Tagged: ESA XMM-Newton Toggle Comment Threads | Keyboard Shortcuts

  • 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.

    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.

    ESA50 Logo large

     
  • 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.

    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.

    ESA50 Logo large

     
  • 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.

    ESA50 Logo large

     
  • richardmitnick 10:08 am on December 21, 2015 Permalink | Reply
    Tags: , , , ESA XMM-Newton, Stephan’s Quintet   

    From ESA: “Sparkling Stephan’s Quintet” 

    ESASpaceForEuropeBanner
    European Space Agency

    21/12/2015
    No Writer Credit

    1
    No image credit

    The Stephan’s Quintet of galaxies was discovered by astronomer Édouard Stephan in 1877. At the time, however, he reported the discovery of ‘new nebulae’, as the concept of other galaxies beyond our Milky Way was only formalised in the 1920s.

    This image combines observations performed at three different wavelengths, with ESA’s Herschel and XMM-Newton space observatories as well as with ground-based telescopes, to reveal the different components of the five galaxies.

    ESA Herschel
    Herschel

    ESA XMM Newton
    XMM-Newton

    Stephan’s Quintet is one of the most spectacular galactic groups known, but only four galaxies from the originally discovered quintet are physically linked – the other was later discovered to be much closer to us. NGC 7320, the galaxy in the lower part the image, lies about 40 million light-years from us, rather than the 300 million light-years of the others.

    3
    NGC 7320 from Hubble

    NASA Hubble Telescope
    NASA/ESA Hubble

    One of them is the bright source above NGC 7320 in this view, two are the intertwined galaxies immediately to the right of image centre, and the fourth is the round patch towards the lower-right corner.

    Later, it was discovered that an additional galaxy, hidden beyond the left edge of this image, sits at a similar distance to these four galaxies, reinstating the group as a quintet.

    By observing these galaxies in infrared light with Herschel – shown in red and yellow – astronomers can trace the glow of cosmic dust. Dust is a minor but crucial ingredient of the interstellar matter in galaxies, which consists mainly of gas and provides the raw material for the birth of new generations of stars.

    One galaxy stands out in the infrared light: the nearby NGC 7320, a spiral galaxy busy building new stars.

    Shown in white, the optical light observed from ground-based telescopes reveals the shapes of the four distant galaxies, which exhibit tails and loops of stars and gas. These intricate features are an effect of their mutual gravitational attraction.

    The intense dynamical activity of the distant group is also portrayed in the distribution of diffuse hot gas, which shines brightly in X-rays and was detected by XMM-Newton.

    Represented in blue, the hot gas appears to sit mostly between the four colliding galaxies. It is likely a mixture of primordial gas predating the formation of the galaxies and intergalactic gas that has been stripped off the galaxies or expelled during their interactions.

    A hint of a shockwave from the interaction of these four galaxies is visible as an almost vertical blue structure on the right of the image centre. This structure of hot gas also seems to trace a filament of infrared-bright dust that might have been heated by the shock.

    At the top end of the shock, the infrared view reveals stars forming both within and outside the galaxies.

    A faint tail of stars, gas and dust extends towards the left, leading to a dwarf galaxy glowing in infrared – the red and yellow object at the tip of the tail.

    Further to the left, a dense concentration of hot gas is also visible in blue at the end of the tail, although it is unclear whether it belongs to the galactic group or is a foreground source.

    See the full article here .

    Another view of Stephan’s Quintet from Hubble:
    2

    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.

    ESA50 Logo large

     
  • richardmitnick 8:33 pm on December 17, 2015 Permalink | Reply
    Tags: , , ESA XMM-Newton, , ,   

    From JPL-Caltech: “NuSTAR Finds Cosmic Clumpy Doughnut Around Black Hole” 

    JPL-Caltech

    December 17, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    1
    Galaxy NGC 1068 can be seen in close-up in this view from NASA’s Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NuSTAR’s high-energy X-rays eyes were able to obtain the best view yet into the hidden lair of the galaxy’s central, supermassive black hole.

