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  • richardmitnick 12:43 pm on March 21, 2018 Permalink | Reply
    Tags: , , , , , Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma in the Canaries Spain,   

    From astronomy.com: “The core of the Milky Way unveiled in clearest infrared image yet” 

    Astronomy magazine

    astronomy.com

    February 27, 2018 [Just now in social media.]
    Jake Parks

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    This new high-resolution map shows the magnetic field lines embedded in gas and dust around the supermassive black hole (Sagittarius A*) residing in the core of the Milky Way. Red areas show regions where warm dust particles and stars are emitting lots of infrared radiation (heat), while dark blue areas show cooler regions that lack pronounced warm and dusty filaments. E. Lopez-Rodriguez/NASA Ames/University of Texas at San Antonio.

    At the center of nearly every galaxy resides a gargantuan black hole. For the Milky Way, the supermassive black hole — dubbed Sagittarius A* — is so massive that its gravity flings stars around at speeds of up to 18.5 million miles (30 million kilometers) per hour.

    SgrA* NASA/Chandra


    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    In order to accelerate stars to these breakneck speeds, astronomers estimate that Sagittarius A* must be about 4 million times more massive than the Sun.

    With such a monstrous and intriguing object located in the center of our galaxy, you would think that astronomers know a great deal about it. However, thanks to the fact that the Milky Way is full of light-blocking gas and dust, many questions still remain about the structure and behavior of Sagittarius A*.

    In a paper published last month in the Monthly Notices of the Royal Astronomical Society, astronomers shed a bit of light on this black hole by producing a new high-resolution map that traces the magnetic field lines present within gas and dust swirling around Sagittarius A*. The team created the map, which is the first of its kind, by observing polarized infrared light that is emitted by warm, magnetically aligned dust grains.

    Because infrared light passes straight through the visual-light-blocking dust located between Earth and the Milky Way’s core, astronomers were able to view the area around Sagittarius A* much more clearly than would have been possible with other types of telescopes. Furthermore, since CanariCam combines infrared imaging with a device that preferentially filters polarized light associated with magnetic fields, the team was able to trace the magnetic field lines around Sagittarius A* in unprecedented detail.

    To create the detailed map, which spans about one light-year on each side of Sagittarius A*, the researchers used the CanariCam infrared camera on the Gran Telescopio Canarias (GTC), located on the island of La Palma, Spain. Because infrared light passes straight through the visual-light-blocking dust located between Earth and the Milky Way’s core, astronomers were able to view the area around Sagittarius A* much more clearly than would have been possible with other types of telescopes. Furthermore, since CanariCam combines infrared imaging with a device that preferentially filters polarized light associated with magnetic fields, the team was able to trace the magnetic field lines around Sagittarius A* in unprecedented detail.

    IAC CanariCam on the Gran Telescopio Canarias at Roque de los Muchachos Observatory island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    “Big telescopes like GTC, and instruments like CanariCam deliver real results,” said Pat Roche, a professor of astrophysics at The University of Oxford, in a press release. “We’re now able to watch material race around a black hole 25,000 light-years away, and for the first time see magnetic fields there in detail.”

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    This version of the map shows to what extent the light is polarized at various locations throughout the image. The longer a line is, the more the light is polarized. Sagittarius A*, our galaxy’s supermassive black hole, is located in the center of the image (0,0). Roche et al (MNRAS 2018)

    These new observations not only make for a wonderful image — the clearest infrared image of our galactic core to date — but also provide astronomers with vital information regarding the relationship between luminous stars and the filaments of gas and dust that stretch between them. One prominent feature in the map shows that dusty filaments connect some of the brightest stars in the center of the Milky Way despite incredibly strong stellar winds. The researchers believe that these filaments remain in place because they are bound by magnetic fields that permeate through the dust.

    Based on map, the team also thinks that a smaller magnetic field exists near the core of the Milky Way, and that the field gets stretched out as intervening filaments are pulled apart by gravity. The researchers point out that the filaments, which are several light-years long, seem to pool below (on the map) Sagittarius A*. The team believes that this likely marks a location where streams of gas and dust orbiting the black hole converge.

    Using the CanariCam on GTC, the researchers plan to continue probing the magnetic fields traced in dusty regions throughout our galaxy. Additionally, they hope to continue gathering more detailed observations of the core of the Milky Way to further study the magnetic field around Sagittarius A*. In particular, they would like to determine how the magnetic field interacts with clouds of dust and gas that orbit farther from the black hole, at distances of several light years.

    But for now, we’ll just have to be satisfied with the latest piece of the puzzle.

    [The work of Andrea Ghez deserves credit here.

    Andrea Mia Ghez is an American astronomer and professor in the Department of Physics and Astronomy at UCLA. In 2004, Discover magazine listed Ghez as one of the top 20 scientists in the United States who have shown a high degree of understanding in their respective fields. Ghez is a member of the UCLA Galactic Center Group

    Andrea Ghez, UCLA

    Andrea’s Favorite star SO-2

    Her current research involves using high spatial resolution imaging techniques, such as the adaptive optics system at the Keck telescopes, to study star-forming regions and the supermassive black hole at the center of the Milky Way known as Sagittarius A*. She uses the kinematics of stars near the center of the Milky Way as a probe to investigate this region. The high resolution of the Keck telescopes gave a significant improvement over the first major study of galactic center kinematics by Reinhard Genzel’s group.


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    In 2004, Ghez was elected to the National Academy of Sciences. She has appeared in a long list of notable media presentations. The documentaries have been produced by organizations such as BBC, Discovery Channel, and The History Channel; in 2006 there was a presentation on Nova. She was identified as a Science Hero by The My Hero Project.]

    See the full article here .

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  • richardmitnick 4:34 pm on February 9, 2018 Permalink | Reply
    Tags: , , , , Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma in the Canaries Spain, , J0815+4729   

    From Astronomy Magazine: “One of the oldest stars in the Milky Way discovered” 

    Astronomy magazine

    Astronomy Magazine

    February 2, 2018
    Jake Parks

    J0815+4729 is a star with both an extreme iron deficiency and a carbon surplus, which suggests it’s one of the oldest stars ever found in the Milky Way.

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    Astronomers recently discovered one of the first stars formed in the Milky Way, J0815+4729, shown here in this artist concept. This low-mass star is one of the most iron-poor and carbon-rich stars found to date, suggesting it formed shortly after the Big Bang. Gabriel Pérez/SMM/IAC.

    In a new study published in The Astrophysical Journal Letters, a team of Spanish astronomers announced the discovery of one of the first stars to form in the Milky Way. The unevolved star, called J0815+4729, is located 7,500 light-years away in the halo of the Milky Way and likely formed just 300 million years after the Big Bang, some 13.5 billion years ago.

    “We know of only a few stars (which can be counted on the fingers of a hand) of this type in the halo [of the Milky Way], where the oldest and most metal-poor stars in our galaxy are found,” said David Aguado, a research student at the IAC and lead author of the study, in a press release.

    The ancient star, which is only 70 percent the mass of the Sun, was initially identified from a dataset generated by the Sloan Digital Sky Survey (SDSS) — a massive survey project that has gathered deep multi-color images for about one third of sky, as well as spectra for more than three million astronomical objects. The researchers specifically selected J0815+4729 for follow-up based on its apparent lack of metals — a term which astronomers apply to any elements larger than hydrogen and helium.

    The research team analyzed the light from J0815+4729 using the ISIS spectrograph on the William Herschel Telescope and the OSIRIS spectrograph on the Gran Telescopio Canarias.

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    ISIS spectrograph on the William Herschel Telescope


    ING 4 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands, 2,396 m (7,861 ft)

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    Based on their spectroscopic follow-up, the team determined J0815+4729 has roughly a million times less calcium and iron than the Sun. This is important because only the earliest generations of stars have such low metallicities. Older stars, on the other hand, are formed out of the accumulated material from previous generations of stars, which produce lots of metals during their final death throes.

    Although J0815+4729 is extremely deficient in calcium and iron, the researchers’ were surprised to find that the star has a comparatively large abundance of carbon, nearly 15 percent more than the Sun. Though it may seem counter-intuitive, previous research suggests that low-mass, extremely metal-poor stars likely develop an overabundance of carbon by accreting it from the first generation of low-metallicity supernovae, which lived very short lives.

    Because J0815+4729 is so metal-poor while also being so carbon-rich, the researcher are confident the star formed long, long ago, when the Milky Way was just establishing itself some 13.5 billion years ago.

    “Theory predicts that these stars could form just after — and using material from — the first supernovae, whose progenitors were the first massive stars in the Galaxy, around 300 million years after the Big Bang,” said Jonay González Hernández, a researcher at IAC and co-author of the study.

    Though the researchers’ have already shown that J0815+4729 is likely one of — if not the — most iron-poor unevolved stars known, they still plan to collect higher-resolution spectra of the star to help derive other important elemental abundances. By doing so, the researchers aim to provide “new fundamental constraints on the early stages of the universe, the formation of the first stars, and the properties of the first supernovae.”

    See the full article here .

