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  • richardmitnick 10:54 am on August 19, 2014 Permalink | Reply
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    From SPACE.com: “Supermassive Death: 3 Stars Eaten by Black Holes” 

    space-dot-com logo


    August 19, 2014
    Ian O’Neill

    Astrophysicists have analyzed two decades-worth of X-ray data and discovered three events inside galactic cores that can be interpreted in only one way: stellar destruction.

    ANALYSIS: Supermassive Black Hole Jet Mystery Solved

    For any given galaxy, it is estimated that a star will be destroyed by the central supermassive black hole approximately once every 10,000 years. The vast majority of known galaxies are thought to contain at least one supermassive black hole in their cores, having a dramatic effect on galactic and stellar evolution. [Images: Black Holes of the Universe]

    As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will be dragged into the black hole’s accretion disk — a hot disk of gas that is gradually pulled into the black hole’s event horizon, bulking up the black hole’s mass, or blasted as energetic jets from its poles.

    Should there be a rapid injection of material — i.e. a star becoming blended and ingested into the accretion disk — powerful X-rays of a specific signature will be generated.

    NEWS: Supermassive Black Holes are Not Doughnuts!

    In a new study by the Moscow Institute of Physics and Technology and Space Research Institute of the Russian Academy of Sciences, astrophysicists trawled through observations from two space observatories to discover three likely occasions where stars have been eaten by supermassive black holes. Their work has been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

    Using data from the German ROSAT and European XMM-Newton space observatories, X-ray data from 1990 (to today) could be accessed and three events in different galaxies were positively identified — designated 1RXS J114727.1 + 494302, 1RXS J130547.2 + 641252 and 1RXS J235424.5-102053. Invaluable to this study was the long-duration observations by ROSAT (which operated from 1990 to 1999) and XMM-Newton (launched in 1999) that could detect the moment of stellar death, keeping track of the X-ray emissions over the years as the star’s material was gradually ingested.

    ROSAT Spacecraft

    ESA XMM Newton

    NEWS: Intermediate Black Hole Implicated in Star’s Death

    No more than two dozen other stellar death event candidates were seen in the observations, but positive identifications probably won’t be available until the launch of the multi-instrument Spectrum-X-Gamma space observatory in 2016.

    Spectrum GammaX
    Spectrum-X-Gamma space observatory

    This work has added some much needed detail to these rare events, indicating that (on average) one star every 30,000 years in any given galaxy will be destroyed by the central supermassive black hole, though the researchers caution that more observations of stars being eaten by supermassive black holes are needed.

    See the full article here.

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  • richardmitnick 10:24 am on August 18, 2014 Permalink | Reply
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    From SPACE.com: ” It’s Confirmed! Black Holes Do Come in Medium Sizes” 

    space-dot-com logo


    August 18, 2014
    Mike Wall

    Black holes do indeed come in three sizes: small, medium and extra large, a new study suggests.

    Astronomers have studied many black holes at either size extreme — “stellar-mass” black holes, which are a few dozen times as weighty as the sun, and supermassive black holes, which can contain millions or billions of times the mass of the sun and lurk at the heart of most, if not all, galaxies.

    Researchers have spotted hints of much rarer medium-size black holes, which harbor between 100 and several hundred thousand solar masses. But it’s tough to weigh these objects definitively — so tough that their existence has been a matter of debate.

    But that debate can now be put to rest, says a research team that has measured an intermediate black hole’s mass with unprecedented precision. A black hole in the nearby galaxy M82 weighs in at 428 solar masses, give or take a hundred suns or so, they report today (Aug. 17) in the journal Nature.

    “Objects in this range are the least expected of all black holes,” study co-author Richard Mushotzky, an astronomy professor at the University of Maryland, said in a statement. “Astronomers have been asking, ‘Do these objects exist, or do they not exist? What are their properties?’ Until now, we have not had the data to answer these questions.”

    Patterns in the light

    Black holes famously gobble up anything that gets too close, including light. But that doesn’t mean astronomers can’t see them; bright X-ray light streams from the superhot disk of material spiraling into a black hole’s mouth.

