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  • richardmitnick 2:04 pm on January 12, 2016 Permalink | Reply
    Tags: , , , Supermassive Black Holes,   

    From Symmetry: “Black holes” 

    Symmetry

    01/12/16
    Ali Sundermier

    Let yourself be pulled into the weird world of black holes.

    Temp 1

    Imagine, somewhere in the galaxy, the corpse of a star so dense that it punctures the fabric of space and time. So dense that it devours any surrounding matter that gets too close, pulling it into a riptide of gravity that nothing, not even light, can escape.

    And once matter crosses over the point of no return, the event horizon, it spirals helplessly toward an almost infinitely small point, a point where spacetime is so curved that all our theories break down: the singularity. No one gets out alive.

    Black holes sound too strange to be real. But they are actually pretty common in space. There are dozens known and probably millions more in the Milky Way and a billion times that lurking outside. Scientists also believe there could be a supermassive black hole at the center of nearly every galaxy, including our own. The makings and dynamics of these monstrous warpings of spacetime have been confounding scientists for centuries.

    A history of black holes

    It all started in England in 1665, when an apple broke from the branch of a tree and fell to the ground. Watching from his garden at Woolsthorpe Manor, Isaac Newton began thinking about the apple’s descent: a line of thought that, two decades later, ended with his conclusion that there must be some sort of universal force governing the motion of apples and cannonballs and even planetary bodies. He called it gravity.

    Newton realized that any object with mass would have a gravitational pull. He found that as mass increases, gravity increases. To escape an object’s gravity, you would need to reach its escape velocity. To escape the gravity of Earth, you would need to travel at a rate of roughly 11 kilometers per second.

    It was Newton’s discovery of the laws of gravity and motion that, 100 years later, led Reverend John Michell, a British polymath, to the conclusion that if there were a star much more massive or much more compressed than the sun, its escape velocity could surpass even the speed of light. He called these objects “dark stars.” Twelve years later, French scientist and mathematician Pierre Simon de Laplace arrived at the same conclusion and offered mathematical proof for the existence of what we now know as black holes.

    In 1915, Albert Einstein set forth the revolutionary theory of general relativity, which regarded space and time as a curved four-dimensional object. Rather than viewing gravity as a force, Einstein saw it as a warping of space and time itself. A massive object, such as the sun, would create a dent in spacetime, a gravitational well, causing any surrounding objects, such as the planets in our solar system, to follow a curved path around it.

    A month after Einstein published this theory, German physicist Karl Schwarzschild discovered something fascinating in Einstein’s equations. Schwarzschild found a solution that led scientists to the conclusion that a region of space could become so warped that it would create a gravitational well that no object could escape.

    Up until 1967, these mysterious regions of spacetime had not been granted a universal title. Scientists tossed around terms like “collapsar” or “frozen star” when discussing the dark plots of inescapable gravity. At a conference in New York, physicist John Wheeler popularized the term “black hole.”

    How to find a black hole

    During star formation, gravity compresses matter until it is stopped by the star’s internal pressure. If the internal pressure does not stop the compression, it can result in the formation of a black hole.

    Some black holes are formed when massive stars collapse. Others, scientists believe, were formed very early in the universe, a billion years after the big bang.

    There is no limit to how immense a black hole can be, sometimes more than a billion times the mass of the sun. According to general relativity, there is also no limit to how small they can be (although quantum mechanics suggests otherwise). Black holes grow in mass as they continue to devour their surrounding matter. Smaller black holes accrete matter from a companion star while the larger ones feed off of any matter that gets too close.

    Black holes contain an event horizon, beyond which not even light can escape. Because no light can get out, it is impossible to see beyond this surface of a black hole. But just because you can’t see a black hole, doesn’t mean you can’t detect one.

    Scientists can detect black holes by looking at the motion of stars and gas nearby as well as matter accreted from its surroundings. This matter spins around the black hole, creating a flat disk called an accretion disk. The whirling matter loses energy and gives off radiation in the form of X-rays and other electromagnetic radiation before it eventually passes the event horizon.

    This is how astronomers identified Cygnus X-1 in 1971. Cygnus X-1 was found as part of a binary star system in which an extremely hot and bright star called a blue supergiant formed an accretion disk around an invisible object. The binary star system was emitting X-rays, which are not usually produced by blue supergiants. By calculating how far and fast the visible star was moving, astronomers were able to calculate the mass of the unseen object. Although it was compressed into a volume smaller than the Earth, the object’s mass was more than six times as heavy as our sun.

    Several different experiments study black holes. The Event Horizon Telescope [EHT] will look at black holes in the nucleus of our galaxy and a nearby galaxy, M87. Its resolution is high enough to image flowing gas around the event horizon.

    Event Horizon Telescope map
    EHT

    Scientists can also do reverberation mapping, which uses X-ray telescopes to look for time differences between emissions from various locations near the black hole to understand the orbits of gas and photons around the black hole.

    The Laser Interferometer Gravitational-Wave Observatory, or LIGO, seeks to identify the merger of two black holes, which would emit gravitational radiation, or gravitational waves, as the two black holes merge.

    Caltech Ligo
    MIT/Caltech Advanced LIGO

    In addition to accretion disks, black holes also have winds and incredibly bright jets erupting from them along their rotation axis, shooting out matter and radiation at nearly the speed of light. Scientists are still working to understand how these jets form.

    What we don’t know

    Scientists have learned that black holes are not as black as they once thought them to be. Some information might escape them. In 1974, Stephen Hawking published results that showed that black holes should radiate energy, or Hawking radiation.

    Matter-antimatter pairs are constantly being produced throughout the universe, even outside the event horizon of a black hole. Quantum theory predicts that one particle might be dragged in before the pair has a chance to annihilate, and the other might escape in the form of Hawking radiation. This contradicts the picture general relativity paints of a black hole from which nothing can escape.

