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  • richardmitnick 5:40 pm on April 15, 2019 Permalink | Reply
    Tags: , , , , , NASA/DTU/ASI NuSTAR X-ray telescope, Supernova remnant W49B   

    From AAS NOVA: “NuSTAR Explores the Aftermath of a Supernova” 

    AASNOVA

    From AAS NOVA

    15 April 2019
    Susanna Kohler

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    Composite view of the supernova remnant W49B, combining X-rays from NASA’s Chandra X-ray Observatory in blue and green, radio data from the NSF’s Very Large Array in pink, and infrared data from Caltech’s Palomar Observatory in yellow. [X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA]

    NASA/Chandra X-ray Telescope

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)


    Caltech Palomar Observatory, located in San Diego County, California, US, at 1,712 m (5,617 ft)

    There’s plenty to learn from the skeletons left behind after supernova explosions tear through their surroundings. An X-ray view from space has revealed new details about a particularly extreme supernova remnant.

    Unexpected Plasmas

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    NuSTAR observations showing the spatial distribution of flux that indicates where overionized plasma resides in supernova remnant W49B. The overionized plasma is more highly concentrated on the western side of the remnant. [Yamaguchi et al. 2018]

    NASA/DTU/ASI NuSTAR X-ray telescope

    When some stars explode as powerful supernovae at the end of their lifetimes, they expel material into their surroundings, enriching the galaxy with heavy elements. As this matter is flung outwards at high speeds, it slams into the interstellar medium, generating shocks that heat the gas and ionize it.

    We can study the young remnants of supernovae — the structures of gas and dust left behind shortly after these explosions — to learn more about how supernovae interact with the interstellar medium. One type of source is particularly intriguing: very young, hot supernova remnants that are “overionized”.

    Overionized plasmas send us mixed signals: their level of ionization is higher than what we expect from the temperature we measure from their electrons. This is most likely an indication that the plasma has recently started cooling very rapidly.

    But what might cause this sudden cooling of the remnant? To learn more, we need detailed observations of a young, hot remnant. Luckily, we’ve got an ideal target — and an ideal instrument.

    Setting Sights

    Supernova remnant W49B is one of the first sources in which we discovered signs of an overionized plasma. It’s the youngest (just ~1,000 years old!), hottest, and most highly ionized among all such objects exhibiting this trait. But W49B’s hot plasma is challenging to observe, and we haven’t yet managed to constrain its detailed high-energy properties.

    A powerful telescope is up to the task, however: the Nuclear Spectroscopic Telescope Array (NuSTAR). This versatile space observatory is ideally suited for exploring the spectroscopic details of the X-rays emitted from the hot plasma in W49B.

    Sudden Expansion

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    Top panel: Diagram of the 1’ x 1’ box regions NuSTAR resolved for spectral analysis (overlaid on a color image of W49B from the Wide Field Infrared Camera at Palomar Observatory). Bottom panel: Plot of the electron temperature (bottom) vs. the density (right) measured for each of the labeled regions. [Adapted from Yamaguchi et al. 2018]

    Led by Hiroya Yamaguchi (Institute of Space and Astronautical Science, JAXA, Japan), a team of scientists used NuSTAR to capture detailed images and spectroscopy of the W49B remnant.

    Yamaguchi and collaborators first confirmed that the overionized plasma is most highly concentrated on the western side of the remnant. They then show that lower electron temperatures — i.e., signs of rapid cooling — are found in the same regions that also have lower density. They measure a gradient from lowest electron temperature and density in the west, to highest in the east.

    Taken together with previous observations that reveal that W49B’s surroundings also have lower density on the western side, these results provide strong evidence that the remnant is cooling via adiabatic expansion. In this picture, the supernova blast wave punched through dense circumstellar matter in early stages of the explosion, expanding slowly. Now it’s suddenly breaking out into the lower-density interstellar medium — on the west side first, because it’s not exactly symmetric — leading to sudden expansion and cooling.

    Does this explanation apply to overionized plasmas in the skeletons of other, similar supernovae? We’ll need more observations to be sure — but NuSTAR has proven itself up to the task!