    About 15 years ago, NASA’s Chandra X-ray Observatory spacecraft spotted such emissions coming from a source in the galaxy M82, which lies about 12 million light-years away from Earth. For a long time, Mushotzky and some other scientists suspected that the object, called M82 X-1, was a medium-size black hole. But those suspicions were tough to confirm.

    NASA Chandra Telescope

    “For reasons that are very hard to understand, these objects have resisted standard measurement techniques,” Mushotzky said.

    In the new study, a team led by University of Maryland doctoral student Dheeraj Pasham took a closer look at M82 X-1. They studied observations made from 2004 to 2010 by NASA’s Rossi X-ray Timing Explorer (RXTE) satellite, which ceased operations in 2012.


    The RXTE data revealed a pair of repeating oscillations in M82 X-1’s X-ray emissions. These oscillations occurred 5.1 times per second and 3.3 times per second, respectively — a ratio of three to two. This fact allowed the team to determine the black hole’s mass.

    “In essence, [the] frequency of these 3:2 ratio oscillations scales inverse[ly] with black hole mass,” Pasham told Space.com via email. “Simply put, if the black hole is small, the orbital periods at the innermost circular orbit are shorter, but if the black hole is big, the orbital periods are longer (smaller frequencies).”

    The researchers calculated M82 X-1’s mass at 428 suns, plus or minus 105 solar masses.

    “In our opinion, and as the paper’s referees seem to agree, this is the most accurate mass measurement of an intermediate-mass black hole to date,” Pasham said.

    Learning about black-hole growth

    Confirming the existence of intermediate black holes could help researchers better understand the supermassive monsters at the cores of galaxies.

    Such behemoths apparently first formed in the universe’s very early days, just a few hundred million years after the Big Bang. They could not have grown so big so fast if their “seeds” were small stellar-mass black holes (which result from the collapse of giant stars), Pasham said.

    “Many theories, therefore, have suggested that these initial seed black holes had to have been a few 100 -1,000 times our sun,” he said. “But we did not have firm evidence for such intermediate-mass black holes.”

    Stellar-mass black holes also often feature paired X-ray oscillations that occur in a 3:2 frequency ratio. Therefore, the new observations suggest that medium-size black holes may behave like scaled-up versions of stellar-mass black hole systems, Pasham added.

    The research is detailed in the Aug. 17 edition of the journal Nature.

    See the full article here.

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  • richardmitnick 9:28 am on August 1, 2014 Permalink | Reply
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    From NASA/NuSTAR: “NuSTAR Celebrates Two Years of Science in Space” 


    July 31, 2014

    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, a premier black-hole hunter among other talents, has finished up its two-year prime mission, and will be moving onto its next phase, a two-year extension.

    “It’s hard to believe it’s been two years since NuSTAR launched,” said Fiona Harrison, the mission’s principal investigator at the California Institute of Technology in Pasadena. “We achieved all the mission science objectives and made some amazing discoveries I never would have predicted two years ago.”

    In this new chapter of NuSTAR’s life, it will continue to examine the most energetic objects in space, such as black holes and the pulsating remains of dead stars. In addition, outside observers — astronomers not on the NuSTAR team — will be invited to compete for time on the telescope.

    “NuSTAR will initiate a general observer program, which will start execution next spring and will take 50 percent of the observatory time,” said Suzanne Dodd, the NuSTAR project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We are very excited to see what new science the community will propose to execute with NuSTAR.”

    NuSTAR blasted into space above the Pacific Ocean on June 13, 2012, with the help of a plane that boosted the observatory and its rocket to high altitudes. After a 48-day checkout period, the telescope began collecting X-rays from black holes, supernova remnants, galaxy clusters and other exotic objects. With its long mast – the length of a school bus — NuSTAR has a unique design that allows it to capture detailed data in the highest-energy range of X-rays, the same type used by dentists. It is the most sensitive high-energy X-ray mission every flown.

    In its prime mission, NuSTAR made the most robust measurements yet of the mind-bending spin rate of black holes and provided new insight into how massive stars slosh around before exploding. Other observations include: the discovery of a highly magnetized neutron star near the center of our Milky Way galaxy, measurements of luminous active black holes enshrouded in dust, and serendipitous discoveries of supermassive black holes.

    NuSTAR is now funded through fiscal year 2016 in its current extended phase.

