Tagged: Supermassive Black Holes Toggle Comment Threads | Keyboard Shortcuts

  • 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


    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.

    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?

    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 .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

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


    September 24, 2015

    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

    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

    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 .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 2:55 pm on September 23, 2015 Permalink | Reply
    Tags: , , , , Supermassive Black Holes   

    From AAS NOVA: ” Collapsing Enormous Stars” 


    Amercan Astronomical Society

    23 September 2015
    Susanna Kohler

    A scene from a computer animation of a star collapsing to form a gamma-ray burst. A recent study suggests such events could happen on a much larger scale in the distant universe. [NASA / SkyWorks Digital]

    One of the big puzzles in astrophysics is how supermassive black holes (SMBHs) managed to grow to the large sizes we’ve observed in the very early universe. In a recent study, a team of researchers examines the possibility that they were formed by the direct collapse of supermassive stars.

    Formation Mystery

    SMBHs billions of times as massive as the Sun have been observed at a time when the universe was less than a billion years old. But that’s not enough time for a stellar-mass black hole to grow to SMBH-size by accreting material — so another theory is needed to explain the presence of these monsters so early in the universe’s history. A new study, led by Tatsuya Matsumoto (Kyoto University, Japan), poses the following question: what if supermassive stars in the early universe collapsed directly into black holes?

    Previous studies of star formation in the early universe have suggested that, in the hot environment of these primordial times, stars might have been able to build up mass much faster than they can today. This could result in early supermassive stars roughly 100,000 times more massive than the Sun. But if these early stars end their lives by collapsing to become massive black holes — in the same way that we believe massive stars can collapse to form stellar-mass black holes today — this should result in enormously violent explosions. Matusmoto and collaborators set out to model this process, to determine what we would expect to see when it happens!

    Energetic Bursts

    The authors modeled the supermassive stars prior to collapse and then calculated whether a jet, created as the black hole grows at the center of the collapsing star, would be able to punch out of the stellar envelope. They demonstrated that the process would work much like the widely-accepted collapsar model of massive-star death, in which a jet successfully punches out of a collapsing star, violently releasing energy in the form of a long gamma-ray burst (GRB).

    Because the length of a long GRB is thought to be proportional to the free-fall timescale of the collapsing star, the collapse of these supermassive stars would create much longer GRBs than are typical of massive stars today. Instead of the typical long-GRB length of ~30 seconds, these ultra-long GRBs would be 104–106 seconds.

    Interestingly, we have already detected a small number of ultralong GRBs; they make up the tail end of the long GRB duration distribution. Could these detections be signals of collapsing supermassive stars in the early universe? According to the authors’ estimates, we could optimistically expect to detect roughly one of these events per year — so it’s entirely possible!

    Tatsuya Matsumoto et al 2015 ApJ 810 64. doi:10.1088/0004-637X/810/1/64

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

  • richardmitnick 7:33 pm on September 21, 2015 Permalink | Reply
    Tags: , , Supermassive Black Holes   

    From Astronomy: “Pairs of galactic supermassive black holes five times rarer than previously thought” 

    Astronomy magazine

    Astronomy Magazine

    September 21, 2015
    NRAO, Socorro, New Mexico

    At left is the galaxy J0702+5002, which the researchers concluded is not an X-shaped galaxy whose form is caused by a merger. At right is the galaxy J1043+3131, which is a “true” candidate for a merged system. Roberts, et al., NRAO/AUI/NSF

    There may be fewer pairs of supermassive black holes orbiting each other at the cores of giant galaxies than previously thought, according to a new study by astronomers who analyzed data from the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) radio telescope.


    Massive galaxies harbor black holes with millions of times more mass than our Sun at their centers. When two such galaxies collide, their supermassive black holes join in a close orbital dance that ultimately results in the pair combining. That process, scientists expect, is the strongest source of the long-sought, elusive gravitational waves, still yet to be directly detected.

    “Gravitational waves represent the next great frontier in astrophysics, and their detection will lead to new insights on the universe,” said David Roberts of Brandeis University. “It’s important to have as much information as possible about the sources of these waves,” he added.

    Astronomers worldwide have begun programs to monitor fast-rotating pulsars throughout our Milky Way Galaxy in an attempt to detect gravitational waves. These programs seek to measure shifts in the signals from the pulsars caused by gravitational waves distorting the fabric of space-time. Pulsars are spinning superdense neutron stars that emit lighthouse-like beams of light and radio waves that allow precise measurement of their rotation rates.