    But as a black hole radiates Hawking radiation, it slowly evaporates until it eventually vanishes. So what happens to all the information encoded on its horizon? Does it disappear, which would violate quantum mechanics? Or is it preserved, as quantum mechanics would predict? One theory is that the Hawking radiation contains all of that information. When the black hole evaporates and disappears, it has already preserved the information of everything that fell into it, radiating it out into the universe.

    Black holes give scientists an opportunity to test general relativity in very extreme gravitational fields. They see black holes as an opportunity to answer one of the biggest questions in particle physics theory: Why can’t we square quantum mechanics with general relativity?

    Beyond the event horizon, black holes curve into one of the darkest mysteries in physics. Scientists can’t explain what happens when objects cross the event horizon and spiral towards the singularity. General relativity and quantum mechanics collide and Einstein’s equations explode into infinities. Black holes might even house gateways to other universes called wormholes and violent fountains of energy and matter called white holes, though it seems very unlikely that nature would allow these structures to exist.

    Sometimes reality is stranger than fiction.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 6:46 am on January 9, 2016 Permalink | Reply
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    From ESA: “Supermassive and super-hungry” 

    ESASpaceForEuropeBanner
    European Space Agency

    08/01/2016
    No writer credit found

    1
    NASA/ESA Hubble and S. Smartt (Queen’s University Belfast)

    This NASA/ESA Hubble Space Telescope image shows the spiral galaxy NGC 4845, located over 65 million light-years away in the constellation of Virgo (The Virgin). The galaxy’s orientation clearly reveals the galaxy’s striking spiral structure: a flat and dust-mottled disc surrounding a bright galactic bulge.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NGC 4845’s glowing centre hosts a gigantic version of a black hole, known as a supermassive black hole. The presence of a black hole in a distant galaxy like NGC 4845 can be inferred from its effect on the galaxy’s innermost stars; these stars experience a strong gravitational pull from the black hole and whizz around the galaxy’s centre much faster than otherwise.

    From investigating the motion of these central stars, astronomers can estimate the mass of the central black hole — for NGC 4845 this is estimated to be hundreds of thousands times heavier than the Sun. This same technique was also used to discover the supermassive black hole at the centre of our own Milky Way — Sagittarius A* — which hits some four million times the mass of the Sun (potw1340a).

    2
    Sagittarius A*. This image was taken with NASA’s Chandra X-Ray Observatory. Ellipses indicate light echoes.

    NASA Chandra Telescope
    NASA/Chandra

    3
    This image, not unlike a pointillist painting, shows the star-studded centre of the Milky Way towards the constellation of Sagittarius. The crowded centre of our galaxy contains numerous complex and mysterious objects that are usually hidden at optical wavelengths by clouds of dust — but many are visible here in these infrared observations from Hubble.
    However, the most famous cosmic object in this image still remains invisible: the monster at our galaxy’s heart called Sagittarius A*. Astronomers have observed stars spinning around this supermassive black hole (located right in the centre of the image), and the black hole consuming clouds of dust as it affects its environment with its enormous gravitational pull.
    Infrared observations can pierce through thick obscuring material to reveal information that is usually hidden to the optical observer. This is the best infrared image of this region ever taken with Hubble, and uses infrared archive data from Hubble’s Wide Field Camera 3, taken in September 2011. It was posted to Flickr by Gabriel Brammer, a fellow at the European Southern Observatory based in Chile. He is also an ESO photo ambassador. Credit: NASA/ESA Hubble and G. Brammer

    The galactic core of NGC 4845 is not just supermassive, but also super-hungry. In 2013 researchers were observing another galaxy when they noticed a violent flare at the centre of NGC 4845. The flare came from the central black hole tearing up and feeding off an object many times more massive than Jupiter. A brown dwarf or a large planet simply strayed too close and was devoured by the hungry core of NGC 4845.

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 1:02 pm on January 5, 2016 Permalink | Reply
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    From U Colorado: “Galactic merger reveals an unusual star-deprived black hole” 

    U Colorado

    University of Colorado Boulder

    January 5, 2016
    Julie Comerford, 303-242-2181
    julie.comerford@colorado.edu

    Trent Knoss, CU-Boulder media relations, 303-735-0528
    trent.knoss@colorado.edu

    1
    Image of the galaxy SDSS J1126+2944 taken with the Hubble Space Telescope and the Chandra X-ray Observatory. The arrow points to the black hole that lost most of its stars due to gravitational stripping processes.

    In a season of post-holiday gym memberships, an unusually star-deprived black hole at the site of two merged galaxies is showing that these massive gravitational voids can shed weight too.

    The recently discovered black hole, which does not have the expected number of stars surrounding it, could provide new insight into black hole evolution and behavior, according to recently published research from the University of Colorado Boulder.

    The findings were announced today during a news briefing at the annual meeting of the American Astronomical Society (AAS) being held this week in Kissimmee, Florida.

    Supermassive black holes exist at the centers of all massive galaxies, including the Milky Way, and contain a mass of between 1 million and 1 billion times that of the sun. The mass of a black hole tends to scale with the mass of its galaxy, and each black hole is typically embedded within a large sphere of stars.

    The galaxy SDSS J1126+2944 is the result of a merger between two smaller galaxies, which brought together a pair of supermassive black holes. One of the black holes is surrounded by a typical amount of stars, but the other black hole is strangely “naked” and has a much lower number of associated stars than expected.

    “One black hole is starved of stars, and has 500 times fewer stars associated with it than the other black hole,” said Julie Comerford, an assistant professor in CU-Boulder’s Department of Astrophysical and Planetary Sciences and the lead investigator of the new research. “The question is why there’s such a discrepancy.”

    One possibility, said Comerford, is that extreme gravitational and tidal forces simply stripped away most of the stars from one of the black holes over the course of the galactic merger.

    The other possibility, however, is that the merger actually reveals a rare “intermediate” mass black hole, with a mass of between 100 and 1 million times that of the sun. Intermediate mass black holes are predicted to exist at the centers of dwarf galaxies and thus have a lower number of associated stars. These intermediate mass black holes can grow and one day become supermassive black holes.

    “Theory predicts that intermediate black holes should exist, but they are difficult to pinpoint because we don’t know exactly where to look,” said Scott Barrows, a postdoctoral researcher at CU-Boulder who co-authored the study. “This unusual galaxy may provide a rare glimpse of one of these intermediate mass black holes.”

    If galaxy SDSS J1126+2944 does indeed contain an intermediate black hole, it would provide researchers with an opportunity to test the theory that supermassive black holes evolve from these lower-mass ‘seed’ black holes.

    Images of the galaxy SDSS J1126+2944 were taken with the Hubble Space Telescope and the Chandra X-ray Observatory, a NASA-operated orbital X-ray telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NASA Chandra Telescope
    NASA/Chandra

    Details of the research were recently published in The Astrophysical Journal. The article is also publicly available at arXiv.

    See the full article here .

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    U Colorado Campus

    As the flagship university of the state of Colorado, CU-Boulder is a dynamic community of scholars and learners situated on one of the most spectacular college campuses in the country. As one of 34 U.S. public institutions belonging to the prestigious Association of American Universities (AAU) – and the only member in the Rocky Mountain region – we have a proud tradition of academic excellence, with five Nobel laureates and more than 50 members of prestigious academic academies.

    CU-Boulder has blossomed in size and quality since we opened our doors in 1877 – attracting superb faculty, staff, and students and building strong programs in the sciences, engineering, business, law, arts, humanities, education, music, and many other disciplines.

    Today, with our sights set on becoming the standard for the great comprehensive public research universities of the new century, we strive to serve the people of Colorado and to engage with the world through excellence in our teaching, research, creative work, and service.

     
  • richardmitnick 4:09 pm on December 3, 2015 Permalink | Reply
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    From phys.org: “Event Horizon Telescope reveals magnetic fields at Milky Way’s central black hole” 

    physdotorg
    phys.org

    December 3, 2015

    1
    In this artist’s conception, the black hole at the center of our galaxy is surrounded by a hot disk of accreting material. Blue lines trace magnetic fields. The Event Horizon Telescope has measured those magnetic fields for the first time with a resolution six times the size of the event horizon (6 Schwarzschild radii). It found the fields in the disk to be disorderly, with jumbled loops and whorls resembling intertwined spaghetti. In contrast, other regions showed a much more organized pattern, possibly in the region where jets (shown by the narrow yellow streamer) would be generated. Credit: M. Weiss/CfA

    Most people think of black holes as giant vacuum cleaners sucking in everything that gets too close. But the supermassive black holes at the centers of galaxies are more like cosmic engines, converting energy from infalling matter into intense radiation that can outshine the combined light from all surrounding stars. If the black hole is spinning, it can generate strong jets that blast across thousands of light-years and shape entire galaxies. These black hole engines are thought to be powered by magnetic fields. For the first time, astronomers have detected magnetic fields just outside the event horizon of the black hole at the center of our Milky Way galaxy.

    “Understanding these magnetic fields is critical. Nobody has been able to resolve magnetic fields near the event horizon until now,” says lead author Michael Johnson of the Harvard-Smithsonian Center for Astrophysics (CfA). The results appear in the Dec. 4th issue of the journal Science.

    “These magnetic fields have been predicted to exist, but no one has seen them before. Our data puts decades of theoretical work on solid observational ground,” adds principal investigator Shep Doeleman (CfA/MIT), who is assistant director of MIT’s Haystack Observatory.

    This feat was achieved using the Event Horizon Telescope (EHT) – a global network of radio telescopes that link together to function as one giant telescope the size of Earth.

    Event Horizon Telescope map
    EHT map

    Since larger telescopes can provide greater detail, the EHT ultimately will resolve features as small as 15 micro-arcseconds. (An arcsecond is 1/3600 of a degree, and 15 micro-arcseconds is the angular equivalent of seeing a golf ball on the moon.)

    Such resolution is needed because a black hole is the most compact object in the universe. The Milky Way’s central black hole, Sgr A* (Sagittarius A-star), weighs about 4 million times as much as our Sun, yet its event horizon spans only 8 million miles – smaller than the orbit of Mercury.

    2
    Sagittarius A*. This image was taken with NASA’s Chandra X-Ray Observatory. Ellipses indicate light echoes.
    Date 23 July 2014

    NASA Chandra Telescope
    NASA/Chandra

    And since it’s located 25,000 light-years away, this size corresponds to an incredibly small 10 micro-arcseconds across. Fortunately, the intense gravity of the black hole warps light and magnifies the event horizon so that it appears larger on the sky – about 50 micro-arcseconds, a region that the EHT can easily resolve.

    The Event Horizon Telescope made observations at a wavelength of 1.3 mm. The team measured how that light is linearly polarized. On Earth, sunlight becomes linearly polarized by reflections, which is why sunglasses are polarized to block light and reduce glare. In the case of Sgr A*, polarized light is emitted by electrons spiraling around magnetic field lines. As a result, this light directly traces the structure of the magnetic field.

    Sgr A* is surrounded by an accretion disk of material orbiting the black hole.

    3
    Image taken by Hubble space telescope of what may be gas accreting onto a black hole in elliptical galaxy NGC 4261

    The team found that magnetic fields in some regions near the black hole are disorderly, with jumbled loops and whorls resembling intertwined spaghetti. In contrast, other regions showed a much more organized pattern, possibly in the region where jets would be generated.

    They also found that the magnetic fields fluctuated on short time scales of only 15 minutes or so.

    “Once again, the galactic center is proving to be a more dynamic place than we might have guessed,” says Johnson. “Those magnetic fields are dancing all over the place.”

    These observations used astronomical facilities in three geographic locations: the Submillimeter Array and the James Clerk Maxwell Telescope [JCMT](both on Mauna Kea in Hawaii), the Submillimeter Telescope on Mt. Graham in Arizona, and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) near Bishop, California.

    CfA Submillimeter Array Hawaii SAO
    CfA Submillimeter Array

    East Asia Observatory James Clerk Maxwell telescope
    JCMT

    CARMA Array
    CARMA Array

    As the EHT adds more radio dishes around the world and gathers more data, it will achieve greater resolution with the goal of directly imaging a black hole’s event horizon for the first time.

    “The only way to build a telescope that spans the Earth is to assemble a global team of scientists working together. With this result, the EHT team is one step closer to solving a central paradox in astronomy: why are black holes so bright?” states Doeleman.

    More information: Resolved magnetic-field structure and variability near the event horizon of Sagittarius A* Science, http://www.sciencemag.org/lookup/doi/10.1126/science.aac7087

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 9:06 pm on November 26, 2015 Permalink | Reply
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    From ICRAR: “Scientists spot jets from supermassive black hole snacking on a star” 

    International Center for Radio Astronomy Research

    International Centre for Radio Astronomy Research

    27 November, 2015
    Contacts

    Dr Gemma Anderson
    ICRAR – Curtin University
    Ph: +61 8 9266 3577
    M: +61 408 955 483
    E: Gemma.Anderson@icrar.org

    Dr James Miller-Jones
    ICRAR – Curtin University
    Ph: +61 8 9266 3785
    M: +61 488 484 825
    E: James.Miller-Jones@icrar.org

    Pete Wheeler
    Media Contact
    M: +61 423 982 018
    E: Pete.Wheeler@icrar.org

    1
    An artist’s impression of a star being drawn toward a black hole and destroyed, triggering a jet of plasma made from debris left over from the stars destruction.
    Credit: Modified from an original image by Amadeo Bachar.

    Scientists have discovered a hungry black hole swallowing a star at the centre of a nearby galaxy.

    The supermassive black hole was found to have faint jets of material shooting out from it and helps to confirm scientists’ theories about the nature of black holes.

    The discovery was published today in the journal Science.

    Astrophysicist Dr Gemma Anderson, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said a supermassive black hole swallowing a star is an extreme event in which the star gets ripped apart.

    “It’s very unusual when a supermassive black hole at the centre of a galaxy actually eats a star, we’ve probably only seen about 20 of them,” she said.

    “Everything we know about black holes suggests we should see a jet when this happens but until now they’ve only been detected in a few of the most powerful systems.

    “Now we’ve finally found one in a more normal event.”

    The discovery is the first time scientists have been able to see both a disk of material falling into a black hole, known as an accretion disk, and a jet in a system of this kind.

    ICRAR astrophysicist Dr James Miller-Jones compared the energy produced by the jets in this event to the entire energy output of the Sun over 10 million years.

    He said it was likely all supermassive black holes swallowing stars launched jets but this discovery was made because the black hole is relatively close to Earth and was studied soon after it was first seen.

    The black hole is only 300 million light years away from us and the team (led by Dr Sjoert van Velzen from The Johns Hopkins University in the USA) were able to make their first observations only three weeks after it was found.

    “We’ve shown that it was just a question of looking at the right time and with enough sensitivity,” Dr Miller-Jones said.

    “Then you can show that a jet exists right at the point you think it should.”

    Dr Anderson began the research while working with the 4 PI SKY team at Oxford University but moved to Western Australia in September.

    She said the event was first picked up by the All-sky Automated Survey for Supernovae (ASAS-SN), which is pronounced ‘assassin’ by astronomers, and followed up with the Arcminute Microkelvin Imager (AMI), a radio telescope, located near Cambridge.

    Arcminute Microkelvin Imager
    Arcminute Microkelvin Imager (AMI) Small Array

    “Hopefully with the increased sensitivity of future telescopes like the Square Kilometre Array we’ll be able to detect jets from other supermassive black holes of this type and discover even more about them,” Dr Anderson said.

    Further information:
    For more information about the 4 PI SKY project visit http://www.4pisky.org

    ICRAR is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.

    Original publication details:

    ‘A radio jet from the optical and X-ray bright stellar tidal disruption flare ASASSN-14li’ published in the journal Science on 26/11/2015. A copy of the paper is available upon request. ​

    See the full article here .

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    ICRAR is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
    ICRAR has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO and the Australian Telescope National Facility, iVEC, and the international SKA Project Office (SPO), based in the UK.

    ICRAR is:

    Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

    SKA Square Kilometer Array
    Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.
    Creating a collaborative environment for scientists and engineers to engage and work with industry to produce studies, prototypes and systems linked to the overall scientific success of the SKA, MWA and ASKAP.

    SKA Murchison Widefield Array
    A Small part of the Murchison Widefield Array

    Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
    Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
    Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
    Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
    Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

     
  • richardmitnick 2:17 pm on November 20, 2015 Permalink | Reply
    Tags: AGN's, , , , Supermassive Black Holes   

    From Nautilus: “This Is Why It’s Hard to Recognize a Black Hole” 

    Nautilus

    Nautilus

    Nov 18, 2015
    Summer Ash

    1
    Black Beauty: The supermassive black hole at the center of this galaxy, around 11 million light years away toward the constellation Centaurus, is currently classified as a quasar. It is roughly 55 million times more massive than our Sun. Its collimated jets, in blue, surpass the diameter of the entire galaxy, extending up to 13,000 light years. The Milky Way, by comparison, is roughly ten times this length. NASA/CXC/CfA/R.Kraft et al.; MPIfR/ESO/APEX/A.Weiss et al.; ESO/WFI.

    Astronomers can sometimes be literal to a fault. We like to call things as we see them. For example, if it’s red and it’s huge: Red Giant. White and small: White Dwarf. Massive explosion: Big Bang. Dark and sucks everything in: Black Hole. Most of the time, classifying objects this way works fine—either it’s new, or it’s something we already know of. But sometimes, as with Pluto, we make new observations that force us to question the name, reassess the object, and identify it differently. You might think this never happens with something as clearly defined as a black hole, but you’d be wrong.

    Though we can’t observe them directly, we can see how the two types of black holes—stellar mass and supermassive—affect their surroundings. Stellar mass black holes, the product of a dying star going supernova and collapsing on itself, are the more familiar, predicted nearly a century ago by [Albert] Einstein’s theory of general relativity; They usually only affect the behavior of the nearest star or two. Supermassive black holes, on the other hand, are over a million times more massive. We still don’t know how these form, but we believe they exist at the center of almost every galaxy, sometimes having the power to alter the appearance of their entire galaxy.

    This capacity for mass distortion makes characterizing supermassive black holes particularly tricky.

    As the stars, gas, and dust in the center of a galaxy get closer and closer to a supermassive black hole, they get packed tighter and tighter into a smaller and smaller space, heating up until, at a critical distance, everything is ripped apart, reduced to atomic particles. When we spot supermassive black holes, it’s this heat radiating away from the orbiting debris—known as an accretion disk—that we actually see, not the black hole itself. Some supermassive black holes “eat” more than others and, in the process, give off significantly more light than their less active brethren. These active galactic nuclei, or AGN for short, are some of the most powerful, most energetic forces in the Universe. Not only do they give off heat, they also often eject material in the form of collimated (beamed) jets, perpendicular to the plane of the disk, which blast their way out of the galaxy’s core—dwarfing in size not just the accretion disk, but also the galaxy itself. What’s more, some AGN have a dusty torus, the geometric equivalent of a donut, in the same plane as their accretion disk, but much, much bigger and thicker. So thick, in fact, that if you looked at them from the side, you wouldn’t see the disk at all, much less the black hole in the center (as seen in the image above).

    Despite having this standard model of an AGN—a supermassive black hole surrounded by an accretion disk with jets streaming out in opposite directions, all encompassed by a dusty torus—making sense of our observations is still a challenge: The light we see doesn’t always paint the same picture. Sometimes we see jets, sometimes we don’t. Sometimes we see the torus, sometimes we don’t. Sometimes we see light so concentrated and bright that we can’t even tell if there’s a galaxy there at all. We label these sightings accordingly: AGN at great distances with cores so bright, they outshine all their stars in optical light, are called quasars (for “quasi-stellar”), like the one pictured above; AGN that glow strongly in the infrared are called Seyferts, after the astronomer Carl Seyfert, who first identified them in 1943; And AGN, with cores and jets whose emitted light dominates in the radio spectrum, are called radio galaxies.

    3
    Resembling a swirling witch’s cauldron of glowing vapors, the black hole-powered core of a nearby active galaxy appears in this colorful NASA Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus.
    This galaxy is designated a type 2 Seyfert, a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects called Active Galactic Nuclei or AGN. AGN have the ability to remove gas from the centers of their galaxies by blowing it out into space at phenomenal speeds. Astronomers studying the Circinus galaxy are seeing evidence of a powerful AGN at the center of this galaxy as well.
    Much of the gas in the disk of the Circinus spiral is concentrated in two specific rings — a larger one of diameter 1,300 light-years, which has already been observed by ground-based telescopes, and a previously unseen ring of diameter 260 light-years.
    In the Hubble image, the smaller inner ring is located on the inside of the green disk. The larger outer ring extends off the image and is in the plane of the galaxy’s disk. Both rings are home to large amounts of gas and dust as well as areas of major “starburst” activity, where new stars are rapidly forming on timescales of 40 – 150 million years, much shorter than the age of the entire galaxy.
    At the center of the starburst rings is the Seyfert nucleus, the believed signature of a supermassive black hole that is accreting surrounding gas and dust. The black hole and its accretion disk are expelling gas out of the galaxy’s disk and into its halo (the region above and below the disk). The detailed structure of this gas is seen as magenta-colored streamers extending towards the top of the image.
    In the center of the galaxy and within the inner starburst ring is a V-shaped structure of gas. The structure appears whitish-pink in this composite image, made up of four filters. Two filters capture the narrow lines from atomic transitions in oxygen and hydrogen; two wider filters detect green and near-infrared light. In the narrow-band filters, the V-shaped structure is very pronounced. This region, which is the projection of a three-dimensional cone extending from the nucleus to the galaxy’s halo, contains gas that has been heated by radiation emitted by the accreting black hole. A “counter-cone,” believed to be present, is obscured from view by dust in the galaxy’s disk. Ultraviolet radiation emerging from the central source excites nearby gas causing it to glow. The excited gas is beamed into the oppositely directed cones like two giant searchlights.
    Located near the plane of our own Milky Way Galaxy, the Circinus galaxy is partially hidden by intervening dust along our line of sight. As a result, the galaxy went unnoticed until about 25 years ago. This Hubble image was taken on April 10, 1999 with the Wide Field Planetary Camera 2.
    The research team, led by Andrew S. Wilson of the University of Maryland, is using these visible light images along with near-infrared data to further understand the dynamics of this powerful galaxy.
    Date 10 April 1999

    If they are all fueled by supermassive black holes, why don’t all AGN look the same? One reason could be our point of view. The theory of AGN unification posits that all AGN have the same basic building blocks (accretion disk, jets, torus); The striking differences we observe, according to this theory, are all due to their orientation in space.

    Here on Earth, we only have one vantage point from which to observe the cosmos. We see galaxies randomly distributed around us, some of them edge-on, some of them face-on, and the rest at all the angles in-between. We cannot fly around to look at these galaxies from any other angle than the one they present to us. But with the advent of supercomputers, we can now simulate these galaxies better than ever before and virtually fly around them as much as we like, enjoying the sights from any angle. We can take an AGN and turn it so we’re looking straight down one of the jets, towards the galactic core, making it resemble a blazar, sort of a blazing quasar. Start tilting the AGN until the jet is rotated ninety degrees away from us, and it appears to morph from a blazar to a quasar to, finally, a Seyfert.

    Yet AGN unification is far from a settled problem in astrophysics. There could be other factors at play than just our point of view, like physical processes in and around black holes we don’t fully understand or measurements we haven’t thought to take. As we build better telescopes and amass new data, we can only hope that we’ll see these active galactic nuclei for what they really are. Otherwise, we might need a lot more names.

    See the full article here .

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    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

     
  • richardmitnick 1:17 pm on October 27, 2015 Permalink | Reply
    Tags: , , Supermassive Black Holes   

    From JPL-Caltech: “Black Hole Has Major Flare” 

    JPL-Caltech

    October 27, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    1

    The baffling and strange behaviors of black holes have become somewhat less mysterious recently, with new observations from NASA’s Explorer missions Swift and the Nuclear Spectroscopic Telescope Array, or NuSTAR.

    NASA SWIFT Telescope
    Swift

    NASA NuSTAR
    NuSTAR

    The two space telescopes caught a supermassive black hole in the midst of a giant eruption of X-ray light, helping astronomers address an ongoing puzzle: How do supermassive black holes flare?

    The results suggest that supermassive black holes send out beams of X-rays when their surrounding coronas — sources of extremely energetic particles — shoot, or launch, away from the black holes.

    “This is the first time we have been able to link the launching of the corona to a flare,” said Dan Wilkins of Saint Mary’s University in Halifax, Canada, lead author of a new paper on the results appearing in the Monthly Notices of the Royal Astronomical Society. “This will help us understand how supermassive black holes power some of the brightest objects in the universe.”

    Supermassive black holes don’t give off any light themselves, but they are often encircled by disks of hot, glowing material. The gravity of a black hole pulls swirling gas into it, heating this material and causing it to shine with different types of light. Another source of radiation near a black hole is the corona. Coronas are made up of highly energetic particles that generate X-ray light, but details about their appearance, and how they form, are unclear.

    Astronomers think coronas have one of two likely configurations. The “lamppost” model says they are compact sources of light, similar to light bulbs, that sit above and below the black hole, along its rotation axis. The other model proposes that the coronas are spread out more diffusely, either as a larger cloud around the black hole, or as a “sandwich” that envelops the surrounding disk of material like slices of bread. In fact, it’s possible that coronas switch between both the lamppost and sandwich configurations.

    The new data support the “lamppost” model — and demonstrate, in the finest detail yet, how the light-bulb-like coronas move. The observations began when Swift, which monitors the sky for cosmic outbursts of X-rays and gamma rays, caught a large flare coming from the supermassive black hole called Markarian 335, or Mrk 335, located 324 million light-years away in the direction of the constellation Pegasus. This supermassive black hole, which sits at the center of a galaxy, was once one of the brightest X-ray sources in the sky.

    “Something very strange happened in 2007, when Mrk 335 faded by a factor of 30. What we have found is that it continues to erupt in flares but has not reached the brightness levels and stability seen before,” said Luigi Gallo, the principal investigator for the project at Saint Mary’s University. Another co-author, Dirk Grupe of Morehead State University in Kentucky, has been using Swift to regularly monitor the black hole since 2007.

    In September 2014, Swift caught Mrk 335 in a huge flare. Once Gallo found out, he sent a request to the NuSTAR team to quickly follow up on the object as part of a “target of opportunity” program, where the observatory’s previously planned observing schedule is interrupted for important events. Eight days later, NuSTAR set its X-ray eyes on the target, witnessing the final half of the flare event.

    After careful scrutiny of the data, the astronomers realized they were seeing the ejection, and eventual collapse, of the black hole’s corona.

    “The corona gathered inward at first and then launched upwards like a jet,” said Wilkins. “We still don’t know how jets in black holes form, but it’s an exciting possibility that this black hole’s corona was beginning to form the base of a jet before it collapsed.”

    How could the researchers tell the corona moved? The corona gives off X-ray light that has a slightly different spectrum — X-ray “colors” — than the light coming from the disk around the black hole. By analyzing a spectrum of X-ray light from Mrk 335 across a range of wavelengths observed by both Swift and NuSTAR, the researchers could tell that the corona X-ray light had brightened — and that this brightening was due to the motion of the corona.

    Coronas can move very fast. The corona associated with Mrk 335, according to the scientists, was traveling at about 20 percent the speed of light. When this happens, and the corona launches in our direction, its light is brightened in an effect called relativistic Doppler boosting.

    Putting this all together, the results show that the X-ray flare from this black hole was caused by the ejected corona.