    See the full article here.

    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA’s Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

    NuSTAR’s mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission’s outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    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 12:34 pm on November 19, 2013 Permalink | Reply
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    From Harvard Astronomy: “Shep Doelman: Imaging Black Holes with The Event Horizon Telescope” 

    Harvard Astronomy Banner
    Harvard Astronomy

    November 19, 2013

    Shep Doelman, sdoeleman@cfa.harvard.edu

    Recent technical advances and observations have now demonstrated that the goal of making an image of a black hole is within reach. Using the technique of Very Long Baseline Interferometry (VLBI), in which widely separated radio dishes are linked together to form an Earth-sized array, our group has succeeded in confirming event horizon scale structures in two super massive black holes: Sagittarius A*, the 4 million solar mass black hole at the center of the Milky Way (Nature, 455, 78, ’08), and M87, a 6 billion solar mass black hole in the giant elliptical galaxy Virgo A (Science, 338, 355, ’12). This has been accomplished by extending the VLBI technique to the highest observing frequencies and bandwidths, which has provided the required angular resolution and sensitivity.


    To achieve true imaging capability, an international collaboration is developing next-generation VLBI instrumentation for deployment on a Global array of mm and submm wavelength facilities. This will extend the current 1.3mm VLBI array to Earth-diameter baselines for which the angular resolution obtained is well matched to the SgrA* and M87 event horizons. Efforts are also aimed at shorter wavelength observations at 0.87mm, where Global baselines can achieve <20 micro arcsecond resolution. This new array is called the Event Horizon Telescope (EHT).

    EHT observations will target modeling and imaging of strong General Relativistic signatures that should become evident hear the black hole. Foremost among these is the black hole ‘shadow’, a consequence of light bending in the black hole’s strong gravity, leading to an annular brightening of the last photon orbit. The size and shape of this shadow is a prediction of Einstein’s GR. Non-imaging analyses of EHT data will be very sensitive to asymmetries caused by orbiting ‘hot-spots’ or Magnetohydrodynamic turbulence in the accretion flow. Observations of M87 will lead to direct imaging of emission at the base of a relativistic AGN jet. The overall goal is to spatially resolve a region of space-time where gravity is dominant, with an aim to test GR and models of black hole accretion and jet formation on Schwarzschild radius scales.

    See the full article here.

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  • richardmitnick 6:57 pm on August 13, 2013 Permalink | Reply
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    From The New York Times: “A Black Hole Mystery Wrapped in a Firewall Paradox” 

    New York Times

    This is copyright protected, so, just a glimpse.

    August 12, 2013

    “A high-octane debate has broken out among the world’s physicists about what would happen if you jumped into a black hole, a fearsome gravitational monster that can swallow matter, energy and even light. You would die, of course, but how? Crushed smaller than a dust mote by monstrous gravity, as astronomers and science fiction writers have been telling us for decades? Or flash-fried by a firewall of energy, as an alarming new calculation seems to indicate?

    ‘I was a yo-yo on this,’ said one of the more prolific authors in the field, Leonard Susskind of Stanford. He paused and added, ‘I haven’t changed my mind in a few months now.’

    Stephen Hawking, the British cosmologist, stunned the world by showing that when the paradoxical quantum laws that describe subatomic behavior were taken into account, black holes would leak particles and radiation, and in fact eventually explode, although for a hole the mass of a star it would take longer than the age of the universe. It was front-page news in 2004 when Dr. Hawking finally said that he had been wrong, and paid off a bet.


    Now, however, some physicists say that Dr. Hawking might have conceded too soon. ‘He had good reason,’ said Dr. Polchinski, ‘but he gave up for the wrong reason.’ Nobody, he explained, had yet figured out exactly how information does get out of a black hole.

    That was the task that four researchers based in Santa Barbara — Ahmed Almheiri, Donald Marolf, and James Sully, all from the University of California, Santa Barbara, and Dr. Polchinski of the Kavli Institute set themselves a year ago. The team (called AMPS, after their initials) found, to their surprise, that following the known laws of physics would lead to a contradiction, the firewall paradox.”

    O.K., so much for a glimpse. See the full article here.

