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  • richardmitnick 9:00 pm on October 20, 2017 Permalink | Reply
    Tags: , , , , , Gemini Observatory, Neutron stars gravitational waves and all the gold in the universe, ,   

    From UCSC: “Neutron stars, gravitational waves, and all the gold in the universe” 

    UC Santa Cruz

    UC Santa Cruz

    14

    A UC Santa Cruz special report

    Tim Stephens

    Astronomer Ryan Foley says “observing the explosion of two colliding neutron stars” [see https://sciencesprings.wordpress.com/2017/10/17/from-ucsc-first-observations-of-merging-neutron-stars-mark-a-new-era-in-astronomy ]–the first visible event ever linked to gravitational waves–is probably the biggest discovery he’ll make in his lifetime. That’s saying a lot for a young assistant professor who presumably has a long career still ahead of him.

    2
    The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.

    “Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.

    These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.

    THE MERGER

    Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.

    Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    1
    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Now, for the first time, scientists can study both the gravitational waves (ripples in the fabric of space-time), and the radiation emitted from the violent merger of the densest objects in the universe.

    3
    The UC Santa Cruz team found SSS17a by comparing a new image of the galaxy N4993 (right) with images taken four months earlier by the Hubble Space Telescope (left). The arrows indicate where SSS17a was absent from the Hubble image and visible in the new image from the Swope Telescope. (Image credits: Left, Hubble/STScI; Right, 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    It’s that combination of data, and all that can be learned from it, that has astronomers and physicists so excited. The observations of this one event are keeping hundreds of scientists busy exploring its implications for everything from fundamental physics and cosmology to the origins of gold and other heavy elements.


    A small team of UC Santa Cruz astronomers were the first team to observe light from two neutron stars merging in August. The implications are huge.

    ALL THE GOLD IN THE UNIVERSE

    It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.

    4
    The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)

    A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.

    Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.

    According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.

    RIPPLES IN THE FABRIC OF SPACE-TIME

    Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.

    Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.

    The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.

    LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.

    LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.

    “This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”

    IN THIS REPORT

    Neutron stars
    A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)

    5
    Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.

    “We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.

    7
    David Coulter, graduate student

    The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.

    “I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.

    “Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.

    8
    Charles Kilpatrick, postdoctoral scholar

    Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.

    9
    Ariadna Murguia-Berthier, graduate student

    “In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”

    At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.

    10
    Matthew Siebert, graduate student

    “It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”

    Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.

    It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.

    11
    César Rojas Bravo, graduate student

    Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.

    Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.

    Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.

    12
    Yen-Chen Pan, postdoctoral scholar

    “There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”

    13
    Enia Xhakaj, graduate student

    IN THIS REPORT

    Scientific Papers from the 1M2H Collaboration

    Coulter et al., Science, Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

    Drout et al., Science, Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

    Shappee et al., Science, Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger

    Kilpatrick et al., Science, Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

    Siebert et al., ApJL, The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source

    Pan et al., ApJL, The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source

    Murguia-Berthier et al., ApJL, A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

    Kasen et al., Nature, Origin of the heavy elements in binary neutron star mergers from a gravitational wave event

    Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)

    Abbott et al., ApJL, Multi-messenger Observations of a Binary Neutron Star Merger

    PRESS RELEASES AND MEDIA COVERAGE


    Watch Ryan Foley tell the story of how his team found the neutron star merger in the video below. 2.5 HOURS.

    Press releases:

    UC Santa Cruz Press Release

    UC Berkeley Press Release

    Carnegie Institution of Science Press Release

    LIGO Collaboration Press Release

    National Science Foundation Press Release

    Media coverage:

    The Atlantic – The Slack Chat That Changed Astronomy

    Washington Post – Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy

    New York Times – LIGO Detects Fierce Collision of Neutron Stars for the First Time

    Science – Merging neutron stars generate gravitational waves and a celestial light show

    CBS News – Gravitational waves – and light – seen in neutron star collision

    CBC News – Astronomers see source of gravitational waves for 1st time

    San Jose Mercury News – A bright light seen across the universe, proving Einstein right

    Popular Science – Gravitational waves just showed us something even cooler than black holes

    Scientific American – Gravitational Wave Astronomers Hit Mother Lode

    Nature – Colliding stars spark rush to solve cosmic mysteries

    National Geographic – In a First, Gravitational Waves Linked to Neutron Star Crash

    Associated Press – Astronomers witness huge cosmic crash, find origins of gold

    Science News – Neutron star collision showers the universe with a wealth of discoveries

    UCSC press release
    First observations of merging neutron stars mark a new era in astronomy

    Credits

    Writing: Tim Stephens
    Video: Nick Gonzales
    Photos: Carolyn Lagattuta
    Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
    Design and development: Rob Knight
    Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

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

    Noted in the vdeo but not in te article:

    NASA/Chandra Telescope

    NASA/SWIFT Telescope

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    Prompt telescope CTIO Chile

    NASA NuSTAR X-ray telescope

    See the full article here .

