamics in the U.S.; the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom; Brera Observatory and the Italian Space Agency in Italy; plus partners in Germany and Japan.

Source: NASA - Missions _ Swift

News Release Number: STScI-2008-17



ABOUT THIS IMAGE:
Peering across 7.5 billion light-years and halfway back to the Big Bang, NASA's Hubble Space Telescope has photographed the fading optical counterpart of a powerful gamma ray burst that holds the record for being the intrinsically brightest naked-eye object ever seen from Earth. For nearly a minute this single star was as bright as 10 million galaxies. Hubble Wide Field and Planetary Camera 2 (WFPC2) images of GRB 080319B, taken on Monday, April 7, show the fading optical counterpart of the titanic blast. The object erupted in a brilliant flash of gamma rays and other electromagnetic radiation at 2:12 a.m. EDT on March 19, and was detected by Swift, NASA's gamma ray burst watchdog satellite. Immediately after the explosion, the gamma ray burst glowed as a dim 5th magnitude "star" in the spring constellation Bootes. Designated GRB 080319B, the intergalactic firework has been fading away ever since then. Hubble astronomers had hoped to see the host galaxy where the burst presumably originated, but were taken aback that the light from the GRB is still drowning out the galaxy's light even three weeks after the explosion. This is particularly surprising because it was such a bright GRB initially. Previously, bright bursts have tended to fade more rapidly, which fits in to the theory that brighter GRBs emit their energy in a more tightly confined beam. The slow fading leaves astronomers puzzling about just where the energy came from to power this GRB, and makes Hubble's next observations of this object in May all the more crucial. Called a long-duration gamma ray burst, such events are theorized to be caused by the death of a very massive star, perhaps weighing as much as 50 times our Sun. Such explosions, sometimes dubbed "hypernovae," are more powerful than ordinary supernova explosions and are far more luminous, in part because their energy seems to be concentrated into a blowtorch-like beam that, in this case, was aimed directly at Earth. The Hubble exposure also shows field galaxies around the fading optical component of the gamma ray burst, which are probably unrelated to the burst itself.

For more information, contact:
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
villard@stsci.edu

Nial Tanvir
University of Leicester
011-44-116-223-1217
nrt3@star.le.ac.uk

Andy Fruchter
Space Telescope Science Institute, Baltimore, Md.
410-338-5018
fruchter@stsci.edu

Object Name: GRB 080319B

Image Type: Astronomical

Credit: NASA, ESA, N. Tanvir (University of Leicester), and A. Fruchter (STScI)

Source: HubbleSite - Newsdesk