    [I had one comment on this article. No where did I see any mention of the "Black Hole War", between Dr. Susskind and Dr. Hawking, or any mention of Dr. Susskind's book of the same name.]

  • richardmitnick 2:54 pm on July 25, 2013 Permalink | Reply
    Tags: , , Black Holes, , , , , , Superfluids   

    From M.I.T.: “Superfluid turbulence through the lens of black holes” 

    Study finds behavior of the turbulent flow of superfluids is opposite that of ordinary fluids.

    July 25, 2013
    Jennifer Chu, MIT News Office

    “A superfluid moves like a completely frictionless liquid, seemingly able to propel itself without any hindrance from gravity or surface tension. The physics underlying these materials — which appear to defy the conventional laws of physics — has fascinated scientists for decades.

    Black hole physics shows that superfluids in turbulence behave much like cigarette smoke. Image: Christine Daniloff

    Think of the assassin T-1000 in the movie “Terminator 2: Judgment Day” — a robotic shape-shifter made of liquid metal. Or better yet, consider a real-world example: liquid helium. When cooled to extremely low temperatures, helium exhibits behavior that is otherwise impossible in ordinary fluids. For instance, the superfluid can squeeze through pores as small as a molecule, and climb up and over the walls of a glass. It can even remain in motion years after a centrifuge containing it has stopped spinning.

    Now physicists at MIT have come up with a method to mathematically describe the behavior of superfluids — in particular, the turbulent flows within superfluids. They publish their results this week in the journal Science.

    ‘Turbulence provides a fascinating window into the dynamics of a superfluid,’ says Allan Adams, an associate professor of physics at MIT. ‘Imagine pouring milk into a cup of tea. As soon as the milk hits the tea, it flares out into whirls and eddies, which stretch and split into filigree. Understanding this complicated, roiling turbulent state is one of the great challenges of fluid dynamics. When it comes to superfluids, whose detailed dynamics depend on quantum mechanics, the problem of turbulence is an even tougher nut to crack.’

    To describe the underlying physics of a superfluid’s turbulence, Adams and his colleagues drew comparisons with the physics governing black holes. At first glance, black holes — extremely dense, gravitationally intense objects that pull in surrounding matter and light — may not appear to behave like a fluid. But the MIT researchers translated the physics of black holes to that of superfluid turbulence, using a technique called holographic duality.

    Consider, for example, a holographic image on a magazine cover. The data, or pixels, in the image exist on a flat surface, but can appear three-dimensional when viewed from certain angles. An engineer could conceivably build an actual 3-D replica based on the information, or dimensions, found in the 2-D hologram.

    ‘If you take that analogy one step further, in a certain sense you can regard various quantum theories as being a holographic image of a world with one extra dimension,’ says Paul Chesler, a postdoc in MIT’s Department of Physics.

    Taking this cosmic line of reasoning, Adams, Chesler and colleagues used holographic duality as a ‘dictionary’ to translate the very well-characterized physics of black holes to the physics of superfluid turbulence.

    To the researchers’ surprise, their calculations showed that turbulent flows of a class of superfluids on a flat surface behave not like those of ordinary fluids in 2-D, but more like 3-D fluids, which morph from relatively uniform, large structures to smaller and smaller structures. The result is much like cigarette smoke: From a burning tip, smoke unfurls in a single stream that quickly disperses into smaller and smaller eddies. Physicists refer to this phenomenon as an “energy cascade.”

    ‘For superfluids, whether such energy cascades exist is an open question,’ says Hong Liu, an associate professor of physics at MIT. ‘People have been making all kinds of claims, but there hasn’t been any smoking-gun type of evidence that such a cascade exists. In a class of superfluids, we produced very convincing evidence for the direction of this kind of flow, which would otherwise be very hard to obtain.’”

    See the full article here.

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  • richardmitnick 11:36 am on July 17, 2013 Permalink | Reply
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    From isgtw: "Mystery solved: X-ray light emitted from black holes" 

    July 17, 2013
    Amber Harmon

    “Exactly how do black holes produce so many high-power X-rays? The answer has remained a mystery to scientists for decades – until now. Supported by 40 years of theoretical progress, astrophysicists have conducted research that finally bridges the gap between theory and observation, demonstrating that gas spiraling toward a black hole inevitably results in X-ray emissions.