    NASA NuSTAR
    NASA/NuSTAR

    2
    This active black hole is one of the most obscured known, meaning that it is surrounded by extremely thick clouds of gas and dust.

    The NuSTAR data revealed that the torus of gas and dust surrounding the black hole, also referred to as a doughnut, is more clumpy than previously thought. doughnuts around active, supermassive black holes were originally proposed in the mid-1980s to be smooth entities. More recently, researchers have been finding that doughnuts are not so smooth but have lumps. NuSTAR’s latest finding shows that this is true for even the thickest of doughnuts.

    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, Virginia. 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, Maryland; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, California; ATK Aerospace Systems, Goleta, California, 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, California. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

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

    The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.

    Until recently, telescopes weren’t able to penetrate some of these doughnuts, also known as tori.

    “Originally, we thought that some black holes were hidden behind walls or screens of material that could not be seen through,” said Andrea Marinucci of the Roma Tre University in Italy, lead author of a new Monthly Notices of the Royal Astronomical Society study describing results from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency’s XMM-Newton space observatory.

    With its X-ray vision, NuSTAR recently peered inside one of the densest of these doughnuts known to surround a supermassive black hole. This black hole lies at the center of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.

    The observations revealed a clumpy, cosmic doughnut.

    “The rotating material is not a simple, rounded doughnut as originally thought, but clumpy,” said Marinucci.

    Doughnut-shaped disks of gas and dust around supermassive black holes were first proposed in the mid-1980s to explain why some black holes are hidden behind gas and dust, while others are not. The idea is that the orientation of the doughnut relative to Earth affects the way we perceive a black hole and its intense radiation. If the doughnut is viewed edge-on, the black hole is blocked. If the doughnut is viewed face-on, the black hole and its surrounding, blazing materials can be detected. This idea is referred to as the unified model because it neatly joins together the different black hole types, based solely upon orientation.

    In the past decade, astronomers have been finding hints that these doughnuts aren’t as smoothly shaped as once thought. They are more like defective, lumpy doughnuts that a doughnut shop might throw away.

    The new discovery is the first time this clumpiness has been observed in an ultra-thick doughnut, and supports the idea that this phenomenon may be common. The research is important for understanding the growth and evolution of massive black holes and their host galaxies.

    “We don’t fully understand why some supermassive black holes are so heavily obscured, or why the surrounding material is clumpy,” said co-author Poshak Gandhi of the University of Southampton in the United Kingdom. “This is a subject of hot research.”

    Both NuSTAR and [ESA]XMM-Newton observed the supermassive black hole in NGC 1068 simultaneously on two occasions between 2014 to 2015.

    ESA XMM Newton
    ESA/XMM-Newton

    On one of those occasions, in August 2014, NuSTAR observed a spike in brightness. NuSTAR observes X-rays in a higher-energy range than XMM-Newton, and those high-energy X-rays can uniquely pierce thick clouds around the black hole. The scientists say the spike in high-energy X-rays was due to a clearing in the thickness of the material entombing the supermassive black hole.

    “It’s like a cloudy day, when the clouds partially move away from the sun to let more light shine through,” said Marinucci.

    NGC 1068 is well known to astronomers as the first black hole to give birth to the unification idea. “But it is only with NuSTAR that we now have a direct glimpse of its black hole through such clouds, albeit fleeting, allowing a better test of the unification concept,” said Marinucci.

    The team says that future research will address the question of what causes the unevenness in doughnuts. The answer could come in many flavors. It’s possible that a black hole generates turbulence as it chomps on nearby material. Or, the energy given off by young stars could stir up turbulence, which would then percolate outward through the doughnut. Another possibility is that the clumps may come from material falling onto the doughnut. As galaxies form, material migrates toward the center, where the density and gravity is greatest. The material tends to fall in clumps, almost like a falling stream of water condensing into droplets as it hits the ground.