    Roberts and his colleagues studied a sample of galaxies called X-shaped radio galaxies, whose peculiar structure indicated the possibility that the radio-emitting jets of superfast particles ejected by disks of material swirling around the central black holes of these galaxies have changed directions. The change, astronomers suggested, was caused by an earlier merger with another galaxy, causing the spin axis of the black hole as well as the jet axis to shift direction.

    Working from an earlier list of 100 such objects, they collected archival data from the VLA to make new, more detailed images of 52 of them. Their analysis of the new images led them to conclude that only 11 are “genuine” candidates for galaxies that have merged, causing their radio jets to change direction. The jet changes in the other galaxies, they concluded, came from other causes.

    Extrapolating from this result, the astronomers estimated that fewer than 1.3 percent of galaxies with extended radio emission have experienced mergers. This rate is five times lower than previous estimates.

    “This could significantly lower the level of very-long-wave gravitational waves coming from X-shaped radio galaxies, compared to earlier estimates,” Roberts said. “It will be very important to relate gravitational waves to objects we see through electromagnetic radiation, such as radio waves, in order to advance our understanding of fundamental physics.”

    Gravitational waves, ripples in space-time, were predicted in 1916 by Albert Einstein as part of his theory of general relativity. The first evidence for such waves came from observations of a pulsar orbiting another star, a system discovered in 1974 by Joseph Taylor and Russell Hulse. Observations of this pair over several years showed that their orbits are decaying at exactly the rate predicted by Einstein’s equations that indicate gravitational waves carrying energy away from the system.

    Taylor and Hulse received the 1993 Nobel Prize in physics for this work, which confirmed a predicted effect of gravitational waves. However, no direct detection of such waves has yet been made.

    Roberts worked with Jake Cohen and Jing Lu from Brandeis, who retrieved the data from the VLA archive and produced the images of the galaxies, and Lakshmi Saripalli and Ravi Subrahmanyan of the Raman research Institute in Bangalore, India.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

  • richardmitnick 5:14 pm on September 16, 2015 Permalink | Reply
    Tags: , , , Supermassive Black Holes   

    From Columbia: “New Support For Converging Black Holes” 

    Columbia U bloc

    Columbia University

    Sep 16 2015
    Kim Martineau

    Crash Expected in 100,000 Years – Far Sooner than Previously Predicted, Says Study

    Columbia researchers predict that a pair of converging supermassive black holes in the Virgo constellation will collide sooner than expected. Above, an artist’s conception of a merger. (P. Marenfeld/NOAO/AURA/NSF)

    Earlier this year, astronomers discovered what appeared to be a pair of supermassive black holes circling toward a collision so powerful it would send a burst of gravitational waves surging through the fabric of space-time itself.

    Now, in a new study in the journal Nature, astronomers at Columbia University provide additional evidence that a pair of closely orbiting black holes is causing the rhythmic flashes of light coming from quasar PG 1302-102.

    Based on calculations of the pair’s mass—together, and relative to each other—the researchers go on to predict a smashup 100,000 years from now, an impossibly long time to humans but the blink of an eye to a star or black hole. Spiraling together 3.5 billion light-years away, deep in the Virgo constellation, the pair is separated by a mere light-week. By contrast, the closest previously confirmed black hole pair is separated by 20 light-years.

    “This is the closest we’ve come to observing two black holes on their way to a massive collision,” said the study’s senior author, Zoltan Haiman, an astronomer at Columbia. “Watching this process reach its culmination can tell us whether black holes and galaxies grow at the same rate, and ultimately test a fundamental property of space-time: its ability to carry vibrations called gravitational waves, produced in the last, most violent, stage of the merger.”

    At the center of most giant galaxies, including our own Milky Way, lies a supermassive black hole so dense that not even light can escape. Over time, black holes grow bigger—millions to billions times more massive than the sun–by gobbling up stars, galaxies and even other black holes.

    A supermassive black hole about to cannibalize its own can be detected by the mysterious flickering of a quasar—the beacon of light produced by black holes as they burn through gas and dust swirling around them. Normally, quasars brighten and dim randomly, but when two black holes are on the verge of uniting, the quasar appears to flicker at regular intervals, like a light bulb on timer.

    Recently, a team led by Matthew Graham, a computational astronomer at the California Institute of Technology, designed an algorithm to pick out repeating light signals from 247,000 quasars monitored by telescopes in Arizona and Australia. Of the 20 pairs of black hole candidates discovered, they focused on the most compelling brightquasar– PG 1302-102. In a January study in Nature, they showed that PG 1302-102 appeared to brighten by 14 percent every five years, indicating the pair was less than a tenth of a light-year apart.