    Published in May in The Astrophysical Journal, the study reveals that gas spiraling toward a black hole through an accretion disk (formed by material in orbit, typically around a star) heats up to roughly 10 million degrees Celsius. The main body of the disk is roughly 2,000 times hotter than the sun, and emits low-energy or “soft” X-rays. However, observations also detect “hard” X-rays, which produce up to 100 times higher energy levels. The collaborators showed for the first time that high-energy light emission is an inevitable outcome of gas being drawn into a black hole.

    As the quality and quantity of high-energy light observations improved over the years, increasing evidence showed that photons are created in a hot, tenuous region called the corona. This corona, boiling violently above the comparatively cool accretion disk, is similar to the corona surrounding the sun, which is responsible for much of the ultra-violet and X-ray luminosity seen in the solar spectrum.

    Collaborators on the study include Julian Krolik, professor of physics and astronomy at Johns Hopkins University in Maryland, US, Jeremy Schnittman, lead author and research astrophysicist at the NASA Goddard Space Flight Center in Maryland, US, and Scott Noble, an associate research scientist at the Center for Computational Relativity and Gravitation at Rochester Institute of Technology in New York, US.”

    See the full article here.

    iSGTW is an international weekly online publication that covers distributed computing and the research it enables.

    “We report on all aspects of distributed computing technology, such as grids and clouds. We also regularly feature articles on distributed computing-enabled research in a large variety of disciplines, including physics, biology, sociology, earth sciences, archaeology, medicine, disaster management, crime, and art. (Note that we do not cover stories that are purely about commercial technology.)

    In its current incarnation, iSGTW is also an online destination where you can host a profile and blog, and find and disseminate announcements and information about events, deadlines, and jobs. In the near future it will also be a place where you can network with colleagues.

    You can read iSGTW via our homepage, RSS, or email. For the complete iSGTW experience, sign up for an account or log in with OpenID and manage your email subscription from your account preferences. If you do not wish to access the website’s features, you can just subscribe to the weekly email.”

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  • richardmitnick 12:39 pm on April 18, 2013 Permalink | Reply
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    From SLAC: “Novel Analysis Method Levels the Quasar Playing Field” 

    April 18, 2013
    Lori Ann White

    “In the nearly six decades since quasars were discovered, the list of these energetic galaxies powered by supermassive black holes has grown to more than 100,000 – enough examples to reveal important information about the quasar population as a whole. But attempts to conduct a celestial census of these powerful objects have been limited by a fundamental problem: Although quasars are bright, they also span billions of light years in distance from Earth. Just as with stars in an urban sky, the closest quasars can be seen even if they are dim, while the oldest and most distant ones can be seen only if they are bright. This means astrophysicists have to study a sample with big differences among individual members, including distance, age, brightness and type of radiation emitted.

    The interaction of a supermassive black hole and a disk of accreting matter, called a quasar, can be seen at the center of a faraway galaxy in this artist’s concept. It consists of a dusty, doughnut-shaped cloud of gas and dust that feeds a central supermassive black hole. As the black hole feeds, the gas and dust heat up and spray out different kinds of light, as illustrated by the white rays.

    Astrophysicists with the Kavli Institute for Particle Astrophysics and Cosmology, a joint SLAC-Stanford institute, found a way to reach past these limitations: They improved an algorithm that homes in on important commonalities of a population of objects while taking into account the limitations and biases for observations made in multiple types of electromagnetic radiation, such as optical light or radio waves – two of the most important wavelengths for studying quasars.

    In the process they shed new light on a contentious question: Are there two types of quasars, with one “louder” in radio than the other, or is there just one type with emissions that vary widely across the electromagnetic spectrum?”

    See the answers in the full article here.

    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

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  • richardmitnick 7:28 pm on March 19, 2013 Permalink | Reply
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    From ESA: “Black hole-star pair orbiting at dizzying speed” 

    ESA Planck
    XMM Newton


    19 March 2013

    ‘ESA’s XMM-Newton space telescope has helped to identify a star and a black hole that orbit each other at the dizzying rate of once every 2.4 hours, smashing the previous record by nearly an hour.

