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  • richardmitnick 5:06 pm on February 7, 2019 Permalink | Reply
    Tags: Adaptive Optics, , , , Bubble Blowing Black Hole Jet’s Impact on Galactic Evolution, , Galaxy MCG 5-4-18, , Shocked molecular and ionized gas resulting from a jet-driven feedback coming from the center of a compact radio galaxy   

    From Gemini Observatory: “Bubble Blowing Black Hole Jet’s Impact on Galactic Evolution” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    February 6, 2019

    Astronomers using adaptive optics on the 8-meter Gemini North telescope [see below] have resolved, for the first time in near-infrared light, a giant elliptical galaxy with a young radio jet down to unprecedented scales. The observations also show how the jets, emanating from a black hole at the center of this galaxy, are heating the interstellar medium, which may have a significant impact on the evolution of the host galaxy.

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    Figure 1. The contours in this image show the flux of the molecular (blue) and ionized (green) emission detected by Gemini/NIFS overlaid on the Hubble Space Telescope image. While the ionized emission is centrally concentrated, the molecular emission extends further to the north and south of the nucleus, suggesting it is part of the massive circumnuclear disk.

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    Figure 2. The paler green region represents low surface-brightness jet plasma filling the jet-driven bubble, which drives a shock into the surrounding gas and causes ionized emission (dark red). Jet plasma also percolates radially through channels in the clumpy circumnuclear disk (blue), driving shocks into neutral gas and causing molecular emission. The pale blue circles represent clouds of neutral gas. The line of sight is indicated by the dashed line; the disk is inclined such that the Western lobe is partially obscured by the disk, whereas the Eastern lobe is completely obscured by the disk.

    Using adaptive optics (AO) and near-infrared imaging on the 8-meter Gemini North telescope in Hawai‘i, a team of astronomers lead by PhD student Henry Zovaro (The Australian National University) report the discovery of shocked molecular and ionized gas resulting from a jet-driven feedback coming from the center of a compact radio galaxy. The discovery offers important information on how such activity can influence the evolution of its host galaxy.

    The galaxy, which goes by the name MCG 5-4-18, is a nearby giant elliptical galaxy harboring a young compact radio source, known as 4C 31.04, powered by a supermassive black hole with powerful jets. The radio source has two edge-brightened lobes (separated by about 320 thousand light years) that may only be a few thousand years old. The researchers demonstrate that 4C 31.04 is currently in a early phase of jet evolution, called the “energy-driven bubble” stage, where the jets inflate a bubble that expands out of the plane of the disk and interacts strongly with the galaxy’s interstellar medium.

    The relative closeness of 4C 31.04 (about 270 megaparsecs, or 900 million light years) enabled the team to probe the interactions between the radio jet and the surrounding interstellar medium using H- and K-band infrared observations obtained with Gemini’s Near-infrared Integral Field Spectrometer (NIFS). “This is the first time that observations in optical or near-infrared have resolved the host galaxy down to scales comparable to the size of the radio lobes,” Zovaro says.

    The shocked gases discovered by the team are important because they serve as tracers of the energetic interactions between the jet and the surrounding material. The study uncovered two different phases of heated gas in the circumnuclear disk: 1) the innermost parts of the disk form a jet-blown bubble of ionized gas 1,300 light years in diameter; and 2) the outer region is comprised of very warm molecular gas, around 1,000 Kelvin, reaching distances greater than 3,000 light years (Figure 1).

    Zovaro explains how the two phases are related (Figure 2): “The bubble pushes a forward shock into the interstellar medium, giving rise to the ionized gas. Jet plasma also percolates into the circumnuclear disk, shocking and radially accelerating gas clouds, warming the interstellar medium and giving rise to the molecular emission.” Zovaro suggests that the warm molecular gas is part of the extended structure of the massive circumnuclear disk. Because the molecular gas cools rapidly, he says, this phase is very short-lived, and only represents a very small fraction of the total warm mass.

    “All of the images of the radio emission that are currently available only show the jets reaching distances of about 100 parsec from the nucleus, whereas our NIFS data show that, in fact, the jet’s plasma reaches all the way out to approximately one kiloparsec in the disk,” Zovaro says, noting that deeper radio observations would be required to detect the jets at such radii. “This is an important finding,” he adds, “because it shows that we can’t simply ignore the effects of radio jets upon the evolution of their host galaxy, even if the radio source appears to be very small.”

    The Gemini observations are featured in the accepted paper in the Monthly Notices of the Royal Astronomical Society.

    See the full article here .


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    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Gemini/South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

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    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

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  • richardmitnick 6:20 pm on November 20, 2018 Permalink | Reply
    Tags: Adaptive Optics, , , , , , Exoplanet Stepping Stones, , HR 8799 c—a young giant gas planet   

    From Caltech: “Exoplanet Stepping Stones” 

    Caltech Logo

    From Caltech

    11/20/2018

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

    Researchers are perfecting technology to one day look for signs of alien life.

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    Artwork of exoplanet HR 8799 c
    Credit: W. M. Keck Observatory/Adam Makarenko


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    Astronomers have gleaned some of the best data yet on the composition of a planet known as HR 8799 c—a young giant gas planet about seven times the mass of Jupiter that orbits its star every 200 years. The team used state-of-the-art instrumentation at the W. M. Keck Observatory to confirm the existence of water in the planet’s atmosphere as well as a lack of methane. While other researchers had previously made similar measurements of this planet, these new, more robust data demonstrate the power of combining high-resolution spectroscopy with a technique known as adaptive optics, which corrects for the blurring effect of Earth’s atmosphere.

    Keck Adaptive Optics

    “This type of technology is exactly what we want to use in the future to look for signs of life on an Earth-like planet. We aren’t there yet, but we are marching ahead,” says Dimitri Mawet, an associate professor of astronomy at Caltech and a research scientist at JPL, which Caltech manages for NASA. He is co-author of a new paper on the findings accepted for publication in The Astronomical Journal [link is below]. The lead author is Ji Wang, formerly a postdoctoral scholar at Caltech and now an assistant professor at The Ohio State University.