    Citation

    “Evidence for Rapid Adiabatic Cooling as an Origin of the Recombining Plasma in the Supernova Remnant W49B Revealed by NuSTAR Observations,” Hiroya Yamaguchi et al 2018 ApJL 868 L35.
    https://iopscience.iop.org/article/10.3847/2041-8213/aaf055/meta

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 10:42 am on February 26, 2019 Permalink | Reply
    Tags: , , , , , , ESO WFI at 2.2 meter MPG/ESO, , , NASA/DTU/ASI NuSTAR X-ray telescope, What remains of the stars-Past and future generations of stars in NGC 300"   

    From European Space Agency: “What remains of the stars-Past and future generations of stars in NGC 300” 

    ESA Space For Europe Banner

    From European Space Agency

    25/02/2019
    ESA/XMM-Newton (X-rays); MPG/ESO (optical); NASA/Spitzer (infrared). Acknowledgement: S. Carpano, Max-Planck Institute for Extraterrestrial Physics

    ESA/XMM Newton


    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

    NASA/Spitzer Infrared Telescope

    1

    This swirling palette of colours portrays the life cycle of stars in a spiral galaxy known as NGC 300.

    Located some six million light-years away, NGC 300 is relatively nearby. It is one of the closest galaxies beyond the Local Group – the hub of galaxies to which our own Milky Way galaxy belongs. Due to its proximity, it is a favourite target for astronomers to study stellar processes in spiral galaxies.

    The population of stars in their prime is shown in this image in green hues, based on optical observations performed with the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at La Silla, Chile.

    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres

    Red colours indicate the glow of cosmic dust in the interstellar medium that pervades the galaxy: this information derives from infrared observations made with NASA’s Spitzer space telescope, and can be used to trace stellar nurseries and future stellar generations across NGC 300.

    A complementary perspective on this galaxy’s composition comes from data collected in X-rays by ESA’s XMM-Newton space observatory, shown in blue. These represent the end points of the stellar life cycle, including massive stars on the verge of blasting out as supernovas, remnants of supernova explosions, neutron stars, and black holes. Many of these X-ray sources are located in NGC 300, while others – especially towards the edges of the image – are foreground objects in our own Galaxy, or background galaxies even farther away.

    The sizeable blue blob immediately to the left of the galaxy’s centre is especially interesting, featuring two intriguing sources that are part of NGC 300 and shine brightly in X-rays.

    One of them, known as NGC 300 X-1, is in fact a binary system, consisting of a Wolf-Rayet star – an ageing hot, massive and luminous type star that drives strong winds into its surroundings – and a black hole, the compact remains of what was once another massive, hot star. As matter from the star flows towards the black hole, it is heated up to temperatures of millions of degrees or more, causing it to shine in X-rays.

    The other source, dubbed NGC 300 ULX1, was originally identified as a supernova explosion in 2010. However, later observations prompted astronomers to reconsider this interpretation, indicating that this source also conceals a binary system comprising a very massive star and a compact object – a neutron star or a black hole – feeding on material from its stellar companion.

    Data obtained in 2016 with ESA’s XMM-Newton and NASA’s NuSTAR observatories revealed regular variations in the X-ray signal of NGC 300 ULX1, suggesting that the compact object in this binary system is a highly magnetized, rapidly spinning neutron star, or pulsar.

    NASA/DTU/ASI NuSTAR X-ray telescope

    The large blue blob in the upper left corner is a much more distant object: a cluster of galaxies more than one billion light years away, whose X-ray glow is caused by the hot diffuse gas interspersed between the galaxies.

    Explore NGC 300 in ESASky

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    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 2:35 pm on February 20, 2019 Permalink | Reply
    Tags: "In Colliding Galaxies a Pipsqueak Shines Bright", A much smaller object is competing with the two behemoths, , , At the center of each galaxy is a supermassive black hole millions of times more massive than the Sun, , Collectively known as Messier 51 the two galaxies are merging, , , NASA/DTU/ASI NuSTAR X-ray telescope, Neither black hole is radiating as brightly in the X-ray range as scientists would expect during a merger, , The neutron star found in Messier 51 is even brighter than average and belongs to a newly discovered class known as ultraluminous neutron stars, The small X-ray source is a neutron star, Two supermassive black holes heat up and devour surrounding material, Whirlpool galaxy a.k.a. Messier 51a M51 and NGC 5194 and its companion galaxy Messier 51b   