    “We’d like to figure out if the unevenness of the material is being generated from outside the doughnut, or within it,” said Gandhi.

    “These coordinated observations with NuSTAR and XMM-Newton show yet again the exciting science possible when these satellites work together,” said Daniel Stern, NuSTAR project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

    See the full article here.

    Another simpler view of NGC 1068 from Hubble:
    4

    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 [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.

    Caltech Logo
    jpl

     
  • richardmitnick 10:18 am on December 14, 2015 Permalink | Reply
    Tags: , , ESA XMM-Newton, Lockman Hole   

    From ESA: “The Lockman Hole in X-rays” 

    ESASpaceForEuropeBanner
    European Space Agency

    1

    14/12/2015

    A special patch of sky can be found close to the Big Dipper, in the northern constellation of Ursa Major, also known as the Great Bear. Appearing to contain no stars and hardly any gas clouds from our Milky Way galaxy, this region is called the Lockman Hole. A unique window into the distant Universe, it was discovered in 1986 by astronomer Felix J. Lockman.

    Since its discovery, astronomers have been surveying the Lockman Hole to study the evolution of galaxies throughout cosmic history. Shortly after the launch of ESA’s XMM-Newton X-ray observatory, which lifted off on 10 December 1999, various teams started looking at this patch of the sky with the new telescope.

    ESA XMM Newton
    ESA/XMM-Newton

    By 2003, they had accumulated over 200 hours of data.

    This image shows a portion of the Lockman Hole based on those observations. Hundreds of distant galaxies can be seen – their light has travelled billions of years before reaching Earth.

    At the core of each of these galaxies is a supermassive black hole, a huge concentration of matter millions to billions of times more massive than the Sun, whose powerful gravity draws large amounts of material from the surroundings. The majority of the black holes depicted here are accreting nearby matter at a very high rate, which results in the emission of light across the electromagnetic spectrum, including X-rays.

    Also portrayed in the image are a few galaxy clusters, gigantic assemblies of galaxies permeated by hot gas that shines brightly in X-rays. The double-lobed red object towards the upper left of the image is one such galaxy cluster: its light has taken over eight billion years to reach us.

    This colour view combines X-ray data collected at energies of 0.5–2 keV (shown in red), 2–4.5 keV (green) and 4.5–10 keV (blue). The image spans half a degree – about the diameter of the full Moon – on the short side; north is up and east to the left. It was first published in 2001, in a paper by G. Hasinger and colleagues.

    See the full article here .

    Another view:
    2
    The Chandra mosaic of a region of the sky known as the Lockman Hole (named after astronomer Felix Lockman, who discovered that this region of the Galaxy is almost free of absorption by neutral hydrogen gas) shows hundreds of X-ray sources. The high spatial resolution of Chandra allowed for the identification of many supermassive black holes in this image. The Lockman Hole data and two other surveys with Chandra and the Hubble Space Telescope have provided a reasonably accurate census of supermassive black holes in the Universe. Astronomers have used this census to study the rate at which these enormous black holes grow by pulling in gas from their surroundings.

    NASA Chandra Telescope
    NASA/Chandra

    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.

    ESA50 Logo large

     
  • richardmitnick 2:48 pm on December 3, 2015 Permalink | Reply
    Tags: , , ESA XMM-Newton   

    From ESA: “Cosmic filaments exposed near huge cluster” 

    ESASpaceForEuropeBanner
    European Space Agency

    2 December 2015
    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

    Dominique Eckert
    University of Geneva, Switzerland and INAF-IASF, Milano, Italy
    Email: Dominique.Eckert@unige.ch

    Mathilde Jauzac
    University of Durham, UKand University of KwaZulu-Natal, Durban, South Africa
    Email: mathilde.jauzac@durham.ac.uk

    Norbert Schartel
    ESA XMM-Newton Project Scientist
    ESA Directorate of Science and Robotic Exploration
    Tel: +34 91 8131 184
    Email: Norbert.Schartel@esa.int

    1
    Components of the galaxy cluster Abell 2744, also known as the Pandora Cluster: galaxies (white), hot gas (red) and dark matter (blue).
    Galaxy clusters are the most massive cosmic structures held together by gravity, consisting of galaxies, hot gas and dark matter. They sit in the densest hubs of the filamentary ‘cosmic web’ that pervades the Universe.
    Using ESA’s XMM-Newton X-ray observatory, astronomers have detected three massive filaments flowing towards the core of Abell 2744 and connecting it with the cosmic web. The filaments also consist of galaxies, hot gas and dark matter. One of them can be seen as the elongated structure on the left side of the image, another one is visible towards the upper right, and the third one below the cluster, slightly towards the right.
    There are also two structures – one on the lower left of the cluster, the other in the upper central part of the image – which are not physically linked to the cluster but are the projection of more distant structures viewed along the same line of sight.
    The astronomers detected the hot gas in the cluster and filaments with X-ray observations and the galaxies with optical observations. To reconstruct the distribution of dark matter, they used the gravitational lensing effect that the mass of the cluster and filaments exerts on more distant galaxies.
    Abell 2744 has a mass of almost two million billion times the mass of our Sun. Light from the cluster galaxies and gas travelled for over 3 billion years to reach Earth.
    The image measures about half a degree across. The image is sprinkled with foreground stars belonging to our Galaxy, the Milky Way, which are visible as the roundish objects with diffraction spikes.

    ESA’s XMM-Newton X-ray observatory has revealed three massive filaments of hot gas flowing towards a cluster of galaxies, uncovering a portion of the cosmic skeleton that pervades the entire Universe.

    Galaxies tend to congregate, forming groups and even larger agglomerates called clusters. These clusters are the most massive cosmic structures held together by gravity. As well as galaxies, they contain large amounts of hot gas and even larger amounts of invisible dark matter.

    On a grander scale, galaxies and galaxy clusters appear to be linked in a gigantic filamentary network, with the most massive clusters sitting in the densest hubs of this ‘cosmic web’.

    Computer simulations indicate that the cosmic web, which consists primarily of dark matter and some ordinary matter, behaves as the scaffolding of the cosmos, providing the framework for stars, galaxies and clusters to form and evolve.

    In the past few decades, astronomers have detected the threadlike structure of the cosmic web in the large-scale distribution of galaxies, and found hints that diffuse gas is arranged in a similar way.

    2
    Four galaxy clusters embedded in the cosmic web, the wispy network of both dark and baryonic matter that is believed to pervade the Universe. This image was extracted from a numerical simulation of the formation and evolution of cosmic structure.
    Four very massive galaxy clusters are visible where the concentration of galaxies (shown in white and purple) is higher. Two of the clusters, in the lower left corner of the image, are in the early phases of a merging process; the other two clusters can be seen in the central part of the image, just above the centre. The filamentary structure formed by the four clusters extends toward the right side of the image, where several less massive systems can be seen.
    Galaxy clusters form in the densest knots of the cosmic web, where filaments intersect. The density of gas in the filaments that link the clusters is represented with different colours, with dark brown indicating less dense regions and brighter colours (from orange to yellow and green) indicating increasingly denser regions.
    The image shows a portion of the cosmic web that spans about 260 million light-years across.

    A new study using ESA’s XMM-Newton X-ray observatory has now uncovered a handful of filaments made of galaxies, gas and dark matter that are flowing towards one of the most massive galaxy clusters in the Universe, obtaining the first, unambiguous detection of gas in the cosmic web.

    ESA XMM Newton
    XMM-Newton

    “This was an unexpected and most welcome discovery,” says Dominique Eckert of the University of Geneva, Switzerland, lead author of the paper reporting the new results in the journal Nature this week.