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  • richardmitnick 11:58 am on May 29, 2017 Permalink | Reply
    Tags: , , , , Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma in the Canaries Spain, , , Spain,   

    From Manu: Stephan’s quintet 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

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    This image is interesting for two things. First, teaches us that effectively galaxies may, throughout its existence, go through phases of intense interaction with other galaxies, interaction that produces an alteration of the delicate balance of forces that keeps the stars in their orbits. In many cases the galaxies are deformed and part of its stars look released abroad producing long tails and bows. At this stage of interacting galaxies also tend to experience a period of intense star formation and, more rarely, maybe her central black hole is activated by turning her into a quasar.

    The other interesting thing that tells us this picture of Stephan’s quintet is that things are not always what they seem. You will note the biggest galaxy has a color a lot more blue than the other four, clearly more yellow. This is because this galaxy is only 40 million light-years away, much closer to us than the other, located some 250 million light-years away. Just by pure chance his image projected above the other. The Quintet, strictly speaking, it should be called quartet!

    Galaxies form groups that may contain a few hundreds of galaxies, of all sizes and shapes. We too, as part of the milky way, we belong to a set of 50 galaxies called a local group.

    Local Group. Andrew Z. Colvin 3 March 2011

    Due to its own gravitational pull, the galaxies of a group are attracted to each other and to avoid collapse and form a single huge object, must constantly be moving within the same group.
    This continual movement can make galaxies collide between them, as is clear in this image taken with Osiris of a small group called Stephan’s quintet.

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    Galactic Wreckage in Stephan’s Quintet.
    A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide color range, from young, blue stars to aging, red stars.
    This portrait of Stephan’s Quintet, also known as Hickson Compact Group 92, was taken by the new Wide Field Camera 3 (WFC3) aboard NASA’s Hubble Space Telescope. Stephan’s Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy about seven times closer to Earth than the rest of the group.
    Three of the galaxies have distorted shapes, elongated spiral arms, and long, gaseous tidal tails containing myriad star clusters, proof of their close encounters. These interactions have sparked a frenzy of star birth in the central pair of galaxies. This drama is being played out against a rich backdrop of faraway galaxies.
    The image, taken in visible and near-infrared light, showcases WFC3’s broad wavelength range.

    NASA/ESA Hubble WFC3

    NASA/ESA Hubble Telescope

    The colors trace the ages of the stellar populations, showing that star birth occurred at different epochs, stretching over hundreds of millions of years. The camera’s infrared vision also peers through curtains of dust to see groupings of stars that cannot be seen in visible light.
    NGC 7319, at top right, is a barred spiral with distinct spiral arms that follow nearly 180 degrees back to the bar. The blue specks in the spiral arm at the top of NGC 7319 and the red dots just above and to the right of the core are clusters of many thousands of stars. Most of the quintet is too far away even for Hubble to resolve individual stars.
    Continuing clockwise, the next galaxy appears to have two cores, but it is actually two galaxies, NGC 7318A and NGC 7318B. Encircling the galaxies are young, bright blue star clusters and pinkish clouds of glowing hydrogen where infant stars are being born. These stars are less than 10 million years old and have not yet blown away their natal cloud. Far away from the galaxies, at right, is a patch of intergalactic space where many star clusters are forming.
    NGC 7317, at bottom left, is a normal-looking elliptical galaxy that is less affected by the interactions.
    Sharply contrasting with these galaxies is the dwarf galaxy NGC 7320 at upper left. Bursts of star formation are occurring in the galaxy’s disk, as seen by the blue and pink dots. In this galaxy, Hubble can resolve individual stars, evidence that NGC 7320 is closer to Earth.
    NGC 7320 is 40 million light-years from Earth. The other members of the quintet reside 290 million light-years away in the constellation Pegasus.
    These farther members are markedly redder than the foreground galaxy, suggesting that older stars reside in their cores. The stars’ light also may be further reddened by dust stirred up in the encounters.
    Spied by Edouard M. Stephan in 1877, Stephan’s Quintet is the first compact group ever discovered.
    WFC3 observed the quintet in July and August 2009. The composite image was made by using filters that isolate light from the blue, green, and infrared portions of the spectrum, as well as emission from ionized hydrogen.
    These Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts installed the WFC3 camera during a servicing mission in May to upgrade and repair the 19-year-old Hubble telescope.
    Denoised by uploader.
    Date July 2009 and August 2009
    Source http://www.hubblesite.org/newscenter/archive/releases/2009/25/image/x/ (direct link)
    Author NASA, ESA, and the Hubble SM4 ERO Team

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain

    See the full article here .

    Please help promote STEM in your local schools.

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