    The black hole in this compact pairing, known as MAXI J1659-152, is at least three times more massive than the Sun, while its red dwarf companion star has a mass only 20% that of the Sun. The pair is separated by roughly a million kilometres.

    The duo were discovered on 25 September 2010 by NASA’s Swift space telescope and were initially thought to be a gamma-ray burst. Later that day, Japan’s MAXI telescope on the International Space Station found a bright X-ray source at the same place.

    More observations from ground and space telescopes, including XMM-Newton, revealed that the X-rays come from a black hole feeding off material ripped from a tiny companion.

    Several regularly-spaced dips in the emission were seen in an uninterrupted 14.5 hour observation with XMM-Newton, caused by the uneven rim of the black hole’s accretion disc briefly obscuring the X-rays as the system rotates, its disc almost edge-on along XMM-Newton’s line of sight.

    From these dips, an orbital period of just 2.4 hours was measured, setting a new record for black hole X-ray binary systems. The previous record-holder, Swift J1753.5–0127, has a period of 3.2 hours.

    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 9:21 pm on December 13, 2012 Permalink | Reply
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    From NASA Swift and Fermi – “Study Reveals a Remarkable Symmetry in Black Hole Jets” 

    NASA Fermi Small

    NASA SWIFT Telescope

    Black holes range from modest objects formed when individual stars end their lives to behemoths billions of times more massive that rule the centers of galaxies. A new study using data from NASA’s Swift satellite and Fermi Gamma-ray Space Telescope shows that high-speed jets launched from active black holes possess fundamental similarities regardless of mass, age or environment. The result provides a tantalizing hint that common physical processes are at work.

    tri image
    Astronomers examining the properties of black hole jets compared 54 gamma-ray bursts (GRB’s) with 234 active galaxies classified as blazars and quasars. Surprisingly, the power and brightness of the jets share striking similarities despite a wide range of black hole mass, age and environment. Regardless of these differences, the jets produce light by tapping into similar percentages of the kinetic energy of particles moving along the jet, suggesting a common underlying physical cause.

    Credit: NASA’s Goddard Space Flight Center

    The particles in some GRB jets have been clocked at speeds exceeding 99.9 percent the speed of light. When the jet breaches the star’s surface, it produces a pulse of gamma rays typically lasting a few seconds. Satellites like Swift and Fermi can detect this emission if the jet is approximately directed toward us.

    To search for a trend across a wide range of masses, the scientists looked at the galactic-scale equivalent of GRB jets. These come from the brightest classes of active galaxies, blazars and quasars, which sport jets that likewise happen to point our way.

    To match the amount of energy given off by a typical blazar in one second, the sun must shine for 317,000 years. To equal the energy a run-of-the-mill GRB puts out in one second, the sun would need to shine for another 3 billion years.

    The finding simplifies astronomers’ understanding of black holes by showing that their activity is governed by the same set of rules — whatever they happen to be — independent of mass, age, or the jet’s brightness and power. The jets tap into similar fractions — between 3 and 15 percent — of the energy wrapped up in the motion of their accelerated particles to power the emission of gamma rays and other forms of light.”

    See the full article here.

    NASA Fermi Banner

    Fermi Space Telescope: Exploring the Extreme Universe
    Fermi is a powerful space observatory that will open a wide window on the universe. Gamma rays are the highest-energy form of light, and the gamma-ray sky is spectacularly different from the one we perceive with our own eyes. With a huge leap in all key capabilities, Fermi data will enable scientists to answer persistent questions across a broad range of topics, including supermassive black-hole systems, pulsars, the origin of cosmic rays, and searches for signals of new physics.

    The mission is an astrophysics and particle physics partnership, developed by NASA in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.

    NASA Swift Banner

    Swift is a first-of-its-kind multi-wavelength observatory dedicated to the study of gamma-ray burst (GRB) science. Its three instruments will work together to observe GRBs and afterglows in the gamma ray, X-ray, ultraviolet, and optical wavebands. The main mission objectives for Swift are to:

    Determine the origin of gamma-ray bursts
    Classify gamma-ray bursts and search for new types
    Determine how the blastwave evolves and interacts with the surroundings
    Use gamma-ray bursts to study the early universe
    Perform the first sensitive hard X-ray survey of the sky

    NASA Goddard


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