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  • richardmitnick 8:53 am on April 19, 2018 Permalink | Reply
    Tags: , , , , , ESA XMM-Newton,   

    From ESA: “Where is the Universe’s missing matter?” 

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    European Space Agency

    18 April 2018

    Jiangtao Li
    University of Michigan, USA
    Email: jiangtal@umich.edu
    Tel: 734-383-2089

    Joel Bregman
    University of Michigan, USA
    Email: jbregman@umich.edu
    Tel: 734-764-2667

    Norbert Schartel
    XMM-Newton Project Scientist
    European Space Agency
    Email: norbert.schartel@esa.int

    1
    Searching galactic haloes for ‘missing’ matter. No image credit.

    ESA/XMM Newton

    Astronomers using ESA’s XMM-Newton space observatory have probed the gas-filled haloes around galaxies in a quest to find ‘missing’ matter thought to reside there, but have come up empty-handed – so where is it?

    All the matter in the Universe exists in the form of ‘normal’ matter or the notoriously elusive and invisible dark matter, with the latter around six times more prolific.

    Curiously, scientists studying nearby galaxies in recent years have found them to contain three times less normal matter than expected, with our own Milky Way Galaxy containing less than half the expected amount.

    Caterpillar Project A Milky-Way-size dark-matter halo and its subhalos circled, an enormous suite of simulations . Griffen et al. 2016

    “This has long been a mystery, and scientists have spent a lot of effort searching for this missing matter,” says Jiangtao Li of the University of Michigan, USA, and lead author of a new paper http://iopscience.iop.org/article/10.3847/2041-8213/aab2af/meta .

    “Why is it not in galaxies — or is it there, but we are just not seeing it? If it’s not there, where is it? It is important we solve this puzzle, as it is one of the most uncertain parts of our models of both the early Universe and of how galaxies form.”

    Rather than lying within the main bulk of the galaxy, the part can be observed optically, researchers thought it may instead lie within a region of hot gas that stretches further out into space to form a galaxy’s halo. These hot, spherical haloes have been detected before, but the region is so faint that it is difficult to observe in detail – its X-ray emission can become lost and indistinguishable from background radiation. Often, scientists observe a small distance into this region and extrapolate their findings but this can result in unclear and varying results.

    Jiangtao and colleagues wanted to measure the hot gas out to larger distances using ESA’s XMM-Newton X-ray space observatory. They looked at six similar spiral galaxies and combined the data to create one galaxy with their average properties.

    “By doing this, the galaxy’s signal becomes stronger and the X-ray background becomes better behaved,” adds co-author Joel Bregman, also of the University of Michigan.

    “We were then able to see the X-ray emission to about three times further out than if observing a single galaxy, which made our extrapolation more accurate and reliable.”

    Massive and isolated spiral galaxies offer the best chance to search for missing matter. They are massive enough to heat gas to temperatures of millions of degrees so that they emit X-rays, and have largely avoided being contaminated by other material through star formation or interactions with other galaxies.

    Still missing

    The team’s results showed that the halo surrounding galaxies like the ones observed cannot contain all of the missing matter after all. Despite extrapolating out to almost 30 times the radius of the Milky Way, nearly three-quarters of the expected material was still missing.

    Milky Way Dark Matter Halo Credit ESO L. Calçada

    There are two main alternative theories as to where it could be: either it is stored in another gas phase that is poorly observed – perhaps either a hotter and more tenuous phase or a cooler and denser one – or within a patch of space that is not covered by our current observations or emits X-rays too faintly to be detected.

    Either way, since the galaxies do not contain enough missing matter they may have ejected it out into space, perhaps driven by injections of energy from exploding stars or by supermassive black holes.

    “This work is important to help create more realistic galaxy models, and in turn help us better understand how our own Galaxy formed and evolved,” says Norbert Schartel, ESA XMM-Newton project scientist. “This kind of finding is simply not possible without the incredible sensitivity of XMM-Newton.”

    “In the future, scientists can add even more galaxies to our study samples and use XMM-Newton in collaboration with other high-energy observatories, such as ESA’s upcoming Advanced Telescope for High-ENergy Astrophysics, Athena, to probe the extended, low-density parts of a galaxy’s outer edges, as we continue to unravel the mystery of the Universe’s missing matter.”

    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 8:20 am on February 3, 2018 Permalink | Reply
    Tags: , , , , ESA XMM-Newton, HD 5980   

    From ESA: “Stellar winds behaving unexpectedly” 

    ESA Space For Europe Banner

    European Space Agency

    2 February 2018

    Yaël Nazé
    Université de Liège
    Belgium
    Tel: +32 4 366 97 20
    Email: naze@astro.ulg.ac.be

    Norbert Schartel
    XMM-Newton Project Scientist
    European Space Agency
    Email: Norbert.Schartel@esa.int

    Markus Bauer
    Head of the Joint Communication Office
    European Space Agency
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: markus.bauer@esa.int

    1
    Stellar wind evolution. The binary star system HD 5980 as observed by ESA’s XMM-Newton between 2000 and 2016.

    ESA’s XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive stars, suggesting that colliding stellar winds don’t behave as expected.