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    UCO Lick Shane Telescope
    UCO Lick Shane Telescope interior
    Shane Telescope at UCO Lick Observatory, UCSC

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    UC Santa Cruz campus
    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
    Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

    Search for extraterrestrial intelligence expands at Lick Observatory
    New instrument scans the sky for pulses of infrared light
    March 23, 2015
    By Hilary Lebow
    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    5
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

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    UCSC is the home base for the Lick Observatory.

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  • richardmitnick 9:34 pm on October 12, 2017 Permalink | Reply
    Tags: , , , , Gemini Large and Long Program, Gemini Observatory,   

    From Gemini: “Celebrate the Large and Long Program: Followup of newly discovered Near-Earth objects from the NEOWISE survey” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    15 Sep 2017
    mschwamb

    Celebrate the Large and Long Program! is a series of blog posts which showcase the high-impact science under the Large and Long Program of Gemini Observatory.

    What is the Large and Long Program?

    The Large and Long Program (LLP) is one of five observing modes Gemini offers to users of our telescopes. These five modes categorize projects based on length and weather conditions required for the observations. Classically, Gemini accepts proposals on a six month basis and recipients awarded with observing time complete their observations within that given semester. Large and Long Programs, on the other hand, provide more flexibility for long term research and last anywhere from one to three years. This extended time frame promotes collaboration across communities and produces significant and high-impact science. Here, we ask past and present Large and Long Programs to share a little about their research and experience with Gemini Observatory.

    Follow up of newly discovered Near-Earth objects from the NEOWISE survey

    NASA/WISE Telescope

    1. Principal Investigator: Name and Affiliation?

    Joseph Masiero, NASA Jet Propulsion Laboratory

    2. How would you describe your Large and Long Program?

    Our Large and Long Program focuses on rapid followup of near-Earth asteroids discovered by the NEOWISE space telescope survey. NEOWISE is an all-sky thermal infrared survey, and excels at finding dark, large asteroids coming close to the Earth. But the NEOWISE survey doesn’t allow the telescope to go back and confirm its discoveries, so we need help from ground-based telescopes. The southern hemisphere has very few telescopes dedicated to NEO followup, so our LLP provides us the critical ability to track down these newly found objects. We use GMOS-South to acquire astrometry of NEO candidate objects, and thus improve the measured orbits for these objects. This data help us better predict where the object will be in the future, and if it poses a hazard to Earth.

    Gemini Observatory GMOS on Gemini South

    3. Why is Gemini best suited for this research?

    Gemini offers us critical access to the southern hemisphere sky, and the ability to quickly take followup observations through its queue observing system. We use these features to quickly track down objects before their positional uncertainty grows too large. Gemini’s large aperture ensure that even our faintest targets can be observed in only a small amount of time.

    4. What has been the best part of your experience with the Large and Long Program?

    The best part of our experience with the LLP has been the rapid acquisition and dissemination of our time-critical data. The end-to-end Gemini system ensures that we can submit triggers, get observations, download data from the Gemini archive, and submit measured positions to the Minor Planet Center quickly enough to ensure these newly discovered near-Earth objects are not lost.

    More about NEOWISE can be found here.

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 2:17 pm on August 11, 2017 Permalink | Reply
    Tags: , , , , , Gemini Confirms a New Class of Variable Stars, Gemini Observatory   

    From Gemini Observatory: “Gemini Confirms a New Class of Variable Stars” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    This post is dedicated to J.G. at WPRB for his kindness to me in my hours of need. I am very grateful for his remarks today.

    August 2, 2017

    1
    Gemini South spectra for three BLAPs. Best fits of stellar atmosphere models are shown with red lines. Effective temperatures, surface gravities, and helium abundances derived for these stars are similar to the values obtained from spectra for the prototype object previously studied. This shows that all the newly discovered variables form a homogeneous class of objects. Credit: Gemini Observatory/AURA/NSF


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

    Gemini confirms a new class of variable stars called Blue Large-Amplitude Pulsators. They are significantly bluer than main sequence stars of the same luminosity demonstrating that they are relatively hot. The new pulsating stars vary with periods ranging from 20 to 40 minutes and amplitudes spanning 0.2 – 0.4 magnitude. These characteristics have not been observed in any known hot pulsators.

