Chandra X-ray Observatory Center
Harvard-Smithsonian Center for Astrophysics
Cambridge, MA
January 14, 2000
A team of scientists from the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., reported on this observation at the 195th national meeting of the American Astronomical Society in Atlanta, Ga. The team is led by Drs. Stephen Murray and Michael Garcia, and includes Drs. Frank Primini, William Forman, Christine Jones, and Ralph Kraft.
Chandra took its first X-ray picture of the Andromeda Galaxy with the Advanced CCD Imaging Spectrometer on October 13, 1999. More than100 individual X-ray sources were seen. One of these sources was at the previously determined position of the central supermassive black hole, which has the mass of 30 million suns. With many X-ray emitting stars in the center of M31 there was a slight chance that one of them might be at this position just by coincidence. The low temperature of the suspected central source, as compared to the other sources, gave the team the clue they needed.
"When we found that what we suspected was the central object was also anomalously cool, we KNEW we had it -- one coincidence might be believable, but two was too much to ignore!" said Garcia.
While the gas falling into the central black hole is cool, it is only cool by comparison to the 100 other X-ray sources in the Andromeda Galaxy. To be detected by an X-ray telescope, the gas must have a temperature of more than a million degrees. The typical X-ray star in the Andromeda Galaxy has a temperature of several tens of millions of degrees. In contrast, the temperature of the supermassive black hole source is a few million degrees.
The Andromeda Galaxy is our nearest neighbor spiral galaxy at a distance of two million light years. It is similar to our own Milky Way in size, shape, and also contains a supermassive black hole at the center. This central black hole has always been a bit odd when compared to central black holes in similar galaxies. Based on its X-ray luminosity, it is much fainter in radio waves than expected.
Such behavior, coupled with Chandra's discovery of the low temperature gas, cannot be accommodated by standard models developed for supermassive black holes in galaxies like the Milky Way and Andromeda.
"The Chandra observation is telling us that an entirely different flow pattern is operating around the Andromeda black hole," said Dr. Eliot Quataert, of the Institute for Advanced Study, Princeton, N.J. "This will require a different class of models than usually considered."
One possibility is that the gas undergoes a large scale boiling motion which slows down the rate at which gas falls into the black hole.
The best previous X-ray pictures were not sharp enough to clearly distinguish the X-ray source associated with the black hole in the center of the Andromeda Galaxy nor did they give information about the temperature of the source.
"A good analogy might be to say that previous X-ray images were taken with a slightly out-of-focus black and white camera, while the Chandra image is taken with a sharp, color camera" said Murray.
Another intriguing feature of this observation is the detection of a diffuse glow that extends for a thousand light years around the central region. It is not known if this is due to many individual sources, or to a hot wind expanding out from the center.
"This is just a first, quick look at our nearest Milky Way analog," Murray emphasized. "I expect that our future pictures will lead to more exciting discoveries in the Andromeda Galaxy."
The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University, University Park.
To follow Chandra's progress, visit the Chandra site at:
http://chandra.harvard.edu/photo/cycle1/0007/index.html
AND
http://chandra.nasa.gov
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.
IMAGE CAPTION:
Image made with the Advanced CCD Imaging Spectrometer (ACIS)
Credit: NASA/CXC/SAO
NASA Headquarters, Washington, DC
Marshall Space Flight Center, Huntsville, AL
Goddard Space Flight Center, Greenbelt, MD
Harvard-Smithsonian Center for Astrophysics, Cambridge, MA
January 13, 2000
Not bad for being on the job only five months.
Chandra has resolved most of the X-ray background, a pervasive glow of X-rays throughout the Universe, which was first discovered in the early days of space exploration. Before now, scientists have not been able to discern the origin of the hard, or high-energy, X-ray background, because until Chandra no telescope has had the technology to resolve it.
"This is a major discovery," said Dr. Alan Bunner, Director of NASA's Structure and Evolution of the Universe science theme. "Since it was first observed 37 years ago, understanding the source of the X-ray background has been a Holy Grail of X-ray astronomy. Now, it is within reach."
The results of the observation will be presented today at the 195th national meeting of the American Astronomical Society in Atlanta, GA. An article describing this work has been submitted to the journal Nature by Dr. Richard Mushotzky of NASA's Goddard Space Flight Center, Greenbelt, MD, Drs. Lennox Cowie and Amy Barger at the University of Hawaii, Honolulu, and Dr. Keith Arnaud of the University of Maryland, College Park.
"We are all very excited by this finding," said Mushotzky. "The resolution of most of the hard X-ray background during the first few months of the Chandra mission is a tribute to the power of this observatory and bodes extremely well for its scientific future."