    The object of the study is Abell 2744, which has been nicknamed the Pandora Cluster owing to its complex and jumbled structure. It is composed of at least four smaller components that are merging.

    “We knew that this is an incredibly massive cluster hosting active processes at its core, and seeing its direct connection to the cosmic web confirms our picture of how structures form in the Universe,” adds Dr Eckert.

    From 30 hours of observations by XMM-Newton in December 2014, the astronomers detected five large structures of hot gas that seem to be linked to the core of Abell 2744.

    Comparing the X-ray data with optical observations, they identified the galaxies that belong to the various filaments, recognising that three of them are physically connected to the cluster, while the other two are the projection of more distant structures viewed along the same line of sight.

    Just like the cluster, the filaments also contain plenty of dark matter. The astronomers have reconstructed its distribution by studying the ‘gravitational lensing’ effect that the mass of the cluster and filaments exerts on distant galaxies, modifying the path of their light and so increasing their brightness and twisting their shapes as seen by us.

    “We initially looked at the inner core of Abell 2744 with the Hubble Space Telescope, with the aim of using the cluster as a strong magnifying lens to detect background galaxies that would be otherwise too faint to observe,” explains co-author Mathilde Jauzac from the University of Durham, UK.

    “After the discovery of X-ray gas in these filaments, we decided to look at the gravitational lensing effect also in the outskirts of the cluster, where background galaxies are only weakly distorted and magnified, but still enable us to study the dark matter distribution near the cluster as well as in the nearby filaments.”

    The combination of observations at different wavelengths revealed how the various components of Abell 2744 and its surroundings coexist.

    From the X-ray data, the astronomers measured the density and temperature of the gas and compared it with the predictions from theory. With gas temperatures of 10–20 million degrees celsius, the filaments are much colder than the centre of the cluster, where the gas reaches 100 million degrees, but hotter than the average temperature in the cosmic web, estimated to be several million degrees.

    The gas and galaxies in the filaments amount to about a tenth of the total mass – the rest being dark matter – which also agrees with expectations.

    While the measurements match well with the astronomers’ theoretical scenario, caution is always in order when drawing conclusions about the Universe as a whole.

    “What we observed is a very special configuration of dense filaments close to an exceptionally massive cluster. We need a much larger sample of less-dense filaments to investigate the nature of the cosmic web in greater detail,” says Dr Eckert.

    For more in-depth investigations, astronomers will have to wait for ESA’s Athena X-ray telescope, planned for launch in 2028.

    ESA Athena spacecraft
    Athena spacecraft

    Athena’s extraordinary sensitivity will make it possible to survey hot gas in the cosmic web across the sky, detecting faint and diffuse filaments and even identifying some of the atomic elements in the gas.

    “With the discovery of filaments around Abell 2744, we are witnessing the build-up of the cosmic web in one of the busiest places in the known Universe, a crucial step in the study of the formation of galaxies and galaxy clusters,” says Norbert Schartel, ESA XMM-Newton Project Scientist.

    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.

    ESA50 Logo large

     
  • richardmitnick 10:59 am on November 27, 2015 Permalink | Reply
    Tags: , , ESA XMM-Newton, ,   

    From JPL-Caltech: “NASA, ESA Telescopes Give Shape to Furious Black Hole Winds” 

    JPL-Caltech

    February 19, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    Felicia Chou
    NASA Headquarters, Washington
    202-358-0257
    felicia.chou@nasa.gov

    1
    Supermassive black holes at the cores of galaxies blast radiation and ultra-fast winds outward, as illustrated in this artist’s conception. New data from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s (ESA’s) XMM-Newton telescopes show that these winds, which contain gases of highly ionized atoms, blow in a nearly spherical fashion, emanating in every direction, as shown in the artwork. The findings rule out the possibility that the winds blow in narrow beams.

    NASA NuSTAR
    NASA/NuSTAR

    ESA XMM Newton
    ESA/XMM-Newton

    With the shape and extent of the winds known, the researchers were able to determine the winds’ strength. The high-speed winds are powerful enough to shut down star formation throughout a galaxy.