    Astronomers using the Multi-Object Spectrograph (GMOS) on the Gemini South telescope have confirmed a new class of variable stars called Blue Large-Amplitude Pulsators (BLAPs). Pawel Pietrukowicz (Warsaw University Observatory, Poland) led the study as part of the Optical Gravitational Lensing Experiment (OGLE), a variability sky survey conducted on the 1.3-meter Warsaw Telescope at Las Campanas Observatory, Chile.

    1.3 meter OGLE Warsaw Telescope at the Las Campanas Observatory in Chile

    Gemini Observatory GMOS on Gemini South

    Following up on the team’s discovery of 14 candidate stars the team used GMOS to obtain spectra for three of the candidates. The Gemini data confirmed these stars have helium-rich atmospheres and high surface temperatures of about 30,000 K, comparable with hot subdwarfs. Nevertheless, Pietrukowicz concludes that the luminosity of these two classes of hot stars differ significantly, with BLAPs having much higher luminosity and much lower gravity than hot subdwarfs. “We found that the new stars are low-mass giants, which vary with exceptionally high amplitudes. This excludes the possibility that they are hot oscillating subdwarfs, leading to the conclusion that BLAPs form a new class of variable stars,” says Pietrukowicz.

    This work is published in the journal Nature Astronomy. The article is also on astro-ph with a .pdf.

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 2:32 pm on June 16, 2017 Permalink | Reply
    Tags: A Partly-cloudy Exoplanet, , , , , Gemini Observatory, The exoplanet 51 Eri b   

    From Gemini: “A Partly-cloudy Exoplanet” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    June 6, 2017

    The first exoplanet discovered using the Gemini Planet Imager (GPI) is a young, cool object between 2–10 Jupiter masses. Identified as 51 Eridani b, new research indicates that its color is redder than similar brown dwarfs and might be due to clouds in its atmosphere. The research also hints that the formation of this exoplanet is likely due to the collapse of icy disk materials followed by the accretion of a thick gas atmosphere – much like the process astronomers think probably formed the gas giants in our Solar System.

    NOAO Gemini Planet Imager on Gemini South

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    1
    GPI images in the K1, K2, LP and MS bands, the emission of host star was blocked. The exoplanet 51 Eri b is indicated by an arrow.

    An international team of astronomers led by Abhijith Rajan (School of Earth and Space Exploration, Arizona State University) observed the exoplanet 51 Eri b using GPI spectroscopy and determined that the planet is redder than similar brown dwarfs seen elsewhere. “This might be due to presence of clouds, similar to young L-type planetary mass companions,” said Rajan. “A possible reason for the presence of clouds, is that the planet is still in transitioning from a partially- to patchy-cloudy atmosphere, with lower mean surface temperatures.”

    The GPI observations, part of the Gemini Planet Imager Exoplanet Survey (GPIES) was combined with mid-infrared photometry at the W.M. Keck Observatory.


    Keck Observatory, Mauna Kea, Hawaii, USA

    These data allowed the team to conclude 51 Eri b appears to be one of the only directly imaged planet that is consistent with cold-start scenario. In this scenario 51 Eri b would have formed by core accretion in which a core is formed very early from planetesimal agglomerations while there is enough gas around it to form a gas giant planet. The result is a low temperature and low luminosity planet. This mechanism is also a widely-held hypothesis explaining the formation of the gas giants in our Solar System.

    Located about 100 light years from Earth, 51 Eri b is between 2–10 times the mass of Jupiter and orbits the star 51 Eridani A. The host star, 51 Eridani A, has a visual magnitude of 5.2 and visible to the naked eye under ideal conditions and easily visible in a pair of binoculars from most of the Earth’s surface!

    More information about GPI and 51 Eri b is available in the October 2015 issue of GeminiFocus (page 3) and in this Gemini Press Release.

    The full results are accepted for publication in The Astronomical Journal.

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 9:35 am on May 18, 2017 Permalink | Reply
    Tags: , , , , Gemini continues to train local teachers in the use of mobile planetarium, Gemini Observatory   

    From Gemini: “Gemini continues to train local teachers in the use of mobile planetarium” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    1

    More than 700 students from the city of Coquimbo were benefited with the functions of the mobile planetarium led by a group of three teachers who participated in the recent training programme of loans from the mobile Planetarium Gemini Observatory.

    Training of teachers was carried out between 2 and 12 of May and was in charge of the manager of the planetarium, Dalma Valenzuela, who guided teachers in basic concepts of astronomy, as well as the sequence of stages The Moon and characteristics of the solar system.

    During this training teachers learned several stories of stars relating to the history of mankind, South American, Polynesian culture and the classical Greek mythology associated with the names of the constellations.

    Quotas to be part of this training during the current year are exhausted. But do not hesitate to contact us to be part of the select group of teachers who will be trained for the 2018.
    Dalma Valenzuela
    dvalenzu@gemini.edu
    +56 51 2205-792

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 3:54 pm on February 27, 2017 Permalink | Reply
    Tags: , , , , First evidence of rocky planet formation in Tatooine system, Gemini Observatory, GMOS Gemini South, SDSS 1557,   

    From Gemini: “First evidence of rocky planet formation in Tatooine system” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    February 23, 2017

    1
    A disc of rocky debris from a disrupted planetesimal surrounds white dwarf plus brown dwarf binary star. The white dwarf is the burn-out core of a star that was probably similar to the Sun, the brown dwarf is only ~60 times heavier than Jupiter, and the two stars go around each other in only a bit over two hours. Credit: Mark Garlick, UCL, University of Warwick and University of Sheffield.

    Using the Gemini Multi-Object Spectrograph (GMOS) on Gemini South, a team led by Jay Farihi (University College London) found, for the first time, a dust and debris disk surrounding a binary star with a white dwarf as a substellar companion.

    3
    GMOS on Gemini South

    To date, almost all of the known planetary systems which include a white dwarf are single stars. Using GMOS spectra Farihi et al. identified critical metal features in the spectrum as well as the higher Balmer lines. From the Gemini data the team estimated a surface temperature of 21,800 Kelvin (about 3.5 times hotter than the Sun) and a mass of ~0.4 solar masses for the white dwarf star and a mass of ~0.063 solar masses for the companion.

    The research is published in the February 27th online issue of Nature Astronomy.

    Evidence of planetary debris surrounding a double sun, ‘Tatooine-like’ system has been found for the first time by a UCL-led team of researchers.

    Published today in Nature Astronomy and funded by the Science and Technology Facilities Council and the European Research Council, the study finds the remains of shattered asteroids orbiting a double sun consisting of a white dwarf and a brown dwarf roughly 1000 light-years away in a system called SDSS 1557.

    The discovery is remarkable because the debris appears to be rocky and suggests that terrestrial planets like Tatooine – Luke Skywalker’s home world in Star Wars – might exist in the system. To date, all exoplanets discovered in orbit around double stars are gas giants, similar to Jupiter, and are thought to form in the icy regions of their systems.

    In contrast to the carbon-rich icy material found in other double star systems, the planetary material identified in the SDSS 1557 system has a high metal content, including silicon and magnesium. These elements were identified as the debris flowed from its orbit onto the surface of the star, polluting it temporarily with at least 1017 g (or 1.1 trillion US tons) of matter, equating it to an asteroid at least 4 km in size.

    Lead author, Dr Jay Farihi (UCL Physics & Astronomy), said: “Building rocky planets around two suns is a challenge because the gravity of both stars can push and pull tremendously, preventing bits of rock and dust from sticking together and growing into full-fledged planets. With the discovery of asteroid debris in the SDSS 1557 system, we see clear signatures of rocky planet assembly via large asteroids that formed, helping us understand how rocky exoplanets are made in double star systems.”

    In the Solar System, the asteroid belt contains the leftover building blocks for the terrestrial planets Mercury, Venus, Earth, and Mars, so planetary scientists study the asteroids to gain a better understanding of how rocky, and potentially habitable planets are formed. The same approach was used by the team to study the SDSS 1557 system as any planets within it cannot yet be detected directly but the debris is spread in a large belt around the double stars, which is a much larger target for analysis.

    The discovery came as a complete surprise, as the team assumed the dusty white dwarf was a single star but co-author Dr Steven Parsons (University of Valparaíso and University of Sheffield), an expert in double star (or binary) systems noticed the tell-tale signs. “We know of thousands of binaries similar to SDSS 1557 but this is the first time we’ve seen asteroid debris and pollution. The brown dwarf was effectively hidden by the dust until we looked with the right instrument”, added Parsons, “but when we observed SDSS 1557 in detail we recognised the brown dwarf’s subtle gravitational pull on the white dwarf.”