    “The nature of the energetic source of X-rays we call the corona is mysterious, but now with the ability to see dramatic changes like this we are getting clues about its size and structure,” said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology in Pasadena, who was not affiliated with the study.

    Many other black hole brainteasers remain. For example, astronomers want to understand what causes the ejection of the corona in the first place.

    NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, for NASA’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR’s mission operations center is at UC Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror archive. JPL is managed by Caltech for NASA.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:37 pm on October 10, 2015 Permalink | Reply
    Tags: , , , Supermassive Black Holes   

    From RAS: “Universe’s hidden supermassive black holes revealed” From July but Well Worth Your Time 

    Royal Astronomical Society

    Royal Astronomical Society

    09 July 2015
    Dr Robert Massey
    Royal Astronomical Society
    Mob: +44 (0)794 124 8035
    rm@ras.org.uk

    Ms Anita Heward
    Royal Astronomical Society
    Mob: +44 (0)7756 034 243
    anitaheward@btinternet.com

    Dr Sam Lindsay
    Royal Astronomical Society
    Mob: +44 (0)7957 566 861
    sl@ras.org.uk

    Durham University Marketing and Communications Office
    Tel: +44 (0)191 334 6075
    communications.team@durham.ac.uk

    Astronomers have found evidence for a large population of hidden supermassive black holes in the Universe. Using NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) satellite observatory, the team of international scientists detected the high-energy x-rays from five supermassive black holes previously clouded from direct view by dust and gas. The findings were presented today at the Royal Astronomical Society’s National Astronomy Meeting, at Venue Cymru, in Llandudno, Wales (Monday 6 July).

    1
    NASA/Nu-STAR Credit: NASA/JPL-Caltech.

    The research, led by astronomers at Durham University, UK, supports the theory that potentially millions more supermassive black holes exist in the Universe, but are hidden from view.

    The scientists pointed NuSTAR at nine candidate hidden supermassive black holes that were thought to be extremely active at the centre of galaxies, but where the full extent of this activity was potentially obscured from view.

    High-energy x-rays found for five of the black holes confirmed that they had been hidden by dust and gas. The five were much brighter and more active than previously thought as they rapidly feasted on surrounding material and emitted large amounts of radiation.

    3
    A Hubble Space Telescope colour image of one of the nine galaxies targeted by NuSTAR. The high energy X-rays detected by NuSTAR revealed the presence of an extremely active supermassive black hole at the galaxy centre, deeply buried under a blanket of gas and dust. Credit: Hubble Legacy Archive, NASA, ESA.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Such observations were not possible before NuSTAR, which launched in 2012 and is able to detect much higher energy x-rays than previous satellite observatories.

    Lead author George Lansbury, a postgraduate student in the Centre for Extragalactic Astronomy, at Durham University, said: “For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view.

    “Thanks to NuSTAR for the first time we have been able to clearly see these hidden monsters that are predicted to be there, but have previously been elusive because of their ‘buried’ state.

    “Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole Universe then the predicted numbers are huge and in agreement with what we would expect to see.”

    Daniel Stern, the project scientist for NuSTAR at NASA’s Jet Propulsion Laboratory in Pasadena, California, added: “High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes. NuSTAR allows us to see how big the hidden monsters are and is helping us learn why only some black holes appear obscured.”

    The research was funded by the Science and Technology Facilities Council (STFC) and has been accepted for publication in The Astrophysical Journal.

    4
    An artist’s illustration of a supermassive black hole, actively feasting on its surroundings. The central black hole is hidden from direct view by a thick layer of encircling gas and dust.

    See the full article here .

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  • richardmitnick 7:48 am on October 5, 2015 Permalink | Reply
    Tags: , , , , , Supermassive Black Holes   

    From COSMOS: “Einstein’s gravitational waves remain elusive” 

    Cosmos Magazine bloc

    COSMOS

    5 Oct 2015
    Alan Duffy

    Could the cataclysmic coming-together of two black holes produce fewer ripples in spacetime than we thought?

    The cosmic do-si-do of two supermassive black holes spiralling towards each other is a cataclysmic dance of such intensity, it should ripple the fabric of spacetime itself – or so says [Albert] Einstein’s general theory of relativity. One hundred years have passed since Einstein first proposed the existence of gravitational waves, but they are yet to be detected directly.

    2
    Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time.

    NASA Gravity Probe B
    NASA/Gravity Probe B

    Astronomers in Australia have spent the past decade conducting the most thorough search yet for gravitational waves released when supermassive black holes circle each other, using the Parkes radio telescope in New South Wales. But as the researchers reported in Science in September, they could find no trace of them.

    Could Einstein be wrong? Or have we misunderstood black holes?

    1
    The Parkes radio telescope in NSW conducted an exhaustive but unsuccessful search for gravitational waves. Credit: CSIRO, Shaun Amy/getty images

    Space must be awash with gravitational waves but they’re extraordinarily weak. If a gravitational wave were to pass through you now, this ripple in spacetime would stretch you taller and thinner, then squash you shorter and fatter. The reason you wouldn’t notice is because your height would be altered by less than the width of a proton (a fraction of the size of an atom).

    CSIRO astronomer Ryan Shannon and his team attempted to detect gravitational waves from black holes by measuring their effect on the pulses of radio waves coming from a neutron star more than 3,600 million billion metres away.

    Neutron stars (another prediction of Einstein’s) were discovered in 1967. They are the crushed cores of large dead stars that, when they ran out of fuel, collapsed under their own immense gravity, squeezing as much mass as our Sun’s into the size of Sydney’s central business district.

    And like an ice-skater who spins faster when she tucks her arms in, a neutron star rotates more rapidly as it collapses. As they spin, some emit a tightly focused beam of radiation that shines like a lighthouse. If the Earth lies in the rotating beams’ path, we detect this radiation as the pulses of radio waves, which earned these neutron stars the nickname pulsars.