    The artwork is based on an image of the Pinwheel galaxy (Messier 101) taken by NASA’s Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    2
    The galaxy Messier 101 (M101, also known as NGC 5457 and also nicknamed the Pinwheel Galaxy) lies in the northern circumpolar constellation, Ursa Major (The Great Bear), at a distance of about 21 million light-years from Earth. This is one of the largest and most detailed photo of a spiral galaxy that has been released from Hubble. The galaxy’s portrait is actually composed of 51 individual Hubble exposures, in addition to elements from images from ground-based photos [CFHT image: Canada-France-Hawaii Telescope/J.-C. Cuillandre/Coelum NOAO image: George Jacoby, Bruce Bohannan, Mark Hanna/NOAO/AURA/NSF.

    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, California. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    2
    This plot of data from two space telescopes, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s (ESA’s) XMM-Newton determines for the first time the shape of ultra-fast winds from supermassive black holes, or quasars. The winds blow in every direction, in a nearly spherical fashion, coming from both sides of a galaxy (only one side is shown here).

    The plot shows the brightness of X-ray light from an extremely luminous quasar called PDS 456, with the highest-energy rays on the right. XMM-Newton sees lower-energy X-rays, and NuSTAR, higher. XMM Newton had previously observed the extremely luminous quasar, called PDS 456, on its own in 2001. At that time, it had measured the X-rays up to an energy level of 11 kiloelectron volts. From those data, researchers detected a dip in the X-ray light, called an absorption feature (see dip in plot). The dip is caused by iron atoms — which are carried by the winds along with other matter — absorbing the X-ray light of a particular energy. What’s more, the absorption feature is ‘blueshifted,” meaning that the winds are speeding toward us (like a train’s whistle shifting to higher frequencies as it races toward you).

    In other words, the 2001 XMM-Newton data had told researchers that at least some of the winds were blowing toward us — but they didn’t reveal whether those winds were confined to a narrow beam along our line of sight, or were blowing in all directions. That’s because XMM-Newton had only detected absorption features, which by definition occur in front of a light source, in this case, the quasar. To probe what was happening to at sides of the quasar, the astronomers needed to find a different type of feature called an emission feature. These occur when iron scatters X-ray light at a particular energy in all directions, not only toward the observer.

    Enter NuSTAR to the X-ray astronomy scene, a high-energy X-ray telescope that was launched in 2012. NuSTAR and XMM-Newton teamed up to observe PDS 456 simultaneously in 2013 and 2014. The results are shown in this plot. NuSTAR data are represented as orange circles and XMM-Newton as blue squares. The NuSTAR data reveal the baseline of the “continuum” quasar light (see gray line) — or what the quasar would look like without any winds. What stands out is the bump to the left of the dips. That’s an iron emission signature, the telltale sign that the black hole winds blow to the sides and in all directions.

    XMM-Newton might have seen the emission feature before, but the feature couldn’t be identified until NuSTAR’s elucidated the baseline quasar light. For example, had the X-ray winds been confined to a beam, then NuSTAR would have seen more brightness at the higher end of the X-ray spectrum, and there would have been no iron emission feature.

    The results demonstrate that, in some cases, two telescopes are better than one at solving tricky problems. By observing the entire X-ray energy range, the astronomers were able to get a more complete picture of what is happening around the quasar.

    “We know black holes in the centers of galaxies can feed on matter, and this process can produce winds. This is thought to regulate the growth of the galaxies,” said Fiona Harrison of the California Institute of Technology (Caltech) in Pasadena, California. Harrison is the principal investigator of NuSTAR and a co-author on a new paper about these results appearing in the journal Science. “Knowing the speed, shape and size of the winds, we can now figure out how powerful they are.”

