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  • richardmitnick 8:16 am on April 20, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory, Keco Cosmic Web Imager from Caltech   

    From Keck Observatory: “W. M. Keck Observatory Achieves First Light with New Instrument” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    4.20.17
    MEDIA CONTACT:
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    “THIS IS AN INSTRUMENT THAT IS BREAKING RECORDS IN SO MANY WAYS, AND I’M REALLY HAPPY THAT WE CAN NOW SHARE THIS EXCITEMENT.”

    W. M. Keck Observatory Achieves
    First Light with New Instrument
    Integral field spectrograph to provide unprecedented view
    of deep space

    `
    Luca Rizzi, support astronomer for W. M. Keck Observatory, gives perspective on KCWI’s size. This Caltech-built instrument is about as large as an ice cream truck and weighs five tons.

    2
    3
    KCWI built AT CALTECH

    W. M. Keck Observatory has captured the very first successful science data from its newest, cutting-edge instrument, the Keck Cosmic Web Imager (KCWI).

    KCWI captures three-dimensional data, as opposed to the traditional two-dimensional image or spectrum of conventional instruments. In a single observation, it records an image of the object at multiple wavelengths allowing scientists to explore both the spatial dimension (as in an image) and the spectral dimension (or color) of an object.

    “I’m thrilled to see this new instrument,” said Keck Observatory Director Hilton Lewis. “It takes years to design and build these very sophisticated instruments. KCWI is a superb example of the application of the most advanced technology to enable the hardest science. I believe it has the potential to transform the science that we do, and continue to keep Keck Observatory right at the forefront of astronomical research.”

    KCWI is extremely sensitive, specifically designed to capture high-resolution spectra of ultra-faint celestial bodies with unprecedented detail. It is able to differentiate even the slightest changes in spectral color with a great degree of accuracy.

    This powerful capability is key for astronomers because a highly-detailed spectral image allows them to identify a cosmic object’s characteristics, including its temperature, motion, density, mass, distance, chemical composition, and more.

    KCWI is designed to study the wispy currents of gas that connect galaxies. The ability to study this “cosmic web” is the driving principle behind KCWI’s design. However, it will also be used to study many other astronomical phenomena including young stars, evolved stars, supernovae, star clusters, and galaxies.

    “I’m incredibly excited. These moments happen only a few times in one’s life as a scientist,” said Principal Investigator Christopher Martin, physics professor at Caltech who developed the concept of KCWI. “To take a powerful new instrument, a tool for looking at the universe in a completely novel way, and install it at the greatest observatory in the world is a dream for an astronomer. This is one of the best days of my life.”

    Martin flew in from California to join the Keck Observatory team as they worked to achieve the milestone moment on Tuesday night, April 11. The following morning, at 2:30 a.m., KCWI successfully achieved first light, with a spectral image of the core of the globular cluster Messier 3.

    4
    This “first-light” image from KCWI (middle) shows more than 100 stars in the core of the globular cluster Messier 3 (right). The boxes are positioned around some of the stars, and connect to their corresponding spectra. The green outlines showcase the highest spectral-resolution setting of KCWI. Each star has a rich spectrum of absorption lines (the dips) that contain information about the velocity and chemical composition of the star.

    Since then, Keck Observatory’s team has been working diligently to install and test KCWI on Keck II, one of the twin 10-meter Keck Observatory telescopes.

    “KCWI will really raise the bar in terms of Keck Observatory’s capabilities,” said Anne Kinney, chief scientist at Keck Observatory. “I think it’ll become the most popular instrument we have because it will be able to do a great breadth of science, increasing our ability to understand and untangle the effects of dark matter in galaxy formation.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

     
  • richardmitnick 12:34 pm on April 14, 2017 Permalink | Reply
    Tags: , , , , , , Keck Observatory   

    From Caltech: “Keck Cosmic Web Imager Achieves ‘First Light'” 

    Caltech Logo

    Caltech

    04/14/2017

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Keck Observatory

    A Caltech-built instrument designed to study the mysteries of the cosmic web—streams of gas connecting galaxies—has captured its first image, an event astronomers call “first light.” The instrument, called the Keck Cosmic Web Imager, or KCWI, was recently installed on the W. M. Keck Observatory in Hawaii.

    2
    Hector Rodriguez, senior mechanical technician, works on the Keck Cosmic Web Imager in a clean room at Caltech. Credit: Caltech

    KCWI captures highly detailed spectral images of cosmic objects to reveal their temperature, motion, density, mass, distance, chemical composition, and more. The instrument is designed to study the wispy cosmic web; it will also observe many other astronomical phenomena, including young stars, evolved stars, supernovas, star clusters, and galaxies.

    “I’m incredibly excited. These moments happen only a few times in one’s life as a scientist,” says principal investigator Christopher Martin, professor of physics at Caltech. “To take a powerful new instrument, a tool for looking at the universe in a completely novel way, and install it at the greatest observatory in the world is a dream for an astronomer. This is one of the best days of my life.”

    Martin and his Caltech team, in collaboration with scientists at UC Santa Cruz and with industrial partners, designed and built the 5-ton instrument—about the size of an ice cream truck. It was then shipped from California to Hawaii on January 12. Since then, Keck Observatory’s team has been working diligently to install and test KCWI on Keck II, one of the twin 10-meter Keck Observatory telescopes.