    A pulsar is the astronomical equivalent of a lighthouse.CREDIT: CAASTRO
    Download mp4 video here.

    A pulsar’s spin is so stable that the pulse it emits is as reliable as the super-accurate tick of an astronomical clock.

    Over the past 11 years the CSIRO’s Parkes radio telescope has been timing the pulses from one such regular and bright pulsar. It spins at more than 300 rotations per second, and each of its 115,836,854,515 rotations over more than a decade has been right on time. But according to Einstein, this shouldn’t be the case.

    According to Einstein’s theory, the gravitational ripples emitted by countless pairs of circling black holes around the Universe should add up, sometimes stretching spacetime between Earth and the pulsar by 10 metres. This stretch should skew the arrival time of pulses from the pulsar by up to one ten-billionth of a second. The Parkes telescope’s timing equipment is accurate enough to detect such a minute change.

    But it didn’t detect any delay.


    As two black holes circle each other, gravitational waves ripple out around them. CREDIT: CAASTRO
    Download mp4 video here.

    The researchers didn’t doubt that gravitational waves exist. They have been detected indirectly. American astronomers Russell Hulse and Joseph Taylor won the 1993 physics Nobel Prize for doing this. They used a pair of neutron stars to measure the astoundingly tiny shortening of the stars’ year – about 30 seconds over three decades – as they spiralled inwards toward each other. Hulse and Taylor calculated that this amount of shortening followed Einstein’s predictions. Some of the energy that kept the stars rotating must have been emitted in the form of gravitational waves.

    So the more likely explanation for the failure of the Parkes research is that we don’t fully understand the black hole mergers that generate gravitational waves.

    Recent observations suggest every galaxy, including our own Milky Way, harbours a supermassive black hole at its core. For reasons still unclear, the mass of the black hole is directly related to the mass of its galaxy – in nearby galaxies where we have been able to make these measurements, at least.

    More distant black holes, which formed earlier, may be smaller than those in nearby galaxies. If so, the spacetime ripples produced as older, more distant black holes meet and begin spiralling in toward each other may be too small for Parkes to pick up – even if there are billions of them.

    Alternatively, early galaxies tend to be more gas-rich. This gas would act like treacle, slowing black holes down. Instead of dancing around each other for billions of years, they “fall in” toward each other much faster, creating a short sharp blast, but ultimately fewer gravitational waves.

    All of which gives Shannon and his team plenty to ponder as they continue their search. Measuring gravitational waves directly would do more than confirm Einstein’s theory of general relativity. It would also be the first time astronomers have looked into the Universe with something other than light. All telescopes, regardless of their size and sophistication, use light waves (be they the long wavelength radio wave variety, visible light, or short wavelength X-rays).

    The observation of gravitational waves would be the dawn of a new era of astronomy. Humanity would look outwards with gravity, and who knows what we might see.

    See the full article here .

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  • richardmitnick 11:33 am on September 24, 2015 Permalink | Reply
    Tags: , , , Supermassive Black Holes   

    From phys.org: “Black hole is 30 times expected size” 

    physdotorg
    phys.org

    September 24, 2015

    1
    A still frame from a movie, illustrating an active galactic nucleus, with jets of material flowing from out from a central black hole. Credit: NASA / Dana Berry / SkyWorks Digital

    The central supermassive black hole of a recently discovered galaxy is far larger than should be possible, according to current theories of galactic evolution. New work, carried out by astronomers at Keele University and the University of Central Lancashire, shows that the black hole is much more massive than it should be, compared to the mass of the galaxy around it. The scientists publish their results in a paper in Monthly Notices of the Royal Astronomical Society.

    The galaxy, SAGE0536AGN, was initially discovered with NASA’s Spitzer space telescope in infrared light.

    NASA Spitzer Telescope
    NASA/Spitzer

    Thought to be at least 9 billion years old, it contains an active galactic nucleus (AGN), an incredibly bright object resulting from the accretion of gas by a central supermassive black hole. The gas is accelerated to high velocities due to the black hole’s immense gravitational field, causing this gas to emit light.

    The team has now also confirmed the presence of the black hole by measuring the speed of the gas moving around it. Using the Southern African Large Telescope [SALT], the scientists observed that an emission line of hydrogen in the galaxy spectrum (where light is dispersed into its different colours – a similar effect is seen using a prism) is broadened through the Doppler Effect, where the wavelength (colour) of light from objects is blue- or red-shifted depending on whether they are moving towards or away from us.

    SALT South African Large Telescope
    SALT South African Large Telescope Interior
    SALT

    The degree of broadening implies that the gas is moving around at high speed, a result of the strong gravitational field of the black hole.

    These data have been used to calculate the black hole’s mass: the more massive the black hole, the broader the emission line. The black hole in SAGE0536AGN was found to be 350 million times the mass of the Sun. But the mass of the galaxy itself, obtained through measurements of the movement of its stars, has been calculated to be 25 billion solar masses. This is seventy times larger than that of the black hole, but the black hole is still thirty times larger than expected for this size of galaxy.

    “Galaxies have a vast mass, and so do the black holes in their cores. This one though is really too big for its boots – it simply shouldn’t be possible for it to be so large”, said Dr Jacco van Loon, an astrophysicist at Keele University and the lead author on the new paper.

    In ordinary galaxies the black hole would grow at the same rate as the galaxy, but in SAGE0536AGN the black hole has grown much faster, or the galaxy stopped growing prematurely. Because this galaxy was found by accident, there may be more such objects waiting to be discovered. Time will tell whether SAGE0536AGN really is an oddball, or simply the first in a new class of galaxies.

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
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