    ESA/XMM Newton

    Massive stars – several times larger than our Sun – lead turbulent lives, burning their nuclear fuel rapidly and pouring large amounts of material into their surroundings throughout their short but sparkling lives.

    These fierce stellar winds can carry the equivalent of Earth’s mass in a month and travel at millions of kilometres per hour, so when two such winds collide they unleash enormous amounts of energy.

    The cosmic clash heats the gas to millions of degrees, making it shine brightly in X-rays.

    Normally, colliding winds change little because neither do the stars nor their orbits. However, some massive stars behave dramatically.

    This is the case with HD 5980, a pairing of two huge stars each 60 times the mass of our Sun and only about 100 million kilometres apart – closer than we are to our star.

    2
    Position of HD 5980
    Released 16/02/2007
    Copyright NASA, ESA, A. Nota (STScI/ESA)
    A Hubble Space Telescope view of the cluster NGC 346 – the arrow indicates the position of HD 5980.

    One had a major outburst in 1994, reminiscent of the eruption that turned Eta Carinae into the second brightest star in the sky for about 18 years in the 19th century.

    3
    Star Eta Carinae
    Released 16/02/2007
    Copyright J. Morse (Univ. of Colorado)/NASA
    The star Eta Carinae was seen to erupt in the 19th century. During the eruption, the star lost 10 to 20 solar masses of material, which now forms a nebula around it. Astronomers observed a similar outburst from HD 5980 in 1993-94. This Hubble Space Telescope’s image thus shows how HD 5980 might look like in a century.

    While it is now too late to study Eta Carinae’s historic eruption, astronomers have been observing HD 5980 with X-ray telescopes to study the hot gas.

    In 2007, Yaël Nazé of the University of Liège, Belgium, and her colleagues discovered the collision of winds from these stars using observations made by ESA’s XMM-Newton and NASA’s Chandra X-ray telescopes between 2000 and 2005.

    Then they looked at it again with XMM-Newton in 2016.

    “We expected HD 5980 to fade gently over the years as the erupting star settled back to normal – but to our surprise it did just the opposite,” says Yaël.

    They found the pair was two and a half times brighter than a decade earlier, and its X-ray emission was even more energetic.

    “We had never seen anything like that in a wind–wind collision.”


    ESA’s XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive stars in the binary star system HD 5980. One of the two stars had a major outburst reminiscent of the 19th-century eruption of Eta Carinae, and astronomers expected that its X-ray emission would fade gently over the years. Instead, they found the pair was two and a half times brighter than a decade earlier, and its X-ray emission was even more energetic, suggesting that colliding stellar winds don’t behave as expected.

    With less material ejected but more light emitted, it was difficult to explain what was happening.

    Finally, they found a theoretical study that offers a fitting scenario.

    “When stellar winds collide, the shocked material releases plenty of X-rays. However, if the hot matter radiates too much light, it rapidly cools, the shock becomes unstable and the X-ray emission dims.

    “This somewhat counterintuitive process is what we thought happened at the time of our first observations, more than 10 years ago. But by 2016, the shock had relaxed and the instabilities had diminished, allowing the X-ray emission to rise eventually.”

    These are the first observations that substantiate this previously hypothetical scenario. Yaël’s colleagues are now testing the new result in greater detail through computer simulations.

    “Unique discoveries like this demonstrate how XMM-Newton keeps providing astronomers with fresh material to improve our understanding of the most energetic processes in the Universe,” says Norbert Schartel, XMM-Newton project scientist at ESA.

    Science paper:
    A changing wind collision, The Astrophysical Journal.

    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 2:06 pm on September 7, 2017 Permalink | Reply
    Tags: , , , , ESA XMM-Newton, , X-rays Reveal Temperament of Possible Planet-hosting Stars   

    From Chandra: “X-rays Reveal Temperament of Possible Planet-hosting Stars” 

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    NASA Chandra Telescope

    NASA Chandra

    September 6, 2017

    1
    Credit X-ray: NASA/CXC/Queens Univ. of Belfast/R.Booth, et al.; Illustration: NASA/CXC/M.Weiss

    X-rays may provide valuable information about whether a star system will be hospitable to life on planets.

    Stellar X-rays mirror magnetic activity, which can produce energetic radiation and eruptions that could impact surrounding planets.

    Researchers used Chandra and XMM-Newton to study 24 stars like the Sun that were at least one billion years old.

    ESA/XMM Newton X-ray telescope

    The latest study indicates older Sun-like stars settle down relatively quickly, boosting prospects for life to develop on planets around them.

    A new study using data from NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton suggests X-rays emitted by a planet’s host star may provide critical clues to just how hospitable a star system could be. A team of researchers looked at 24 stars similar to the Sun, each at least one billion years old, and how their X-ray brightness changed over time.

    Since stellar X-rays mirror magnetic activity, X-ray observations can tell astronomers about the high-energy environment around the star. In the new study the X-ray data from Chandra and XMM-Newton revealed that stars like the Sun and their less massive cousins calm down surprisingly quickly after a turbulent youth.

    To understand how quickly stellar magnetic activity level changes over time, astronomers need accurate ages for many different stars. This is a difficult task, but new precise age estimates have recently become available from studies of the way that a star pulsates using NASA’s Kepler and ESA’s CoRoT missions. These new age estimates were used for most of the 24 stars studied here.

    Astronomers have observed that most stars are very magnetically active when they are young, since the stars are rapidly rotating. As the rotating star loses energy over time, the star spins more slowly and the magnetic activity level, along with the associated X-ray emission, drops.

    Although it is not certain why older stars settle down relatively quickly, astronomers have ideas they are exploring. One possibility is that the decrease in rate of spin of the older stars occurs more quickly than it does for the younger stars. Another possibility is that the X-ray brightness declines more quickly with time for older, more slowly rotating stars than it does for younger stars.

    A paper describing these results has been accepted for publication in the Monthly Notices of the Royal Astronomical Society, and is available online. The other co-authors are Victor Silva Aguirre from Aarhus University in Denmark and Scott Wolk from CfA.

    A Quick Look at GJ 176

    See the full article here .

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    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 7:40 am on May 23, 2017 Permalink | Reply
    Tags: , , , , ESA XMM-Newton, Nice to see: XMM-Newton's by-catch   

    From SRON- “Nice to see: XMM-Newton’s by-catch” 

    sron-bloc
    SRON

    23 May 2017
    No writer credit found

    ESA/XMM Newton

    1
    Credit: ESA/XMM-Newton/ R. Saxton / A.M. Read, CC BY-SA 3.0 IGO

    The XMM-Newton X-ray telescope, carrying two Reflection Grating Spectrometers developed by SRON Netherlands Institute for Space Research, was launched in 1999. It is orbiting earth since then. Its mission is to study high-energy phenomena in the Universe, such as black holes and neutron stars. When the telescope moves between specific target it stills collects scientific data (slews). This recent map shows 30,000 sources detected during 2114 of these slews. Some of the sources have been observed up to 15 times. After correcting for overlaps between slews, 84% of the sky has been covered. Lower energy sources are shown in red while higher energy sources are blue. The size of each source is proportional to its brightness. The centre of the plot corresponds to the centre of the Milky Way.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Objects above and below the centre of the plane of our Galaxy are mostly external galaxies that are emitting X-rays from their massive black holes.

    See the full article here .

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    sron-campus

    How did the Earth and life on it evolve? How do stars and planets evolve? How did the universe evolve? What is the position of the Earth and humankind in that immense universe? These are fundamental questions that have always intrigued humankind. Moreover, people have always possessed an urge to explore and push back the boundaries of science and technology.

    Science

    Since the launch of Sputnik in 1957, Dutch astronomers have seen the added value of space missions for science. Reaching beyond the Earth’s atmosphere would open up new windows on the universe and provide fantastic views of our home planet. It would at last be possible to pick up cosmic radiation that never normally reached the Earth’s surface, such as X-rays, ultraviolet and infrared radiation. A wealth of scientific information from every corner of the universe would then become available.

    The first Dutch scientific rocket experiments and contributions to European and American satellites in the early 1960s, formed the start of an activity in which a small country would develop an enviable reputation: scientific space research.

    Groundbreaking technology

    Nowadays we take for granted images of the Earth from space, beautiful photos from the Hubble Space Telescope or landings of space vehicles on nearby planets. Yet sometimes we all too easily forget that none of these scientific successes would have been possible without the people who developed groundbreaking technology. Technology that sooner or later will also prove useful to life on Earth.

     
  • richardmitnick 10:02 pm on March 3, 2017 Permalink | Reply
    Tags: , , , , ESA XMM-Newton, IRAS 13224−3809, ,   

    From Astronomy: “This nearby supermassive black hole packs a pretty big punch” 

    Astronomy magazine

    Astronomy Magazine

    March 01, 2017
    Alison Klesman

    1
    NGC 6814 is a stunning example of a Seyfert galaxy. Like IRAS 13224−3809, this galaxy hosts a bright, highly X-ray variable supermassive black hole at its center. ESA/Hubble & NASA; Acknowledgement: Judy Schmidt (Geckzilla)

    Supermassive black holes are associated with the vast majority of galaxies. They’re believed to evolve with their host galaxies and even to affect galaxy growth over time, owing to their ability to gobble up vast amounts of gas and dust and shoot high-energy radiation back out into their surroundings.

    There are measurable correlations between the mass of a supermassive black hole and the properties of its host galaxy’s bulge, such as the luminosity of the bulge and the movements of stars within it. The reasons for these correlations are still unknown, but astronomers have long believed that supermassive black holes affect the star formation around them via some sort of feedback process.

    In a letter printed today in Nature, a group of astronomers led by Michael Parker at the Institute of Astronomy in Cambridge, UK, report their observations of IRAS 13224−3809, a nearby Seyfert galaxy hosting an active galactic nucleus, or AGN. Seyfert galaxies shine intensely in infrared light due to the activity of their supermassive black holes, which are relatively low mass but are accreting at high rates. IRAS 13224−3809 hosts a central supermassive black hole weighing about 6,000,000 times the mass of our Sun.

    Parker and his coauthors studied observations of IRAS 13224−3809 taken with the X-ray Multi-Mirror Mission [ESA/XMM-Newton] over the course of 17 days and with the Nuclear Spectroscopic Telescope Array [NASA/NuSTAR] over the course of six days. They observed X-ray variability on scales of minutes to weeks.

    ESA/XMM Newton
    ESA/XMM Newton

    NASA/NuSTAR
    NASA/NuSTAR

    By looking at the X-ray spectrum of the source, they were able to determine that this object offers a relatively unhindered view right down into the inner portions of the accretion disk near the black hole itself.

    When astronomers “look” at a supermassive black hole, they’re actually observing light from the accretion disk of matter around the black hole, which hasn’t yet fallen past the event horizon and become invisible. Supermassive black holes show variability over time in a variety of wavelengths, including optical light, infrared light, and X-rays. This variability is believed to arise from changes in the accretion disk, such as clumps of matter or outflows of gas and radiation.

    IRAS 13224−3809’s black hole shows extraordinary X-ray variability — in fact, it’s the most variable AGN observed at X-ray wavelengths. Parker’s group was able to watch the effects of an ultrafast outflow, which is associated with areas of the accretion disk within a few hundred times the size of the event horizon. Ultrafast outflows, or UFOs, are outflows moving faster than about 6,000 miles per second (10,000 km/s). They’re believed to be triggered by X-ray radiation associated with accretion at the innermost portions of the disk, just a few times the size of the event horizon.

    IRAS 13224−3809’s outflow was clocked at 44,000 miles per second (71,000 km/s), or about 0.236 times the speed of light. This puts it in the top 5 percent of UFOs ever observed. What’s more, the power it’s putting out is on par with quasars that are three orders of magnitude more massive.

    Because of their immense power, IRAS 13224−3809’s outflows may be strong enough to drive feedback in its host galaxy, just as more massive quasars do in the much more distant universe.

    While all black holes are variable, the timescale of variability typically scales with size. This makes sense when you think of variability relating to the accretion disk, which also scales with size. Thus, IRAS 13224−3809 shows much faster variability than the variability observed in quasars, which are similar but much more massive objects. Parker and his group were able to watch IRAS 13224−3809’s X-ray light undergo changes that took only hours, rather than months in a quasar.

    Studying IRAS 13224−3809 could thus help astronomers finally start to answer questions about how UFOs and other outflows are created. It could also shed light on how black hole feedback affects the host galaxy. This object’s unique properties would allow studies to be performed more easily and with much shorter observing times than those focused on faraway, slower-acting quasars.

    See the full article here .

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  • richardmitnick 7:33 am on February 22, 2017 Permalink | Reply
    Tags: , , , , ESA XMM-Newton, furthest pulsar in the Universe, , The brightest   

    From ESA: “The brightest, furthest pulsar in the Universe” 

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    European Space Agency

    21 February 2017
    Markus Bauer








    ESA Science and Robotic Exploration Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

    Gian Luca Israel
    INAF, Osservatorio Astronomico di Roma, Italy
    Email: gianluca@oa-roma.inaf.it

    Norbert Schartel
    XMM-Newton project scientist
    Email: Norbert.Schartel@esa.int

    1
    NGC 5907 X-1: record-breaking pulsar

    ESA’s XMM-Newton has found a pulsar – the spinning remains of a once-massive star – that is a thousand times brighter than previously thought possible.

    ESA/XMM Newton
    ESA/XMM Newton

    The pulsar is also the most distant of its kind ever detected, with its light travelling 50 million light-years before being detected by XMM-Newton.

    Pulsars are spinning, magnetised neutron stars that sweep regular pulses of radiation in two symmetrical beams across the cosmos. If suitably aligned with Earth these beams are like a lighthouse beacon appearing to flash on and off as it rotates. They were once massive stars that exploded as a powerful supernova at the end of their natural life, before becoming small and extraordinarily dense stellar corpses.

    This X-ray source is the most luminous of its type detected to date: it is 10 times brighter than the previous record holder. In one second it emits the same amount of energy released by our Sun in 3.5 years.

    XMM-Newton observed the object several times in the last 13 years, with the discovery a result of a systematic search for pulsars in the data archive – its 1.13 s periodic pulses giving it away.

    The signal was also identified in NASA’s Nustar archive data, providing additional information.

    NASA NuSTAR
    NASA/NuSTAR

    “Before, it was believed that only black holes at least 10 times more massive than our Sun feeding off their stellar companions could achieve such extraordinary luminosities, but the rapid and regular pulsations of this source are the fingerprints of neutron stars and clearly distinguish them from black holes,” says Gian Luca Israel, from INAF-Osservatorio Astronomica di Roma, Italy, lead author of the paper describing the result published in Science this week.

    The archival data also revealed that the pulsar’s spin rate has changed over time, from 1.43 s per rotation in 2003 to 1.13 s in 2014. The same relative acceleration in Earth’s rotation would shorten a day by five hours in the same time span

    “Only a neutron star is compact enough to keep itself together while rotating so fast,” adds Gian Luca.

    Although it is not unusual for the rotation rate of a neutron star to change, the high rate of change in this case is likely linked to the object rapidly consuming mass from a companion.

    “This object is really challenging our current understanding of the ‘accretion’ process for high-luminosity stars,” says Gian Luca. “It is 1000 times more luminous than the maximum thought possible for an accreting neutron star, so something else is needed in our models in order to account for the enormous amount of energy released by the object.”

    The scientists think there must be a strong, complex magnetic field close to its surface, such that accretion onto the neutron star surface is still possible while still generating the high luminosity.

    “The discovery of this very unusual object, by far the most extreme ever discovered in terms of distance, luminosity and rate of increase of its rotation frequency, sets a new record for XMM-Newton, and is changing our ideas of how such objects really ‘work’,” says Norbert Schartel, ESA’s XMM-Newton project scientist.

    An accreting pulsar with extreme properties drives an ultraluminous X-ray source in NGC 5907 by G.L. Israel is published in Science.

    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 8:27 pm on February 6, 2017 Permalink | Reply
    Tags: ESA XMM-Newton, , ,   

    From Chandra: “XJ1500+0154: Black Hole Meal Sets Record for Duration and Size” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    February 6, 2017
    Megan Watzke, press release
    Chandra X-ray Center, Cambridge, Mass.
    617-496-7998
    mwatzke@cfa.harvard.edu

    1
    Illustration
    Credit X-ray: NASA/CXC/UNH/D.Lin et al, Optical: CFHT, Illustration: NASA/CXC/M.Weiss
    Observation Date 23 Feb 2015
    Observation Time 10 hours
    Instrument ACIS

    A supermassive black hole in a small galaxy 1.8 billion light years away has been partaking in a decade-long binge of a star.

    This is known as a tidal disruption event and happens when an object gets too close to a black hole and is torn apart by gravity.

    Other similar events have been seen before but this one is much longer, representing an unusually massive meal.

    A trio of orbiting X-ray telescopes, including Chandra, was used to make this discovery.

    A trio of X-ray observatories has captured a remarkable event in their data: a decade-long binge by a black hole almost two billion light years away. This discovery was made using data from NASA’s Chandra X-ray Observatory, Swift Observatory, and ESA’s XMM-Newton, as reported in our press release.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE. This is when an object, such as a star, wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest (shown as the red material in the illustration) becomes hotter as it falls toward the black hole, generating a distinct X-ray flare. A wind blowing away from this infalling material is shown in blue.

    Among observed TDEs, this event involved either the most massive star to be completely ripped apart and devoured by a black hole or the first instance where a smaller star was completely ripped apart. The resulting X-ray source is known as XJ1500+154 and is located in a small galaxy about 1.8 billion light years from Earth. The optical image in the left inset shows this galaxy and a cross to mark the location of XJ1500+0154. This image reveals that XJ1500+0154 is found in the center of the galaxy, implying that the source likely originates from a supermassive black hole that resides there. The image on the right shows XJ1500+0154 in the Chandra image covering the same field.

    The source was not detected in a Chandra observation on April 2, 2005, but was detected in an XMM-Newton observation on July 23, 2005, and reached peak brightness in a Chandra observation on June 5, 2008.

    ESA/XMM Newton
    ESA/XMM Newton

    These observations show that the source became at least 100 times brighter in X-rays. Since then, Chandra, Swift, and XMM-Newton have observed it multiple times.

    The X-ray data also indicate that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.

    This TDE may help answer the question as to how supermassive black holes in the early universe grow. If supermassive black holes can grow, from TDEs or other means, at rates above those corresponding to the Eddington limit, this could explain how supermassive black holes were able to reach masses about a billion times higher than the sun when the universe was only about a billion years old.

    A paper describing these results appears in the February 6th issue of Nature Astronomy. The authors are Dacheng Lin (University of New Hampshire), James Guillochon (Harvard-Smithsonian Center for Astrophysics), Stefanie Komossa (QianNan Normal University for Nationalities), Enrico Ramirez-Ruiz (University of California, Santa Cruz), Jimmy Irwin (University of Alabama), Peter Maksym (Harvard-Smithsonian), Dirk Grupe (Morehead State University), Olivier Godet (CNRS), Natalie Webb (CNRS), Didier Barret (CNRS), Ashley Zauderer (New York University), Pierre-Alain Duc (CEA-Saclay), Eleazar Carrasco (Gemini Observatory), and Stephen Gwyn (Herzberg Institute of Astrophysics).

    CFHT Telescope, Mauna Kea, Hawaii, USA
    CFHT Interior
    CFHT referenced for optical without comment

    See the full article here .

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    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 4:34 am on April 28, 2016 Permalink | Reply
    Tags: , , ESA XMM-Newton, Powerful winds spotted from mysterious X-ray binaries   

    From ESA: “Powerful winds spotted from mysterious X-ray binaries” 

    ESA Space For Europe Banner

    European Space Agency

    28 April 2016
    Ciro Pinto
    Institute of Astronomy, University of Cambridge
    United Kingdom
    Tel: +44 1223 339281
    Email: cpinto@ast.cam.ac.uk

    Norbert Schartel
    ESA XMM-Newton Project Scientist
    Email: Norbert.Schartel@esa.int

    Markus Bauer








    ESA Science Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

    1
    High-speed winds from X-ray binary. No image credit.

    ESA’s XMM-Newton has discovered gas streaming away at a quarter of the speed of light from very bright X-ray binaries in two nearby galaxies.

    ESA/XMM Newton
    ESA/XMM Newton

    At X-ray wavelengths, the celestial sky is dominated by two types of astronomical objects: supermassive black holes, sitting at the centres of large galaxies and ferociously devouring the material around them, and binary systems, consisting of a stellar remnant – a white dwarf, neutron star or black hole – feeding on gas from a companion star.

    Sag A* NASA's Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way
    Sag A* NASA’s Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    ALMA composite  HD 142527 binary star system
    ALMA composite HD 142527 binary star system

    In both cases, the gas forms a swirling disc around the compact and very dense central object: friction in the disc causes the gas to heat up and emit light at many wavelengths, with a peak in X-rays.

    Not all of the gas is swallowed by the central object though, and some of it might even be pushed away by powerful winds and jets.

    But an intermediate class of objects was discovered in the 1980s and is still not well understood. Ten to a hundred times brighter than ordinary X-ray binaries, these sources are nevertheless too faint to be linked to accreting supermassive black holes, and in any case, are usually found far from the centre of their host galaxy.

    “We think these ‘ultra-luminous X-ray sources’ are somewhat special binary systems, sucking up gas at a much higher rate than an ordinary X-ray binary,” explains Ciro Pinto from the Institute of Astronomy in Cambridge, UK.

    “Some host highly magnetised neutron stars, while others might conceal the long-sought-after intermediate-mass black holes, which have masses around 1000 times the mass of the Sun. But in the majority of cases, the reason for their extreme behaviour is still unclear.”

    2
    The irregular galaxy NGC 5408 viewed by the NASA/ESA Hubble Space Telescope.

    Ciro is the lead author of a new study*, based on observations from ESA’s XMM-Newton, revealing for the first time strong winds gusting at very high speed from two of these exotic objects. The discovery, published in this week’s issue of the journal Nature, confirms that these sources conceal a compact object accreting matter at extraordinarily high rates.

    Ciro and his colleagues delved into the XMM-Newton archives and collected several days’ worth of observations of three ultra-luminous X-ray sources, all hosted in nearby galaxies located less than 22 million light-years from our Milky Way.

    The data were obtained over several years with the Reflection Grating Spectrometer, a highly sensitive instrument that allowed them to spot very subtle features in the spectrum of the X-rays from the sources.

    3
    NGC 1313 viewed by the NASA/ESA Hubble Space Telescope.

    In all three sources, the scientists were able to identify X-ray emission from gas in the outer portions of the disc surrounding the central compact object, slowly flowing towards it.

    But two of the three sources – known as NGC 1313 X-1 and NGC 5408 X-1 – also show clear signs of X-rays being absorbed by gas that is streaming away from the central source at an extremely rapid 70 000 km/s – almost a quarter of the speed of light.

    “This is the first time we’ve seen winds streaming away from ultra-luminous X-ray sources,” says Ciro.

    “And there’s more, since the very high speed of these outflows is telling us something about the nature of the compact objects in these sources, which are frantically devouring matter.”

    While the hot gas is pulled inwards by the central object’s gravity, it also shines brightly, and the pressure exerted by the radiation pushes it outwards. This is a balancing act: the greater the mass, the faster it draws the surrounding gas. But this also causes the gas to heat up faster, emitting more light and increasing the pressure that blows the gas away.

    There is a theoretical limit to how much matter can be accreted by an object of a given mass, called the ‘Eddington luminosity’. It was first calculated for stars by astronomer Arthur Eddington, but it can also be applied to compact objects like black holes and neutron stars.

    Eddington’s calculation refers to an ideal case in which both the matter being accreted onto the central object and the radiation being emitted by it do so equally in all directions.

    But the sources studied by Ciro and his collaborators are being fed through an accretion disc that is likely being puffed up by internal pressure of the gas flowing at a fast pace towards the central object.

    In such a configuration, the material in the disc can shine 10 times or more above the Eddington limit and, as part of the gas eludes the gravitational grasp from the central object, very high-speed winds can arise like the ones observed by XMM-Newton.

    “By observing X-ray sources that are radiating beyond the Eddington limit, it is possible to study their accretion process in great detail, investigating by how much the limit can be exceeded and what exactly triggers the outflow of such powerful winds,” says Norbert Schartel, ESA XMM-Newton Project Scientist.

    The nature of the compact objects hosted at the core of the sources observed in this study is, however, still uncertain, although the scientists suspect it might be stellar-mass black holes, with masses of several to a few dozen times that of the Sun.

    To investigate further, the team is still scrutinising the data archive of XMM-Newton, searching for more sources of this type, and are also planning future observations, in X-rays as well as at optical and radio wavelengths.

    “With a broader sample of sources and multi-wavelength observations, we hope to finally uncover the physical nature of these powerful, peculiar objects,” concludes Ciro.

    Science paper:
    Resolved atomic lines reveal outflows in two ultraluminous X-ray sources in Nature.
    [No link provided]

    See the full article here .

    Please help promote STEM in your local schools.

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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 10:02 am on March 31, 2016 Permalink | Reply
    Tags: , , , ESA XMM-Newton,   

    From ESA- “Found: Andromeda’s first spinning neutron star” 

    ESA Space For Europe Banner

    European Space Agency

    31 March 2016
    Paolo Esposito
    INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan, Italy
    Email: paoloesp@iasf-milano.inaf.it

    Gian Luca Israel
    INAF-Osservatorio Astronomica di Roma, Italy
    Email: gianluca@oa-roma.inaf.it

    Andrea De Luca
    INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan, Italy
    Email: deluca@iasf-milano.inaf.it

    Norbert Schartel
    XMM-Newton project scientist
    Email: Norbert.Schartel@esa.int

    1
    Andromeda’s spinning neutron star
    Released 31/03/2016
    ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent/XMM-Newton/EPIC/W. Pietsch, MPE; data: P. Esposito et al (2016)

    ESA/Herschel
    ESA/Herschel

    Decades of searching in the Milky Way’s nearby ‘twin’ galaxy Andromeda have finally paid off, with the discovery of an elusive breed of stellar corpse, a neutron star, by ESA’s XMM-Newton space telescope.

    Andromeda Galaxy NASA Hubble
    Andromeda Galaxy NASA/ESA Hubble

    ESA/XMM Newton
    ESA/XMM Newton

    Andromeda, or [Messier] 31, is a popular target among astronomers. Under clear, dark skies it is even visible to the naked eye. Its proximity and similarity in structure to our own spiral galaxy, the Milky Way, make it an important natural laboratory for astronomers. It has been extensively studied for decades by telescopes covering the whole electromagnetic spectrum.

    Despite being extremely well studied, one particular class of object had never been detected: spinning neutron stars.

    Neutron stars are the small and extraordinarily dense remains of a once-massive star that exploded as a powerful supernova at the end of its natural life. They often spin very rapidly and can sweep regular pulses of radiation towards Earth, like a lighthouse beacon appearing to flash on and off as it rotates.

    These pulsars can be found in stellar couples, with the neutron star cannibalising its neighbour. This can lead to the neutron star spinning faster, and to pulses of high-energy X-rays from hot gas being funnelled down magnetic fields on to the neutron star.

    Binary systems hosting a neutron star like this are quite common in our own Galaxy, but regular signals from such a pairing had never before been seen in Andromeda.

    Now, astronomers systematically searching through the archives of data from XMM-Newton X-ray telescope have uncovered the signal of an unusual source fitting the bill of a fast-spinning neutron star.

    It spins every 1.2 seconds, and appears to be feeding on a neighbouring star that orbits it every 1.3 days.

    “We were expecting to detect periodic signals among the brightest X-ray objects in Andromeda, in line with what we already found during the 1960s and 1970s in our own Galaxy,” says Gian Luca Israel, from INAF-Osservatorio Astronomica di Roma, Italy, one of the authors of the paper describing the results, “But persistent, bright X-ray pulsars like this are still somewhat peculiar, so it was not completely a sure thing we would find one in Andromeda.

    “We looked through archival data of Andromeda spanning 2000–13, but it wasn’t until 2015 that we were finally able to identify this object in the galaxy’s outer spiral in just two of the 35 measurements.”

    While the precise nature of the system remains unclear, the data imply that it is unusual and exotic.

    “It could be what we call a ‘peculiar low-mass X-ray binary pulsar’ – in which the companion star is less massive than our Sun – or alternatively an intermediate-mass binary system, with a companion of about two solar masses,” says Paolo Esposito of INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan, Italy.

    “We need to acquire more observations of the pulsar and its companion to help determine which scenario is more likely.”

    “The well-known Andromeda galaxy has long been a source of exciting discoveries, and now an intriguing periodic signal has been detected by our flagship X-ray mission,” adds Norbert Schartel, ESA’s XMM-Newton project scientist.

    “We’re in a better position now to uncover more objects like this in Andromeda, both with XMM-Newton and with future missions such as ESA’s next-generation high-energy observatory, Athena.”

    The science team:
    P. Esposito,1? G. L. Israel,2 A. Belfiore,1 G. Novara,3 L. Sidoli,1 G. A. Rodr´ıguez Castillo,2
    A. De Luca,1 A. Tiengo,1;3;4 F. Haberl,5 R. Salvaterra,1 A. M. Read,6 D. Salvetti,1 S. Sandrelli,7
    M. Marelli,1 J. Wilms8 and D. D’Agostino9

    1INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica – Milano, via E. Bassini 15, I-20133 Milano, Italy
    2INAF–Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Italy
    3IUSS–Istituto Universitario di Studi Superiori, piazza della Vittoria 15, I-27100 Pavia, Italy
    4INFN–Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, via A. Bassi 6, I-27100 Pavia, Italy
    5Max-Planck-Institut f¨ur extraterrestrische Physik, Giessenbachstraße, D-85748 Garching, Germany
    6Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, U.K.
    7INAF–Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano, Italy
    8ECAP–Erlangen Centre for Astroparticle Physics, Sternwartstrasse 7, D-96049 Bamberg, Germany
    9CNR–Istituto di Matematica Applicata e Tecnologie Informatiche, via de Marini 6, I-16149 Genova, Italy

    See the full article here .

    Please help promote STEM in your local schools.

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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 10:25 am on January 14, 2016 Permalink | Reply
    Tags: A Milky Way twin swept by an ultra-fast X-ray wind, , , ESA XMM-Newton   

    From ESA: “A Milky Way twin swept by an ultra-fast X-ray wind” 

    ESASpaceForEuropeBanner
    European Space Agency

    14 January 2016
    Markus Bauer
    ESA Science and Robotic Exploration Communication Officer
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: Markus.Bauer@esa.int

    Anna Lia Longinotti
    Catedrática CONACYT
    Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE Puebla, Mexico)
    Email: annalia@inaoep.mx

    Matteo Guainazzi
    ESA ASTRO-H Resident Astronomer
    Institute of Space and Astronautical Science
    Japan Aerospace Exploration Agency
    Email: Matteo.Guainazzi@sciops.esa.int

    Norbert Schartel
    ESA XMM-Newton project scientist
    Email: norbert.Schartel@esa.int

    Temp 1
    Winds from a spiral galaxy. Artist’s depiction. No image credit found.

    ESA’s XMM-Newton has found a wind of high-speed gas streaming from the centre of a bright spiral galaxy like our own that may be reducing its ability to produce new stars.

    ESA XMM Newton
    XMM-Newton

    It is not unusual to find hot winds blowing from the swirling discs of material around supermassive black holes at the centre of active galaxies.

    If powerful enough, these winds can influence their surroundings in various ways. Their primary effect is to sweep away reservoirs of gas that might otherwise have formed stars, but it is also possible that they might trigger the collapse of some clouds to form stars.

    Such processes are thought to play a fundamental role in galaxies and black holes throughout the Universe’s 13.8 billion years.

    But they were thought to affect only the largest objects, such as massive elliptical galaxies formed through the dramatic collision and merging of two or more galaxies, which sometimes trigger the winds powerful enough to influence star formation.

    Now, for the first time, these winds have been seen in a more normal kind of active galaxy known as a Seyfert, which does not appear to have undergone any merging.

    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[/ESA] Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus.

    NASA Hubble Telescope
    NASA/ESA Hubble

    When observed in visible light, almost all Seyfert galaxies have a spiral shape similar to our own Milky Way. However, unlike the Milky Way, Seyferts have bright cores that shine across the entire electromagnetic spectrum, a sign that the supermassive black holes at their centres are not idle but are devouring their surroundings.

    The supermassive black hole at the heart of this particular Seyfert, known as IRAS17020+4544 and located 800 million light-years from Earth, has a mass of nearly six million Suns, drawing in nearby gas and making it shine moderately.

    XMM-Newton has found that the winds from around the black hole are moving at 23 000–33 000 km/s, about 10% the speed of light.

    An important finding is that the wind from the centre is sufficiently energetic to heat the gas in the galaxy and suppress star formation – the first time it has been seen in a relatively normal spiral galaxy.

    “It’s the first solid case of an ultra-fast X-ray outflow observed in a ‘normal’ Seyfert galaxy,” says Anna Lia Longinotti from the Instituto Nacional de Astrofísica, Óptica y Electrónica of Puebla, Mexico, lead author of the paper describing the results in Astrophysical Journal Letters.

    Temp 1
    The peculiar wind of a spiral galaxy. Image: Sloan Digital Sky Survey; Spectrum: Longinotti et al (2015)

    The galaxy has another surprise: the X-ray emission from the fast winds from galactic cores are usually dominated by iron atoms with many of their electrons stripped off, but this galaxy’s winds turn out to be rather unusual, exhibiting lighter elements like oxygen, with no iron detected.

    “I was actually very surprised to discover that this wind is made mostly of oxygen because nobody has seen a galaxy like this before,” says Anna Lia.

    Because the galaxy is broadly similar to our own, it raises questions about the history of the Milky Way and the role that our own central black hole may have played.

    “We know, also thanks to recent results obtained by XMM-Newton, that the four-million-solar-mass black hole in our own galaxy has undergone phases of much stronger activities, even only a few hundred years ago,” says co-author Matteo Guainazzi, ESA astronomer currently at the Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency.

    “Of course we cannot be sure, but our discovery implies that fast outflows like those found in IRAS17020+4544 may have once swept through our own Galaxy during one of these active phases.

    “This possibility was not considered before, because this ‘feedback’ from X-ray winds was previously observed only in galaxies very different from the Milky Way.”

    “XMM-Newton continues to make discoveries with the potential to question our understanding of how the stars in a galaxy and the supermassive black hole at its centre co-evolve throughout the history of the Universe,” says Norbert Schartel, ESA’s XMM-Newton project scientist.

    Notes for Editors

    X-ray high-resolution spectroscopy reveals feedback in a Seyfert Galaxy from an ultra fast wind with complex ionization and velocity structure,” by A.L Longinotti et al is published in The Astrophysical Journal Letters.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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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