    “KCWI will really raise the bar in terms of Keck Observatory’s capabilities,” says Anne Kinney, chief scientist at Keck Observatory. “I think it will become the most popular instrument we have, because it will be able to do a great breadth of science, increasing our ability to understand and untangle the effects of dark matter in galaxy formation.”

    The W. M. Keck Observatory is a private 501(c)3 nonprofit organization and a scientific partnership of Caltech, the University of California, and NASA.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
    Caltech buildings

     
  • richardmitnick 7:30 am on April 6, 2017 Permalink | Reply
    Tags: , , , , , Keck Observatory,   

    From Swinburne: “The monster galaxy that grew up too fast” 

    Swinburne U bloc

    Swinburne University

    6 April 2017
    Lea Kivivali
    +61 3 9214 5428
    lkivivali@swin.edu.au

    1
    Artist’s impression of galaxy ZF-COSMOS-20115. The galaxy has likely blown off all the gas that caused its rapid star formation and mass growth and rapidly turned into a compact red galaxy. *
    No image credit.

    An international team of astronomers has, for the first time, spotted a massive, inactive galaxy from a time when the Universe was only 1.65 billion years old.

    Astronomers expect most galaxies from this epoch to be low-mass minnows, busily forming stars. However, this galaxy is ‘a monster’ and inactive, according to Professor Karl Glazebrook, Director of Swinburne’s Centre for Astrophysics and Supercomputing, who led the team.

    The researchers found that within a short time period this massive galaxy, known as ZF-COSMOS-20115, formed all its stars (three times more than our Milky Way today) through an extreme star-burst event. But it stopped forming stars only a billion years after the Big Bang to become a quiescent or ‘red and dead’ galaxy – common in our Universe today, but not expected to exist at this ancient epoch.

    The galaxy is also small and extremely dense, it has 300 billion stars crammed into a region of space about the same size as the distance from the Sun to the nearby Orion Nebula.

    Astrophysicists are still debating just how galaxies stop forming stars. Until recently, models suggested dead galaxies or ‘red nuggets’ such as this should only exist from around three billion years after the Big Bang.

    “This discovery sets a new record for the earliest massive red galaxy. It is an incredibly rare find that poses a new challenge to galaxy evolution models to accommodate the existence of such galaxies much earlier in the Universe.”

    This research builds on an earlier Swinburne study that suggested such dead galaxies could exist based on finding dim red objects in extremely deep near-infrared images.

    MOSFIRE spectrograph studies the faintest, most distant galaxies

    In this latest study, astronomers used the W M Keck telescopes in Hawai’i to confirm the signatures of these galaxies, through the new and unique MOSFIRE spectrograph. They took deep spectra at near-infrared wavelengths to seek out the definitive features signifying the presence of old stars and a lack of active star formation.

    Keck Observatory, Mauna Kea, Hawaii, USA

    Keck/MOSFIRE on Keck 1, Mauna Kea, Hawaii, USA

    “We used the most powerful telescope in the world, but we still needed to stare at this galaxy for more than two nights to reveal its remarkable nature,” co-author Professor Vy Tran, from Texas A&M University, says.

    Even with large telescopes such as the Keck with a 10 metre mirror, a long viewing time is required to detect absorption lines which are very weak compared to the more prominent emission lines generated by star-forming active galaxies.

    “By collecting enough light to measure this galaxy’s spectrum, we decipher the cosmic narrative of what stars and elements are present in these galaxies and construct a timeline of when they formed their stars,” Professor Tran says.

    The observed star-formation rate of this galaxy produces less than one fifth the mass of the Sun a year in new stars, but at its peak 700 million years previously this galaxy formed 5000 times faster.

    “This huge galaxy formed like a firecracker in less than 100 million years, right at the start of cosmic history,” Professor Glazebrook says.

    “It quickly made a monstrous object, then just as suddenly it quenched and turned itself off. As to how it did this we can only speculate. This fast life and death so early in the Universe is not predicted by our modern galaxy formation theories.”

    Co-author Dr Corentin Schreiber of Leiden University, who first measured the spectrum, speculates that these early firecrackers are obscured behind a veil of dust and that future observations using sub-millimetre wave telescopes will spot these.

    ”Sub-millimetre waves are emitted by the hot dust which blocks other light and will tell us when these firecrackers exploded and how big a role they played in developing the primordial universe,” says Dr Schreiber.

    With the launch of the James Webb Space Telescope in 2018, astronomers will be able to build up large samples of these dead galaxies due to its high sensitivity, large mirror, and the advantage of no atmosphere in space.

    NASA/ESA/CSA Webb Telescope annotated

    This research has been published in Nature.

    The team included researchers from:

    Swinburne University of Technology, Australia; Leiden University, Netherlands; University of Geneva, Switzerland; Texas A & M University, USA; Macquarie University, Australia; Australian Astronomical Observatory; Max Planck Institute for Astronomy, Germany; The Australian National University.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    Swinburne U Campus

    Swinburne is a large and culturally diverse organisation. A desire to innovate and bring about positive change motivates our students and staff. The result is in an institution that grows and evolves each year.