    Intrigued, Haiman and his colleagues wondered if they could build a theoretical model to explain the repeating signal. If the black holes were as close as predicted, one had to be circling a much larger counterpart at nearly a tenth ofthe speed of light, they hypothesized. At that speed, the smaller black hole would appear to brighten as it approached Earth’s line of sight under the relativistic Doppler beaming effect.

    If correct, they predicted they would find a five-year cycle in the quasar’s ultraviolet emissions—only two-and-a-half times more variable in its intensity. Analyzing UV observations collected by NASA’s Hubble and GALEX space telescopes they found exactly that.

    Previous explanations for the repeating signal include a warp in the debris disks orbiting the black holes, a wobble in the axis of one black hole and a lopsided debris disk formed as one black hole draws material off the other–all creating the impression of a periodic flicker from Earth.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Columbia U Campus

    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

  • richardmitnick 1:20 pm on September 4, 2015 Permalink | Reply
    Tags: , , Supermassive Black Holes, Tidal streams   

    From AAS: ” Don’t Cross the (Tidal) Streams” 


    Amercan Astronomical Society

    4 September 2015
    Susanna Kohler

    In this simulated TDE, a star is pulled apart by the tidal forces of a black hole. A recent study of the streams of stellar material in TDEs explains why we might be missing many of them. [NASA/S. Gezari (JHU)/J. Guillochon (UCSC)]

    In a tidal disruption event (TDE) ,an unfortunate star passes too close to a dormant supermassive black hole (BH) and gets torn apart by tidal forces, feeding the BH for a short time. Oddly, we’re not finding nearly as many TDEs — typically detected due to their distinctive observational signatures — as theory says we should. A recent study suggests that we might be missing many of these events, due to the way the streams of shredded stars fall onto the BHs.

    Signatures of Shredding

    When a BH tears a star apart, the star’s material is stretched out into what’s known as a tidal stream. That stream continues on a trajectory around the BH, with roughly half the material eventually falling back on the BH, whipping around it in a series of orbits. Where those orbits intersect each other, the material smashes together and circularizes, forming a disk that then accretes onto the BH.

    What does a TDE look like? We don’t observe anything until after the tidal streams collide and the material begins to accrete onto the BH. At that point we observe a sudden peak in luminosity, which then gradually decreases (scaling roughly as time-5/3) as the tail end of what’s left of the star accretes and the BH’s food source eventually runs out.

    So why have we only been observing about a tenth as many TDEs as theory predicts we should see? By studying the structure of tidal streams in TDEs, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Enrico Ramirez-Ruiz (UC Santa Cruz) have found a potential reason — and the culprit is general relativity.

    Dark Years

    The authors run a series of simulations of TDEs around black holes of varying masses and spins to see what form the resulting tidal streams take over time. They find that precession of the tidal stream due to the BH’s gravitational effects changes how the stream interacts with itself, and therefore what we observe. Some cases behave like what we expect for what’s currently considered a “typical” TDE — but some don’t.

    For cases where the relativistic effects are small (such as BHs with masses less than a few 106 solar masses), the tidal stream collides with itself after only a few windings around the BH, quickly forming a disk. The disk forms far from the BH, however, so it takes a long time to accrete. As a result, the observed flare can take 100 times longer to peak than what’s typically expected for a TDE, so we might be failing to identify these sources as TDEs.

    Furthermore, for cases where the BH is both massive and has a spin of a ≳ 0.2, the tidal stream doesn’t collide with itself right away. Instead, it can take many windings around the BH before the first intersection. In these cases, it may potentially be years after a star gets ripped apart before the material accretes and we’re able to observe the event!


    James Guillochon and Enrico Ramirez-Ruiz 2015 ApJ 809 166. doi:10.1088/0004-637X/809/2/166

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

  • richardmitnick 12:39 pm on August 11, 2015 Permalink | Reply
    Tags: , , , Supermassive Black Holes   

    From Chandra: “RGG 118: Oxymoronic Black Hole Provides Clues to Growth” 

    NASA Chandra

    August 11, 2015

    Credit X-ray: NASA/CXC/Univ of Michigan/V.F.Baldassare, et al; Optical: SDSS
    Release Date August 11, 2015

    Astronomers have identified the smallest supermassive black hole found in the center of a galaxy.