    Taking pictures of planets that orbit other stars—exoplanets—is a formidable task. Light from the host stars far outshines the planets, making them difficult to see. More than a dozen exoplanets have been directly imaged so far, including HR 8799 c and three of its planetary companions. In fact, HR 8799 is the only multiple-planet system to have its picture taken. Once an image is obtained, astronomers can use instruments, called spectrometers, to break apart the planet’s light, like a prism turning sunlight into a rainbow, thereby revealing the fingerprints of chemicals. So far, this strategy has been used to learn about the atmospheres of several giant exoplanets.

    The next step is to do the same thing but for smaller planets that are closer to their stars (the closer a planet is to its star and the smaller its size, the harder is it to see). The ultimate goal is to look for chemicals in the atmospheres of Earth-like planets that orbit in the star’s “habitable zone,” including any biosignatures that might indicate life, such as water, oxygen, and methane. Mawet’s group hopes to do just this with an instrument on the upcoming Thirty Meter Telescope, a giant telescope being planned for the late 2020s by several national and international partners, including Caltech.

    But for now, the scientists are perfecting their technique using Keck—and, in the process, learning about the compositions and dynamics of giant planets.

    “Right now, with Keck, we can already learn about the physics and dynamics of these giant exotic planets, which are nothing like our own solar system planets,” says Wang.

    In the new study, the researchers used an instrument on Keck called NIRSPEC (near-infrared cryogenic echelle spectrograph), a high-resolution spectrometer that works in infrared light.

    Keck Nirspec on Keck 2

    They coupled the instrument with adaptive optics, a method for creating crisper pictures using a guide star in the sky as a means to measure and correct the blurring turbulence of Earth’s atmosphere.

    This is the first time the technique has been demonstrated on directly imaged planets using what is known as the L-band, a type of infrared light with a wavelength of around 3.5 micrometers. This region of the electromagnetic spectrum contains many detailed chemical fingerprints.

    “The L-band has gone largely overlooked before because the sky is brighter at this wavelength,” says Mawet. “If you were an alien with eyes tuned to the L-band, you’d see an extremely bright sky. It’s hard to see exoplanets through this veil.”

    The researchers say that the addition of adaptive optics made the L-band more accessible for the study of the planet HR 8799 c. In their study, they made the most precise measurements yet of the atmospheric constituents of the planet, confirming it has water and lacks methane as previously thought.

    “We are now more certain about the lack of methane in this planet,” says Wang. “This may be due to mixing in the planet’s atmosphere. The methane, which we would expect to be there on the surface, could be diluted if the process of convection is bringing up deeper layers of the planet that don’t have methane.”

    The L-band is also good for making measurements of a planet’s carbon-to-oxygen ratio—a tracer of where and how a planet forms. Planets form out of swirling disks of material around stars, specifically from a mix of hydrogen-, oxygen-, and carbon-rich molecules, such as water, carbon monoxide, and methane. These molecules freeze out of the planet-forming disks at different distances from the star—at boundaries called snowlines. By measuring a planet’s carbon-to-oxygen ratio, astronomers can thus learn about its origins.

    Mawet’s team is now gearing up to turn on their newest instrument at Keck, called the Keck Planet Imager and Characterizer (KPIC). The team will also use adaptive optics-aided high-resolution spectroscopy that can see planets that are fainter than HR 8799 c and closer to their stars.

    “KPIC is a springboard to our future Thirty Meter Telescope instrument,” says Mawet.

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level

    “For now, we are learning a great deal about the myriad ways in which planets in our universe form.”

    The Astronomical Journal study, titled, “Detecting Water in the Atmosphere of HR 8799 c with L-band High Dispersion Spectroscopy Aided By Adaptive Optics,” was funded by Caltech. Other authors include Jonathan Fortney and Callie Hood of UC Santa Cruz; Caroline Morley of Harvard University; and Björn Benneke of University of Montreal.

    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.”

    Caltech campus


    Caltech campus

     
  • richardmitnick 4:11 pm on October 8, 2018 Permalink | Reply
    Tags: Adaptive Optics, , , , , Excitation of sodium atoms in the mesosphere creates an artificial point of light at a precise known location and elevation, Laser guide star systems, Laser Guide Stars Measure Geomagnetism,   

    From Optics & Photonics: “Laser Guide Stars Measure Geomagnetism” 

    From Optics & Photonics

    08 October 2018
    Stewart Wills

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    Polar mesospheric clouds. [Image: NASA]

    Laser-created “guide stars” form a key part of the adaptive-optics (AO) techniques that have revolutionized astronomy, by setting up ways for ground-based telescopes to see through atmospheric distortions.

    ESO VLT 4 lasers on Yepun

    ESO VLT AOF new laser at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    In work published this year, several research groups have found another use for these laser-induced artificial lanterns: pinning down the shape and intensity of Earth’s magnetic field at a scientifically crucial—and, previously, largely inaccessible—range.

    Wobbling beacons

    In AO techniques using guide stars, a powerful laser adjacent to a ground-based telescope zaps a small piece of Earth’s middle atmosphere, or mesosphere, 85 to 100 km above the telescope. The consequent excitation of sodium atoms in the mesosphere creates an artificial point of light at a precise, known location and elevation. That winking light source, in turn, gives the telescope operators on the ground a known point to grab onto, and lets them computationally cancel out (via wavefront-shaping techniques) the turbulence in the lower atmosphere. The result? A sharper view of the stars beyond.

    In 2011, scientists led by James Higbie of Bucknell University, USA, suggested that laser guide stars for AO might also function as tiny, remote magnetometers for measuring Earth’s mesospheric magnetic field [PNAS]. The approach would work through measurements of the precession, or wobbling, of the laser-excited sodium atoms in the magnetic field.

    More specifically, as the circularly polarized laser beam excites the sodium atoms, it also spin-polarizes them, which causes them to wobble like spinning tops in the magnetic field. The frequency of that precession, which depends on the local field strength, can be read via changes in the fluorescence signal captured by a ground-based detector.

    Such measurements, if they could be made to work, would prove a nice win for geophysics. That’s because the mesosphere occupies a difficult-to-access middle zone between space-based and ground-based measurements of the magnetic field. Yet understanding that elusive part of the field is crucial to a complete picture of overall geomagnetism, for scientific applications ranging from plate tectonics to ocean circulation to space weather.

    In May of this year, a group of U.S. researchers finally put the idea of using wobbling laser guide stars as magnetometers to the test (Journal of Geophysical Research). The team fired a 1.33-W laser to excite mesospheric sodium atoms, and then gathered the backscattered guide star light with a 1.55-m-aperture telescope. By measuring the precession, they were able to obtain a value of the field consistent with several models “within a fraction of a percent.” But the method’s sensitivity, at 162 nT/Hz½, fell considerably short of the level of around 1 nT/Hz½ thought to be necessary for useful measurements of mesospheric magnetic-field variations.

    In work published at the end of September, scientists from Germany, Italy, Canada and the United States reported a significant improvement on that accuracy (Nature Communications). They aimed a continuous-wave laser from the European Southern Observatory’s laser guide star unit adjacent to the William Herschel Telescope on La Palma, Canary Islands at the mesosphere, delivering roughly 2 W of laser power to the sky.

    Glistening against the awesome backdrop of the night sky above ESO’s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    The team then captured the received light with a 40-cm-aperture telescope mounted on the AO system’s receiver control unit. The received light, after passing through a photomultiplier tube, was then sent to a digital signal-processing stack for backing out the precession from the fluorescence signal, and for tuning the laser to reduce scintillation noise from the atmosphere.

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    A team of scientists from Germany, Italy, Canada and the U.S. used a ground-based laser developed for astronomical adaptive optics, equipped with an acousto-optical modulator (AOM), to excite sodium atoms in the mesosphere. Ground-based measurement of the optical signal was used to estimate the precession of the spin-polarized sodium atoms and, thus, of the Earth’s magnetic field in that area. [Image: F.P. Bustos et al., Nature Communications]

    Boosting sensitivity

    By focusing on a narrower resonance frequency in the precession signal, the international team reported, the researchers were able to achieve accuracy of 0.28 mG/Hz½ (28 nT/Hz½)—“an order of magnitude better sensitivity” than the U.S. team’s result early in the year, albeit still below the ultimate 1-nT/Hz½ target. The international group suggested that the results could be improved still further; using higher laser powers, for example, would allow researchers to boost the number of atoms interrogated by the method, sharpening sensitivity.

    The researchers also noted an interesting side-effect of the recent work. By digging into the details of resonance frequencies tied to the excited sodium atoms’ spin-relaxation rate, they were able to suss out information on the rates of atomic collisions in the mesosphere. Getting such quantitative information on collisional dynamics, the team wrote, is “important for the optimization of sodium laser guide stars and mesospheric magnetometers”—and could thus further improve the potential usefulness of these beacons for astronomy and geophysics alike.

    See the full article here .

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    Optics & Photonics News (OPN) is The Optical Society’s monthly news magazine. It provides in-depth coverage of recent developments in the field of optics and offers busy professionals the tools they need to succeed in the optics industry, as well as informative pieces on a variety of topics such as science and society, education, technology and business. OPN strives to make the various facets of this diverse field accessible to researchers, engineers, businesspeople and students. Contributors include scientists and journalists who specialize in the field of optics. We welcome your submissions.

     
  • richardmitnick 1:44 pm on August 3, 2018 Permalink | Reply
    Tags: Adaptive Optics, , , , , , , Frank Eisenhauer,   

    From ESOblog: Advancing Technology for Galactic Observations 

    ESO 50 Large

    From ESOblog

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    Science Snapshots

    3 August 2018

    In May 2018, the star S2 made its closest approach to the black hole at the centre of the Milky Way. Observing this event was no easy task. The centre is full of dense dust clouds, impenetrable at visual wavelengths. The unique instruments GRAVITY and SINFONI, able to take highly precise measurements, needed to be developed for these observations. Frank Eisenhauer, a member of the Galactic Centre group at Max Planck Institute for Extraterrestrial Physics and principal investigator for GRAVITY and SINFONI, talks about observing the close approach of S2 in the second of a three blog post series.

    ESO GRAVITY in the VLTI

    ESO SINFONI


    ESO/SINFONI

    Q: Can you tell us a bit about what observations your team aimed to make about the galactic centre?

    A: We knew that the star S2 would make a close flyby of the black hole in the centre of the Milky Way in 2018, making it possible to study the effects predicted by Einstein’s theory of general relativity. We expected the motion of the star to deviate from a Keplerian orbit based on Newton’s laws. Our observations aimed to see these differences, so, to see any visible changes, we had to improve our observation accuracy by several orders of magnitude compared to previous measurements.

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    This simulation shows the orbits of stars very close to the supermassive black hole at the heart of the Milky Way. The area is a perfect laboratory to test gravitational physics and specifically Einstein´s general theory of relativity. Credit: ESO/L. Calçada/spaceengine.org

    Q: What did you and your team do to prepare for this year’s observations?

    A: Our instrument — GRAVITY — was finished about three years ago and arrived in Chile, the site of ESO’s telescopes. Then the most intense period started: making GRAVITY work together with all four telescopes of the Very Large Telescope (VLT). In the summer of 2016, we had our first observations of the galactic centre, which, for the first time, showed not only S2 but also the black hole with unprecedented resolution. Since then they have become our faithful companions whenever we visit for a look. For the closest approach in 2018, the team returned for further observations every month.


    Animation of the path that an incoming light ray traces through the GRAVITY instrument. Note the intricate design and complex interaction of the various components for the four telescopes. For interferometry to work, the light paths have to be superposed with a precision of a fraction of the wavelength – less than 1 micrometre.
    Credit: MPE

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    The VLTI Delay Lines, which lie below the ground at Paranal, inside a 168-m tunnel. They form an essential part of this very complicated optical system by ensuring that the light beams from several telescopes arrive in phase at the common interferometric focus. Credit: Enrico Sacchetti/ESO

    Q: What kind of telescope did the team use to observe the galactic centre?

    A: So, we needed a “super-telescope”, which we created by combining the four largest ESO telescopes of the Very Large Telescope (VLT) with a technique called interferometry. This technique is well established in radio astronomy, i.e. when observing at longer wavelengths, but many thought it would be impossible to achieve that level of sensitivity and accuracy at infrared wavelengths. And, yes, it was not easy. But the star would not wait for us — and in the end, we were ready in time!

    Q: Can you explain how infrared interferometry works?
    The optical path lengths between the four telescopes and our instrument have to be controlled with the precision of a fraction of the wavelength

    A: With an interferometer, you combine the light received from different telescopes. The big challenge is to combine this light properly, or “in phase” as the physicists say. This means that the optical path lengths between the four telescopes and our instrument have to be controlled with the precision of a fraction of the wavelength—several hundred times smaller than the thickness of a human hair—while the telescopes are separated by as much as 130 metres.


    Learn more about the first successful test of Einstein’s General Theory of Relativity near a supermassive black hole in ESOcast 173.
    Credit: MPE

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    Every day, before the observations start, each telescope undergoes a complete start up during which each of its function is checked, like a plane before take off. Here, Yepun, the fourth Unit Telescope, has been moved to a very low altitude, revealing the cell holding its main mirror and the SINFONI integral-field spectrograph. Credit: ESO

    Q: Can you tell us a bit about the ESO instruments used and the differences between them?

    A: The group around Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics (MPE) started to observe the galactic centre with the SHARP I camera on the New Technology Telescope in the 1990s. At that time, high-quality infrared detectors became available and we were the first to use them to peer through the dust cloud obscuring the galactic centre. Then came NACO with the VLT, which lead to the breakthrough with the first orbit measurement in 2002. In parallel, we developed SINFONI, the first near-infrared imaging spectrograph for the VLT, which has given us crucial velocity measurements since its installation in 2003. And, finally, GRAVITY now combines all four VLT telescope to a “130-m super-telescope.”

    Q: What about these instruments makes it possible to see through the curtain of dust and stars?

    A: The galactic centre is hidden behind dense dusts clouds — but this is only true for visible light. If you go to infrared wavelengths, you can see through to the stars beyond. However, part of this radiation is absorbed by the Earth’s atmosphere, and in particular water vapour in the air. This meant we needed to go to a high place, with less atmosphere above us, and a dry place, i.e. a desert. This is why the Paranal observatory, on top of a high mountain in the Atacama desert, was the perfect place for these observations. But even for the best observing conditions, the atmosphere’s turbulence blurs the images, which is why we need adaptive optics (AO).

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    Q: Can you tell us a bit about the Adaptive Optics system for IR imaging? Are there any challenges using AO to observe the Galactic Centre?

    A: Adaptive optics means that you measure the distortion from the Earth’s atmosphere a few hundred times per second, and correct it in real time with a deformable mirror. For this, you need a bright reference star. Unfortunately, there are no really bright stars at visible wavelengths close to the galactic centre to measure these distortions. Therefore you have two options: create your own artificial star with a laser beacon, as done with SINFONI, or build an infrared wavefront sensor as we did for GRAVITY.

    Q: What advancements in observing technology have made it possible for us to study the galactic centre as compared to 20 or 25 years ago when observations of the galactic centre were really becoming possible?

    A: When the group at MPE started observing the galactic centre in the 1990s, we could observe with 150 milliarcsecond resolution. This is about the angle under which a stadium 300 metres diameter would appear on the Moon. Now, with GRAVITY, we can observe with a resolution as good as 2 milliarcseconds, and measure the separation between the star S2 and the black hole with a precision of just a few tens of microarcseconds. The latter is equivalent to observing two objects on the Moon that are separated by the length of a pencil.

    Q: What do you find most exciting about studying the galactic centre?

    A: To see so many miracles predicted by the general theory of relativity all in one place: the black hole, stars moving at incredible speed, the time dilation, and many other phenomena. The centre of the Milky Way is and will remain our Rosetta stone for deciphering these wonders.

    See the full article here .


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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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    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

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    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

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    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

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    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 8:01 am on July 18, 2018 Permalink | Reply
    Tags: A new adaptive optics mode called laser tomography, Adaptive Optics, , , , , , , , Narrow-Field adaptive optics mode   

    From European Southern Observatory: “Supersharp Images from New VLT Adaptive Optics” 

    ESO 50 Large

    From European Southern Observatory

    18 July 2018

    Joël Vernet
    ESO MUSE and GALACSI Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6579
    Email: jvernet@eso.org

    Roland Bacon
    MUSE Principal Investigator / Lyon Centre for Astrophysics Research (CRAL)
    France
    Cell: +33 6 08 09 14 27
    Email: rmb@obs.univ-lyon1.fr

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

    1
    ESO’s Very Large Telescope (VLT) has achieved first light with a new adaptive optics mode called laser tomography — and has captured remarkably sharp test images of the planet Neptune, star clusters and other objects. The pioneering MUSE instrument in Narrow-Field Mode, working with the GALACSI adaptive optics module, can now use this new technique to correct for turbulence at different altitudes in the atmosphere. It is now possible to capture images from the ground at visible wavelengths that are sharper than those from the NASA/ESA Hubble Space Telescope. The combination of exquisite image sharpness and the spectroscopic capabilities of MUSE will enable astronomers to study the properties of astronomical objects in much greater detail than was possible before.

    ESO MUSE on the VLT

    GALACSI Adaptive Optics System for VLT


    ESOcast 172 Light: Supersharp Images from New VLT Adaptive Optics (4K UHD)


    Zooming in on the globular star cluster NGC 6388

    The MUSE (Multi Unit Spectroscopic Explorer) instrument on ESO’s Very Large Telescope (VLT) works with an adaptive optics unit called GALACSI. This makes use of the Laser Guide Star Facility, 4LGSF, a subsystem of the Adaptive Optics Facility (AOF). The AOF provides adaptive optics for instruments on the VLTs Unit Telescope 4 (UT4). MUSE was the first instrument to benefit from this new facility and it now has two adaptive optics modes — the Wide Field Mode and the Narrow Field Mode [1].

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    The MUSE Wide Field Mode coupled to GALACSI in ground-layer mode corrects for the effects of atmospheric turbulence up to one kilometre above the telescope over a comparatively wide field of view. But the new Narrow Field Mode using laser tomography corrects for almost all of the atmospheric turbulence above the telescope to create much sharper images, but over a smaller region of the sky [2].

    3
    These images of the planet Neptune were obtained during the testing of the Narrow-Field adaptive optics mode of the MUSE/GALACSI instrument on ESO’s Very Large Telescope. The image on the right is without the adaptive optics system in operation and the one on the left after the adaptive optics are switched on. Credit: ESO/P. Weibacher (AIP)

    With this new capability, the 8-metre UT4 reaches the theoretical limit of image sharpness and is no longer limited by atmospheric blur. This is extremely difficult to attain in the visible and gives images comparable in sharpness to those from the NASA/ESA Hubble Space Telescope. It will enable astronomers to study in unprecedented detail fascinating objects such as supermassive black holes at the centres of distant galaxies, jets from young stars, globular clusters, supernovae, planets and their satellites in the Solar System and much more.

    Adaptive optics is a technique to compensate for the blurring effect of the Earth’s atmosphere, also known as astronomical seeing, which is a big problem faced by all ground-based telescopes. The same turbulence in the atmosphere that causes stars to twinkle to the naked eye results in blurred images of the Universe for large telescopes. Light from stars and galaxies becomes distorted as it passes through our atmosphere, and astronomers must use clever technology to improve image quality artificially.

    To achieve this four brilliant lasers are fixed to UT4 that project columns of intense orange light 30 centimetres in diameter into the sky, stimulating sodium atoms high in the atmosphere and creating artificial Laser Guide Stars. Adaptive optics systems use the light from these “stars” to determine the turbulence in the atmosphere and calculate corrections one thousand times per second, commanding the thin, deformable secondary mirror of UT4 to constantly alter its shape, correcting for the distorted light.

    MUSE is not the only instrument to benefit from the Adaptive Optics Facility. Another adaptive optics system, GRAAL, is already in use with the infrared camera HAWK-I. This will be followed in a few years by the powerful new instrument ERIS. Together these major developments in adaptive optics are enhancing the already powerful fleet of ESO telescopes, bringing the Universe into focus.

    ESO GRAAL adaptive optics system.

    ESO GRAAL

    ESO HAWK-I on the ESO VLT

    This new mode also constitutes a major step forward for the ESO’s Extremely Large Telescope, which will need Laser Tomography to reach its science goals. These results on UT4 with the AOF will help to bring ELT’s engineers and scientists closer to implementing similar adaptive optics technology on the 39-metre giant.
    Notes

    [1] MUSE and GALACSI in Wide-Field Mode already provides a correction over a 1.0-arcminute-wide field of view, with pixels 0.2 by 0.2 arcseconds in size. This new Narrow-Field Mode from GALACSI covers a much smaller 7.5-arcsecond field of view, but with much smaller pixels just 0.025 by 0.025 arcseconds to fully exploit the exquisite resolution.

    [2] Atmospheric turbulence varies with altitude; some layers cause more degradation to the light beam from stars than others. The complex adaptive optics technique of Laser Tomography aims to correct mainly the turbulence of these atmospheric layers. A set of pre-defined layers are selected for the MUSE/GALACSI Narrow Field Mode at 0 km (ground layer; always an important contributor), 3, 9 and 14 km altitude. The correction algorithm is then optimised for these layers to enable astronomers to reach an image quality almost as good as with a natural guide star and matching the theoretical limit of the telescope.

    See the full article here .


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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 EEuropean Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO La Silla HELIOS (HARPS Experiment for Light Integrated Over the Sun)

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

    ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres

    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile, at an altitude 3,046 m (9,993 ft)

    ESO/APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 1:27 pm on May 15, 2018 Permalink | Reply
    Tags: Adaptive Optics, , , , , IFA at Manua Kea U Hawaii Manoa,   

    From U Hawaii IFA at Manua Kea: “Robo-AO” 

    U Hawaii

    From University of Hawaii

    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA
    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA

    1

    From U Hawaii IFA at Manua Kea

    Archived News: 2015-2016

    June 26th, 2016: The Robo-AO team is at the SPIE Astronomical Telescopes and Instrumentation in Edinburgh, Scottland with 4 talks and 2 posters that used Robo-AO data or technology:

    3

    C. Baranec The Rapid Transient Surveyor
    D. Atkinson Next-generation performance of SAPHIRA HgCdTe APDs
    C. Ziegler SRAO: optical design and the dual-knife-edge WFS
    N. Law SRAO: the southern robotic speckle + adaptive optics system
    C. Ziegler The Robo-AO KOI survey: laser adaptive optics imaging of every Kepler exoplanet candidate
    M. Salama Robo-AO Kitt Peak: status of the system and optimizing the sensitivity of a sub-electron readnoise IR camera to detect low-mass companions

    4
    March 9th, 2016 Robo-AO was found to be the second most scientifically productive laser adaptive optics system in 2015 (behind Keck). With the redeployment to Kitt Peak last year, and four papers currently under review, we’re optimistic this productivity will continue well into the future.

    Histogram of refereed science publications from the world’s laser adaptive optics systems.

    Figure adopted from P. Wizinowich (Keck) and used with permission.
    5

    November 12th, 2015 The Robo-AO system has been installed at the 2.1-m telescope at Kitt Peak and we are in the middle of comissioning. For more frequent updates, please see our Robo-AO Facebook page.

    6
    The Robo-AO ultraviolet laser at the Kitt Peak 2.1-m telescope.

    7
    Robo-AO mounted on the Palomar Observatory 1.5m telescope. The adaptive optics and camera systems are in the box mounted on the back end of the telescope. The large box on top of the telescope is the support electronics rack, and the UV laser guide star system is mounted on the bottom of the telescope. Image credit: C. Baranec

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

     
  • richardmitnick 5:58 pm on December 18, 2017 Permalink | Reply
    Tags: Adaptive Optics, , , , , , ESO Signs Contract for ELT Laser Sources   

    From ESO: “ESO Signs Contract for ELT Laser Sources” 

    ESO 50 Large

    European Southern Observatory

    18 December 2017
    Frank Lison
    TOPTICA Projects GmbH
    Email: Frank.Lison@toptica-projects.com

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

    1

    ESO has signed a new agreement with TOPTICA, the German photonics company, for the production of lasers to be used in ESO’s Extremely Large Telescope (ELT) adaptive optics system. TOPTICA [1], in partnership with the Canadian company MPB Communications Inc. (MPBC) [2], will build at least four laser sources for the ELT [3], helping the telescope to achieve unprecedented spatial resolution for an optical/infrared ground-based telescope. The ELT is scheduled to see first light in 2024.

    The laser system for the adaptive optics system on the ELT will be based on the Four Laser Guide Star Facility (4LGSF) on ESO’s Very Large Telescope (VLT). The Adaptive Optics Facility, which uses the 4LGSF, has already shown spectacular improvement in image sharpness on the VLT (eso1724). The TOPTICA/MPBC Guidestar Alliance was the main contractor for the laser system on the VLT (eso1613).

    Adaptive optics compensate for the blurring effect of the Earth’s atmosphere, enabling astronomers to obtain much sharper images. Lasers are used to create multiple artificial guide stars high in the Earth’s atmosphere. These points of light are used as reference light sources to allow the adaptive optics system to compensate for turbulence in the Earth’s atmosphere. Unlike natural guide stars, laser guide stars can be positioned anywhere to allow the full power of adaptive optics to be used over almost the entire sky.

    Anticipated observations enabled by the ELT’s powerful built-in adaptive optics system include everything from studying black holes to investigating some of the youngest galaxies in the distant Universe.

    Notes

    [1] TOPTICA is responsible for the laser system engineering and contributes its diode and frequency-conversion technology. The work will be executed by TOPTICA Projects GmbH, which focuses on specialised laser systems such as laser guide stars.

    [2] The construction of the high-powered Raman fibre amplifiers and fibre laser pump modules will be performed by MPB Communications Inc. of Montreal, Canada. MPBC has a history of providing high power Raman fibre amplifiers for submarine communications and scientific work.

    [3] The ELT is designed to potentially have up to eight laser guide star systems in future.

    See the full article here .

    Please help promote STEM in your local schools.
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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”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

     
  • richardmitnick 10:07 pm on December 15, 2017 Permalink | Reply
    Tags: A valuable STEM (Science Technology Engineering and Mathematics) opportunity for education and workforce development, Adaptive Optics, AO is a technique used to remove the distortions caused by turbulence in the Earth’s atmosphere, , , , , High-impact research on the hunt for habitable exoplanets, , The Keck telescopes were the first large telescopes to be equipped with adaptive optics and subsequently laser guide stars, W. M. Keck Observatory Awarded NSF Grant to Boost Performance of Adaptive Optics System   

    From Keck: “W. M. Keck Observatory Awarded NSF Grant to Boost Performance of Adaptive Optics System” 

    Keck Observatory

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

    Keck Observatory

    December 15, 2017
    No writer credit.

    1
    Adaptive optics (AO) measures and then corrects the atmospheric turbulence using a deformable mirror that changes shape 1,000 times per second. Initially, AO relied on the light of a star that was both bright and close to the target celestial object. But there are only enough bright stars to allow AO correction in about one percent of the sky. In response, astronomers developed Laser Guide Star Adaptive Optics using a special-purpose laser to excite sodium atoms that sit in an atmospheric layer 60 miles above Earth. Exciting the atoms in the sodium layers creates an artificial “star” for measuring atmospheric distortions which allows the AO to produce sharp images of celestial objects positioned nearly anywhere in the sky. IMAGE CREDIT: ANDREW RICHARD HARA, http://www.andrewhara.com

    One of the most scientifically productive adaptive optics (AO) systems on Earth is getting a major upgrade, one that will further advance high-impact research on the hunt for habitable exoplanets, the supermassive black hole at the center of the Milky Way, and the nature of Dark Matter and Dark Energy.

    The National Science Foundation (NSF) has awarded funding to the W. M. Keck Observatory on Maunakea, Hawaii for a significant enhancement of the performance of the AO system on the Keck II telescope.

    “The Keck telescopes were the first large telescopes to be equipped with adaptive optics and subsequently laser guide stars. All major astronomical telescopes now have laser guide star AO systems. Despite this competition, Keck Observatory’s AO systems have remained the most scientifically productive in the world. This upgrade will help maintain our science community’s competitive advantage,” said Principal Investigator Peter Wizinowich, chief of technical development at Keck Observatory.

    AO is a technique used to remove the distortions caused by turbulence in the Earth’s atmosphere. This results in sharper, more detailed astronomical images. This upgrade will further improve the clarity of the images formed by the telescope.

    The project will deliver a faster, more flexible real-time controller (RTC), as well as a better, lower noise camera for wavefront sensing. This will reduce the camera readout and computation time between the time that an image is captured and a correction for atmospheric blurring is made.

    4

    “Any delay means the correction is applied for atmospheric turbulence that has already started to change. Even if the correction happens in just a few milliseconds, we want to reduce the delay to a minimum. The new RTC computer and camera uses advanced technology to do just that,” said Sylvain Cetre, a software engineer at Keck Observatory who plays a lead role in developing the new RTC.

    Recognizing this as a valuable STEM (Science, Technology, Engineering, and Mathematics) opportunity for education and workforce development, Keck Observatory will include a postdoc as well as a Hawaii college student from the summer Akamai Internship Program to work on the development of the project.

    “Part of Keck Observatory’s mission is to train and prepare future generations so the work continues long after we are gone,” said Jason Chin, a senior engineer at Keck Observatory and project manager for the new RTC. “Many of Hawaii’s finest students, scientists, and engineers end up working on the mainland away from their families. We want to show them there is a vibrant tech industry in Hawaii. One of the ways we do that is by participating in the Akamai Internship Program, which has one of the highest retention rates for Hawaii college students staying in the STEM field. We are proud that many are working in our local tech industry.”

    Co-Principal Investigators Andrea Ghez, Director of the UCLA Galactic Center Group, Jessica Lu, Assistant Astronomy Professor at UC Berkeley, Dimitri Mawet, Associate Astronomy Professor at Caltech, and Tommaso Treu, Physics and Astronomy Professor at UCLA, will also involve graduate and postdoc students. Their teams will use the new capabilities of Keck Observatory’s AO system to pursue science projects in three fields of study:

    1.Characterizing planets around low mass stars via direct imaging and spectroscopy

    2.Testing Einstein’s Theory of General Relativity and understanding supermassive black hole interactions at the Galactic Center

    3.Constraining Dark Matter, the Hubble constant, and Dark Energy via strong gravitational lensing

    “These instrumentation improvements will not only enhance the scientific return of our existing AO system, but it will also provide an excellent platform for future improvements,” said Wizinowich. “We were very pleased to learn that our proposal was successful.”

    The upgrade is expected to be completed by the end of 2020.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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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.


    Keck UCal

     
  • richardmitnick 7:22 am on May 27, 2017 Permalink | Reply
    Tags: Adaptive Optics, , Fifth force, , , ,   

    From KECK: “New Method of Searching for Fifth Force” 

    Keck Observatory

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

    Keck Observatory

    1
    The orbits of two stars, S0-2 and S0-38 located near the Milky Way’s supermassive black hole will be used to test Einstein’s theory of General Relativity and potentially generate new gravitational models. IMAGE CREDIT: S. SAKAI/A.GHEZ/W. M. KECK OBSERVATORY/ UCLA GALACTIC CENTER GROUP

    W. M. Keck Observatory Data Leads To First Of Its Kind Test of Einstein’s Theory of General Relativity.

    May 26, 2017
    No writer credit found.

    A UCLA-led team has discovered a new way of probing the hypothetical fifth force of nature using two decades of observations at W. M. Keck Observatory, the world’s most scientifically productive ground-based telescope.

    There are four known forces in the universe: electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force. Physicists know how to make the first three work together, but gravity is the odd one out. For decades, there have been theories that a fifth force ties gravity to the others, but no one has been able to prove it thus far.

    “This is really exciting. It’s taken us 20 years to get here, but now our work on studying stars at the center of our galaxy is opening up a new method of looking at how gravity works,” said Andrea Ghez, Director of the UCLA Galactic Center Group and co-author of the study.

    The research is published in the current issue of Physical Review Letters.

    Ghez and her co-workers analyzed extremely sharp images of the center of our galaxy taken with Keck Observatory’s adaptive optics (AO). Ghez used this cutting-edge system to track the orbits of stars near the supermassive black hole located at the center of the Milky Way.

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

    Their stellar path, driven by gravity created from the supermassive black hole, could give clues to the fifth force.

    “By watching the stars move over 20 years using very precise measurements taken from Keck Observatory data, you can see and put constraints on how gravity works. If gravitation is driven by something other than Einstein’s theory of General Relativity, you’ll see small variations in the orbital paths of the stars,” said Ghez.

    2
    Pictured above: UCLA Professor of Astrophysics and Galactic Center Group Director Andrea Ghez, a Keck Observatory astronomer and recipient of the 2015 Bakerian Medal. IMAGE CREDIT: KYLE ALEXANDER

    This is the first time the fifth force theory has been tested in a strong gravitational field such as the one created by the supermassive black hole at the center of the Milky Way. Historically, measurements of our solar system’s gravity created by our sun have been used to try and detect the fifth force, but that has proven difficult because its gravitational field is relatively weak.

    “It’s exciting that we can do this because we can ask a very fundamental question – how does gravity work?” said Ghez. “Einstein’s theory describes it beautifully well, but there’s lots of evidence showing the theory has holes. The mere existence of supermassive black holes tells us that our current theories of how the universe works are inadequate to explain what a black hole is.”

    Ghez and her team, including lead author Aurelien Hees and co-author Tuan Do, both of UCLA, are looking forward to summer of 2018. That is when the star S0-2 will be at its closest distance to our galaxy’s supermassive black hole. This will allow the team to witness the star being pulled at maximum gravitational strength – a point where any deviations to Einstein’s theory is expected to be the greatest.

    About Adaptive Optics

    W. M. Keck Observatory is a distinguished leader in the field of adaptive optics (AO), a breakthrough technology that removes the distortions caused by the turbulence in the Earth’s atmosphere.

    Keck Observatory pioneered the astronomical use of both natural guide star (NGS) and laser guide star adaptive optics (LGS AO) and our current systems now deliver images three to four times sharper than the Hubble Space Telescope. AO has imaged the four massive planets orbiting the star HR8799, measured the mass of the giant black hole at the center of our Milky Way Galaxy, discovered new supernovae in distant galaxies, and identified the specific stars that were their progenitors.

    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 8:58 am on May 25, 2017 Permalink | Reply
    Tags: Adaptive Optics, , , , , ,   

    From Nautilus: “Opening a New Window into the Universe” 

    Nautilus

    Nautilus

    April 2017
    Andrea Ghez, UCLA, UCO

    7
    Andrea Ghez. PBS NOVA

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California

    Keck Observatory, Mauna Kea, Hawaii, USA

    New technology could bring new insights into the nature of black holes, dark matter, and extrasolar planets.

    Earthbound telescopes see stars and other astronomical objects through a haze. The light waves they gather have traveled unimpeded through space for billions of years, only to be distorted in the last millisecond by the Earth’s turbulent atmosphere. That distortion is now even more important, because scientists are preparing to build the three largest telescopes on Earth, each with light-gathering surfaces of 20 to 40 meters across.

    The new giant telescopes:

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile


    TMT-Thirty Meter Telescope, proposed for Mauna Kea, Hawaii, USA


    Giant Magellan Telescope, to be at Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

    In principle, the larger the telescope, the higher the resolution of astronomical images. In practice, the distorting veil of the atmosphere has always limited what can be achieved. Now, a rapidly evolving technology known as adaptive optics can strip away the veil and enable astronomers to take full advantage of current and future large telescopes. Indeed, adaptive optics is already making possible important discoveries and observations, including: the discovery of the supermassive black hole at the center of our galaxy, proving that such exotic objects exist; the first images and spectra of planetary systems around other stars; and high-resolution observations of galaxies forming in the early universe.

    But adaptive optics has still not delivered its full scientific potential.

    ESO 4LGSF Adaptive Optics Facility (AOF)

    Existing technology can only partially correct the atmospheric blurring and cannot provide any correction for large portions of the sky or for the majority of the objects astronomers want to study.

    The project we propose here to fully exploit the potential of adaptive optics by taking the technology to the next level would boost research on a number of critical astrophysical questions, including:

    What are supermassive black holes and how do they work? Adaptive Optics has opened a new approach to studying supermassive black holes—through stellar orbits—but only the brightest stars, the tip of the iceberg, have been measured. With next generation adaptive optics we will be able to take the next leap forward in our studies of these poorly understood objects that are believed to play a central role in our universe. The space near the massive black hole at the center of our galaxy, for example, is a place where gravitational forces reach extreme levels. Does Einstein’s general theory of relativity still apply, or do exotic new physical phenomena emerge? How do these massive black holes shape their host galaxies? Early adaptive optics observations at the galactic center have revealed a completely unexpected environment, challenging our notions on the relationship between black holes and galaxies, which are a fundamental ingredient to cosmological models. One way to answer both of these questions is to find and measure the orbits of faint stars that are closer to the black hole than any known so far—which advanced adaptive optics would make possible.
    The first direct images of an extrasolar planet—obtained with adaptive optics—has raised fundamental questions about star and planet formation. How exactly do new stars form and then spawn planets from the gaseous disks around them? New, higher resolution images of this process—with undistorted data from larger telescopes—can help answer this question, and may also reveal how our solar system was formed. In addition, although only a handful of new-born planets has been found to date, advanced adaptive optics will enable astronomers to find many more and help determine their composition and life-bearing potential.
    Dark matter and dark energy are still completely mysterious, even though they constitute most of the universe.


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

    But detailed observations using adaptive optics of how light from distant galaxies is refracted around a closer galaxy to form multiple images—so-called gravitational lensing—can help scientists understand how dark matter and dark energy change space itself.

    In addition, it is clear that telescopes endowed with advanced adaptive optics technology will inspire a whole generation of astronomers to design and carry out a multitude of innovative research projects that were previously not possible.

    4
    The laser system used to make artificial guide stars that sense the blurring effects of the Earth’s atmosphere being used on both Keck I and Keck II during adaptive optics observations of the center of our Galaxy. Next Generation Adaptive Optics would have multiple laser beams for each telescope. Ethan Tweedie

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

    The technology of adaptive optics is quite simple, in principle. First, astronomers measure the instantaneous turbulence in the atmosphere by looking at the light from a bright, known object—a “guide star”—or by using a laser tuned to make sodium atoms in a thin layer of the upper atmosphere fluoresce and glow as an artificial guide star.

    6
    ESO VLT Adaptive Optics new Guide Star laser light

    The turbulence measurements are used to compute (also instantaneously) the distortions that turbulence creates in the incoming light waves. Those distortions are then counteracted by rapidly morphing the surface of a deformable mirror in the telescope. Measurements and corrections are done hundreds of times per second—which is only possible with powerful computing capability, sophisticated opto-mechanical linkages, and a real-time control system. We know how to build these tools.

    Of course, telescopes that operate above the atmosphere, such as the Hubble Space Telescope, don’t need adaptive optics.

    NASA/ESA Hubble Telescope

    But both the Hubble and the coming next generation of space telescopes are small compared to the enormous earth-based telescopes now being planned.


    LSST Camera, built at SLAC



    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    And for the kinds of research that require very high resolution, such as the topics mentioned above and many others, there is really no substitute for the light-gathering power of telescopes too huge to be put into space.

    The next generation of adaptive optics could effectively take even the largest earth-bound telescopes “above the atmosphere” and make them truly amazing new windows on the universe. We know how to create this capability—the technology is in hand and the teams are assembled. It is time to put advanced adaptive optics to work.

    Creating Next Generation Adaptive Optics

    Adaptive optics (AO) imaging technology is used to improve the performance of optical systems by correcting distortions on light waves that have traveled through a turbulent medium. The technology has revolutionized fields from ophthalmology and vision science to laser communications. In astronomy, AO uses sophisticated, deformable mirrors controlled by fast computers to correct, in real-time, the distortion caused by the turbulence of the Earth’s atmosphere. Telescopes equipped with AO are already producing sharper, clearer views of distant astronomical objects than had ever before been possible, even from space. But current AO systems only partially correct for the effects of atmospheric blurring, and only when telescopes are pointed in certain directions. The aim of Next Generation Adaptive Optics is to overcome these limitations and provide precise correction for atmospheric blurring anywhere in the sky.

    One current limitation is the laser guide star that energizes sodium atoms in the upper atmosphere and causes them to glow as an artificial star used to measure the atmospheric distortions. This guide “star” is relatively close, only about 90 kilometers above the Earth’s surface, so the technique only probes a conical volume of the atmosphere above the telescope, and not the full cylinder of air through which genuine star light must pass to reach the telescope. Consequently, much of the distorting atmospheric structure is not measured. The next generation AO we propose will employ seven laser guide stars, providing full coverage of the entire cylindrical path travelled by light from the astronomical object being studied.

    6
    The next generation of adaptive optics will have several laser-created artificial guide stars, better optics, higher performance computers, and more advanced science instruments. Such a system will deliver the highest-definition images and spectra over nearly the entire sky and will enable unique new means of measuring the properties of stars, planets, galaxies, and black holes.
    J.Lu (U of Hawaii) & T. Do (UCLA)

    This technique can map the 3-D structure of the atmosphere, similar to how MRI medical imaging maps the human body. Simulations demonstrate that the resulting corrections will be excellent and stable, yielding revolutionary improvements in imaging. For example, the light from a star will be concentrated into a tiny area of the focal plane camera, and be far less spread out than it is with current systems, giving sharp, crisp images that show the finest detail possible.

    This will be particularly important for existing large telescopes such as the W. M. Keck Observatory (WMKO) [above]—currently the world’s leading AO platform in astronomy. Both our team—the UCLA Galactic Center Group (GCG)—and the WMKO staff have been deeply involved in the development of next generation AO systems.

    The quantum leap in the quality of both imaging and spectroscopy that next generation AO can bring to the Keck telescopes will likely pave the way for advanced AO systems on telescopes around the globe. For the next generation of extremely large telescopes, however, these AO advances will be critical. This is because the cylindrical volume of atmosphere through which light must pass to reach the mirrors in such large telescopes is so broad that present AO techniques will not be able to provide satisfactory corrections. For that reason, next generation AO techniques are critical to the future of infrared astronomy, and eventually of optical astronomy as well.

    The total proposed budget is $80 million over five years. The three major components necessary to take the leap in science capability include the laser guide star system, the adaptive optics system, and a powerful new science instrument, consisting of an infrared imager and an infrared spectrograph, that provides the observing capability to take advantage of the new adaptive optics system. This investment in adaptive optics will also help develop a strong workforce for other critical science and technology industries, as many students are actively recruited into industry positions in laser communications, bio-medical optics, big-data analytics for finance and business, image sensing and optics for government and defense applications, and the space industry. This investment will also help keep the U.S. in the scientific and technological lead. Well-funded European groups have recognized the power of AO and are developing competitive systems, though the next generation AO project described here will set an altogether new standard.

    Federal funding agencies find the science case for this work compelling, but they have made clear that it is beyond present budgetary means. Therefore, this is an extraordinary opportunity for private philanthropy—for visionaries outside the government to help bring this ambitious breakthrough project to reality and open a new window into the universe.

    Andrea Ghez is the Lauren B. Leichtman & Arthur E. Levine Chair in Astrophysics Director, UCLA Galactic Center Group.

    See the full article here .

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