     
  • richardmitnick 8:40 am on March 30, 2017 Permalink | Reply
    Tags: , , Keck Observatory, , , TXS 0828+193, TXS0211−122   

    From Keck and IAC via phys.org: “Expanding super bubble of gas detected around massive black holes in the early universe” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    2

    Instituto de Astrofísica e Ciências do Espaço

    phys.org

    1
    Left – Composite image of a large gas blob of glowing hydrogen gas, shown by a Lyman-alpha optical image (colored yellow) from the Subaru telescope (NAOJ). A galaxy located in the blob is visible in a broadband optical image (white) from the Hubble Space Telescope and an infrared image from the Spitzer Space Telescope (red). Finally, the Chandra X-ray Observatory image in blue shows evidence for a growing supermassive black hole in the center of the galaxy. Radiation and outflows from this active black hole are powerful enough to light up and heat the gas in the blob.

    In a study led by Sandy Morais, a PhD student at Instituto de Astrofísica e Ciências do Espaço and Faculty of Sciences of the University of Porto (FCUP), researchers found massive super bubbles of gas and dust around two distant radio galaxies about 11.5 billion light years away.

    Andrew Humphrey (IA & University of Porto), the leader of the project, commented: “By studying violent galaxies like these, we have gained a new insight into the way supermassive black holes affect the evolution of the galaxies in which they reside.”

    The researchers used two of the largest observatories available today, the Keck II (Hawaii) and the Gran Telescópio de Canárias (GTC), to observe TXS0211−122 and TXS 0828+193, two powerful radio galaxies, harboring the most energetic type of Active Galactic Nuclei (AGN) known. This type of galaxy houses the most massive black holes and have the most powerful continuous energy ejections known.

    The team discovered expanding super bubbles of gas around each of TXS 0211-122 and TXS 0828+193, most likely caused by “feedback” activity whereby the AGN injects vast quantities of energy into its host galaxy, creating a powerful wind that sweeps up gas and dust into an expanding super bubble.

    Study of the symbiosis between the supermassive black hole and the galaxy is a key to understanding the evolution of the most massive galaxies. Ultraviolet emission from the black hole’s accretion disk can inhibit star formation temporarily, by ionizing the Interstellar medium, and the great outflows of gas towards the black hole can lead to permanent inhibition of star formation.

    1
    Schematic of the expanding gas Bubble, over a radio image of the full field of TXS 0828+193. Credit: Morais et al. 2017

    More information: S. G. Morais et al. Ionization and feedback in Lyα haloes around two radio galaxies at∼ 2.5, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stw2926

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Institute of Astrophysics and Space Sciences

    Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

     
    • RIcardo Reis 5:49 am on March 31, 2017 Permalink | Reply

      This research was NOT made by Instituto de Astrofisica de Canarias in Spain, but by Instituto de Astrofísica e Ciências do Espaço in Portugal.
      In fact, if you check the paper (https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stw2926), this research has no one from IAC.

      Like

    • richardmitnick 7:47 am on March 31, 2017 Permalink | Reply

      Thank you very much for the correction. I did not read far enough and got myself stuck in the acronym. I believe that I have sufficiently corrected the post. Please look at it again and let me know what you think.

      Thanks again for your help.

      Like

  • richardmitnick 6:50 pm on March 7, 2017 Permalink | Reply
    Tags: Keck Observatory, , Oort cloud comet C/2014 Q2 also called Lovejoy   

    From Keck: “NASA Study Using Keck Telescope Hints at Possible Change in Water ‘Fingerprint’ of Comet” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    March 6, 2017.
    Contact:
    Elizabeth Zubritsky
    NASA Goddard Space Flight Center
    elizabeth.a.zubritsky@nasa.gov

    Rich Matsuda
    W. M. Keck Observatory
    (808) 881-3822
    communications@keck.hawaii.edu

    1
    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun. Credit: Courtesy of Damian Peach

    A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.

    Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.

    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.

    The team focused on Lovejoy’s water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the “D” in HDO. From these measurements, the researchers calculated the D-to-H ratio – a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system. Researchers also use the D-to-H value to try to understand how much of Earth’s water may have come from comets versus asteroids.

    The scientists compared their findings from the Keck observations with another team’s observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference: After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant. This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

    “The change we saw with this comet is surprising, and highlights the need for repeated measurements of D-to-H in comets at different positions in their orbits to understand all the implications,” said Lucas Paganini, a researcher with the Goddard Center for Astrobiology and lead author of the study, available online in the Astrophysical Journal Letters.

    Changes in the water production are expected as comets approach the sun, but previous understanding suggested that the release of these different forms of water normally rise or fall more-or-less together, maintaining a consistent D-to-H value. The new findings suggest this may not be the case.

    “If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth’s water compared to asteroids,” Paganini said, “especially, if these are based on a single measurement of the D-to-H value in cometary water.”

    The production of HDO in comets has historically been difficult to measure, because HDO is a much less abundant form of water. Lovejoy, for example, released on the order of 1,500 times more H2O than HDO. Lovejoy’s brightness made it possible to measure HDO when the comet passed near Earth, and the improved detectors that are being installed in some ground-based telescopes will permit similar measurements in fainter comets in the future.

    The apparent change in Lovejoy’s D-to-H may be caused by the higher levels of energetic processes – such as radiation near the sun – that might have altered the characteristics of water in surface layers of the comet. In this case, a different D-to-H value might indicate that the comet has “aged” into a different stage of its lifecycle. Alternatively, prior results might have ignored possible chemical alteration occurring in the comet’s tenuous atmosphere.