The Chandra team looked at a small section of the sky, a circle about one-fifth the size of a full moon, and resolved about 80% of the X-ray glow in this region into specific light sources. Stretched across the entire sky, this adds up to approximately 70 million sources, most of which are galaxies.
One-third of the sources are galaxies whose cores shine bright in X-rays, yet do not shine in visible light. There may be tens of millions of these "veiled galactic nuclei" in the Universe. Each of these galaxies likely harbors a massive black hole at its core that produces X-rays as gas is pulled toward it at nearly the speed of light.
A second new class of objects, comprising approximately one- third of the sources, is assumed to be "ultra-faint galaxies." Mushotzky said that these sources may emit little or no optical light, either because the dust around the galaxy blocks the light totally or because the optical light is eventually absorbed during its long journey across the Universe.
In the latter scenario, Mushotzky said that these sources would be well over 14 billion light years away and thus the earliest, most distant objects ever identified.
Resolution of the X-ray background relied on a 27.7-hour Chandra observation using the Advanced CCD Imaging Spectrometer in early December 1999, and also utilized data from the Japan-U.S. Advanced Satellite for Cosmology and Astrophysics.
For images connected to this release, and to follow Chandra's progress, visit the Chandra sites at http://chandra.nasa.gov"> and http://chandra.harvard.edu
Marshall Space Flight Center
Hunstville, AL
MAssachusetts Institute of Technology
Cambridge, MA
Chandra X-ray Observatory Center
Harvard-Smithsonian Center for Astrophysics
Cambridge, MA
January 14, 2000
The results were reported by Professor Claude Canizares of the Massachusetts Institute of Technology (MIT), Cambridge, at the 195th national meeting of the American Astronomical Society in Atlanta, Ga. Drs. Kathryn Flanagan, David Davis, and John Houck of MIT collaborated with Canizares in this investigation.
E0102-72 is the remnant of a supernova explosion located in our neighbor galaxy, the Small Magellanic Cloud, nearly 200,000 light years away. It was created by the explosion of a star that was more than ten times as massive as our Sun. We are seeing the aftermath of the explosion a thousand or more years after the outburst. Shock waves are heating gas to temperatures of nearly 10 million degrees, so it glows with X-rays that are detected by Chandra's instruments.
By using the High Energy Transmission Grating Spectrometer (HETG), astronomers were able to pinpoint the distribution of each chemical element individually and measure the velocities of different parts of the expanding ring. They also show the shock wave in a kind of "freeze- frame," revealing the progressive heating of the stellar matter as it plows into the surrounding gas. This is the first time such detailed X-ray information has ever been obtained for a supernova remnant, and should provide critical clues to the nature of supernovae.
The grating spectrometer, which was built by an MIT team led by Canizares, spreads the X-rays according to their wavelength, giving distinct images of the object at specific wavelengths characteristic of each chemical element. Small wavelength shifts caused by the Doppler effect are used to measure the expansion velocities of each element independently.
"We've been studying these supernova remnants for decades, but now we're getting the kind of information we need to really test the theories," said Canizares.
"Understanding supernovae helps us to learn about the processes that formed chemical elements like those which are found on Earth and are necessary for life," said Flanagan.
Most of the oxygen in the universe, for example, is synthesized in the interiors of relatively few massive stars like the one being studied here. When they explode, they expel the newly manufactured elements which become part of the raw material for new stars and planets. The amount of oxygen in the E0102-72 ring is enough for thousands of solar systems.
By measuring the expansion velocity of the ring, the team can estimate the amount of energy liberated in the explosion. The expansion energy would be enough to power the sun for 3 billion years. The ring has more complex structure and motion than can be explained by current simplified theories, suggesting complexity in the explosion itself or in the surrounding interstellar matter.
The supernova remnant also provides a laboratory for atomic physics. The observations show how the atoms in the expelled matter behave when heated to such high temperatures. The images reveal the progressive stripping of electrons from the atoms after the super-sonic shock wave has passed.
The Chandra observation was taken using the HETG in conjunction with the Advanced CCD Imaging Spectrometer (ACIS) on September 28 and October 10, 1999. ACIS was built by Pennsylvania State University, University Park, and the Massachusetts Institute of Technology, Cambridge.
To follow Chandra's progress or download images visit the Chandra
sites at
http://chandra.harvard.edu/photo/cycle/0015/index.html
AND
http://chandra.nasa.gov
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.
Further information on the HETG
IMAGE CAPTION:
Chandra X-ray Observatory ACIS/High Energy Transmission Grating Image
Credit:NASA/MIT
Marshall Space Flight Center
Huntsville, AL
Chandra X-ray Observatory Center
Cambridge, MA
Penn State University
University Park, PA
January 14, 2000
The Orion region is a dense congregation of about 2,000 very young stars formed during the past few million years. The discovery of such a wealth of X-ray stars in the closest massive star-forming region to Earth (only 1,500 light years away) is expected to have a profound impact on our understanding of star formation and evolution.
"We've detected X-rays from so many fantastic objects, such as very young massive stars and stars so small that they may evolve into brown dwarfs," said Gordon Garmire, Evan Pugh Professor at Penn State University, University Park. "Chandra's superb angular resolution has resolved this dense cluster of stars with arcsecond accuracy and unsurpassed sensitivity."
Garmire leads the team using Chandra's ACIS detector, the Advanced CCD Imaging Spectrometer, conceived and developed for NASA by Penn State University and the Massachusetts Institute of Technology.
The brilliant Orion region has awed humankind for millennia. The most massive and brightest of these nascent stars are in the Orion Trapezium, which illuminates the Orion Nebula, also known as Messier 42. The Trapezium and its luminous gas can be seen with the unaided eye in the winter sky in the "sword" of the Orion constellation.
Young stars, such as those found in Orion, are known to be much brighter in X-rays than middle-aged stars such as the Sun. The elevated X-ray emission is thought to arise from violent flares in strong magnetic fields near the surfaces of young stars. The Sun itself was probably thousands of times brighter in X-rays during its first few million years.
Although the enhanced magnetic activity of young stars has been known for some time, the physical causes and evolution of the activity are poorly understood, according to Dr. Eric Feigelson, professor of astronomy and astrophysics at Penn State.
"With hundreds of stars observed simultaneously, possessing a wide range of properties such as mass and rotation rates, we hope the Orion observation will help unravel the astrophysical principles underlying this phenomenon," Feigelson said. "X-ray astronomy now penetrates as deeply into the clouds as the best infrared and optical telescopes, permitting us to study high-energy processes during the earliest phases of star formation."
"This Chandra image is a milestone in the field of X-ray astronomy and very gratifying to me personally," said Garmire. "Chandra's sensitivity is 20 times better than achieved with the best previous X-ray telescopes."
A number of the ACIS X-ray sources in the Orion observation have special importance. Several are associated with a distinct cluster of higher-mass stars deeply embedded within the murky Orion Molecular Cloud, including the infrared-luminous Becklin-Neugebauer object.
"This is the first time X-ray astronomy has resolved individual massive stars still embedded in their natal cloud," said Dr. Leisa Townsley, research associate in astronomy and astrophysics at Penn State.
At least three ACIS sources are associated with cluster members with masses so small (roughly 1/20th of the Sun's mass), that they will evolve into brown dwarfs rather than true stars.
"They more closely resemble proto-Jupiters than proto-stars," said Dr. Yohko Tsuboi, visiting research scholar in astronomy and astrophysics at Penn State. "Over a dozen X-ray sources have no known counterpart, even in the most sensitive Hubble Space Telescope or infrared studies. These too may be very low-mass stars."
The ACIS team studying the Orion X-ray source includes Profs. Feigelson and Garmire and research scientists Patrick Broos, Leisa Townsley, and Yohko Tsuboi at Penn State; Steven Pravdo at the Jet Propulsion Laboratory; and Lynne Hillenbrand at the California Institute of Technology.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.
To follow Chandra's progress or download images visit the Chandra
sites at:
http://chandra.harvard.edu/photo/cycle1/0054/index.html
AND
http://chandra.nasa.gov
FOR FURTHER INFORMATION AND IMAGES:
A web site associated with this press release provides high-resolution digital images (JPEG, TIFF and PostScript formats) and hypertext links to images of the Orion Nebula at non-X-ray wavelengths plus related material.
IMAGE CAPTION:
Image made with the Advanced CCD Imaging Spectrometer (ACIS)
Credit: NASA/PSU
NASA Space Science News for Dec 21, 1999
Going Prospecting Inside a Supernova: Astronomers have used NASA's orbital Chandra X-ray Observatory to make an important new discovery about how silicon, iron, and other elements are produced in supernova explosions.
SPECIAL NOTE:
The Science@NASA team would like to say farewell and offer a special word of thanks to Dave Dooling. Dave has served as the senior writer for Science@NASA for over three years, bringing our readers to the cutting edge of NASA's most interesting science research through the vehicle of the Internet. As a result of funding constraints for science communications at NASA/Marshall, Dave is leaving our team on Dec 21. Our readers will miss Dave's skillfully crafted stories, and his colleagues will miss his wit, creativity and professionalism. Dave's final story will be an upcoming article on the bright gamma-ray burst of December 16, 1999.
Rutgers University
Marshall Space Flight Center
Chandra X-ray Observatory Center
Dec. 21, 1999
The findings appear online in the Astrophysical Journal Letters.
and are slated for print publication on Jan. 10, 2000. Authors of the paper "Nucleosynthesis and Mixing in Cassiopeia A" are Hughes, Rutgers graduate student Cara Rakowski, Dr. David Burrows of Pennsylvania State University, University Park, Penn., and Dr. Patrick Slane of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.
According to Hughes, one of the most profound accomplishments of twentieth century astronomy is the realization that nearly all of the elements other than hydrogen and helium were created in the interiors of stars. "During their lives, stars are factories that take the simplest element, hydrogen, and convert it into heavier ones," he said. "After consuming all the hydrogen in their cores, stars begin to evolve rapidly, until they finally run out of fuel and begin to collapse. In stars 10 times or so more massive than our sun, the central parts of the collapsing star may form a neutron star or a black hole, while the rest of the star is blown apart in a tremendous supernova explosion." Supernovae are rare, occurring only once every 50 years or so in a galaxy like our own.
"When I first looked at the Chandra image of Cas A, I was amazed by the clarity and definition," said Hughes. "The image was much sharper than any previous one and I could immediately see lots of new details."
Equal in significance to the image clarity is the potential the Chandra data held for measuring the composition of the various knots and filaments of stellar material visible in Cas A. Not only could the astronomers determine the composition of many knots in the remnant from the Chandra data, they were also able to infer where in the exploding star the knots had originated.
For example, the most compact and brightest knots were composed mostly of silicon and sulfur, with little or no iron. This pointed to an origin deep in the star's interior where the temperatures had reached three billion degrees during the collapse and resulting supernova. Elsewhere, they found fainter features that contained significant amounts of iron as well as some silicon and sulfur. This material was produced even deeper in the star, where the temperatures during the explosion had reached higher values of four to five billion degrees.
When Hughes and his collaborators compared where the compact silicon-rich knots and fainter iron-rich features were located in Cas A, they discovered that the iron-rich features from deepest in the star were near the outer edge of the remnant. This meant that they had been flung the furthest by the explosion that created Cas A. Even now this material appears to be streaming away from the site of the explosion with greater speed than the rest of the remnant.
By studying the Cas A Chandra data further, astronomers hope to identify which of the several processes proposed by theoretical studies is likely to be the correct mechanism for explaining supernova explosions, both in terms of the dynamics and elements they produce.
"In addition to understanding how iron and the other elements are produced in stars, we also want to learn how it gets out of stars and into the interstellar medium. This is why the study of supernovae and supernova remnants is so important," said Hughes. "Once released from stars, newly- created elements can then participate in the formation of new stars and planets in a great cycle that has gone on numerous times already. It is remarkable to realize that our planet Earth and indeed even humanity itself is part of this vast cosmic cycle."
The Chandra observation was taken with the Advanced CCD Imaging Spectrometer (ACIS) Aug. 19, 1999. ACIS was built by Pennsylvania State University, and the Massachusetts Institute of Technology, Cambridge, Mass.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.
High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF ) and other information associated with this release are available on the Internet at:
http://chandra.harvard.edu/photo/casajph/
Marshall Space Flight Center
Huntsville, AL
Massachusetts Institute of Technology
Chandra X-ray Observatory Center
Dec. 14, 1999
The Chandra observations were made under the direction of a team of
scientists from the Massachusetts Institute of Technology (MIT) in
Cambridge, led by Walter Lewin and his graduate student, Derek Fox.
When combined with simultaneous observations by radio and optical
telescopes, the X-ray observations tell about the thickness of the shell
that was blown off, its density, its speed, and how much material was
shed by the star before it exploded.
Chandra observed an X-ray glow from SN1999em with the total power
of 50,000 suns. Ten days later it observed the supernova for another
nine hours, and found that the X-rays had faded to half their previous
intensity. The optical luminosity, which had the brightness of 200
million suns, had faded somewhat less. No radio emission was
detected at any time.
With this information, the MIT group and their colleagues are already
piecing together a picture of the catastrophic explosion. Observations
by optical astronomers showed that SN1999em was a Type II supernova
produced by the collapse of the core of a star ten or more times as
massive as the sun. The intense heat generated in the collapse produces
a cataclysmic rebound that sends high speed debris flying outward at
speeds in excess of 20 million miles per hour. The debris crashes into
matter shed by the former star before the explosion. This awesome
collision generates shock waves that heat expanding debris to three
million degrees. The X-ray glow from this hot gas was detected by
Chandra and gives astrophysicists a better understanding of the
dynamics of the explosion, as well as the behavior of the doomed
star in the years before the explosion.
"The combination of X-ray detection and radio non-detection is unusual,
but may have less to do with the supernova and more to do with the
great sensitivity of Chandra," said Roger Chevalier of University of
Virginia, Charlottesville. Chevalier explained that the combined
observations indicate that SN1999em shed a relatively small amount
of matter before it exploded, compared to other supernovae observed
in X-rays. The Chandra observation is important because it may
represent a more common type of supernova.
The Chandra observation also provides an inside look at the hectic,
exciting world of the international "quick response" network that
scientists have set up to track and investigate supernovae.
On Friday, October 29, Alex Fillipenko of the University of California,
Berkeley, notified Bob Kirshner at Harvard-Smithsonian Center for
Astrophysics, Cambridge, Mass., that his automated supernova search
project had a good candidate in a relatively nearby spiral galaxy, NGC
1637. Nearby in this case means about 25 million light years from
Earth. Wei Dong Li, who is visiting Fillipenko's group from the Beijing
Astronomical Observatory in China, called his colleagues in Beijing,
who confirmed the supernova when the Earth rotated into a position
to make viewing from China possible. The astronomers also notified
the International Astronomical Union's central bureau for astronomical
telegrams in Cambridge, Mass., from which the discovery was broadcast
worldwide. Radio astronomers Christina Lacey and Kurt Weiler at the
Naval Research Laboratory in Washington, D.C., Schuyler van Dyk at the
California Institute of Technology, Pasadena and Richard Sramek at the
National Radio Astronomy Observatory's Very Large Array, Socorro, N.M.,
were alerted.
Kirshner then got in touch via e-mail with Harvey Tananbaum, director
of the Chandra X-ray Center at Harvard-Smithsonian a little before 11
p.m. on Saturday night. The Chandra operations team replanned the
telescope's observation activities and by Monday morning, and by
Monday morning, Chandra was pointed at the supernova and observed
it for about nine hours.
Lewin, who had been awarded the rights to Chandra's first observation
of a nearby supernova, was ecstatic. "This is a unique chance that we
have been hoping for!!!!" he wrote in an e-mail to Tananbaum.
"I was impressed by how rapid the Chandra response was, " said Kirshner.
"Supernovae expand quickly and cool quickly, so each day we delay
observing the supernova it has changed irretrievably," Filippenko said.
"We caught this really early, only a day or two after the explosion. We
were lucky."
The Chandra observation was taken with the Advanced CCD Imaging
Spectrometer (ACIS) on November 1 and 2, and 11 and 12, 1999 in two
separate observations that lasted approximately nine hours each. ACIS
was built by Pennsylvania State University, University Park, and MIT.
To follow Chandra's progress, visit the Chandra sites at:
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the
Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor
for the spacecraft. The Smithsonian's Chandra X-ray Center controls
science and flight operations from Cambridge, Mass.
High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF)
and other information associated with this release are available on the
Internet at:
High resolution digital versions of the
X-ray image (JPG, 300 dpi TIFF) and other informatioin associated with this
release.
NASA Headquarters, Washington, DC
December 9, 1999
For years astronomers have been searching unsuccessfully for
large quantities of matter they believed must be flowing into the
central regions of galaxy clusters. The Chandra image of Hydra A
displays for the first time long snake-like strands of 35 million
degree gas extending away from the center of the cluster. These
structures show that the inflow of cooling gas is deflected by
magnetic fields produced by explosions from a central black hole.
The X-ray image also reveals a bright wedge (shown in white)
of hot multimillion degree gas pushing into the heart of the
cluster. Like the legendary Hercules, who had to contend with the
multiple heads of the monstrous Hydra, astrophysicists now know
they must deal with the effects of magnetic fields, star
formation, rotation and black holes if they are to understand what
is happening in the inner regions of the galaxy cluster.
As the largest gravitationally bound objects in the universe,
galaxy clusters provide crucial clues for understanding the origin
and fate of the universe. Each large cluster such as Hydra A
contains hundreds of galaxies and enough gaseous material to make
a thousand more galaxies. One intriguing question has been the
ultimate fate of this colossal gas reservoir. Early X-ray
observations indicated that the gas in the inner regions of Hydra
A should be cooling and slowly settling into the center of the
cluster to form new galaxies or hundreds of trillions of dim
stars. As astronomers began searching for this cool matter, they
were puzzled to find that the new galaxies and stars were not
detected in sufficient numbers.
The Chandra results on Hydra A, which is 840 million light
years from Earth, may point to a resolution of this problem. The
inflow of cooling gas may be deflected by magnetic fields, and
even pushed back into the cluster by explosions from the vicinity
of a supermassive black hole at the core of the central galaxy.
"In Hydra, you can see the whole cycle," said Brian McNamara
of the Harvard-Smithsonian Center for Astrophysics. "You have the
hot gas cloud, the disk of material feeding the black hole, and
the evidence that the explosion from the gas near the black hole
is pushing the hot gas around."
Indeed, combined radio and X-ray observations suggest that a
vast bubble of high energy particles is pushing the hot gas aside,
creating the Hydra-like loops of hot gas. Similar processes are
likely to be at work in other galaxy clusters, and in newly
forming galaxies that are collapsing from a cloud of gas. By
using images with Chandra and other telescopes, astronomers may
eventually conquer a "monstrous" problem of cosmic significance.
The Chandra image was taken with the Advanced CCD Imaging
Spectrometer (ACIS) on October 30, 1999, in an observation that
lasted about six hours.
High resolution digital versions of the X-ray image (JPG, 300
dpi TIFF) and other information associated with this release are
available on the Internet at:
http://chandra.harvard.edu/photo/0087/
or through links at:
NASA's Marshall Space Flight Center, Huntsville, AL, manages
the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime
contractor for the spacecraft. The Smithsonian's Chandra X-ray
Center controls science and flight operations from Cambridge, MA.
Chandra Xray Observatory Center
November 16, 1999
3C295 appears as a giant, basketball-shaped galaxy that contains several
time the mass of our Milky Way galaxy. Astronomers think that it has
grown over the eons as mass from the colossal gas cloud cooled and
settled onto the galaxy.
The bright X-ray knots visible for the first time in the Chandra image are
probably an indirect result of this dumping of gas onto 3C295. The central
knot coincides with the center of the galaxy; these X rays are most likely
due to matter falling into a supermassive black hole. The upper and lower
knots are in the same location as two large lobes of radio emission. The
distance from the top to the bottom knot is about 100,000 light years,
comparable to the diameter of our Milky Way galaxy. The total X-ray
power in the knots is three times greater than all the power produced
by our galaxy.
X-ray and radio observations indicate that 3C295 was wracked by an
awesome explosion that occurred about a million years ago in the center
of the galaxy. Chandra observations suggest that the explosion is related
to an excess of matter falling into the massive black hole. In much the
same way that a torrent of water pouring down a drain can produce a
back pressure if the flow is more than the drain can handle, the enormous
energy released by too much matter flowing into a black hole could trigger
an explosion. Great quantities of matter and energy would be hurled back
into the surrounding gas cloud, in a powerful payback for eons of being
dumped on by a cosmic bully.
The Chandra image was taken with the Advanced CCD Imaging
Spectrometer (ACIS) on August 30, 1999 in an observation that lasted
about six hours. ACIS was built by Penn State Univ. and MIT. The image
has been colorized to highlight the intense X-radiation from the X-ray
knots in 3C295.
To follow Chandra's progress, visit the Chandra site at:
jttp://chandra.harard.edu
AND
NASA's Marshall Space Flight Center in Huntsville, AL, manages the
Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor
for the spacecraft. The Smithsonian's Chandra X-ray Center controls
science and flight operations from Cambridge, MA.
High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF)
and other information associated with this release are available on the
Internet at:
http://chandra.harvard.edu/photo/0166
or via links in:
October 12, 1999
The new X-ray observation shows three distinct structures: an outer,
horseshoe shaped ring about two light-years in diameter, a hot inner core
about 3 light-months in diameter, and a hot central source less than a
light-month in diameter which may contain the superstar. In one month, light
travels a distance of approximately 489 billion miles (about 788 billion
kilometers).
All three structures are thought to represent shock waves produced by matter
rushing away from the superstar at supersonic speeds. The temperature of the
shock-heated gas ranges from 60 million degrees Kelvin in the central
regions to 3 million degrees K on the outer structure.
An earlier image of Eta Carinae by the Hubble Space Telescope revealed two
spectacular bubbles of gas expanding in opposite directions away from a
central bright region at speeds in excess of a million miles per hour. The
inner region visible in the Chandra image has never been resolved before,
and appears to be associated with a central disk of high velocity gas
rushing out at much higher speeds perpendicular to the bipolar optical
nebula.
"It is not what I expected," said Chandra researcher Dr. Fred Seward of the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "I expected
to see a strong point source with a little diffuse emission cloud around it.
Instead, we see just the opposite -- a bright cloud of diffuse emission, and
much less radiation from the center."
"The Chandra image poses a problem for one of the currently most favored
theories for the X-ray emission from the central region of Eta Carinae,"
agreed Professor Kris Davidson of the University of Minnesota in
Minneapolis. "Namely that it is due to the collision of shells of material
thrown off by two stars circling one another. In such a scenario, you would
expect to see a much stronger point source."
Eta Carinae is one of the most enigmatic and intriguing objects in our
galaxy. Between 1837 and 1856 it increased dramatically in brightness to
become the most prominent star in the sky except for Sirius, even though it
is 7,500 light years away, more than 80 times the distance to Sirius. This
"Great Eruption," as it is called, had an energy comparable to a supernova,
yet did not destroy the star, which faded to become a dim star, invisible to
the naked eye. Since 1940, Eta Carinae has begun to brighten again, becoming
visible to the naked eye.
Modern day observations of Eta Carinae have shown it to be the most luminous
object known in our galaxy. It radiates at the rate of several million times
that of the Sun. Most of the radiation is at infrared wavelengths, from dust
in the bipolar nebula.
Astronomers still do not know what lies at the heart of Eta Carinae. Most
believe that it is powered by an extremely massive star that may be a
hundred times as massive as the Sun. Such stars produce intense amounts of
radiation that cause violent instabilities before they explode as a
supernova.
The Chandra X-ray image gives a glimpse deep into the nebula where the
fastest material being thrown off by Eta Carinae is found. The outer ring
provides evidence of another large explosion that occurred over a thousand
years ago. Further Chandra observations of Eta Carinae are planned for the
near future and should give astronomers deeper insight into this cryptic
colossus.
NASA Science News for October 9, 1999
Image of Eta Carina reveals shocking details of mysterious star: NASA's
Chandra X-ray Observatory has imaged Eta Carinae, the Milky Way's most luminous
star. This exploding star, which also has been imaged by the Hubble Space
Telescope, is huffing and puffing its way to eventual self-destruction.
NASA Science News for September 29, 1999
"The gift that keeps on giving" offers a new answer and a new puzzle for
astronomers: Another fabulous discovery from Chandra X-ray Observatory shows a
bright ring of fire around the pulsar at the heart of the Crab Nebula.
Scientists believe this is a link between the Crab's powerhouse and its light
show.
NASA Headquarters, Washington, DC
Sept. 28, 1999
Cambridge, MA
Harvard-Smithsonian Center for Astrophysics
Cambridge, MAThe End of Days -- Chandra Catches X-ray Glow From Supernova
Through a combination of serendipity and skill, scientists have used
NASA's Chandra X-ray Observatory to capture a rare glimpse of
X-radiation from the early phases of a supernova, one of the most
violent events in nature. Although more than a thousand supernovae
have been observed by optical astronomers, the early X-ray glow
from the explosions has been detected in less than a dozen cases.
http://chandra.harvard.edu
and
http://chandra.nasa.gov
Marshall Space Flight Center, Huntsville, AL
Harvard-Smithsonian Center for Astrophysics, Cambridge, MACHANDRA PLOUGHS UP A SNAKE IN HYDRA A
NASA's Chandra X-ray Observatory image of the Hydra A galaxy
cluster has revealed a possible solution to a Herculean puzzle
about the fate of the largest objects in the universe.
Harvard-Smithsonian Center for Astrophysics
Cambridge, MA 02138COSMIC PAYBACK -- GIANT GALAXY REACTS TO BEING DUMPED ON
The NASA Chandra X-ray Observatory image of the distant galaxy 3C295
shows an explosive galaxy enveloped by a vast cloud of fifty million degree
gas. The gas cloud, which is visible only with an X-ray telescope, contains
more than a hundred galaxies and enough material to make a thousand more.
The galaxies are too cool to be visible in X rays. Roughly two million light
years in diameter, the cloud and its cluster of galaxies are among the most
massive objects in the universe. It is so distant that we see it as it was
five billion years ago.
http://chandra.nasa.govNew Chandra X-ray Observatory images reveal 'shocking' details of mysterious
superstar's activity
New images of the mysterious superstar Eta Carinae by NASA's Chandra X-ray
Observatory reveal a surprising hot inner core -- creating more questions
than answers for astronomers.
Marshall Space Flight Center, Huntsville, AL
Chandra X-ray Observatory Center, Cambridge, MACHANDRA DISCOVERS X-RAY RING AROUND COSMIC POWERHOUSE IN CRAB NEBULA
After barely two months in space, NASA's Chandra X-ray
Observatory has taken a stunning image of the Crab Nebula, the
spectacular remains of a stellar explosion, and has revealed
something never seen before: a brilliant ring around the nebula's
heart.
Combined with observations from the Hubble Space Telescope, the image provides important clues to the puzzle of how the cosmic "generator," a pulsing neutron star, energizes the nebula, which still glows brightly almost 1,000 years after the explosion.
"The inner ring is unique," said Professor Jeff Hester of Arizona State University, Tempe, AZ. "It has never been seen before, and it should tell us a lot about how the energy from the pulsar gets into the nebula. It's like finding the transmission lines between the power plant and the light bulb."
Professor Mal Ruderman of Columbia University, New York, NY, agreed. "The X-rays Chandra sees are the best tracer of where the energy is. With images such as these, we can directly diagnose what is going on."
What is going on, according to Dr. Martin Weisskopf, Chandra Project Scientist from NASA's Marshall Space Flight Center, Huntsville, AL, is awesome. "The Crab pulsar is accelerating particles up to the speed of light and flinging them out into interstellar space at an incredible rate."
The image shows tilted rings or waves of high-energy particles that appear to have been flung outward over the distance of a light year from the central star, and high-energy jets of particles blasting away from the neutron star in a direction perpendicular to the spiral.
Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous X-ray images have shown the outer parts of the jet and hinted at the ring structure. With Chandra's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with Chandra's Advanced CCD Imaging Spectrometer and High Energy Transmission Grating.
The Crab Nebula, easily the most intensively studied object beyond our solar system, is the remnant of a star that was observed to explode in 1054 A.D. Chinese astronomers in that year reported a "guest star" that appeared suddenly and remained visible for weeks, even during daytime. From gamma-ray telescopes to radio telescopes, the Crab has been observed using virtually every astronomical instrument that could see that part of the sky.
Unraveling the mysteries of the Crab has proven to be the door to insight after insight into the workings of the universe. The Crab convincingly tied the origin of enigmatic "pulsars" to the stellar cataclysms known as supernovae. Observations of the expanding cloud of filaments in the Crab were instrumental in confirming the cosmic origin of the chemical elements from which planets (and people) are made.
The nebula is located 6,000 light years from Earth in the constellation Taurus. The Crab pulsar, which was discovered by radio astronomers in 1968, is a neutron star rotating 30 times per second. Neutron stars are formed in the seconds before a supernova explosion when gravity crushes the central core of the star to densities 50 trillion times that of lead and a diameter of only 12 miles.
Another consequence of the dramatic collapse is that neutron stars are rapidly rotating and highly magnetized. Like a gigantic cosmic generator, the rotating magnet generates 10 quadrillion volts of electricity, 30 million times that of a typical lightning bolt.
"It is an incredibly efficient generator," Ruderman explained. "More than ninety-five percent efficient. There's nothing like it on Earth."
NASA's Marshall Space Flight Center manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.
Chandra images are posted to the Internet.
NASA Science News for September 28, 1999
Peering into the heart of a Crab - A brilliant ring around a cosmic powerhouse at the heart of the Crab Nebula will be revealed today in new images to be released from the Chandra X-ray Observatory. The Crab is one of the most beautiful - and most studied - bodies in the skies, and serves as a Rosetta Stone for modern astrophysics. This story sets the stage for today's conference by summarizing what we know about the Crab nebula.
NASA Headquarters, Washington, DC
Marshall Space Flight Center, Huntsville, AL
Chandra X-ray Center, Harvard-Smithsonian Observatory, Cambridge, MA
Sept. 23, 1999
The ring is the first such structure ever discovered, and, along with observations from the Hubble Space Telescope, provides important clues to the puzzle of how the neutron star powerhouse energizes the Crab Nebula.
Panelists will be:
The briefing will be carried live on NASA Television with question-and-answer capability for reporters covering the briefing from participating NASA centers and from the Chandra Operations Control Center in Cambridge, MA. NASA Television is available on transponder 9C, satellite GE-2 at 85 degrees West longitude, vertical polarization, frequency 3880 MHz, audio of 6.8 MHz.
Chandra images and additional information will be available following the briefing on the Internet at:
and
Previous news on the Chandra X-Ray observatory and its discoveries
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