    Supermassive black holes blast matter into their host galaxies, with X-ray-emitting winds traveling at up to one-third the speed of light. In the new study, astronomers determined PDS 456, an extremely bright black hole known as a quasar more than 2 billion light-years away, sustains winds that carry more energy every second than is emitted by more than a trillion suns.

    “Now we know quasar winds significantly contribute to mass loss in a galaxy, driving out its supply of gas, which is fuel for star formation,” said the study’s lead author, Emanuele Nardini of Keele University in England.

    “This is a great example of the synergy between XMM-Newton and NuSTAR,” said Norbert Schartel, XMM-Newton project scientist at ESA. “The complementarity of these two X-ray observatories is enabling us to unveil previously hidden details about the powerful side of the universe.”

    “For an astronomer, studying PDS 456 is like a paleontologist being given a living dinosaur to study,” said study co-author Daniel Stern of NASA’s Jet Propulsion Laboratory in Pasadena. “We are able to investigate the physics of these important systems with a level of detail not possible for those found at more typical distances, during the ‘Age of Quasars.'”

    NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.

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

    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 [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.

    Caltech Logo
    jpl

     
  • richardmitnick 10:23 am on August 20, 2015 Permalink | Reply
    Tags: , , Centre of the Milky Way Galaxy, ESA XMM-Newton   

    From ESA: “The tumultuous heart of our Galaxy” 

    ESASpaceForEuropeBanner
    European Space Agency

    1
    X-ray view of the Galactic Centre

    20 August 2015

    This new image of powerful remnants of dead stars and their mighty action on the surrounding gas from ESA’s XMM-Newton X-ray observatory reveals some of the most intense processes taking place at the centre of our galaxy, the Milky Way.

    ESA XMM Newton
    XMM-Newton

    The bright, point-like sources that stand out across the image trace binary stellar systems in which one of the stars has reached the end of its life, evolving into a compact and dense object – a neutron star or black hole. Because of their high densities, these compact remnants devour mass from their companion star, heating the material up and causing it to shine brightly in X-rays.

    The central region of our galaxy also contains young stars and stellar clusters, and some of these are visible as white or red sources sprinkled throughout the image, which spans about one thousand light-years.

    Most of the action is occurring at the centre, where diffuse clouds of gas are being carved by powerful winds blown by young stars, as well as by supernovas, the explosive demise of massive stars.

    The supermassive black hole sitting at the centre of the Galaxy is also responsible for some of this action. Known as Sagittarius A*, this black hole has a mass a few million times that of our Sun, and it is located within the bright, fuzzy source to the right of the image centre.

    3
    Sagittarius A* Credits: X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI

    While black holes themselves do not emit light, their immense gravitational pull draws in the surrounding matter that, in the process, emits light at many wavelengths, most notably X-rays. In addition, two lobes of hot gas can be seen extending above and below the black hole.

    Astronomers believe that these lobes are caused either directly by the black hole, which swallows part of the material that flows onto it but spews out most of it, or by the cumulative effect of the numerous stellar winds and supernova explosions that occur in such a dense environment.

    This image, showing us an unprecedented view of the Milky Way’s energetic core, was put together in a new study by compiling all observations of this region that were performed with XMM-Newton, adding up to about one and a half months of monitoring in total.

    2
    The Galactic Centre through the emission of heavy elements

    The large, elliptical structure to the lower right of Sagittarius A* is a super-bubble of hot gas, likely puffed up by the remnants of several supernovas at its centre. While this structure was already known to astronomers, this study confirms for the first time that it consists of a single, gigantic bubble rather than the superposition of several, individual supernova remnants along the line of sight.

    Another huge pocket of hot gas, designated the ‘Arc Bubble‘ due to its crescent-like shape, can be seen close to the image centre, to the lower left of the supermassive black hole. It is being inflated by the forceful winds of stars in a nearby stellar cluster, as well as by supernovae; the remnant of one of these explosions, a candidate pulsar wind nebula, was detected at the core of the bubble.