    From JPL-Caltech: “In Colliding Galaxies, a Pipsqueak Shines Bright” 

    NASA JPL Banner

    From JPL-Caltech

    February 20, 2019

    Calla Cofield
    Jet Propulsion Laboratory, Pasadena, Calif.
    626-808-2469
    calla.e.cofield@jpl.nasa.gov

    1
    Bright green sources of high-energy X-ray light captured by NASA’s NuSTAR mission are overlaid on an optical-light image of the Whirlpool galaxy a.k.a. Messier 51a, M51a, and NGC 5194 (in the center of the image) and its companion galaxy, Messier 51b (the bright greenish-white spot above the Whirlpool), taken by the Sloan Digital Sky Survey.Credit: NASA/JPL-Caltech, IPAC

    NASA/DTU/ASI NuSTAR X-ray telescope

    SDSS 2.5 meter Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft)

    In the nearby Whirlpool galaxy and its companion galaxy, Messier 51b, two supermassive black holes heat up and devour surrounding material. These two monsters should be the most luminous X-ray sources in sight, but a new study using observations from NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) mission shows that a much smaller object is competing with the two behemoths.

    The most stunning features of the Whirlpool galaxy – officially known as Messier 51a – are the two long, star-filled “arms” curling around the galactic center like ribbons. The much smaller Messier 51b clings like a barnacle to the edge of the Whirlpool. Collectively known as Messier 51, the two galaxies are merging.

    At the center of each galaxy is a supermassive black hole millions of times more massive than the Sun. The galactic merger should push huge amounts of gas and dust into those black holes and into orbit around them. In turn, the intense gravity of the black holes should cause that orbiting material to heat up and radiate, forming bright disks around each that can outshine all the stars in their galaxies.

    But neither black hole is radiating as brightly in the X-ray range as scientists would expect during a merger. Based on earlier observations from satellites that detect low-energy X-rays, such as NASA’s Chandra X-ray Observatory, scientists believed that layers of gas and dust around the black hole in the larger galaxy were blocking extra emission. But the new study, published in The Astrophysical Journal, used NuSTAR’s high-energy X-ray vision to peer below those layers and found that the black hole is still dimmer than expected.

    “I’m still surprised by this finding,” said study lead author Murray Brightman, a researcher at Caltech in Pasadena, California. “Galactic mergers are supposed to generate black hole growth, and the evidence of that would be strong emission of high-energy X-rays. But we’re not seeing that here.”

    Brightman thinks the most likely explanation is that black holes “flicker” during galactic mergers rather than radiate with a more or less constant brightness throughout the process.

    “The flickering hypothesis is a new idea in the field,” said Daniel Stern, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena and the project scientist for NuSTAR. “We used to think that the black hole variability occurred on timescales of millions of years, but now we’re thinking those timescales could be much shorter. Figuring out how short is an area of active study.”

    Small but Brilliant

    Along with the two black holes radiating less than scientists anticipated in Messier 51a and Messier 51b, the former also hosts an object that is millions of times smaller than either black hole yet is shining with equal intensity. The two phenomena are not connected, but they do create a surprising X-ray landscape in Messier 51.

    The small X-ray source is a neutron star, an incredibly dense nugget of material left over after a massive star explodes at the end of its life. A typical neutron star is hundreds of thousands of times smaller in diameter than the Sun – only as wide as a large city – yet has one to two times the mass. A teaspoon of neutron star material would weigh more than 1 billion tons.

    Despite their size, neutron stars often make themselves known through intense light emissions. The neutron star found in M51 is even brighter than average and belongs to a newly discovered class known as ultraluminous neutron stars. Brightman said some scientists have proposed that strong magnetic fields generated by the neutron star could be responsible for the luminous emission; a previous paper by Brightman and colleagues about this neutron star supports that hypothesis. Some of the other bright, high-energy X-ray sources seen in these two galaxies could also be neutron stars.

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

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA JPL Campus

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

    Caltech Logo

    NASA image

     
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