    “Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun,” said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author of the study. “The infrared technique provides a snapshot of the comet’s output by measuring the production of H2O and HDO simultaneously. This is especially important because it eliminates many sources of systematic uncertainty.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

     
  • richardmitnick 1:43 pm on January 31, 2017 Permalink | Reply
    Tags: , , , , , Keck Observatory, vortex coronagraph   

    From Caltech: “Keck Observatory’s New Planet Imager Delivers First Science” 

    Caltech Logo
    Caltech
    01/30/2017

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    An image of the brown dwarf HIP 79124 B, which is separated from its host star by 23 astronomical units (an astronomical unit is the distance between our sun and Earth). The vortex coronagraph was used to suppress the much brighter host star, allowing its dim companion to be imaged for the first time. Credit: NASA/JPL-Caltech

    2
    An image of the dusty disk of planetary material surrounding the star called HD 141569, located 380 light-years away. It was taken using the vortex coronagraph on the W.M. Keck Observatory. The vortex suppressed the star in the center, revealing light from the innermost ring of planetary material around the star (blue). The disk is made of olivine particles and extends from 23 to 70 astronomical units from the star—around where the outer planets lie in our solar system. Credit: NASA/JPL-Caltech

    3
    A picture of a vortex mask (left), which is made out of synthetic diamond. The mask is 1 centimeter in diameter and 0.3 millimeters thick. The vortex’s engraved pattern of grooves is very similar to a compact disk, making it look like a miniature version of a CD. The image at right zooms into the mask’s center with a scanning electron microscope. This view reveals the microstructure of the mask, highlighting its concentric grooves, which have a thickness of about 1/100th that of a human hair. No image credit.

    A new instrument on the W. M. Keck Observatory in Hawaii has delivered its first images, showing a ring of planet-forming dust around a star and, separately, a cool star-like body, called a brown dwarf, lying near to its companion star.

    The device, called the vortex coronagraph, was recently installed inside the Near Infrared Camera 2 (NIRC2), the workhorse infrared imaging camera at Keck. The vortex coronagraph has the potential to image planetary systems and brown dwarfs closer to their host stars than was possible previously. It was invented in 2005 by Dimitri Mawet while he was at the University of Liège in Belgium. Mawet is currently associate professor of astronomy at Caltech and a senior research scientist at NASA’s Jet Propulsion Laboratory (JPL). The Keck vortex coronagraph was built by the University of Liège, Uppsala University in Sweden, JPL, and Caltech.

    “The vortex coronagraph allows us to peer into the regions around stars where giant planets like Jupiter and Saturn supposedly form,” says Mawet. “Before now, we were only able to image gas giants that are born much farther out. With the vortex, we will be able to see planets orbiting as close to their stars as Jupiter is to our sun, or about two to three times closer than what was possible before.”

    The new vortex results are presented in two papers, both published in the January 2017 issue of The Astronomical Journal. One study, led by Gene Serabyn of JPL, the overall lead of the Keck vortex project, presents the first direct image of the brown dwarf called HIP 79124 B. This brown dwarf is located 23 astronomical units from a star in a nearby star-forming region called Scorpius-Centaurus (an astronomical unit is the distance between our sun and Earth).

    “The ability to see very close to stars also allows us to search for planets around more distant stars, where the planets and stars would appear closer together. Having the ability to survey distant stars for planets is important for catching planets still forming,” says Serabyn, who also led team that tested a predecessor of the vortex device at the Hale Telescope at Caltech’s Palomar Observatory near San Diego.

    Caltech Palomar 200 inch Hale Telescope, at Mt Wilson, CA, USA
    Caltech Palomar 200 inch Hale Telescope interior
    Caltech Palomar 200 inch Hale Telescope, at Mt Wilson, CA, USA

    In 2010, the team took images of three planets orbiting in the distant reaches of the star system called HR 8799.

    The second vortex study, led by Mawet, presents an image of the innermost of three rings of dusty planet-forming material around the young star called HD 141569 A. The results, when combined with infrared data from NASA’s Spitzer and WISE missions, and the European Space Agency’s Herschel mission, reveal that the star’s planet-forming material is made up of pebble-size grains of olivine, one of the most abundant silicates in Earth’s mantle. In addition, the data show that the temperature of the innermost ring imaged by the vortex is around 100 Kelvin (or minus 173 Celsius degrees), a bit warmer than our asteroid belt.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    NASA/WISE Telescope
    NASA/WISE Telescope

    ESA/Herschel spacecraft
    “ESA/Herschel spacecraft

    “The three rings around this young star are nested like Russian dolls and undergoing dramatic changes reminiscent of planetary formation,” says Mawet. “We have shown that silicate grains have agglomerated into pebbles, which are the building blocks of planet embryos.”

    How the vortex sees planets

    The first science images and results from the vortex instrument demonstrate its ability to image planet-forming regions hidden under the glare of stars. Stars outshine planets by a factor of a few thousands to a few billions, making the dim light of planets very difficult to see. The closer a planet is to its star, the more difficult it is to image. To deal with this challenge, researchers have invented Instruments called coronagraphs, which typically use tiny masks to block the starlight, much like blocking the bright sun with your hand or a car visor to see better.

    What makes the vortex coronagraph unique is that it does not block the starlight with a mask, but instead redirects the light away from the detectors using a technique in which light waves are combined and canceled out. Because the vortex doesn’t require a mask, it has the advantage of taking images of regions closer to stars than other coronagraphs. Mawet likens the process to the eye of a storm.

    “The instrument is called a vortex coronagraph because the starlight is centered on an optical singularity, which creates a dark hole at the location of the image of the star,” says Mawet. “Hurricanes have a singularity at their centers where the wind speeds drop to zero—the eye of the storm. Our vortex coronagraph is basically the eye of an optical storm where we send the starlight.”

    A team at the University of Liège, led by Olivier Absil, designed a portion of the Keck vortex coronagraph called the phase mask, which consists of concentric microstructures that force the starlight waves to swirl about the mask’s center, creating the vortex singularity. This mask was forged at Uppsala University by Mikael Karlsson and his team, who etched the concentric microstructures into synthetic diamond. The etching is done in a plasma chamber where the diamond is bombarded by argon and oxygen ions, ripping the carbon atoms out of the diamond crystal.

    The vortex was installed at Keck in the spring of 2015 by Keith Matthews, chief instrument scientist at Caltech, who has worked on dozens of astronomical instruments in his more than 50-year career at the Institute. The coronagraph was optimized and is operated with the help of the Keck Observatory staff. “Once the device is in there, users can operate it remotely from the base of the mountain or even from their home universities,” says Matthews.

    What’s next for the vortex

    In the future, the vortex will look at many more young planetary systems, in particular planets near the “ice lines,” which are the region around a star where temperatures have become cold enough for volatile molecules, such as water, methane, and carbon dioxide, to condense into solid icy grains. Ice lines are thought to delineate the transition between rocky planets and gas giants.

    Surveys of the ice-line region by the vortex coronagraph will help answer ongoing puzzles about a class of hot, giant planets found extremely close to their stars—the “hot Jupiters” and “hot Neptunes.” Did these planets first form close to the ice lines and migrate in, or did they form in situ, right next to their star? “With a bit of luck, we might catch planets in the process of migrating through the planet-forming disk, by looking at these very young objects,” says Mawet.

    This month, a privately funded project called Breakthrough Initiatives announced that it is partnering with the European Southern Observatory to use similar vortex technology to find and image a putative Earth-like planet in the nearby Alpha Centauri star system. What’s more, results from Keck’s vortex coronagraph will help with a planet imager planned for the future Thirty Meter Telescope and with proposed NASA space missions, such as the Habitable Exoplanet Imaging Mission (HabEx) and the Large UV/Optical/IR Surveyor (LUVOIR), which would use next-generation vortex coronagraphs currently being designed in Mawet’s group at Caltech.

    The challenge of these facilities is to image planets even closer to their stars than those at the ice line, which includes Earth-like rocky planets. When combined with data from spectrograph instruments, which can identify molecules in planets’ atmospheres, the images could help astronomers identify possible signs of life.

    “The power of the vortex lies in its ability to image planets very close to their star, something that we can’t do for Earth-like planets yet,” says Serabyn. “The vortex coronagraph may be key to taking the first images of a pale blue dot like our own.”

    The Keck Observatory is managed by Caltech and the University of California. In 1996, the NASA joined as a one-sixth partner in the Keck Observatory. JPL is managed by Caltech for NASA.

    See the full article here .

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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

     
  • richardmitnick 10:59 am on October 22, 2016 Permalink | Reply
    Tags: , , Io's volcanism, Keck Observatory   

    From Keck: “Long-Term, Hi-Res Tracking of Eruptions on Jupiter’s Moon Io” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    October 20, 2016
    SCIENCE CONTACT
    Katherine de Kleer
    kdekleer@berkeley.edu

    Imke de Pater
    imke@berkeley.edu

    MEDIA CONTACT
    Bill Brown
    W. M. Keck Observatory
    (808) 881-3514

    1
    All hot spot detections from August 2013 through December 2015 shown on a full map of Io. Each circle represents a new detection; the size of the circle corresponds logarithmically to the intensity, and more opaque regions are where a hot spot was detected multiple times. The color and symbol indicate the type of eruption, following the legend. Loki Patera is at 310 West, 10 North and KurdalagonPatera is at 220 West, 50 South. Credit: Katherine de Kleer and Imke de Pater, UC Berkeley.

    Jupiter’s moon Io continues to be the most volcanically active body in the solar system, as documented by the longest series of frequent, high-resolution observations of the moon’s thermal emission ever obtained.

    Using near-infrared adaptive optics on two of the world’s largest telescopes– the 10-meter Keck II and the 8-meter Gemini North, both located near the summit of the dormant volcano Maunakea in Hawaii – University of California, Berkeley astronomers tracked 48 volcanic hotspots on the surface over a period of 29 months from August 2013 through the end of 2015.

    Gemini/North telescope at Mauna Kea, Hawaii, USA
    Gemini/North telescope at Mauna Kea, Hawaii, USA

    2
    Images of Io at different near-infrared wavelengths; the name of the filter is indicated in the black box at the start of each section. The bright spots are thermal emissions from Io’s myriad volcanoes. Note the increasing number of hot spots detected at longer wavelengths, i.e. towards the bottom of the figure. Credit: Katherine de Kleer and Imke de Pater, UC Berkeley

    Without adaptive optics – a technique that removes the atmospheric blur to sharpen the image – Io is merely a fuzzy ball. Adaptive optics can separate features just a few hundred kilometers apart on Io’s 3,600-kilometer-diameter surface.

    “On a given night, we may see half a dozen or more different hot spots,” said Katherine de Kleer, a UC Berkeley graduate student who led the observations. “Of Io’s hundreds of active volcanoes, we have been able to track the 50 that were the most powerful over the past few years.”

    She and Imke de Pater, a UC Berkeley professor of astronomy and of earth and planetary science, observed the heat coming off of active eruptions as well as cooling lava flows and were able to determine the temperature and total power output of individual volcanic eruptions.They tracked their evolution over days, weeks and sometimes even years.

    Interestingly, some of the eruptions appeared to progress across the surface over time, as if one triggered another 500 kilometers away.

    “While it stretches the imagination to devise a mechanism that could operate over distances of 500 kilometers, Io’s volcanism is far more extreme than anything we have on Earth and continues to amaze and baffle us,” de Kleer said.

    De Kleer and de Pater will discuss their observations at a media briefing on Oct. 20 during a joint meeting of the American Astronomical Society’s Division for Planetary Sciences and the European Planetary Science Congress in Pasadena, California. Papers describing the observations have been accepted for future publication by the journal Icarus.

    Tidal heating

    Io’s intense volcanic activity is powered by tidal heating — heating from friction generated in Io’s interior as Jupiter’s intense gravitational pull changes by small amounts alongIo’s orbit. Models for how this heating occurs predict that most of Io’s total volcanic power should be emitted either near the poles or near the equator, depending on the model, and that the pattern should be symmetric between the forward- and backward-facing hemispheres in Io’s orbit (that is, at longitudes 0-180 degrees versus 180-360 degrees).

    That’s not what they saw. Over the observational period, August 2013 through December 2015, the team obtained images of Io on 100 nights. Though they saw a surprising number of short-lived but intense eruptions that appeared suddenly and subsided in a matter of days, every single one took place on the trailing face of Io (180-360 degrees longitude) rather than the leading face, and at higher latitudes than more typical eruptions.

    “The distribution of the eruptions is a poor match to the model predictions,” de Kleer said, “but future observations will tell us whether this is just because the sample size is too small, or because the models are too simplified. Or perhaps we’ll learn that local geological factors play a much greater role in determining where and when the volcanoes erupt than the physics of tidal heating do.”

    One key target of interest was Io’s most powerful persistent volcano, Loki Patera, which brightens by more than a factor of 10 every 1-2 years. A patera is an irregular crater, usually volcanic.

    Many scientists believe that Loki Patera is a massive lava lake, and that these bright episodes represent its overturning crust, like that seen in lava lakes on Earth. In fact, the heat emissions from Loki Patera appear to travel around the lake during each event, as if from a wave moving around a lake triggering the destabilization and sinking of portions of crust. Prior to 2002, this front seemed to travel around the cool island in the center of the lake in a counter-clockwise direction.

    After an apparent cessation of brightening events after 2002, de Pater observed renewed activity in 2009.

    “With the renewed activity, the waves traveled clockwise around the lava lake,” she noted.

    Another volcano, Kurdalagon Patera, produced unusually hot eruptions twice in the spring of 2015, coinciding with the brightening ofan extended cloud of neutral material that orbits Jupiter.This provides circumstantial evidence that eruptions on the surface are the source of variability in this neutral cloud, though it’s unclear why other eruptions were not also associated with brightening, de Kleer said.

    De Kleer noted that the Keck and Gemini telescopes, both atop the dormant volcano Maunakea, complement one another. Gemini North’s queue scheduling allowed more frequent observations – often several a week – while Keck’s instruments are sensitive also to longer wavelengths (5 microns), showing cooler features such as older lava flows that are invisible in the Gemini observations.

    The astronomers are continuing their frequent observations of Io, providing a long-term database of high spatial resolution images that not even Galileo, which orbited Jupiter for eight years, was able to achieve.

    The work is supported by a grant from the National Science Foundation (AST-1313485)and de Kleer’s NSF Graduate Research Fellowship(DGE-1106400).

    Link to science paper.
    Link to science paper.

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
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  • richardmitnick 1:10 pm on September 13, 2016 Permalink | Reply
    Tags: , , Explaining Why the Universe Can Be Transparent, Keck Observatory,   

    From UC Riverside: “Explaining Why the Universe Can Be Transparent” 

    UC Riverside bloc

    UC Riverside

    September 12, 2016
    Sean Nealon

    1
    Reionization as illustrated by data from the Hubble and Chandra space telescopes. Credit: NASA/CXC/M.Weiss.

    Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.

    The study led by Naveen Reddy, an assistant professor in the Department of Physics and Astronomy at UC Riverside, marks the first quantitative study of how the gas content within galaxies scales with the amount of interstellar dust.

    This analysis shows that the gas in galaxies is like a “picket fence,” where some parts of the galaxy have little gas and are directly visible, whereas other parts have lots of gas and are effectively opaque to ionizing radiation. The findings were just published in The Astrophysical Journal.

    The ionization of hydrogen is important because of its effects on how galaxies grow and evolve. A particular area of interest is assessing the contribution of different astrophysical sources, such as stars or black holes, to the budget of ionizing radiation.

    Most studies suggest that faint galaxies are responsible for providing enough radiation to ionize the gas in the early history of the universe. Moreover, there is anecdotal evidence that the amount of ionizing radiation that is able to escape from galaxies depends on the amount of hydrogen within the galaxies themselves.

    The research team led by Reddy developed a model that can be used to predict the amount of escaping ionizing radiation from galaxies based on straightforward measurements on how “red,” or dusty, their spectra appear to be.

    Alternatively, with direct measurements of the ionizing escape fraction, their model may be used to constrain the intrinsic production rate of ionizing photons at around two billion years after the Big Bang.

    These practical applications of the model will be central to the interpretation of escaping radiation during the cosmic “dark ages,” a topic that is bound to flourish with the coming of 30-meter telescopes, which will allow for research unfeasible today, and the James Webb Space Telescope, NASA’s next orbiting observatory and the successor to the Hubble Space Telescope.

    The research ties back to some 400,000 years after the Big Bang, when the universe entered the cosmic “dark ages,” where galaxies and stars had yet to form amongst the dark matter, hydrogen and helium.

    A few hundred million years later, the universe entered the “Epoch of Reionization,” where the gravitational effects of dark matter helped hydrogen and helium coalesce into stars and galaxies. A great amount of ultraviolet radiation (photons) was released, stripping electrons from surrounding neutral environments, a process known as “cosmic reionization.”

    Reionization, which marks the point at which the hydrogen in the Universe became ionized, has become a major area of current research in astrophysics. Ionization made the Universe transparent to these photons, allowing the release of light from sources to travel mostly freely through the cosmos.

    The data for this research was acquired through the low resolution imaging spectrograph on the W.M. Keck Observatory.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory Interior
    Keck Observatory, Mauna Kea, Hawaii, USA

    The collaborators of this research are Charles Steidel (Caltech), Max Pettini (University of Cambridge), Milan Bogosavljevic (Astronomical Observatory, Belgrade) and Alice Shapley (UCLA).

    The papers are Spectroscopic Measurements of the Far-Ultraviolet Dust Attenuation Curve at z~3 and The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift.

    See the full article here .

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    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 9:19 am on September 7, 2016 Permalink | Reply
    Tags: Astronomers Discover Rare Fossil Relic of Early Milky Way, , , , Keck Observatory, , Terzan 5   

    From ESO and Hubble: “Astronomers Discover Rare Fossil Relic of Early Milky Way” 

    ESO 50 Large

    European Southern Observatory

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    7 September 2016
    Francesco Ferraro
    Università degli Studi di Bologna
    Bologna, Italy
    Tel: +39 051 20 9 5774
    Email: francesco.ferraro3@unibo.it

    Davide Massari
    INAF – Osservatorio Astronomico di Bologna
    Bologna, Italy
    Tel: +51 2095318
    Email: davide.massari@oabo.inaf.it

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Tel: +49 176 62397500
    Email: mjaeger@partner.eso.org

    1

    Using ESO’s Very Large Telescope and other telescopes a fossilised remnant of the early Milky Way harbouring stars of hugely different ages has been revealed by an international team of astronomers. This stellar system resembles a globular cluster, but is like no other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way and bridges the gap in understanding between our galaxy’s past and its present.

    Terzan 5, 19 000 light-years from Earth in the constellation of Sagittarius (the Archer) and in the direction of the galactic centre, has been classified as a globular cluster for the forty-odd years since its detection. Now, an Italian-led team of astronomers have discovered that Terzan 5 is like no other globular cluster known.

    The team scoured data from the Multi-conjugate Adaptive Optics Demonstrator [MAD] [1], installed at the Very Large Telescope, as well as from a suite of other ground-based and space telescopes [2]. They found compelling evidence that there are two distinct kinds of stars in Terzan 5 which not only differ in the elements they contain, but have an age-gap of roughly 7 billion years [3].

    ESO MAD bench
    ESO MAD

    The ages of the two populations indicate that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation. “This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study, from INAF, Italy, and the University of Groningen, Netherlands.

    Its unusual properties make Terzan 5 the ideal candidate for a living fossil from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.

    “We think that some remnants of these gaseous clumps could remain relatively undisrupted and keep existing embedded within the galaxy,” explains Francesco Ferraro from the University of Bologna, Italy, and lead author of the study. “Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way.”

    While the properties of Terzan 5 are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way. These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

    This assumption is strengthened by the original mass of Terzan 5 necessary to create two stellar populations: a mass similar to the huge clumps which are assumed to have formed the bulge during galaxy assembly around 12 billion years ago. Somehow Terzan 5 has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

    “Some characteristics of Terzan 5 resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation,“ continues Ferraro.

    Hence, this discovery paves the way for a better and more complete understanding of galaxy assembly. “Terzan 5 could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” explains Ferraro while commenting on the importance of the discovery. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivaled view into the complicated history of the Milky Way.
    Notes

    [1] The Multi-Conjugate Adaptive Optics Demonstrator (MAD) is a prototype multi-conjugate adaptive optics system which aims to demonstrate the feasibility of different MCAO reconstruction techniques in the framework of the E-ELT concept and the second generation VLT Instruments.

    [2] The researchers also used data from the Advanced Camera for Surveys [ACS]and the Wide Field Camera 3 [WFC3] on board the NASA/ESA Hubble Space Telescope and NIRC2 (the Near-Infrared Camera, second generation) at the W. M. Keck Observatory.

    NASA/ESA Hubble ACS
    “NASA/ESA Hubble ACS

    NASA Hubble WFC3
    NASA/ESA Hubble WFC3

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory, Mauna Kea, Hawaii, USA

    Keck NIRC2 Camera
    Keck NIRC2 Camera

    [3] The two detected stellar populations have ages of 12 billion years and 4.5 billion years respectively.

    More information

    Link to science paper.

    The team is composed of F. R. Ferraro (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy) , D. Massari (INAF – Osservatorio Astronomico di Bologna, Italy & Kapteyn Astronomical Institute, University of Groningen, Netherlands), E. Dalessandro (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy; INAF – Osservatorio Astronomico di Bologna, Italy) , B. Lanzoni (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy), L. Origlia (INAF – Osservatorio Astronomico di Bologna, Italy), R. M. Rich (Department of Physics and Astronomy, University of California, Los Angeles, USA) and A. Mucciarelli (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy).

    See the full ESO article here .

    See the full Hubble article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

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  • richardmitnick 1:57 pm on August 25, 2016 Permalink | Reply
    Tags: , , Dark galaxy Dragonfly 44, , , , Keck Observatory   

    From Keck: “Scientists Discover Massive Galaxy Made of 99.99 Percent Dark Matter” 

    Keck Observatory

    August 25, 2016

    SCIENCE CONTACT
    Pieter van Dokkum
    Yale University
    New Haven, Connecticut, USA
    Tel: +1-203-432-3000
    E-mail: pieter.vandokkum@yale.edu

    MEDIA CONTACT

    Steve Jefferson
    W. M. Keck Observatory
    (808) 881-3827
    sjefferson@keck.hawaii.edu

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    1
    The dark galaxy Dragonfly 44. The image on the left is a wide view of the galaxy taken with the Gemini North telescope using the Gemini Multi-Object Spectrograph (GMOS). The close-up on the right is from the same very deep image, revealing the large, elongated galaxy, and halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy. Dragonfly 44 is very faint for its mass, and consists almost entirely of Dark Matter. Credit: Pieter van Dokkum, Roberto Abraham, Gemini; Sloan Digital Sky Survey.

    Using the world’s most powerful telescopes, an international team of astronomers has discovered a massive galaxy that consists almost entirely of Dark Matter. Using the W. M. Keck Observatory and the Gemini North telescope – both on Maunakea, Hawaii – the team found a galaxy whose mass is almost entirely Dark Matter. The findings are being published in The Astrophysical Journal Letters today.

    Gemini/North telescope at Manua Kea, Hawaii, USA
    GEMINI/North GMOS
    Gemini/North telescope at Manua Kea, Hawaii, USA; GEMINI/North GMOS

    Even though it is relatively nearby, the galaxy, named Dragonfly 44, had been missed by astronomers for decades because it is very dim. It was discovered just last year when the Dragonfly Telephoto Array observed a region of the sky in the constellation Coma.

    U Toronto Dunlap Dragonfly telescope Array
    U Toronto Dunlap Dragonfly telescope Array

    Upon further scrutiny, the team realized the galaxy had to have more than meets the eye: it has so few stars that it quickly would be ripped apart unless something was holding it together.

    To determine the amount of Dark Matter in Dragonfly 44, astronomers used the DEIMOS instrument installed on Keck II to measure the velocities of stars for 33.5 hours over a period of six nights so they could determine the galaxy’s mass.

    Keck/DEIMOS
    Keck/DEIMOS

    The team then used the Gemini Multi-Object Spectrograph (GMOS) on the 8-meter Gemini North telescope on Maunakea in Hawaii to reveal a halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy.

    “Motions of the stars tell you how much matter there is, van Dokkum said. “They don’t care what form the matter is, they just tell you that it’s there. In the Dragonfly galaxy stars move very fast. So there was a huge discrepancy: using Keck Observatory, we found many times more mass indicated by the motions of the stars, then there is mass in the stars themselves.”

    The mass of the galaxy is estimated to be a trillion times the mass of the Sun – very similar to the mass of our own Milky Way galaxy. However, only one hundredth of one percent of that is in the form of stars and “normal” matter; the other 99.99 percent is in the form of dark matter. The Milky Way has more than a hundred times more stars than Dragonfly 44.

    Finding a galaxy with the mass of the Milky Way that is almost entirely dark was unexpected. “We have no idea how galaxies like Dragonfly 44 could have formed,” Roberto Abraham, a co-author of the study, said. “The Gemini data show that a relatively large fraction of the stars is in the form of very compact clusters, and that is probably an important clue. But at the moment we’re just guessing.”

    “This has big implications for the study of Dark Matter,” van Dokkum said. “It helps to have objects that are almost entirely made of Dark Matter so we don’t get confused by stars and all the other things that galaxies have. The only such galaxies we had to study before were tiny. This finding opens up a whole new class of massive objects that we can study.

    “Ultimately what we really want to learn is what Dark Matter is,” van Dokkum said. “The race is on to find massive dark galaxies that are even closer to us than Dragonfly 44, so we can look for feeble signals that may reveal a Dark Matter particle.”

    Additional co-authors are Shany Danieli, Allison Merritt, and Lamiya Mowla of Yale, Jean Brodie of the University of California Observatories, Charlie Conroy of Harvard, Aaron Romanowsky of San Jose State University, and Jielai Zhang of the University of Toronto.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    DEIMOS (DEep Imaging Multi-Object Spetrograph) boasts the largest field of view (16.7 arcmin by 5 arcmin) of any of the Keck Observatory instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
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