    The rich data set compiled in this study contains observations that span the full range of X-ray energies covered by XMM-Newton; these include some energies corresponding to the light emitted by heavy elements such as silicon, sulphur and argon, which are produced primarily in supernova explosions. By combining these additional information present in the data, the astronomers obtained another, complementary view of the Galactic Centre, which reveals beautifully the lobes and bubbles described earlier on.

    In addition, this alternative view also displays the emission, albeit very faint, from warm plasma in the upper and lower parts of the image. This warm plasma might be the collective macroscopic effect of outflows generated by star formation throughout this entire central zone.

    Another of the possible explanations for such emission links it to the turbulent past of the now not-so-active supermassive black hole. Astronomers believe that, earlier on in the history of our galaxy, Sagittarius A* was accreting and ejecting mass at a much higher rate, like the black holes found at the centre of many galaxies, and these diffuse clouds of warm plasma could be a legacy of its ancient activity.

    Related scientific papers:
    The XMM-Newton view of the central degrees of the Milky Way, by G. Ponti et al.

    The Galactic Centre XMM-Newton monitoring project is supported by the Bundesministerium für Wirtschaft und Technologie/Deutsches Zentrum für Luft- und Raumfahrt (BMWI/DLR, FKZ 50 OR 1408) and the Max Planck Society.

    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.

    ESA50 Logo large

     
  • richardmitnick 11:54 am on July 27, 2015 Permalink | Reply
    Tags: , , ESA XMM-Newton, Planetary Nebulas   

    From ESA: “Born-again planetary nebula” 

    ESASpaceForEuropeBanner
    European Space Agency

    27/07/2015
    No Writer Credit

    1

    Beneath the vivid hues of this eye-shaped cloud, named Abell 78, a tale of stellar life and death is unfolding. At the centre of the nebula, a dying star – not unlike our Sun – which shed its outer layers on its way to oblivion has, for a brief period of time, come back to echo its past glory.

    Releasing their outer shells is the usual fate for any star with a mass of 0.8–8 times that of the Sun. Having exhausted the nuclear fuel in their cores after burning for billions of years, these stars collapse to become dense, hot white dwarf stars. Around them, the ejected material strikes the ambient gas and dust, creating beautiful clouds known as ‘planetary nebulas’. This curious name was adopted by 18th-century astronomers who discovered these ‘puffing’ stars and thought their round shape similar to that of planets.

    However, the resurgence to life seen in this image is an exceptional event for a planetary nebula. Only a handful of such born-again stars have been discovered, and here the intricate shape of the cloud’s glowing material gives away its turbulent history.

    Although nuclear burning of hydrogen and helium had ceased in the core of the dying star, causing it to collapse under its own weight and its envelope to expand into a bubble, some of the star’s outer layers became so dense that fusion of helium resumed there.

    The renewed nuclear activity triggered another, much faster wind, blowing more material away. The interplay between old and new outflows has shaped the cloud’s complex structure, including the radial filaments that can be seen streaming from the collapsing star at the centre.

    The interaction between slow and fast winds gusting in the environment of Abell 78 heated the gas to over a million degrees, making it shine brightly in X-rays. Astronomers detected this hot gas with ESA’s XMM-Newton space observatory, revealing striking similarities with another born-again planetary nebula, Abell 30.

    ESA XMM Newton
    XMM-Newton

    This three-colour image combines X-ray data collected in 2013 by XMM-Newton (blue) with optical observations obtained using two special filters that reveal the glow of oxygen (green) and helium (red). The optical data were gathered in 2014 with the Andalusian Faint Object Spectrograph and Camera at the Nordic Optical Telescope on La Palma, in the Canary Islands. A study of the X-ray emission from Abell 78 is presented in a paper by J.A. Toalá et al. 2015.

    Nordic Optical Telescope
    Nordic Opitcal Telescope Interior
    Nordic Optical telescope

    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.

    ESA50 Logo large

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: