Chandra Catches "Piranha" Black Holes

These two galaxy clusters, known as CL 0542-4100 and CL 0848.6+4453, are part of a sample used to count the fraction of galaxies with rapidly growing black holes, also known as active galactic nuclei (AGN). In the Chandra images of these two galaxy clusters, red corresponds to low-energy X-rays, the green to intermediate-energy, and the blue to high-energy X-rays. In each of these two fields, five AGN are found, although one of these may not be a member of the cluster. Many of the AGN are blue sources, as expected, since AGN are known to produce very high-energy X-rays. The diffuse emission is hot gas in the cluster and other point-like sources in the image are nearly all unrelated to the galaxy cluster.

The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. The four galaxy clusters in the distant sample, including the two shown here, are seen when the Universe is only about 58% of its current age. The nearby sample of galaxy clusters, obtained in an earlier study, is seen at about 82% of the Universe’s current age. It was found that the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span.

The reason for this difference is that earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. There was so much fuel in young clusters that the piranha-like black holes were able to thrive by growing much faster than their counterparts in nearby clusters.

Image credit: NASA/CXC/Ohio State Univ./J.Eastman et al.

+ Read full caption/access larger images

Source: NASA - Chandra - Multimedia

July 27, 2007: Deep in the heart of the Milky Way galaxy lurks an extraordinary black hole. Astronomers call it "supermassive." It has been feeding on the core of our galaxy so long, the hole has accumulated more than a million Suns of mass inside its pinprick belly.

How do we know it's there? You can't see a black hole. It reveals itself whenever an errant star or cloud of gas meanders too close. Matter falling into the hole is ripped apart and superheated, emitting bursts of high-energy radiation just before it disappears over the event horizon. Occasionally a burp of X-rays emanates from the Milky Way's core, and astronomers check off another meal.

Above: Matter swirls into a growing supermassive black hole--an artist's concept. [More]

Today these burps are seldom, but among astronomers it is widely thought that the Milky Way's "monster in the middle" used to be more active--frighteningly so. Paul Martini of Ohio State University (OSU) explains: "Billions of years ago, when our galaxy was young, there was more 'food' in the core—lots more gas and stars for the black hole to consume." He believes there could have been "a real feeding frenzy" lighting up the center of the Milky Way like a beacon visible half-way across the Universe.

Could this be true?

Finding out requires traveling back in time--a trick, believe it or not, astronomers are able to perform. "By looking at galaxies billions of light years away, we can see them as they were billions of years ago," explains Martini. "This can give us a clue to the state of the Milky Way when it was young."

So, in an effort led by OSU astronomy graduate student Jason Eastman, Martini and colleagues used data from NASA's Chandra X-ray Observatory to examine 12 clusters of galaxies ranging in distance from 2.4 to 5.7 billion light years away. Their purpose: to learn how galactic cores change over time.

What they saw reminded Eastman of "piranhas in a very well-fed aquarium." Younger galaxies tended to be very active; supermassive black holes at their cores were furiously consuming matter and producing copious X-rays in the process.

Older galaxies, on the other hand, were relatively calm; the frenzy was subsiding. "It's not that the black holes were no longer hungry," says Eastman, "they were just running out of things to eat." The ratio of active X-ray cores in the galaxies they analyzed, younger vs. older, was about 20 to 1.


Above: A Chandra X-ray image of one of the clusters
of galaxies used in Eastman et al's study. [More]

"The food, or fuel for a central black hole, is primarily thought to be interstellar gas," adds Martini. "It is likely that an occasional star is also swallowed, but most researchers agree that clouds of gas are the main fuel source."

Hence the big picture: When galaxies are young, a black hole forms at the core. Why? "Because that is the bottom of the galaxy's gravitational potential well," answers Martini. "Gas, stars, even smaller black holes will settle to the center of the galaxy over time." At first, gas is abundant, and the black hole feeds greedily, announcing itself to the cosmos via high-energy X-rays. As time passes, the core is depleted of gas and feeding subsides. By the time a galaxy is as old as the Milky Way (10+ billion years), the central black hole has grown to millions of solar masses, but only takes an occasional meal. The fish is hungry, but the water is nearly empty.

A note to the stars: Beware the Piranha.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass.

Author: Dr. Tony Phillips | Production Editor: Dr. Tony Phillips | Credit: Science@NASA

____________________________________________

More Information

Chandra X-ray Observatory -- home page

"One limitation of the piranha analogy," notes Martini, "is that it implies a black hole actively seeks out food, whereas in practice the black hole is more like a Venus fly trap that waits for food to come within reach of its gravitational pull." So, in the center of our galaxy lurks a hungry, supermassive, x-ray burping … Venus Fly Trap? Extraordinary, indeed.

Source: Science@NASA

An artist concept of dusty gas around NGC 5044
NASA/JPL-Caltech/R. Hurt (SSC)

Written by Linda Vu, Spitzer Science Center
August 16, 2007

New evidence from NASA's Spitzer Space Telescope shows that supermassive black holes at the centers of elliptical galaxies keep the galactic "thermostat" so high gas cannot cool, stunting the birth of new stars.

For the first time ever, astronomers have detected dust grains mingling with blazing hot gas at temperatures of 10 million degrees Kelvin (about 10 million degrees Celsius, or 17 million degrees Fahrenheit), in an area surrounding the elliptical-shaped galaxy called NGC 5044. Scientists hope this new finding will provide insight into how supermassive black holes reduce the stellar fertility in elliptical galaxies by heating gas.

Similar to raindrops forming in Earth's clouds, stars form when dense cosmic clouds of gas and dust condense. Scientists suspect that if the gas surrounding a galaxy never cools enough to condense, then new stars cannot form.

"Generally we see X-ray emission from hot gas surrounding elliptical galaxies, extending far beyond their visible stars, but we do not fully understand the mechanisms that keep the gas from cooling. Our observation of plumes of dusty, hot gas shows that heating by massive black holes in the galactic cores may be a possible mechanism," said Dr. Pasquale Temi, of the NASA Ames Research Center and the SETI Institute in Calif. Temi is the principal investigator of the study slated to appear in the Astrophysical Journal.

"This is a very surprising discovery. Typically you wouldn't expect to see dust grains surviving in this type of heat -- this is like finding a snowflake in hell," says Dr. William Mathews, of the University at California at Santa Cruz. "We think that NGC 5044 is revealing a transient heating process that is common and astronomically important."

Galaxies in the universe come in many shapes and sizes. Spiral galaxies, like our own Milky Way, are usually active in star formation. By contrast, elliptical galaxies are stellar retirement communities because they are made up of older stars, and don't form many new stars. Many elliptical galaxies, like NGC 5044, are found at the centers of galaxy clusters that are filled with enormous amounts of hot gas. Why the gas doesn't cool and form new stars is a subject of intense debate among astronomers.

Both Temi and Mathews believe that many elliptical galaxies are being heated by the supermassive black holes at their centers through a process called "feedback heating." They suspect that this mechanism may also explain why the Spitzer Space Telescope detected so many dust grains in such a harsh cosmic environment.

Observations with NASA's Hubble Space Telescope have shown small, massive clouds of dusty gas near the cores of many elliptical galaxies. Astronomers think these clouds may play a crucial role in feedback heating. They suspect this material probably gravitated toward the galaxy's center after being ejected by nearby dying stars, as part of their normal life cycle.

When some of this dusty gas approaches the host galaxy's central supermassive black hole, a large amount of energy is released -- enough to heat nearby gas to extremely high temperatures, making it buoyant. Like smoke carrying ashes away from a fire, scientists believe that this buoyant gas floats away from the galaxy's center carrying some dust with it. As plumes of this dusty smoke fill the galaxy's surrounding area, gas around the galaxy is also heated. Temi's team was the first to see this cosmic smoke with Spitzer's super-sensitive infrared eyes.

"Whenever the central back hole takes another gulp of the dusty gas hovering around the galaxy's center, enough energy will be fed back to heat up more of the surrounding gas, and feedback heating will happen all over again, maintaining the temperature of the surrounding gas," says Mathews. He notes that both the heating and buoyant removal of gas from the galaxy's center reduces the likelihood of star formation.

Team members say that the most remarkable feature of this heating process is the huge disparity -- about a billion -- between the size of the black hole energy source and the surrounding atmosphere of hot gas. They note that if the black hole were the size of a human, the scale of the heated gas would extend to the Moon.

"Astronomers have long hypothesized about feedback heating in the hot cluster gas surrounding elliptical galaxies, but Spitzer has given us the first piece of observational evidence that this might actually be occurring in elliptical galaxies across the universe," says Temi.

In addition to Temi and Mathews, other team members include Dr. Fabrizio Brighenti of the University of Bologna.

Source: NASA/CalTech - Spitzer- Newsroom

NASA/JPL-Caltech/R. Hurt (SSC)


Dust in Hell

Astronomers using NASA's Spitzer Space Telescope have detected dust grains mingling with blazing hot gas at temperatures of 10 million degrees Kelvin (about 10 million degrees Celsius, or 17 million degrees Fahrenheit) in an area surrounding the elliptical-shaped galaxy called NGC 5044. Scientists liken this to finding a "snowflake in hell" and suspect that a supermassive black hole at the galaxy's center must have recently heated nearby cold, dusty gas through a process called "feedback heating."

In this artist's rendition, dust grains mixed with heated, outflowing gas can be seen as brown wisps to the north and south of the central yellow spot. The yellow region at the center represents a supermassive black hole in the galaxy's core that may be responsible for heating surrounding gas and dust.

Source: NASA/CalTech - Spitzer- Newsroom

Woah.. Thank's for sharing Waspie..

The Rochester Institute of Technology press release is reproduced below:

Release Date: Sept. 17, 2007
Contact: Susan Gawlowicz
585-475-5061 or smmuns@rit.edu




When black holes crash into each other at the center of a galaxy, the safest place to be is on the other side of the computer simulating the drama.

Scientists who study black holes simulate cataclysmic collisions on supercomputers that work around the clock churning out computations that would sizzle the latest desktop model.

Rochester Institute of Technology’s Center for Computational Relativity and Gravitation recently won $330,000 from the National Science Foundation to build a new computer cluster that will maintain the center’s competitive level of research in computational astrophysics and numerical relativity, a research field dedicated to proving Einstein’s theory of general relativity. The center’s research is relevant to such projects as the Laser Interferometer Gravitational Wave Observatory and the space-based Laser Interferometer Space Antenna, among others.

RIT scientist Manuela Campanelli leads the Center for Computational Relativity and Gravitation and the team that, in 2005, solved the 10 equations in Einstein’s theory of general relativity for strong field gravity—a discovery made possible through advances in computer technology and the team’s fresh approach to the problem.

Upon her arrival to RIT earlier this year, Campanelli and her team joined forces with those of physics professor David Merritt, who built his own supercomputer named “gravitySimulator”—a 32-node GRAPE (GRAvity PipEline) cluster for gravitational dynamics simulations.

Now, Campanelli’s team is building a new computer to remain at the forefront of their field. The computer, called “newHorizons,” will make the Center for Computational Relativity and Gravitation host to one of the largest computing facilities in the region.

“The new cluster will be the main work horse of the center,” says Campanelli, associate professor in RIT’s School for Mathematical Sciences. “It will give us the ability to do more refined simulations. It will also allow students to be able to work with us on projects.”

The computer cluster is a special-purpose machine designed with the best technology available, says Carlos Lousto, associate professor in the School for Mathematical Sciences.

“The kinds of computations we do are different, new,” says Lousto. “Before simulations can advance to the next level, all components of the computer must communicate.”

Lousto designed and built the computer using hardware from California-based Western Scientific. The 85 nodes that make this computer “super” each has its own dual processor, or four amounts of computing units per node. Direct communication between the nodes is made possible by AMD processors, allowing for high-speed interconnections called HTX or hyper thread connections.

Another unusual characteristic is that each node has 16 gigabytes of memory or a total of 1.4 terabytes of memory. In addition, infinite band technology makes the computer especially fast, moving “packages” of information with a lag time or latency of 2.9-microseconds—the fastest rate possible. The computer, which will have 36 terabytes of storage space, will operate at its maximum capacity 24 hours a day for four to five years.

Node-by-node, RIT’s new supercomputer outperforms the computers at the national labs, Lousto says.

“Other scientists have satellites and telescopes to do scientific research,” says Yosef Zlochower, a research assistant professor in the School for Mathematical Sciences. “We have supercomputers. It’s how we implement and test ideas. And because our simulations can take weeks, we needed the fastest machine possible.”

Computer scientist Hans-Peter Bischof and his students will also use newHorizon to visualize the results of the simulations. “A supercomputer like newHorizon is needed, in order to create useful visualizations out of terabytes of data,” says Bischof, associate professor in computer science at RIT.

The computer is kept in an air-conditioned room that never rises above 62 degrees Fahrenheit. The powerful, 20-ton air conditioning system cools the 85 nodes, each of which consumes 500 watts of electricity and generates a considerable amount of heat. Lousto designed the computer to maximize airflow and space between the clusters to prevent heat-related damage to the machine.

In addition, an automated alert system connected to a heat sensor will detect a rise in room temperature. And, if the electricity fails, powerful back-up batteries will keep the computer going for 15 minutes.

“The battery power will allow for a clean shut down of the machine without damage to hardware and loss of data,” Lousto says.

For more information about the Center for Computational Relativity and Gravitation, visit http://ccrg.rit.edu. The center is located in RIT’s School of Mathematical Sciences.



Rochester Institute of Technology is internationally recognized for academic leadership in computing, engineering, imaging technology, and fine and applied arts, in addition to unparalleled support services for students with hearing loss. More than 15,800 full- and part-time students are enrolled in RIT’s 340 career-oriented and professional programs, and its cooperative education program is one of the oldest and largest in the nation.

For nearly two decades, U.S. News & World Report has ranked RIT among the nation’s leading comprehensive universities. The Princeton Review features RIT in its 2007 Best 361 Colleges rankings and named the university one of America’s “Most Wired Campuses.” RIT is also featured in Barron’s Best Buys in Education.

Source: RIT Press Release

The Duke University press release is reproduced below:

Researchers' equations suggest gravitational lensing could lead astronomers to 'naked singularities,' if such entities exist despite being banned by 'cosmic censorship'


A supermassive black hole is thought to lurk in Sagittarius A East
at our own galaxy's center

Monday, September 24, 2007

Durham, NC -- Researchers from Duke University and the University of Cambridge think there is a way to determine whether some black holes are not actually black.

Finding such an unmasked form of what physicists term a singularity "would shock the foundation of general relativity," said Arlie Petters, a Duke professor of mathematics and physics who worked with Marcus Werner, Cambridge graduate student in astrophysics, on a report posted online Monday, Sept. 24, for the research journal Physical Review D.

"It would show that nature has surprises even weirder than black holes," Petters added.

Albert Einstein originally theorized that stars bigger than the sun can collapse and compress into singularities, entities so confining and massively dense that the laws of physics break down inside them.

Astronomers have since found indirect evidence for these entities, which are popularly known as black holes because of the "cosmic censorship conjecture." This conjecture is that "realistic" singularities -- meaning those that can be formed in nature -- must always hide within a barrier known as an "event horizon" from which light can never escape. That makes them appear perpetually black to the rest of the universe.

But cosmic censorship is "an open conjecture that is very difficult to prove, and very difficult to disprove," said Petters.

And, despite the general support for the universality of black holes, Kip Thorne and John Preskill, two experts in the cosmology of relativity at the California Institute of Technology, have suggested for more than a decade that naked singularities could exist in certain instances. Now Petters and Werner have devised a way to test for their presence.

Astronomers cannot say for sure whether all black holes are actually black, having never fully penetrated the obscuring outward matter surrounding such objects, Petters said. As their main evidence, scientists can only point to effects that the massive gravitational pull of certain unseen entities exert on surrounding matter. Those effects include emissions of highly energetic radiation, or the extreme orbits of nearby stars.

Petters is an expert in "gravitational lensing," another effect of relativity that permits massive sources of gravity to split light from background astronomical features into multiple images.

In earlier reports in the November, 2005 and February, 2006 issues of Physical Review D, he and Charles Keeton of Rutgers University suggested a way to use gravitational lensing to show whether cosmic censorship can ever be violated.

However, that evaluation was limited to non-spinning singularities that are considered only theoretically possible. The suspected singularities astronomers have found in space so far all appear to be rapidly spinning, sometimes at more than 1,000 times a second.

So Petters and Werner teamed up to see if they could generalize such an application of gravitational lensing to all realistic spinning singularities. Their surprising result was yes, Petters said.

In work supported by the National Science Foundation in the United States and the Science and Technology Facilities Council in the United Kingdom, the pair employed a finding that a black hole could be shed of its event horizon and become a naked singularity if its angular momentum -- an effect of its spin -- is greater than its mass.

That would translate into a spin of a few thousand rotations a second in the case of a black hole weighing about 10 times more than our Sun, said Werner.

In the event that the required conditions were met, Petters' and Werner's calculations show that a naked singularity's massive gravitation would split the light of background stars or galaxies in telltale ways that are potentially detectable by astronomers using existing or soon-to-be instruments.

Those possible ways are outlined by six different equations in their study that connect a singularity's spin to the separations, angular alignments and brightness of the two split images.

"If you ask me whether I believe that naked singularities exist, I will tell you that I'm sitting on the fence," said Petters. "In a sense, I hope they are not there. I would prefer to have covered-up black holes. But I'm still open-minded enough to entertain the 'otherwise' possibility."

Werner and Petters first began interacting in the Duke professor's native Belize, where Petters has established an institute for math and science education and the Cambridge graduate student had come to help excavate a Mayan ruin.

Their collaboration then moved to the Duke campus. Petters is currently serving as one of Werner's thesis advisors.

For more information, contact: Monte Basgall | (919) 681-8057 | monte.basgall@duke.edu

Source: Duke University press release

Cool stuff! So basically gravitational lensing may make some singularities visible? Is that right? Is it possible that we could actually "see" the beginning of the universe?

By the way, the Space News on this site is great!

For Release: October 9, 2007


The hit song that proclaimed, "All we are is dust in the wind," may have some cosmic truth to it. New findings from NASA's Spitzer Space Telescope suggest that space dust -- the same stuff that makes up living creatures and planets -- was manufactured in large quantities in the winds of black holes that populated our early universe.

The findings are a significant new clue in an unsolved mystery: where did all the dust in the young universe originate?

"We were surprised to find what appears to be freshly made dust entrained in the winds that blow away from supermassive black holes," said Ciska Markwick-Kemper of the University of Manchester, U.K. Markwick-Kemper is lead author of a new paper appearing in an upcoming issue of the Astrophysical Journal Letters. "This could explain where the dust came from that was needed to make the first generations of stars in the early universe."

Space dust is essential to the formation of planets, stars, galaxies and even life as we know it. The dust in our corner of the universe was piped out by dying stars that were once a lot like our sun. But, when the universe was less than a tenth of its present age of 13.7 billion years, sun-like stars hadn't been around long enough to die and make dust. So, what produced the precious substance back when the universe was just a toddler?

Theorists have long-postulated that short-lived, massive exploding stars, or supernovae, might be the source of this mysterious dust, while others have proposed that a type of energetic, growing supermassive black hole, called a quasar, could be a contributing factor. A quasar consists of a supermassive black hole surrounded by a dusty doughnut-shaped cloud that feeds it. Theoretically, dust could form in the outer portion of the winds that slowly blow away from this doughnut cloud.

"Quasars are like the Cookie Monster," said co-author Sarah Gallagher of the University of California at Los Angeles, who is currently a visiting astronomer at the University of Western Ontario, Canada. "They are messy eaters, and they can consume less matter than they spit out in the form of winds."

Nobody has found conclusive proof that either quasar winds or supernovae can create enough dust to explain what is observed in the early universe. Markwick-Kemper and her team decided to test the former theory and investigate a quasar, called PG2112+059, located in the center of a galaxy about 8 billion light-years way. Although this particular quasar is not located in the early universe, because it is closer, it is an easier target for addressing the question of whether quasars can make dust. The team used Spitzer's infrared spectrograph instrument to split apart infrared light from the quasar and look for signs of various minerals.

They found a mix of the ingredients that make up glass, sand, marble and even rubies and sapphires. While the mineral constituting glass was expected, the minerals for sand, marble and rubies were a surprise. Why? These minerals are not typically detected floating around galaxies, suggesting they could have been freshly formed in the winds rushing away from the quasar.

For instance, the ingredient that makes up sand, crystalline silicate, doesn't survive for long free-floating in space. Radiation from stars zaps the minerals back to an amorphous, glass-like state. The presence of crystalline silicate therefore suggests something -- possibly the quasars winds -- is churning out the newly made substance.

Markwick-Kemper and her team say the case of the missing dust is not firmly shut. They hope to study more quasars for further evidence of their dust-making abilities. Also, according to the astronomers, quasars may not be the only source of dust in the early universe. "Supernovae might have been more important for creating dust in some environments, while quasars were more important in others," said Markwick-Kemper. "For now, we are very excited to have identified the different species of dust in a quasar billions of light-years away."

Other authors of this paper include Dean Hines of the Space Science Institute, Boulder, Colo., and Jeroen Bouwman of the Max Planck Institute for Astronomy, Heidelberg, Germany. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. Spitzer's infrared spectrograph was built by Cornell University, Ithaca, N.Y. Its development was led by Jim Houck of Cornell.

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

jpl2007-114
ssc2007-16

Source: NASA/CalTech - Spitzer- Newsroom

Credit: NASA/JPL-Caltech/F. Markwick-Kemper (University of Manchester)


A Wealth of Dust Grains in Quasar Winds

This plot of data captured by NASA's Spitzer Space Telescope reveals dust entrained in the winds rushing away from a quasar, or growing black hole. The quasar, called PG2112+059, is located deep inside a galaxy 8 billion light-years away. Astronomers believe the dust might have been forged in the winds, which would help explain where dust in the very early universe came from.

The data were captured by Spitzer's infrared spectrograph, an instrument that splits apart light from the quasar into a spectrum that reveals telltale signs of different minerals. Each type of mineral, or dust grain, has a unique signature, as can be seen in the graph, or spectrum, above.

The strongest features are from the mineral amorphous olivine, or glass (purple); the mineral forsterite found in sand (blue); and the mineral corundum found in rubies (light blue). The detection of forsterite and corundum is highly unusual in galaxies without quasars. Therefore, their presence is a key clue that these grains might have been created in the quasar winds and not by dying stars as they are in our Milky Way galaxy. Forsterite is destroyed quickly in normal galaxies by radiation, so it must be continually produced to be detected by Spitzer.

Corundum is hard, and provides a seed that softer, more common minerals usually cover up. As a result, corundum is usually not seen in spectra of galaxies. Since Spitzer did detect the mineral, it is probably forming in a clumpy environment, which is expected in quasar winds. All together, the signatures of the unusual minerals in this spectrum point towards dust grains forming in the winds blowing away from quasars.

Source: NASA/CalTech - Spitzer- Newsroom

Credit: NASA/JPL-Caltech/T. Pyle (SSC)


Dust in the Quasar Wind

Dusty grains -- including tiny specks of the minerals found in the gemstones peridot, sapphires, and rubies -- can be seen blowing in the winds of a quasar, or active black hole, in this artist's concept. The quasar is at the center of a distant galaxy.

Astronomers using NASA's Spitzer Space Telescope found evidence that such quasar winds might have forged these dusty particles in the very early universe. The findings are another clue in an ongoing cosmic mystery: where did all the dust in our young universe come from?

Dust is crucial for efficient star formation as it allows the giant clouds where stars are born to cool quickly and collapse into new stars. Once a star has formed, dust is also needed to make planets and living creatures. Dust has been seen as far back as when the universe was less than a tenth of its current age, but how did it get there? Most dust in our current epoch forms in the winds of evolved stars that did not exist when the universe was young.

Theorists had predicted that winds from quasars growing in the centers of distant galaxies might be a source of this dust. While the environment close to a quasar is too hot for large molecules like dust grains to survive, dust has been found in the cooler, outer regions. Astronomers now have evidence that dust is created in these outer winds.

Using Spitzer's infrared spectrograph instrument, scientists found a wealth of dust grains in a quasar called PG2112+059 located at the center of a galaxy 8 billion light-years away. The grains -- including corundum (sapphires and rubies); forsterite (peridot); and periclase (naturally occurring in marble) -- are not typically found in galaxies without quasars, suggesting they might have been freshly formed in the quasar's winds.

Source: NASA/CalTech - Spitzer- Newsroom

Astronomers have located an exceptionally massive black hole in orbit around a huge companion star. This result has intriguing implications for the evolution and ultimate fate of massive stars.

The black hole is part of a binary system in M33, a nearby galaxy about 3 million light years from Earth. By combining data from NASA's Chandra X-ray Observatory and the Gemini telescope on Mauna Kea, Hawaii, the mass of the black hole, known as M33 X-7, was determined to be 15.7 times that of the Sun. This makes M33 X-7 the most massive stellar black hole known. A stellar black hole is formed from the collapse of the core of a massive star at the end of its life.

Chandra X-ray Image of M33 X-7

These two Chandra images show M33 X-7 when the black hole in this binary is not being eclipsed (left) and when it is being eclipsed (right). M33 X-7 is located in the center of the image. X-rays from a disk of hot gas close to the black hole cause M33 X-7 to be bright when it is outside eclipse. During eclipse some X-rays are still detected because of scattering of the disk's X-rays by the companion star's atmosphere or wind. The other X-ray sources are unrelated to M33 X-7. The differences in shape between the sources in the two panels are an instrumental effect.
(Credit: NASA/CXC/CfA/P.Plucinsky et al.)

"This discovery raises all sorts of questions about how such a big black hole could have been formed," said Jerome Orosz of San Diego State University, lead author of the paper appearing in the October 18th issue of the journal Nature.

M33 X-7 orbits a companion star that eclipses the black hole every three and a half days. The companion star also has an unusually large mass, 70 times that of the Sun. This makes it the most massive companion star in a binary system containing a black hole.

Chandra X-ray & Hubble Optical Images of M33 X-7

The composite image includes data from NASA's Chandra X-ray Observatory (blue) and the Hubble Space Telescope. The bright objects in the inset image are young, massive stars around M33 X-7, and the bright, blue Chandra source is M33 X-7 itself. X-rays from Chandra reveals how long the black hole is eclipsed by the companion star, which indicates the size of the companion.
(Credit: X-ray: NASA/CXC/CfA/P.Plucinsky et al.; Optical: NASA/STScI/SDSU/J.Orosz et al. )

"This is a huge star that is partnered with a huge black hole," said coauthor Jeffrey McClintock of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Eventually, the companion will also go supernova and then we'll have a pair of black holes."

The properties of the M33 X-7 binary system - a massive black hole in a close orbit around a massive companion star - are difficult to explain using conventional models for the evolution of massive stars. The parent star for the black hole must have had a mass greater than the existing companion in order to have formed a black hole before the companion star.

Gemini Optical Image of M33 X-7

Astronomers have located an exceptionally massive black hole - almost 16 times the mass of the Sun - in orbit around a huge companion star. By combining observations from NASA's Chandra X-ray Observatory with optical data from the Gemini telescope, the black hole known as M33 X-7 was determined to be the most massive black hole in its class. This result has intriguing implications for the evolution and ultimate fate of massive stars.
(Credit: AURA/Gemini Obs./SDSU/J.Orosz et al.)

Kitt Peak Optical Image of M33

An artist's conception shows M33 X-7, a binary system in the galaxy M33 where a large star is in orbit with a black hole. Material from the large blue companion star is seen being pulled toward the black hole by its powerful gravity. A disk of this material (orange) is swept into orbit around the black hole, fed by winds flowing out from the star. This wind is disrupted by the black hole, causing turbulence and ripples beyond the disk.
(Credit: NASA/CXC/M.Weiss)

Such a massive star would have had a radius larger than the present separation between the stars, so the stars must have been brought closer while sharing a common outer atmosphere. This process typically results in a large amount of mass being lost from the system, so much that the parent star should not have been able to form a 15.7 solar-mass black hole.

The black hole's progenitor must have shed gas at a rate about 10 times less than predicted by models before it exploded. If even more massive stars also lose very little material, it could explain the incredibly luminous supernova seen recently as SN 2006gy. The progenitor for SN 2006gy is thought to have been about 150 times the mass of the Sun when it exploded.

"Massive stars can be much less extravagant than people think by hanging onto a lot more of their mass toward the end of their lives," said Orosz. "This can have a big effect on the black holes that these stellar time-bombs make."

Coauthor Wolfgang Pietsch was also the lead author of an article in the Astrophysical Journal that used Chandra observations to report that M33 X-7 is the first black hole in a binary system observed to undergo eclipses. The eclipsing nature enables unusually accurate estimates for the mass of the black hole and its companion.

"Because it's eclipsing and because it has such extreme properties, this black hole is an incredible test-bed for studying astrophysics," said Pietsch.

The length of the eclipse seen by Chandra gives information about the size of the companion. The scale of the companion's motion, as inferred from the Gemini observations, gives information about the mass of the black hole and its companion. Other observed properties of the binary were used to constrain the mass estimates.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Gemini is an international partnership managed by the Association of Universities for Research in Astronomy under a cooperative agreement with the National Science Foundation.
Additional information and images are available at:


Source: Chandra - Press Room

News Release Number: STScI-2007-35


What has appeared as a mild-mannered elliptical galaxy in previous studies is revealing its wild side in new images taken with NASA's Hubble Space Telescope.

The Hubble photos show shells of stars around a bright quasar, known as MC2 1635+119, which dominates the center of the galaxy. The shells' presence indicates a titanic clash with another galaxy in the relatively recent past.

The collision also is funneling gas into the galaxy's center and is feeding a supermassive black hole. The accretion onto the black hole is the source of the quasar's energy. This observation supports the idea that at least some quasars are born from interactions between galaxies.

"This observation is providing more evidence that mergers are crucial for triggering quasars," said Gabriela Canalizo of the University of California, Riverside, who led the study. "Most quasars were active in the early universe, which was smaller, so galaxies collided more frequently.

"Astronomers have long speculated that quasars are fueled by interactions that bring an inflow of gas to the black holes in the centers of galaxies. Since this quasar is relatively nearby, about 2 billion light-years away, it is a great laboratory for studying how more distant quasars are turned on."

Discovered nearly 50 years ago, quasars are among the brightest objects in the universe. They reside in the centers of galaxies and are powered by supermassive black holes.

Previous studies of this galaxy with ground-based telescopes showed a normal-looking elliptical containing an older population of stars. It took the razor-sharp vision of Hubble's Advanced Camera for Surveys and the spectroscopic acuity of the W.M. Keck Observatory in Hawaii to uncover the faint, thin shells.

The new Hubble observations reveal at least five inner shells and additional debris traveling away from the galaxy's center. The shells, which sparkle with stars, resemble ripples forming in a pond when a stone is tossed in. They formed when a galaxy was shredded by tidal forces during the collision. Some of the galaxy's stars were swept up in the elliptical galaxy's gravitational field, creating the outward-moving shells. The farthest shell is about 40,000 light-years away from the center.

"This is the most spectacular shell galaxy seen at this distance," said team member Francois Schweizer of the Carnegie Observatories in Pasadena, California.

Computer simulations estimate that the encounter happened 1.7 billion years ago. The merger itself occurred over a few hundred million years and stoked a flurry of star birth. Spectroscopic data from Keck reveal that many of the stars in the galaxy are 1.4 billion years old, which is consistent with the age of the merger. This activity happened before light left the quasar and began its long journey to Earth.

The shell stars are mixing with the stars in the galaxy as they travel outward. Eventually, the shells will dissipate and the stars will be scattered throughout the galaxy.

"This could be a transitory phase, common to most ellipticals, that lasts only 100 million to a billion years," Canalizo said. "So, seeing these shells tells us that the encounter occurred in the relatively recent past. Hubble caught the shells at the right time."

Canalizo and her team have not determined the type of merger responsible for the shells and the quasar activity. Their evidence points to two possible collision scenarios.

"The shells' formation and the current quasar activity may have been triggered by an interaction between two large galaxies or between a large galaxy and a smaller galaxy," explained team member Nicola Bennert of the University of California, Riverside."We need high-resolution spectroscopic observations of the quasar host galaxy to determine the type of merger."

The quasar is part of an Advanced Camera for Surveys study of five galaxies, all roughly 2 billion light-years away, that are known to harbor quasars. The other four galaxies analyzed also display evidence of encounters, Canalizo said. Her team also is using Hubble's Wide Field Planetary Camera 2 to sample 14 more galaxies with quasars.

"We want to know whether most quasars at current epochs begin their lives as mergers, or whether they simply occur in old ellipticals to which nothing very interesting has happened recently," Canalizo said.

The team's results will appear in the November 10 issue of The Astrophysical Journal.

Canalizo’s team consists of Nicola Bennert of the University of California, Riverside; Bruno Jungwiert of the University of California, Riverside and the Astronomical Institute, Academy of Sciences of the Czech Republic, Prague; Alan Stockton of the University of Hawaii, Honolulu; Francois Schweizer of the Carnegie Observatories, Pasadena; Mark Lacy of the California Institute of Technology, Pasadena; and Chien Peng of the Space Telescope Science Institute.

CONTACT

Donna Weaver/Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4493/4514
dweaver@stsci.edu
villard@stsci.edu

Gabriela Canalizo
University of California, Riverside, Calif.
951-827-5310
gabriela.canalizo@ucr.edu

Source: HubbleSite - Newsdesk

Shells of Stars Ring Quasar in Giant Elliptical Galaxy

News Release Number: STScI-2007-39



ABOUT THIS IMAGE:
These sharp images taken with NASA's Hubble Space Telescope reveal at least five shells of stars surrounding a brilliant quasar at the heart of a giant elliptical galaxy. The image at left shows the quasar, known as MC2 1635+119, and its host galaxy (center) against a backdrop of distant galaxies. In the image at top,right, the shells can barely be seen because of the bright light from the central quasar.

The image at bottom, right was enhanced to reveal details of the faint shells. In both right-hand images, the objects below and to the left of the shells are background galaxies. A foreground star resides at top, left. The shells have never been seen before in this galaxy, located about 2 billion light-years away. They are evidence that the giant galaxy clashed with another galaxy in the relatively recent past. The shells are similar to ripples forming in a pond when a stone is tossed in. They sparkle with stars that were swept up from the encounter. The interaction may be providing enough fuel to power the quasar, which dominates the galaxy's center. This observation supports the idea that quasars are born from mergers between galaxies.

The images were taken June 28 and July 4, 2005 with Hubble's Advanced Camera for Surveys.

The observation team consists of Gabriela Canalizo and Nicola Bennert of the University of California, Riverside; Bruno Jungwiert of the University of California, Riverside/Astronomical Institute, Academy of Sciences of the Czech Republic, Prague; Alan Stockton of the University of Hawaii, Honolulu; Francois Schweizer of the Carnegie Observatories, Pasadena; Mark Lacy of the California Institute of Technology, Pasadena; and Chien Peng of the Space Telescope Science Institute, Baltimore.

Object Names: MC2 1635+119, MC2 1635+11.9

Image Type: Astronomical/Illustration

Credit: NASA, ESA, and G. Canalizo (University of California, Riverside)

Source: HubbleSite - Newsdesk

Quasar MC2 1635+119 and Host Galaxy

News Release Number: STScI-2007-39



Object Names: MC2 1635+119, MC2 1635+11.9

Image Type: Astronomical

Credit: NASA, ESA, and G. Canalizo (University of California, Riverside)

Source: HubbleSite - Newsdesk

Quasar MC2 1635+119

News Release Number: STScI-2007-39



Object Names: MC2 1635+119, MC2 1635+11.9

Image Type: Astronomical

Credit: NASA, ESA, and G. Canalizo (University of California, Riverside)

Source: HubbleSite - Newsdesk

Quasar MC2 1635+119 (Enhanced)

News Release Number: STScI-2007-39



Object Names: MC2 1635+119, MC2 1635+11.9

Image Type: Astronomical

Credit: NASA, ESA, and G. Canalizo (University of California, Riverside)

Source: HubbleSite - Newsdesk

PASADENA, Calif. - Astronomers have unmasked hundreds of black holes hiding deep inside dusty galaxies billions of light-years away.

The massive, growing black holes, discovered by NASA's Spitzer and Chandra space telescopes, represent a large fraction of a long-sought missing population. Their discovery implies there were hundreds of millions of additional black holes growing in our young universe, more than doubling the total amount known at that distance.


Image above: This image, taken with Spitzer's infrared vision,
shows a fraction of these black holes, which are located deep in
the bellies of distant, massive galaxies (circled in blue).
Image credit: NASA/JPL-Caltech/ Commissariat a l'Energie Atomique

"Active, supermassive black holes were everywhere in the early universe," said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Ariz. "We had seen the tip of the iceberg before in our search for these objects. Now, we can see the iceberg itself." Dickinson is a co-author of two new papers appearing in the Nov. 10 issue of the Astrophysical Journal. Emanuele Daddi of the Commissariat a l'Energie Atomique in France led the research.

The findings are also the first direct evidence that most, if not all, massive galaxies in the distant universe spent their youths building monstrous black holes at their cores.

For decades, a large population of active black holes has been considered missing. These highly energetic structures belong to a class of black holes called quasars. A quasar consists of a doughnut-shaped cloud of gas and dust that surrounds and feeds a budding supermassive black hole. As the gas and dust are devoured by the black hole, they heat up and shoot out X-rays. Those X-rays can be detected as a general glow in space, but often the quasars themselves can't be seen directly because dust and gas blocks them from our view.

"We knew from other studies from about 30 years ago that there must be more quasars in the universe, but we didn't know where to find them until now," said Daddi.


Image above: An artist's concept of a growing
black hole.
Image credit: NASA/JPL-Caltech

Daddi and his team initially set out to study 1,000 dusty, massive galaxies that are busy making stars and were thought to lack quasars. The galaxies are about the same mass as our own spiral Milky Way galaxy, but irregular in shape. At 9 to 11 billion light-years away, they existed at a time when the universe was in its adolescence, between 2.5 and 4.5 billion years old.

When the astronomers peered more closely at the galaxies with Spitzer's infrared eyes, they noticed that about 200 of the galaxies gave off an unusual amount of infrared light. X-ray data from Chandra, and a technique called "stacking," revealed the galaxies were, in fact, hiding plump quasars inside. The scientists now think that the quasars heat the dust in their surrounding doughnut clouds, releasing the excess infrared light.

"We found most of the population of hidden quasars in the early universe," said Daddi. Previously, only the rarest and most energetic of these hidden black holes had been seen at this early epoch.

The newfound quasars are helping answer fundamental questions about how massive galaxies evolve. For instance, astronomers have learned that most massive galaxies steadily build up their stars and black holes simultaneously until they get too big and their black holes suppress star formation.

The observations also suggest that collisions between galaxies might not play as large a role in galaxy evolution as previously believed. "Theorists thought that mergers between galaxies were required to initiate this quasar activity, but we now see that quasars can be active in unharassed galaxies," said co-author David Alexander of Durham University, United Kingdom.

"It's as if we were blindfolded studying the elephant before, and we weren't sure what kind of animal we had," added co-author David Elbaz of the Commissariat a l'Energie Atomique. "Now, we can see the elephant for the first time."

The new observations were made as part of the Great Observatories Origins Deep Survey, the most sensitive survey to date of the distant universe at multiple wavelengths.

Consistent results were recently obtained by Fabrizio Fiore of the Osservatorio Astronomico di Roma, Italy, and his team. Their results will appear in the Jan. 1, 2008, issue of Astrophysical Journal.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

The National Optical Astronomy Observatory is operated by the Association of Universities for Research in Astronomy under a cooperative agreement with the National Science Foundation.

For more information and graphics, visit _http://www.spitzer.caltech.edu/spitzer and _http://www.nasa.gov/spitzer; and _http://chandra.harvard.edu/ and _http://www.nasa.gov/mission_pages/chandra/main/index.html

Media contact: Whitney Clavin/818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

2007-122

Source: NASA - Spitzer - News

Missing Black Holes Found!

10.25.07

A long-lost population of active supermassive black holes, or quasars, has been uncovered by NASA's Spitzer and Chandra space telescopes. This image, taken with Spitzer's infrared vision, shows a fraction of these black holes, which are located deep in the bellies of distant, massive galaxies (circled in blue).

Spitzer originally scanned the field of galaxies shown in the picture as part of a multiwavelength program called the Great Observatories Origins Deep Survey, or Goods. This picture shows a portion of the Goods field called Goods-South. When astronomers saw the Spitzer data, they were surprised to find that hundreds of the galaxies between 9 and 11 billion light-years away were shining with an unexpected excess of infrared light. They then followed up with X-ray data from Chandra of the same field, and applied a technique called stacking, which adds up the faint light of multiple galaxies. The results revealed that the infrared-bright galaxies are hiding many black holes that had been theorized about before but never seen. This excess infrared light is being produced by the growing black holes.

The other smudges in this picture are distant galaxies, most of which are closer to us than the circled galaxies, causing them to appear brighter.

This image was taken by Spitzer's multiband imaging photometer at a wavelength of 24 microns. It shows the faintest distant objects ever observed with Spitzer at this wavelength.

Image credit: NASA/JPL-Caltech/ Commissariat a l'Energie Atomique

+ Larger image

Source: NASA - Spitzer - Multimedia

Stacks of Light

10.25.07

These two images show "stacked" Chandra images for two different classes of distant, massive galaxy detected with Spitzer. Image stacking is a procedure used to detect emission from objects that is too faint to be detected in single images. To enhance the signal, images of these faint objects are stacked on top of one another.

In both images, low-energy X-rays are shown in orange and high-energy X-rays in blue, and the stacked object is in the center of the image (the other sources beyond the center of the image are X-ray sources that were directly detected and are not part of the source stacking). On the left is a stacked Chandra image of the "normal" galaxies seen with Spitzer. The infrared emission for these young, massive galaxies is consistent with expectations for star formation. The Chandra image shows mainly low-energy X-ray emission at the center as expected. On the right, is a stacked Chandra image for galaxies with infrared emission exceeding the levels likely to be caused by star formation. These galaxies contain active galactic nuclei, or quasars, in their centers. These are luminous objects powered by the rapid growth of supermassive black holes. The obscured quasars show much higher levels of high-energy X-ray emission because the less energetic X-rays are mostly absorbed by gas.

Image credit: NASA/CXC/Durham/D.Alexander

+ Larger image

Source: NASA - Spitzer - Multimedia

Bursting with Stars and Black Holes

10.25.07

A growing black hole, called a quasar, can be seen at the center of a faraway galaxy in this artist's concept. Astronomers using NASA's Spitzer and Chandra space telescopes discovered swarms of similar quasars hiding in dusty galaxies in the distant universe.

The quasar is the orange object at the center of the large, irregular-shaped galaxy. It consists of a dusty, doughnut-shaped cloud of gas and dust that feeds a central supermassive black hole. As the black hole feeds, the gas and dust heat up and spray out X-rays, as illustrated by the white rays. Beyond the quasar, stars can be seen forming in clumps throughout the galaxy. Other similar galaxies hosting quasars are visible in the background.

The newfound quasars belong to a long-lost population that had been theorized to be buried inside dusty, distant galaxies, but were never actually seen. While some quasars are easy to detect because they are oriented in such a way that their X-rays point toward Earth, others are oriented with their surrounding doughnut-clouds blocking the X-rays from our point of view. In addition, dust and gas in the galaxy itself can block the X-rays.

Astronomers had observed the most energetic of this dusty, or obscured, bunch before, but the "masses," or more typical members of the population, remained missing. Using data from Spitzer and Chandra, the scientists uncovered many of these lost quasars in the bellies of massive galaxies between 9 and 11 billion light-years away. Because the galaxies were also busy making stars, the scientists now believe most massive galaxies spent their adolescence building up their stars and black holes simultaneously.

The Spitzer observations were made as part of the Great Observatories Origins Deep Survey program, which aims to image the faintest distant galaxies using a variety of wavelengths.

Image credit: NASA/JPL-Caltech

+ High-resolution JPEG (3.2Mb)

Source: NASA - Spitzer - Multimedia

Do you think this discovery, When mass estimates are calculated, will effect the search for "Dark Matter". I mean the finding of so many black holes and Quasars should effect the Universal Mass equation!

Paris - An international team of astronomers have unexpectedly found hundreds of expanding "supermassive" black holes buried deep inside galaxies billions of light years from Earth.

The astounding discovery is the first direct evidence that most - perhaps all - huge galaxies in the far reaches of the universe generated cavernous black holes during their infancy, when about 3,5-billion years old.

The findings more than double the total number of black holes known to exist at that distance, and suggest that there were hundreds of millions more growing in the early universe.

These supermassive entities are known as high-energy quasars, a form of black hole, found in a young galaxies, that is surrounded by a thick halo of gas and dust which shoot off X-rays as they are sucked into the void.

The X-rays, which can be detected as a general glow in space even when the quasars themselves cannot be seen, are what tipped off the scientists that they had stumbled across something extraordinary.

At nine to 10-billion light years distant, what scientists see today existed about 10-billion years ago, when the universe was still a fledgling between 2,5 and 4,5-billion years old.
go

imagine... what they look like now.. it might be gone? or bigger! freaks me out.

It's mostly probable that it is still there, black holes last an unbelieveble amount of years, but true.

Errr.. surely they last forever ? They just keep on accreting mass ?

Meow Purr.

Nope... black holes don't last forever, almost forever but not ( because of the incredible amount of years they last).

Black holes slowly but VERY slowly desintegrate until they are nothing, the desintegrate out of existence. Amazing isn't it? But this progress takes a very very long time. Most problably "googles" of years, as said by scientists.

They are believed to be the last objects in existence in the universe after the new dark era arrives. Why will there be a dark era again? No more stars and no more matter and energy to make stars. And why is that? Well it's a long and complicated subject.

Please, do tell. Perhaps better to create a new thread, but you can't leave us hanging like that!

like our banks

yes! I very much agree.

The Harvard-Smithsonian Center for Astrophysics press release is reproduced below:

Release No.: 2007-28
For Release: Tuesday, October 30, 2007

Cambridge, MA - Cambridge, MA - Using two NASA satellites, astronomers have discovered a black hole that obliterates a record announced just two weeks ago. The new black hole, with a mass 24 to 33 times that of our Sun, is the heftiest known black hole that orbits another star.

The record-breaker belongs to the category of "stellar-mass" black holes. Formed in the death throes of massive stars, they are smaller than the monster black holes found in galactic cores. The previous record holder for largest stellar-mass black hole is a 16-solar-mass black hole in the galaxy M33, announced on October 17.

This artist's conception shows the biggest stellar-mass black hole (upper left), which weighs 24 to 33 times as much as the Sun. It is pulling gas from a companion Wolf-Rayet star (lower right). Experts say the black hole was "born fat, it didn't grow fat."
Credit: Aurore Simonnet/Sonoma State University/NASA

This close-up from the artist's conception shows gas spiraling into the heftiest known solar-mass black hole. The gas heats up and emits X-rays, which allows astronomers to deduce the black hole's presence.
Credit: Aurore Simonnet/Sonoma State University/NASA

"We weren’t expecting to find a stellar-mass black hole this massive," says Andrea Prestwich of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., lead author of the discovery paper in the November 1 Astrophysical Journal Letters. "We now know that black holes that form from dying stars can be much larger than we had realized."

The black hole is located in the nearby dwarf galaxy IC 10, 1.8 million light-years from Earth in the constellation Cassiopeia. Prestwich’s team could measure the black hole’s mass because it has an orbiting companion: a hot, highly evolved star. The star is ejecting gas in the form of a wind. Some of this material spirals toward the black hole, heats up, and gives off powerful X-rays before crossing the point of no return.

In November 2006, Prestwich and her colleagues observed the dwarf galaxy with NASA’s Chandra X-ray Observatory. The group discovered that the galaxy’s brightest X-ray source, IC 10 X-1, exhibits sharp changes in X-ray brightness. Such behavior suggests a star periodically passing in front of a companion black hole and blocking the X-rays, creating an eclipse. In late November, NASA’s Swift satellite confirmed the eclipses and revealed details about the star’s orbit. The star in IC 10 X-1 appears to orbit in a plane that lies nearly edge-on to Earth’s line of sight, so a simple application of Kepler’s Laws show that the companion black hole has a mass of at least 24 Suns.

There are still some uncertainties in the black hole’s mass estimate, but as Prestwich notes, ”Future optical observations will provide a final check. Any refinements in the IC 10 X-1 measurement are likely to increase the black hole’s mass rather than reduce it.”

The black hole’s large mass is surprising because massive stars generate powerful winds that blow off many Suns worth of gas before the stars explode. Calculations suggest massive stars in our galaxy leave behind black holes no heavier than about 15 Suns.

The IC 10 X-1 black hole has gained mass since its birth by gobbling up gas from its companion star, but the rate is so slow that the black hole would have gained no more than 1 or 2 solar masses. "This black hole was born fat; it didn’t grow fat," says astrophysicist Richard Mushotzky of NASA Goddard Space Flight Center in Greenbelt, Md., who is not a member of the discovery team.

The progenitor star probably started its life with 60 or more solar masses. Like its host galaxy, it was probably deficient in elements heavier than hydrogen and helium. In massive, luminous stars with a high fraction of heavy elements, the extra electrons of elements such as carbon and oxygen “feel” the outward pressure of light and are more susceptible to being swept away in stellar winds. But with its low fraction of heavy elements, the IC 10 X-1 progenitor shed comparatively little mass before it exploded, so it could leave behind a heavier black hole.

"Massive stars in our galaxy today are probably not producing very heavy stellar-mass black holes like this one," says coauthor Roy Kilgard of Wesleyan University in Middletown, Conn. "But there could be millions of heavy stellar-mass black holes lurking out there that were produced early in the Milky Way’s history, before it had a chance to build up heavy elements."

This release is being issued jointly with NASA _http://www.nasa.gov/vision/universe/starsgalaxies/overweight_hole.html
Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
Director of Public Affairs
Harvard-Smithsonian Center for Astrophysics
617-495-7462
daguilar@cfa.harvard.edu

Christine Pulliam
Public Affairs Specialist
Harvard-Smithsonian Center for Astrophysics
617-495-7463
cpulliam@cfa.harvard.edu

Source: CfA Press Release

In athletic events such as swimming or running, a world record will often stand for several years before it’s broken. The same thing usually holds true for astronomical records as well.


Image above: In this artist’s portrayal of the IC 10 X-1 system, the black
hole lies at the upper left and its companion star is on the right. The two
objects orbit around a center of gravity once every 34.4 hours. The stellar
companion is a type known as a Wolf-Rayet star. Such stars are highly evolved
and destined to explode as supernovae. The black hole companion is shedding
its outer envelope in a powerful wind, and some of this gas is captured by the
black hole’s powerful gravity.
+ Click for high resolution (1.2 Mb) JPG
Credit: Aurore Simonnet/Sonoma State University/NASA.

But in the case of black holes that form when their parent stars explode as a supernova, a record established less than two weeks ago has just been shattered. Black holes are objects with such strong gravity that nothing, not even light, can escape their grasp.

On October 17, astronomers using NASA’s Chandra X-ray Observatory announced that a black hole in the galaxy M33 contains 16 times the mass of the Sun. For two weeks it was the heaviest known black hole of its type. Such black holes are known as "stellar-mass" black holes, because they have masses typical of stars.

But in a paper to be published on November 1, another team is announcing a stellar-mass black hole with at least 24 times the mass of the Sun, and perhaps as many as 33 solar masses.

The team, led by Andrea Prestwich of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., used both Chandra and NASA’s Swift satellite to make its discovery.


Image above: The galaxy IC 10 is an irregular dwarf galaxy about
1.8 million light-years from Earth.
+ Click for high resolution (1.1 Mb) JPG
Credit: Adam Block/NOAO/AURA/NSF.

Prestwich is quick to point out that breaking a record is not nearly as important to scientists as learning something new about how black holes form. "We now know that black holes that form from dying stars can be much larger than we had realized," she says. The black hole resides in a small, irregular-shaped galaxy known as IC 10, which is a relatively nearby galaxy 1.8 million light-years from Earth. The black hole is accompanied by a companion star in its journey through space. The two stars orbit around each other. The companion star is blowing off large amounts of gas in a gusty wind, and some of this gas is trapped by the black hole’s powerful gravity. This material is destined to fall into the black hole and disappear from the universe, but as it spirals into the black hole, it heats up and radiates X-rays.

Using Chanda, Prestwich and her colleagues noticed that the system normally emits a lot of X-rays, but every so often, the X-rays disappear. To find out what was happening, she targeted this system with Swift and looked at it over the course of about 10 days in late November 2006. The team found that the X-rays periodically cut off. As the two objects orbit each other, the companion star periodically passes in front of the black hole as seen from Earth, and blocks the X-rays. This is just like the Moon passing in front of the Sun and blocking its light, an event known as an eclipse.

The Swift observations, as well as observations from the Gemini Telescope in Hawaii, told Prestwich and her group how fast the two stars go around each other, This information allowed the team to measure the mass of the black hole. When taking into account the various uncertainties, they determined the black hole has at least 24 times the Sun’s mass, and perhaps as many as 33. Even at the lower end of 24 solar masses, the IC 10 black hole is considerably heavier than the 16-solar-mass black hole in M33.

The discovery raises the obvious question of how this black hole got to be so big. Calculations performed on computers suggest that even the most massive stars in our Milky Way Galaxy leave behind black holes with no more than 15 or 20 solar masses. Even if these stars begin their lives with 100 solar masses, they blow off almost all of their mass in winds and in the supernova explosions that end their lives.

But the black hole in IC 10 probably formed from a star with a different chemical composition than the stars that currently reside in our Milky Way. Specifically, the parent star probably had a very low fraction of elements heavier than hydrogen and helium, the two lightest elements on the Periodic Table. Computer calculations show that such stars will blow off less gas in winds before they explode, so they can leave behind heavier black holes.

Prestwich’s colleague Roy Kilgard of Wesleyan University in Middletown, Conn., points out that massive stars in our galaxy today are probably not producing very heavy stellar-mass black holes. But, he adds, "There could be millions of heavy stellar-mass black holes lurking out there that were produced early in the Milky Way’s history, before it had a chance to build up heavy elements."

Even though the IC 10 black hole breaks the record for largest stellar-mass black hole, it’s puny compared to black holes in the centers of large galaxies. These monsters formed early in the universe’s history by a mechanism that remains unknown. They contain millions or even billions of times the mass of our Sun, and are thus known as "supermassive" black holes.


Robert Naeye
Goddard Space Flight Center

Source: NASA - Exploring the Universe - Stars and Galaxies

The Rochester Institute of Technology press release is reproduced below:

Release Date: Sept. 17, 2007
Contact: Susan Gawlowicz
585-475-5061 or smmuns@rit.edu




Supermassive black holes can produce powerful winds that shape a galaxy and determine their own growth, confirms a group of scientists from Rochester Institute of Technology.

The RIT team has, for the first time, observed the vertical launch of rotating winds from glowing disks of gas, known as accretion disks, surrounding supermassive black holes in the centers of galaxies. The findings are reported in the Nov. 1 issue of Nature.

Gas flowing into a supermassive black hole first accumulates in a rapidly spinning accretion disk, which forms the engine of a quasar, a type of active galactic nucleus found in some galaxies and an extremely powerful source of radiation.

“Gas flowing in from the galaxy ‘fuels’ the quasar,” says Andrew Robinson, associate professor of physics at RIT and an author of the study. “Gas flowing out from the quasar regulates black hole growth and galaxy formation.”

The RIT team, consisting of Stuart Young, David Axon and Robinson, together with colleagues James Hough and James Smith from the University of Hertfordshire in England, studied the winds of gas coming off the quasar PG 1700+518, located in a galaxy at a distance of approximately 3 billion light-years from Earth. Robinson and Smith obtained the data using the William Herschel Telescope on the Canary Islands.

Previous studies have pointed to the critical role winds play in the early or active phase of a galaxy, when a growing supermassive black hole draws in gas from the surrounding cloud and shines luminously—brighter than all of the stars in a galaxy.

“It has long been thought that such winds are launched from the accretion disk but, until now, this idea has been based on purely theoretical arguments,” says David Axon, professor and head of the physics department at RIT.

The RIT team’s study of PG 1700+518 shows that gas is both moving vertically away from the disk and also rotating at a speed similar to the disk’s rotation speed—direct observational confirmation that the disk is launching a wind. The study also helps to resolve the long-standing mystery of how the accretion disk rids itself of angular momentum—a property associated with rotational motion that inhibits the inward flow of gas towards the central black hole just as it keeps the Earth in orbit around the sun.

“If it wasn’t removed, angular momentum would actually completely stop the accretion and turn off the quasar,” says Young, a post-doctoral fellow at RIT, formerly of the University of Hertfordshire, and the lead author of the paper “The Rotating Wind of the Quasar PG 1700+518.” “Our work suggests that the disk removes some of its excess angular momentum by launching a wind, so allowing accretion to happen in the first place to produce the quasar and allow the black hole to grow.”

Quasar accretion disks are too small to be imaged directly. The RIT team confirmed theories about quasar winds by using polarimetry, a technique that measures the polarization of the light from the quasar, a property that can arise when light, or electromagnetic radiation, is scattered or reflected. This technique gives scientists ways to analyze astronomical sources from different perspectives.

“We can’t actually see the accretion disk,” adds Robinson. “We can see its radiation, but we can’t actually see its structure. In a picture, a quasar looks just like a star, so it’s proven very difficult to confirm these theories by observation.”

He continues: “In quasars, like PG1700+518, we believe that light emitted by the accretion disk becomes polarized because it is scattered by electrons in the wind; the process is similar to scattering of sunlight by molecules in Earth’s atmosphere, which makes the sky appear blue.”

Analyzing changes in the polarization of the light with wavelength, or the property that determines color, can reveal information about the internal structure of a source and the motions of the emitting and scattering gas.

During the last 20 years, studying the polarized light from active galactic nuclei has allowed scientists to make sense of a confusing variety of different types of active galaxy.

“When you look at an active galactic nucleus from above you see one kind of active galaxy,” Robinson says. “When you look at it from the side you see another kind. Polarimetry makes clear that they are the same. Scientists used to think there were different types of active galaxies. Now we know they are only different because we are looking at them from different angles.”

During the next phase of their research, the RIT scientists will analyze the polarization properties of scattered light from many more objects to learn if powerful disk winds are launched only in a relatively short-lived phase, when the black hole is growing rapidly, or if they are launched only by quasars, which have the most massive black holes, or by all active galactic nuclei.

“The polarization process makes this very interesting because you get this discrimination between angles, and you get different viewpoints,” Robinson says. “And so the observed properties of the nucleus depend on angle, whether or not the direct view is obscured.”



Contacts:

Andrew Robinson, associate professor of physics at RIT
axrsps@rit.edu, 585-475-2726
Susan Gawlowicz, senior news specialist, RIT University News Services smguns@rit.edu, 585-475-5061

About RIT: Rochester Institute of Technology is internationally recognized for academic leadership in computing, engineering, imaging technology, and fine and applied arts, in addition to unparalleled support services for students with hearing loss. More than 15,800 full- and part-time students are enrolled in RIT’s 340 career-oriented and professional programs, and its cooperative education program is one of the oldest and largest in the nation.

For nearly two decades, U.S. News & World Report has ranked RIT among the nation’s leading comprehensive universities. The Princeton Review features RIT in its 2007 Best 361 Colleges rankings and named the university one of America’s “Most Wired Campuses.” RIT is also featured in Barron’s Best Buys in Education.

Source: RIT Press Release

I would be greatly pleased if you could tell us about the Dark Era! Common, my brains becoming like a sponge, the more I learn, the more I want to know! (which in one way is a disadvantage) I've never really heard about the Dark Era. I still can't believe they found all of these black holes all at once!

News Release Number: STScI-2007-37


A powerful jet from a supermassive black hole is blasting a nearby galaxy, according to new data from NASA observatories. This never-before witnessed galactic violence may have a profound effect on planets in the jet's path and trigger a burst of star formation in its destructive wake.

Known as 3C 321, the system contains two galaxies in orbit around each other. Data from NASA's Chandra X-ray Observatory show both galaxies contain supermassive black holes at their centers, but the larger galaxy has a jet emanating from the vicinity of its black hole. The smaller galaxy apparently has swung into the path of this jet.

This "death star galaxy" was discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. The Very Large Array (VLA) in Socorro, N.M., and the Multi-Element Radio Linked Interferometer Network (MERLIN) telescopes in the United Kingdom also were needed for the finding.

"We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy like we're seeing here," said Dan Evans, a scientist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. and leader of the study. "This jet could be causing all sorts of problems for the smaller galaxy it is pummeling."

Jets from supermassive black holes produce high amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed.

Jets produced by supermassive black holes transport enormous amounts of energy far from the black holes and enable them to affect matter on scales vastly larger than the size of the black hole. Learning more about jets is a key goal for astrophysical research.

"We see jets all over the universe, but we're still struggling to understand some of their basic properties," said co-investigator Martin Hardcastle of the University of Hertfordshire in the United Kingdom. "This system of 3C 321 gives us a chance to learn how they're affected when they slam into something like a galaxy and what they do after that."

The effect of the jet on the companion galaxy is likely to be substantial, because the galaxies in 3C 321 are extremely close at a distance of only about 20,000 light-years apart. They lie approximately the same distance as Earth is from the center of the Milky Way galaxy.

A bright spot in the VLA and MERLIN images shows where the jet has struck the side of the galaxy, dissipating some of the jet's energy. The collision disrupted and deflected the jet.

"This is a fascinating result, and we can be glad that we're seeing it from a safe distance," said Neil Tyson, an astrophysicist from the American Museum of Natural History in New York, who is not part of the research team. "Knowing how lethal the radiation from the jet could be, I wouldn't want to be anywhere near its line of fire."

Another unique aspect of the discovery in 3C 321 is how relatively short-lived this event is on a cosmic time scale. Features seen in the VLA and Chandra images indicate that the jet began impacting the galaxy about one million years ago, a small fraction of the system's lifetime. This means that such an alignment is quite rare in the nearby universe, making 3C 321 an important opportunity to study such a phenomenon.

It is possible the event is not all be bad news for the galaxy being struck by the jet. The massive influx of energy and radiation from the jet could induce the formation of large numbers of stars and planets after its initial wake of destruction is complete.

The results from Evans and his colleagues will appear in The Astrophysical Journal.

For more images and information about 3C 321, visit:
_http://chandra.harvard.edu/photo/2007/3c321/.

CONTACT
Grey Hautaluoma
Headquarters, Washington
(Phone: 202/358-0668)
grey.hautaluoma-1@nasa.gov

Jennifer Morcone
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256/544-7199)
jennifer.j.morcone@nasa.gov
Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
(Phone: 617/496-7998)
mwatzke@head.cfa.harvard.edu

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone: 410/338-4514)
villard@stsci.edu

Source: HubbleSite - Newsdesk

3C 321: Galaxy Fires at Neighboring Galaxy