    The mass of the black hole is about 50,000 times that of the Sun, using data from the 6.5-meter Clay Telescope.

    X-rays from hot gas swirling towards the black hole were detected by Chandra.

    The black hole may help us understand the formation of much larger supermassive black holes.

    Astronomers using NASA’s Chandra X-ray Observatory and the 6.5-meter Clay Telescope in Chile have identified the smallest supermassive black hole ever detected in the center of a galaxy, as described in our latest press release. This oxymoronic object could provide clues to how much larger black holes formed along with their host galaxies 13 billion years or more in the past.

    Astronomers estimate this supermassive black hole is about 50,000 times the mass of the Sun. This is less than half the previous lowest mass for a black hole at the center of a galaxy.

    The tiny heavyweight black hole is located in the center of a dwarf disk galaxy, called RGG 118, about 340 million light years from Earth. Our graphic shows a Sloan Digital Sky Survey [SDSS] image of RGG 118 and the inset shows a Chandra image of the galaxy’s center.

    SDSS Telescope
    SDSS at Apache Point, NM, USA

    The X-ray point source is produced by hot gas swirling around the black hole.

    Researchers estimated the mass of the black hole by studying the motion of cool gas near the center of the galaxy using visible light data from the Clay Telescope. They used the Chandra data to figure out the brightness in X-rays of hot gas swirling toward the black hole. They found that the outward push of radiation pressure of this hot gas is about 1% of the black hole’s inward pull of gravity, matching the properties of other supermassive black holes.

    Clay Telescope

    Previously, a relationship has been noted between the mass of supermassive black holes and the range of velocities of stars in the center of their host galaxy. This relationship also holds for RGG 118 and its black hole.

    The black hole in RGG 118 is nearly 100 times less massive than the supermassive black hole found in the center of the Milky Way. It is also about 200,000 times less massive than the heaviest black holes found in the centers of other galaxies.

    Astronomers are trying to understand the formation of billion-solar-mass black holes that have been detected from less than a billion years after the Big Bang. The black hole in RGG 118 gives astronomers an opportunity to study a nearby small supermassive black hole in lieu of the first generation of black holes that are undetectable with current technology.

    Astronomers think that supermassive black holes may form when a large cloud of gas, weighing about 10,000 to 100,000 times that of the Sun, collapses into a black hole. Many of these black hole seeds then merge to form much larger supermassive black holes. Alternately, a supermassive black hole seed could come from a giant star, about 100 times the Sun’s mass, that ultimately forms into a black hole after it runs out of fuel and collapses.

    Researchers will continue to look for other supermassive black holes that are comparable in size or even smaller than the one in RGG 118 to help choose between the two options mentioned above and refine their understanding of how these objects grow.

    A preprint of these results is available online. The other co-author of the paper is Jenny Greene, from Princeton University in Princeton, New Jersey. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

  • richardmitnick 2:31 pm on July 9, 2015 Permalink | Reply
    Tags: , , , , Supermassive Black Holes   

    From JPL: “Distant Black Hole Wave Twists Like Giant Whip” 


    July 9, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California

    This cartoon shows how magnetic waves, called Alfvén S-waves, propagate outward from the base of black hole jets. The jet is a flow of charged particles, called a plasma, which is launched by a black hole. The jet has a helical magnetic field (yellow coil) permeating the plasma. The waves then travel along the jet, in the direction of the plasma flow, but at a velocity determined by both the jet’s magnetic properties and the plasma flow speed. The BL Lac jet examined in a new study is several light-years long, and the wave speed is about 98 percent the speed of light.

    Fast-moving magnetic waves emanating from a distant supermassive black hole undulate like a whip whose handle is being shaken by a giant hand, according to a study using data from the National Radio Astronomy Observatory’s Very Long Baseline Array. Scientists used this instrument to explore the galaxy/black hole system known as BL Lacertae (BL Lac) in high resolution.

    This artist’s [famous and iconic]concept illustrates a supermassive black hole with millions to billions times the mass of our sun. Supermassive black holes are enormously dense objects buried at the hearts of galaxies. (Smaller black holes also exist throughout galaxies.) In this illustration, the supermassive black hole at the center is surrounded by matter flowing onto the black hole in what is termed an accretion disk. This disk forms as the dust and gas in the galaxy falls onto the hole, attracted by its gravity.

    Also shown is an outflowing jet of energetic particles, believed to be powered by the black hole’s spin. The regions near black holes contain compact sources of high energy X-ray radiation thought, in some scenarios, to originate from the base of these jets. This high energy X-radiation lights up the disk, which reflects it, making the disk a source of X-rays. The reflected light enables astronomers to see how fast matter is swirling in the inner region of the disk, and ultimately to measure the black hole’s spin rate.

    For more information, visit http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/.

    Fast Facts:

    › Black hole jets set magnetic waves in motion like whips being jerked from side to side.

    › The findings help researchers understand how black holes produce jets.

    Fast-moving magnetic waves emanating from a distant supermassive black hole undulate like a whip whose handle is being shaken by a giant hand, according to a new study using data from the National Radio Astronomy Observatory’s Very Long Baseline Array.


    Scientists used this instrument to explore the galaxy/black hole system known as BL Lacertae (BL Lac) in high resolution.

    “The waves are excited by a shaking motion of the jet at its base,” said David Meier, a now-retired astrophysicist from NASA’s Jet Propulsion Laboratory and the California Institute of Technology, both in Pasadena.

    The team’s findings, detailed in the April 10 issue of The Astrophysical Journal, mark the first time so-called Alfven (pronounced Alf-vain) waves have been identified in a black hole system.

    Alfven waves are generated when magnetic field lines, such as those coming from the sun or a disk around a black hole, interact with charged particles, or ions, and become twisted or coiled into a helical shape. In the case of BL Lac, the ions are in the form of particle jets that are flung from opposite sides of the black hole at near light speed.

    “Imagine running a water hose through a slinky that has been stretched taut,” said first author Marshall Cohen, an astronomer at Caltech. “A sideways disturbance at one end of the slinky will create a wave that travels to the other end, and if the slinky sways to and fro, the hose running through its center has no choice but to move with it.”

    A similar thing is happening in BL Lac, Cohen said. The Alfven waves are analogous to the propagating sideways motions of the slinky, and as the waves propagate along the magnetic field lines, they can cause the field lines — and the particle jets encompassed by the field lines — to move as well.

    It’s common for black hole particle jets to bend — and some even swing back and forth. But those movements typically take place on timescales of thousands or millions of years. “What we see is happening on a timescale of weeks,” Cohen said. “We’re taking pictures once a month, and the position of the waves is different each month.”

    “By analyzing these waves, we are able to determine the internal properties of the jet, and this will help us ultimately understand how jets are produced by black holes,” said Meier.

    Interestingly, from the vantage of astronomers on Earth, the Alfven waves emanating from BL Lac appear to be traveling about five times faster than the speed of light, but it’s only an optical illusion. The illusion is difficult to visualize but has to do with the fact that the waves are traveling slightly off our line of sight at nearly the speed of light. At these high speeds, time slows down, which can throw off the perception of how fast the waves are actually moving.

    Other Caltech authors on the paper include Talvikki Hovatta, a former Caltech postdoctoral scholar. Scientists from the University of Cologne and the Max Planck Institute for Radioastronomy in Germany; the Isaac Newton Institute of Chile; Aalto University in Finland; the Astro Space Center of Lebedev Physical Institute, the Pulkovo Observatory, and the Crimean Astrophysical Observatory in Russia; Purdue University in Indiana and Denison University in Granville, Ohio.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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, 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.

    Caltech Logo

  • richardmitnick 8:16 am on June 19, 2015 Permalink | Reply
    Tags: , , , , Supermassive Black Holes   

    From ALMA: “ALMA Weighs Supermassive Black Hole at Center of Distant Spiral Galaxy” 

    ESO ALMA Array

    18 June 2015
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    E-mail: cblue@nrao.edu

    Richard Hook
    Public Information Officer, ESO
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630
    E-mail: hiramatsu.masaaki@nao.ac.jp

    Composite image of the barred spiral galaxy NGC 1097. By studying the motion of two molecules, ALMA was able to determine that the supermassive black hole at the galactic center has a mass 140 million times greater than our Sun. The ALMA data is in red (HCO+) and green/orange (HCN) superimposed on an optical image taken by the Hubble Space Telescope. Credit: ALMA (NRAO/ESO/NAOJ), K. Onishi; NASA/ESA Hubble Space Telescope; NRAO/AUI/NSF

    Supermassive black holes lurk at the center of virtually every large galaxy. These cosmic behemoths can be millions to billions of times more massive than the Sun. Determining just how massive, however, has been daunting, especially for spiral galaxies and their closely related cousins barred spirals.

    In a new proof-of-concept observation, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have measured the mass of the supermassive black hole at the center of NGC 1097 — a barred spiral galaxy located approximately 45 million light-years away in the direction of the constellation Fornax. The researchers determined that this galaxy harbors a black hole 140 million times more massive than our Sun. In comparison, the black hole at the center of the Milky Way is a lightweight, with a mass of just a few million times that of our Sun.

    Temp 1
    NGC 1097 observed in the optical light with VLT operated by ESO. Credit: ESO/R. Gendler

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small

    ESO 50


  • richardmitnick 3:23 pm on June 10, 2015 Permalink | Reply
    Tags: , , Supermassive Black Holes   

    From Chandra: “NGC 5813: Chandra Finds Evidence for Serial Black Hole Eruptions” 

    NASA Chandra

    June 10, 2015



    Credit X-ray: NASA/CXC/SAO/S.Randall et al., Optical: SDSS
    Release Date June 10, 2015

    -Chandra data show the supermassive black hole at the center of NGC 5813 has erupted multiple times over 50 million years.
    -NGC 5813 is a group of galaxies that is immersed in an enormous reservoir of hot gas.
    -Cavities, or bubbles, in the hot gas that Chandra detects gives information about the black hole’s eruptions.
    -Chandra’s observations of NGC 5813 are the longest ever of a galaxy group taken in X-ray light.

    Astronomers have used NASA’s Chandra X-ray Observatory to show that multiple eruptions from a supermassive black hole over 50 million years have rearranged the cosmic landscape at the center of a group of galaxies.

    Scientists discovered this history of black hole eruptions by studying NGC 5813, a group of galaxies about 105 million light years [1 light year = about 6 trillion miles] from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible light data (red, green and blue).

    Galaxy groups are like their larger cousins, galaxy clusters, but instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically comprised of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays.

    Local Group
    Milky Way’s Local [Galaxy] Group

    The erupting supermassive black hole is located in the central galaxy of NGC 5813. The black hole’s spin, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic, high-speed jet.

    The researchers were able to determine the length of the black hole’s eruptions by studying cavities, or giant bubbles, in the multi-million degree gas in NGC 5813. These cavities are carved out when jets from the supermassive black hole generate shock waves that push the gas outward and create huge holes.

    The latest Chandra observations reveal a third pair of cavities in addition to two that were previously found in NGC 5813, representing three distinct eruptions from the central black hole. (Mouse over the image for annotations of the cavities.) This is the highest number of pairs of cavities ever discovered in either a group or a cluster of galaxies. Similar to how a low-density bubble of air will rise to the surface in water, the giant cavities in NGC 5813 become buoyant and move away from the black hole.

    To understand more about the black hole’s history of eruptions, the researchers studied the details of the three pairs of cavities. They found that the amount of energy required to create the pair of cavities closest to the black hole is lower than the energy that produced the older two pairs. However, the rate of energy production, or power, is about the same for all three pairs. This indicates that the eruption associated with the inner pair of cavities is still occurring.

    Each of the three pairs of cavities is associated with a shock front, visible as sharp edges in the X-ray image. These shock fronts, akin to sonic booms for a supersonic plane, heat the gas, preventing most of it from cooling and forming large numbers of new stars.

    Close study of the shock fronts reveals that they are actually slightly broadened, or blurred, rather than being very sharp. This may be caused by turbulence in the hot gas. Assuming this is the case, the authors found a turbulent velocity – that is, the average speed of random motions of the gas – of about 160,000 miles per hour (258,000 kilometers per hour). This is consistent with the predictions of theoretical models and estimates based on X-ray observations of the hot gas in other groups and clusters.

    A paper describing these results was published in the June 1st, 2015 issue of The Astrophysical Journal and is available online. The first author is Scott Randall from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA and the co-authors are Paul Nulsen, Christine Jones, William Forman and Esra Bulbul from CfA; Tracey Clarke from the Naval Research Laboratory in Washington DC; Ralph Kraft from CfA; Elizabeth Blanton from Boston University in Boston, MA; Lawrence David from CfA; Norbert Werner from Stanford University in Stanford, CA; Ming Sun from University of Alabama in Huntsville, AL; Megan Donahue from Michigan State University in East Lansing, MI; Simona Giacintucci from University of Maryland in College Park, MD and Aurora Simionescu from the Japan Aerospace Exploration Agency in Kanagawa, Japan.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

Compose new post
Next post/Next comment
Previous post/Previous comment
Show/Hide comments
Go to top
Go to login
Show/Hide help
shift + esc

Get every new post delivered to your Inbox.

Join 475 other followers

%d bloggers like this: