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Black Hawk Receives Coarse Gold Results From Dun Glen Project

July 20, 2010 By vani Leave a Comment

FOX ISLAND, Wash., July 19 /PRNewswire-FirstCall/ — Black Hawk Exploration, Inc. (OTC Bulletin Board: BHWX), announced further news to our press release of July 1st, 2010, which showed the results of the additional assays from potential gold bearing dumps at Dun Glen. The 12 previous samples were drawn from a single 60 foot trench. ALS Chemex reported to BHWX that all samples had indications of gold mineralization and 4 samples graded between .1 and .28 oz per ton. These were re-submitted to ALS Chemex for additional fire screen testing to detect the coarse gold nugget effects. The results from the additional 4 fire screen evaluations are as follows:

Location

Au PPM

Au opt

Fire Screen (ppm)

Increased %

DGD-08

5.10

0.15

7.02

+38%

DGD-09

9.75

.28

13.05

+34%

(DGD-07 and DGD-11 showed decreases of 10% and 23% from the original Fire Assay)

These results are in addition to 3 additional dumps previously sampled. Each of these associated dump targets had overall averages as follows: the Auld Lang Syne of 0.15 oz per ton gold, the Black Hole of 0.23 oz per ton gold and the Monroe of 0.04 oz per ton gold. The sampling on the Black Hole and Monroe dumps had areas on the dumps with numerous values higher than 0.2 oz per ton gold. The Black Hole, in particular, had 18 out of 87 samples greater than 0.2 oz per ton gold and four samples were greater than 0.8 oz per ton gold (0.83, 1.86, 4.27, and 4.77 opt gold). “We are pleased with the results from samples DGD-08 and DGD-09 which showed significant increases. The fire screen results showed a greater amount of gold in the assayed results from the fraction testing for coarse gold (ie, nugget effect),” stated Black Hawk’s CEO Kevin M. Murphy.

Black Hawk provides a free report “Summary with Recommendations for Dun Glen Project” which is only available via electronic format. If you wish to receive a copy of the report, please request by emailing to CEO@BlackHawkExploration.com

About Black Hawk Exploration, Inc.:

Black Hawk is a diversified metals and energy exploration company with its current focus on gold and silver discovery through its Dun Glen holdings. Black Hawk is committed to an aggressive program of value added property acquisition, project generation, asset diversity and building shareholder value.

“Safe Harbor” Statement:

Under The Private Securities Litigation Reform Act of 1995: The statements in all press releases that relate to the company’s expectations, with regard to the future impact on the company’s results from new projects in development, are forward-looking statements. A complete disclosure of our “SAFE HARBOR” statement is posted on our website at www.BlackHawkExploration.com under the heading “NEWS”.

SOURCE Black Hawk Exploration, Inc.

Filed Under: International News Tagged With: Als Chemex, assays, Auld Lang Syne, Black Hawk, black hole, Dumps, Dun, Electronic Format, Exploration Inc, Fire Screen, firstcall, Fox Island, Further News, Gold Mineralization, Gold Nugget, hawk, Kevin M Murphy, Nugget Effect, otc bulletin board, PRNewswire

BA strikes pension deal to keep merger on track

June 23, 2010 By vani Leave a Comment

(Reuters) – British Airways said it had agreed a recovery plan for its 3.7 billion pound pension deficit, potentially removing a final obstacle to its planned merger with Spain’s Iberia.

BA said it had reached a deal with the trustees of its Airways Pension Scheme, which last December had a deficit of 1 billion pounds and its New Airways Pension Scheme, which had a 2.7 billion pound black hole.

The airline said on Tuesday the proposals would avoid closing the schemes and maintain BA’s annual contributions at the current level of 330 million pounds, plus agreed annual increases in line with inflation expectations averaging 3 percent.

BA will, however, make additional deficit contributions if its year-end cash balance exceeds 1.8 billion pounds and the two schemes will also be provided with 250 million pounds of additional security over the company’s assets which would become payable in the event of British Airways’ insolvency.

Iberia has the right to pull out of its planned merger with BA if doesn’t deem the pension recovery plan to be satisfactory.

“Iberia has three months to reach a decision on the pension recovery plan,” BA said in a statement.

(Reporting by Matt Scuffham; Editing by Paul Hoskins)

Filed Under: International News Tagged With: 1 Billion, additional security, airline, assets, Ba Strikes, black hole, British Airways, cash balance, Hoskins, iberia, inflation expectations, insolvency, merger, obstacle, Pension Deal, pension scheme, proposals, reuters, three months, year-end

Supermassive black hole gets kicked out of galaxy

May 12, 2010 By vani Leave a Comment

Washington, May 12 (ANI): An international team of astronomers has discovered what appears to be a supermassive black hole leaving its home galaxy at high speed.

For her final-year project, undergraduate student Marianne Heida of the University of Utrecht, worked at the SRON Netherlands Institute for Space Research, using the Chandra Source Catalog (made using the orbiting Chandra X-ray Observatory) to compare hundreds of thousands of sources of X-rays with the positions of millions of galaxies.

Normally each galaxy contains a supermassive black hole at its center. The material that falls into black holes heats up dramatically on its final journey and often means that black holes are strong X-ray sources.

X-rays are also able to penetrate the dust and gas that obscures the center of a galaxy, giving astronomers a clear view of the region around the black hole, with the bright source appearing as a starlike point.

Looking at one galaxy in the catalog, Marianne noticed that the point of light was offset from the center and yet was so bright that it could well be associated with a supermassive black hole.

The black hole appears to be in the process of being expelled from its galaxy at high speed. Given that these objects can have masses equivalent to 1 billion Suns, it takes a special set of conditions to cause this to happen.

Marianne”s newly-discovered object is probably the result of the merger of two smaller black holes. Supercomputer models suggest that the larger black hole that results is shot away at high speed, depending on the direction and speed in which the two black holes rotate before their collision.

In any case, it provides a fascinating insight into the way in which supermassive black holes develop in them center of galaxies.

Marianne”s research — which was carried out under the supervision of SRON researcher Peter Jonker — suggests this discovery may be only the tip of the iceberg, with others subject to future confirmation using the Chandra Observatory.

“We have found many more objects in this strange class of X-ray sources. With Chandra we should be able to make the accurate measurements we need to pinpoint them more precisely and identify their nature,” she said.

Finding more recoiling black holes will provide a better understanding of the characteristics of black holes before they merge.

In future, it might even be possible to observe this process with the planned LISA satellite, an instrument capable of measuring the gravity waves that the two merging black holes emit.

Ultimately this information will let scientists know if supermassive black holes in the cores of galaxies really are the result of many lighter black holes merging together.

This discovery appears in a paper in the journal Monthly Notices of the Royal Astronomical Society. (ANI)

Filed Under: International News Tagged With: black hole, Bright Source, chandra x ray, Final Journey, Final Year Project, Galaxy Washington, Heida, home galaxy, Peter Jonker, ray observatory, ray sources, source catalog, space research, Sron Netherlands Institute, Supercomputer Models, supermassive black holes, Tip Of The Iceberg, undergraduate student, university of utrecht, x rays

Fresh evidence for ‘survivor’ black holes from NASA

April 30, 2010 By vani Leave a Comment

Washington, April 30 (ANI): NASA”s Chandra X-ray Observatory and ESA”s XMM-Newton has brought out new evidence about the existence of two mid-sized black holes close to the center of a nearby starburst galaxy.

The black holes, known as ‘survivor’ black holes, avoided falling into the center of the galaxy and could be examples of the seeds required for the growth of supermassive black holes in galaxies, including the one in the Milky Way.

The researchers who were on a look-out for the black holes that are in-between recently found signatures in X-ray data of two mid-sized black holes in the starburst galaxy M82 located 12 million light years from Earth.

“This is the first time that good evidence for two mid-sized black holes has been found in one galaxy,” said Hua Feng of the Tsinghua University in China, who led two papers describing the results.

“Their location near the center of the galaxy might provide clues about the origin of the Universe”s largest black holes – supermassive black holes found in the centers of most galaxies,” Feng added.

The evidence for these two ‘survivor’ black holes comes from how their X-ray emission varies over time and analysis of their X-ray brightness and spectra, i.e., the distribution of X-rays with energy.

Chandra and XMM-Newton data has shown that the X-ray emission for one of these objects changes in a distinctive manner similar to stellar-mass black holes found in the Milky Way.

Thus, the team estimated this black hole”s mass is between 12,000 and 43,000 times the mass of the Sun. This mass is large enough for the black hole to generate copious X-rays by pulling gas directly from its surroundings.

The black hole is located at a projected distance of 290 light years from the center of M82.

The second object, located 600 light years in projection away from the center of M82, was observed by both Chandra and XMM-Newton.

“This result is one of the strongest pieces of evidence to date for the existence of an intermediate-mass black hole. This looks just like well-studied examples of stellar-mass black holes, except for being more than 20 times as massive,” Feng said. (ANI)

Filed Under: International News Tagged With: black hole, center of the galaxy, chandra x ray, Distinctive Manner, Hua Feng, mass of the sun, Milky Way, million light years, NASA, Nearby Starburst Galaxy, new evidence, origin of the universe, ray emission, ray observatory, s chandra, supermassive black holes, Tsinghua University, University In China, x rays, XMM-NEWTON

Highway funding shortfall

March 23, 2010 By vani Leave a Comment

The Clarence Valley mayor says he was staggered to hear about a six-billion-dollar black hole in Pacific Highway funding.

Richie Williamson says he learned about the funding shortfall at a meeting with the Roads and Traffic Authority in Sydney last week.

He says the situation jeopardises the timeframe for completion of the dual-carriageway project.

“It’s a staggering amount of money, and there is a staggering amount of work that needs to be done if the Pacific Highway is going to be dual carriageway by 2016,” Cr Williamson said.

“The Prime Minister said he was committed to that number 2016 recently so there is a staggering amount of funds needed if that is the case,” he said.

Filed Under: International News Tagged With: amount of money, black hole, Clarence Valley, Cr Williamson, federal-state-issues, grafton-2460, Prime Minister, programs-and-initiatives, Roads And Traffic, Roads And Traffic Authority, shortfall, six billion, sydney, Timeframe, urban-development-and-planning

Invading black holes cause ‘cosmic flashes’

September 19, 2009 By admin Leave a Comment

Washington, September 19 (ANI): Mathematicians at the University of Leeds, UK, have determined that cosmic flashes, known as gamma ray bursts, are produced by jets of plasma that originate from invading black holes.

Gamma ray bursts are beams of high-energy radiation that are similar to the radiation emitted by explosions of nuclear weapons.

The orthodox model for this cosmic jet engine involves plasma being heated by neutrinos in a disk of matter that forms around a black hole, which is created when a star collapses.

But, mathematicians at the University of Leeds, have come up with a different explanation: the jets come directly from black holes, which can dive into nearby massive stars and devour them.

Their theory is based on recent observations by the Swift satellite, which indicates that the central jet engine operates for up to 10,000 seconds – much longer than the neutrino model can explain.

Mathematicians believe that this is evidence for an electromagnetic origin of the jets, that is, that the jets come directly from a rotating black hole, and that it is the magnetic stresses caused by the rotation that focus and accelerate the jet’s flow.

For the mechanism to operate, the collapsing star has to be rotating extremely rapidly.

This increases the duration of the star’s collapse as the gravity is opposed by strong centrifugal forces.

One particularly peculiar way of creating the right conditions involves not a collapsing star, but a star invaded by its black hole companion in a binary system.

The black hole acts like a parasite, diving into the normal star, spinning it with gravitational forces on its way to the star’s centre, and finally eating it from the inside.

“The neutrino model cannot explain very long gamma ray bursts and the Swift observations, as the rate at which the black hole swallows the star becomes rather low quite quickly, rendering the neutrino mechanism inefficient, but the magnetic mechanism can,” said Professor Komissarov from the School of Mathematics at the University of Leeds.

“Our knowledge of the amount of the matter that collects around the black hole and the rotation speed of the star allow us to calculate how long these long flashes will be – and the results correlate very well with observations from satellites,” he added. (ANI)

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Brit teen Lotto winner confesses to have blown 205K pounds on coke

August 30, 2009 By admin Leave a Comment

London, Aug 30 (ANI): Lottery winning teenager Callie Rogers has admitted that her instant riches led her to a ‘drug spree’ as she spent almost 250,000 pounds on cocaine.

The 22-year-old now has only 20,000 pounds left from her 1.9million pound jackpot that she won at 16 years of age.

She told News of the World: “I honestly wish I’d never won the lottery money – and knowing what I know now I should have just given it all back to them.

“I was just too young to cope with suddenly having that amount in the bank when I’d come from nothing.

“In the past six years I’ve sunk into a black hole – a black hole that at one point I thought I could never crawl out of.

“I was spending a fortune on cocaine, a nasty evil drug which tears your life apart. I’ll be honest, about 1/4 million pounds of my win has been wasted on it. Most of it wasn’t for me, it was for my ex Nicky Lawson who was addicted to it.

“But it was all my money that bought it. And that makes me absolutely disgusted with myself for allowing that to happen. I might as well have thrown it down the toilet.”

She added: “I started taking coke within weeks of winning the Lottery and pretty soon I was hooked. It made me forget about all the problems in my life and at the start made me feel like everything was OK.

“But that didn’t last long and soon drugs made me fall into a deep, dark place. Somewhere which made me feel I didn’t want to live any more.

“I honestly just felt so low I thought in death I’d find a safer happier place.”

“I won’t lie, I’ve blown most of it,” she said.

“But, do you know what? I don’t care.

“Because all that money has brought me is heartache. Yes I enjoyed buying fast cars, holidays and clothes for the baby but honestly I’m glad it’s nearly all gone.

“I have the 20,000 pounds in the bank, and that’s about it. But that’s a lot more than most 22-year-olds,” she added. (ANI)

Filed Under: Uncategorized Tagged With: black hole, clothes, cocaine, Coke, drugs, fast cars, fortune, Happier Place, holidays, Lawson, London, lottery money, lotto winner, news of the world, rogers, six years, spree, teenager, toilet, winning the lottery

Black hole at centre of galaxy twice as big as originally thought

August 25, 2009 By admin Leave a Comment

London, August 24 (ANI): New estimates bys scientists suggest that the black hole at the centre of the M87 galaxy may be twice as big as originally thought, and possibly large enough to measure directly.

M87 is 55 million light years away. Its central black hole devours vast amounts of gas and spews out a huge jet of particles that extends far into intergalactic space.

According to a report in New Scientist, Karl Gebhardt at the University of Texas at Austin and Thomas Jens of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, weighed M87 by running existing data through a new model that simulates the galaxy on a supercomputer.

Unlike earlier efforts, the model accounts for the invisible halo of dark matter thought to surround the galaxy.

Their analysis credited the monstrous central black hole with a mass of 6.4 billion suns, which was much more than was expected.

M87′s black hole, when viewed from Earth, would be the same apparent size as the nearer black hole at the centre of the Milky Way.

This puts M87′s hole within reach of radio astronomy techniques that measure a black hole directly, by tracing its dark silhouette against the glow of surrounding gas. (ANI)

Filed Under: Science News Tagged With: apparent size, black hole, dark matter, extraterrestrial physics, garching germany, karl gebhardt, m87 galaxy, max planck institute, max-planck, Milky Way, million light years, model accounts, new model, New Scientist, radio astronomy techniques, silhouette, spews, supercomputer, texas at austin, university of texas at austin

Led Zeppelin may fill Jackson’s 50-show O2 run with ABBA

July 4, 2009 By admin Leave a Comment

London, July 4 (ANI): ‘Led Zeppelin’ have apparently been approached to alternate shows with Abba, and fill in for the 50-show run previously planned for Michael Jackson at London’s O2 arena.

AEG Live, promoters for the late King of Pop’s slated comeback tour, were said to be trying hard to woo both the bands to reform.

“Only Michael Jackson could sell out 50 nights at such a big arena, but Led Zeppelin and Abba combined might just rival him. There is huge money on the table,” British tabloid The Sun quoted a source as saying.

Jackson was due to begin his ‘This Is It’ gigs on July 13.

His sudden death on June 25 has left the organisers facing a multi-million pound black hole, if they are unable fill the slots. (ANI)

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ABBA approached to fill Jacko’s 50-show O2 run

July 2, 2009 By admin Leave a Comment

London, July 2 (ANI): Pop legends ABBA have apparently been approached to fill in for the 50-show run previously planned for Michael Jackson at London’s O2 arena.

AEG Live, the promoters for the King of Pop’s slated comeback tour, are said to be trying hard to woo the renowned band out of retirement.

“There’s a little foursome out in Sweden we keep talking to,” British tabloid The Sun quoted the firm’s chief David Campbell as saying.

Jackson was due to begin his This Is It gigs on July 13.

His sudden death has left the organisers facing a multi-million pound black hole if they are unable fill the slots. (ANI)

Filed Under: Entertainment News Tagged With: abba, aeg, black hole, british tabloid the sun, chief david, comeback tour, david campbell, foursome, king of pop, London, London Arena, London Live, Michael Jackson, o2, organisers, pop legends, promoters, retirement, slots, sudden death, Sweden, tabloid the sun

Cosmic “ghost” found lurking around supermassive black hole

May 29, 2009 By admin Leave a Comment

Washington, May 29 (ANI): NASA’s Chandra X-ray Observatory has found a cosmic “ghost” lurking around a distant supermassive black hole, which is the first detection of such a high-energy apparition, and may be evidence of a huge eruption produced by the black hole.

The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken.

The source, a.k.a. HDF 130, is over 10 billion light-years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate.

“We’d seen this fuzzy object a few years ago, but didn’t realize until now that we were seeing a ghost”, said Andy Fabian of the Cambridge University in the United Kingdom.

“It’s not out there to haunt us, rather it’s telling us something – in this case what was happening in this galaxy billions of year ago,” he added.

Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light.

When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy.

However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang – the cosmic background radiation.

Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band.

This process produces an extended X-ray source that lasts for another 30 million years or so.

“This ghost tells us about the black hole’s eruption long after it has died,” said co-author Scott Chapman, also of Cambridge University. “This means we don’t have to catch the black holes in the act to witness the big impact they have,” he added.

This is the first X-ray ghost ever seen after the demise of radio-bright jets.

In HDF 130, only a point source is detected in radio images, coinciding with the massive elliptical galaxy seen in its optical image.

This radio source indicates the presence of a growing supermassive black hole.

“This result hints that the X-ray sky should be littered with such ghosts, especially if black hole eruptions are as common as we think they are in the early Universe,” said co-author Caitlin Casey, also of Cambridge. (ANI)

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Astronomers probe close to supermassive black hole’s edge

May 28, 2009 By admin Leave a Comment

Paris, May 28 (ANI): Astronomers have used new data from ESA’s (European Space Agency’s) XMM-Newton spaceborne observatory, to probe closer than ever to a supermassive black hole lying deep at the core of a distant active galaxy.

The galaxy – known as 1H0707-495 – was observed during four 48-hr-long orbits of XMM-Newton around Earth, starting in January 2008.

The black hole at its center was thought to be partially obscured from view by intervening clouds of gas and dust, but these current observations have revealed the innermost depths of the galaxy.

“We can now start to map out the region immediately around the black hole,” said Andrew Fabian, at the University of Cambridge, who headed the observations and analysis.

X-rays are produced as matter swirls into a supermassive black hole.

The X-rays illuminate and are reflected from the matter before its eventual accretion. Iron atoms in the flow imprint characteristic iron lines on the reflected light.

XMM-Newton detected two bright features of iron emission in the reflected X-rays that had never been seen together in an active galaxy.

These bright features are known as the iron L and K lines, and they can be so bright only if there is a high abundance of iron.

Seeing both in this galaxy suggests that the core is much richer in iron than the rest of the galaxy.

The direct X-ray emission varies in brightness with time. During the observation, the iron L line was bright enough for its variations to be followed.

A painstaking statistical analysis of the data revealed a time lag of 30 seconds between changes in the X-ray light observed directly, and those seen in its reflection from the disc.

This delay in the echo enabled the size of the reflecting region to be measured, which leads to an estimate of the mass of the black hole at about 3 to 5 million solar masses.

The observations of the iron lines also reveal that the black hole is spinning very rapidly and eating matter so quickly that it verges on the theoretical limit of its eating ability, swallowing the equivalent of two Earths per hour.

This new technique will enable the astronomers to map out the process in all its glorious complexity, taking them to previously unseen regions at the very edges of this and other supermassive black holes. (ANI)

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Rogue black holes may wander the Milky Way

May 2, 2009 By admin Leave a Comment

Washington, April 30 (ANI): New calculations by scientists suggest that hundreds of massive rogue black holes, left over from the galaxy-building days of the early universe, may wander the Milky Way.

The calculations have been made by Ryan O’Leary and Avi Loeb from the Harvard-Smithsonian Center for Astrophysics.

Though the research indicates that rogue black holes may roam the Milky Way, the good news is that the Earth is safe, as the closest rogue black hole should reside thousands of light-years away.

Astronomers are eager to locate them, though, for the clues they will provide to the formation of the Milky Way.

“These black holes are relics of the Milky Way’s past,” said Loeb. “You could say that we are archaeologists studying those relics to learn about our galaxy’s history and the formation history of black holes in the early universe,” he added.

According to theory, rogue black holes originally lurked at the centers of tiny, low-mass galaxies. Over billions of years, those dwarf galaxies smashed together to form full-sized galaxies like the Milky Way.

Each time two proto-galaxies with central black holes collided, their black holes merged to form a single, “relic” black hole.

During the merger, directional emission of gravitational radiation would cause the black hole to recoil.

A typical kick would send the black hole speeding outward fast enough to escape its host dwarf galaxy, but not fast enough to leave the galactic neighborhood completely.

As a result, such black holes would still be around today in the outer reaches of the Milky Way halo.

Hundreds of rogue black holes should be traveling the Milky Way’s outskirts, each containing the mass of 1,000 to 100,000 suns.

They would be difficult to spot on their own because a black hole is visible only when it is swallowing, or accreting, matter.

One telltale sign could mark a rogue black hole: a surrounding cluster of stars yanked from the dwarf galaxy when the black hole escaped.

Only the stars closest to the black hole would be tugged along, so the cluster would be very compact.

Due to the cluster’s small size on the sky, appearing to be a single star, astronomers would have to look for more subtle clues to its existence and origin.

The number of rogue black holes in our galaxy depends on how many of the proto-galactic building blocks contained black holes at their cores, and how those proto-galaxies merged to form the Milky Way.

Finding and studying them will provide new clues about the history of our galaxy. (ANI)

Filed Under: Uncategorized Tagged With: archaeologists, avi loeb, black hole, Cluster Of Stars, dwarf galaxies, dwarf galaxy, early universe, formation history, galactic neighborhood, gravitational radiation, harvard smithsonian center, harvard smithsonian center for astrophysics, history of black holes, light-years, low-mass, Milky Way, outer reaches, recoil, relics, telltale sign

Black holes that can regulate the rate at which they grow

March 26, 2009 By admin Leave a Comment

Washington, March 26 (ANI): New results from NASA’s Chandra X-ray Observatory have suggested that a special class of black holes have a mechanism for regulating the rate at which they grow, and can shut off the high-speed jets they produce.

Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called “micro-quasars”.

The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return.

This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star.

As the material swirls toward the black hole, an accretion disk forms.

This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation.

These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915.

Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999.

These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole.

The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge.

“We think the jet and wind around this black hole are in a sort of tug of war,” said Joseph Neilsen, Harvard graduate student and lead author of the research paper. “Sometimes one is winning and then, for reasons we don’t entirely understand, the other one gets the upper hand,” he added.

The latest Chandra results also show that the wind and the jet carry about the same amount of matter away from the black hole.

This is evidence that the black hole is somehow regulating its accretion rate, which may be related to the toggling between mass expulsion via either a jet or a wind from the accretion disk.

Self-regulation is a common topic when discussing supermassive black holes, but this is the first clear evidence for it in stellar-mass black holes.

According to Julia Lee, assistant professor in the Astronomy department at the Harvard-Smithsonian Center for Astrophysics, “It is exciting that we may be on the track of explaining two mysteries at the same time: how black hole jets can be shut down and also how black holes regulate their growth.” By Sarda Lahangir (ANI)

Filed Under: Science News Tagged With: accretion disk, black hole, black holes, chandra x ray, companion star, eleven times, event horizon, harvard graduate student, mass of the sun, Neilsen, point of no return, Quasars, radio jet, ray observatory, s chandra, spectrograph, speed jets, timescales, tug-of-war, x rays

Scientists observe the largest exploding star yet seen

March 24, 2009 By admin Leave a Comment

Washington, March 24 (ANI): Scientists at the Weizmann Institute of Science and San Diego State University have observed the largest exploding star yet seen, which is the size of 50 suns.

While exploding stars, called supernovae, have been viewed with everything from the naked eye to high-tech research satellites, no one had directly observed what happens when a really huge star blows up.

Dr. Avishay Gal-Yam of the Weizmann Institute’s Faculty of Physics and Professor Douglas Leonard of San Diego State University recently located and calculated the mass of a gigantic star on the verge of exploding, following through with observations of the blast and its aftermath.

As they continued to track the spectacular event, they found that most of the star’s mass collapsed in on itself, resulting in a large black hole.

Their findings have lent support to the reigning theory that stars ranging from tens to hundreds of times the mass of our sun all end up as black holes.

Until now, none of the supernovae stars that scientists had managed to measure had exceeded a mass of 20 suns.

Gal-Yam and Leonard were looking at a specific region in space using the Keck Telescope on Mauna Kea in Hawaii and the Hubble Space Telescope.

Identifying the about-to-explode star, they calculated its mass to be equal to 50-100 suns. Continued observation revealed that only a small part of the star’s mass was flung off in the explosion.

According to Gal-Yam, most of the material was drawn into the collapsing core as its gravitational pull mounted.

In subsequent telescope images of that section of the sky, the star seems to have disappeared. In other words, the star has now become a black hole – so dense that light can’t escape. (ANI)

Filed Under: Science News Tagged With: 100 suns, black hole, black holes, diego state university, exploding star, exploding stars, gigantic star, gravitational pull, Hubble Space Telescope, hubble telescope, keck telescope, mauna kea, naked eye, professor douglas, research satellites, san diego state university, Spectacular Event, telescope images, verge, weizmann institute of science, yam