    The team studied the binary system and the chemical composition of the debris by measuring the absorption of different wavelengths of light or ‘spectra’, using the Gemini Observatory South telescope and the European Southern Observatory Very Large Telescope, both located in Chile.

    Co-author Professor Boris Gänsicke (University of Warwick) analysed these data and found they all told a consistent and compelling story. “Any metals we see in the white dwarf will disappear within a few weeks, and sink down into the interior, unless the debris is continuously flowing onto the star. We’ll be looking at SDSS 1557 next with Hubble, to conclusively show the dust is made of rock rather than ice.”

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 2:41 pm on February 7, 2017 Permalink | Reply
    Tags: Fading Active Galactic Nuclei, , Gemini Observatory   

    From Gemini: “Gemini Explores Fading Active Galactic Nuclei ID’d by Galaxy Zoo” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    February 7, 2017

    Gemini follows up on candidate galaxies with fading active galactic nuclei (AGN) first identified thanks to the Galaxy Zoo citizen science project. Researchers find that these galaxies show a significant reduction in ionizing photons within the last 20,000 years. Additionally, the gas clouds around these fading AGN are dominated by rotation, unlike those around radio-loud AGN, which are outflows coming from the nuclei.

    1
    Figure 1: Minimum ionizing luminosity of extended AGN-ionized clouds along the projected radius. These Hubble Space Telescope data show a luminosity drop in the last 20,000 years before our direct view of the nucleus, characteristic for all AGN of this study.

    William C. Keel (University of Alabama) and his collaborators used Hα narrowband filters on the Hubble Space Telescope (HST) in conjunction with multi-object spectroscopy with the Gemini Multi-Object Spectrograph (GMOS) integral-field unit (IFU) on the Gemini North telescope on Maunakea to observe a set of fading active galactic nuclei (AGN). These fading AGN, identified in the Galaxy Zoo project, appear to have experienced a significant reduction in luminosity within 20,000 years or less based on this research.

    This work focused on nine AGN which are accompanied by extended ionized gas clouds larger than 10 kiloparsecs from these galaxies’ nuclei. Because these clouds span galaxy scales (or even larger) they can implicitly tell us about the luminosity history of the AGN. A common feature in this subset of AGN is a radial drop in luminosity within 20,000 year timeframes which can be observed in Figure 1, where rapid drops in the number of ionizing photons is shown.

    2
    Figure 2: [O III] emission-line profiles from the GMOS IFU spectra overlaid on the HST [O III] images for Mkn 1498, one of the galaxies studied in this work. This galaxy displays a ringlike emission feature dominated by rotation with a velocity range of ±175 km/sec, (the 700 km/sec referenced in the legend refers to the entire velocity range shown in each miniature line profile plot).

    The research team also used the GMOS IFU spectra to measure line ratios in these regions to probe their ionization mechanism and look for kinematic evidence of outflows – marked by large velocity ranges and often bipolar patterns in velocity – or other phenomena.

    The team’s results confirm what was hinted at by earlier, and less complete data (by the same team), that these fading AGN are structurally different from radio-loud AGN which are dominated by outflows. Instead, these fading AGN are dominated by rotation and consist largely of externally illuminated tidal debris. The rotation can be observed in Figure 2, based on Gemini data which shows shifting of the [O III] emission line due to rotation of the gas cloud.

    In summary, these results support the idea that AGN with extended emission regions are bright for periods 10,000-100,000 years, interspersed with substantially fainter episodes. Further work by the group will examine the ionization of circumnuclear gas, where direct AGN radiation may no longer be the most important source, and more detailed modeling of the gas motions in these galaxies.

    This work is accepted in The Astrophysical Journal and the paper can be found here.

    Also read this Galaxy Zoo blog posting describing this work.

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 2:48 pm on December 28, 2016 Permalink | Reply
    Tags: , , , , Gemini Observatory, Korea Astronomy and Space Science Institute (KASI)   

    From Gemini: “Promoting Collaboration between Gemini and Korea” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    28 Dec 2016
    Manuel Paredes

    1
    The group of astronomers finished the workshop with a visit to the Gemini South telescope located on Cerro Pachón. Photo courtesy of Seok-Jun Chang.

    Around 60 scientists from all around the world, gathered in the joint Chile-Korea-Gemini workshop on Accretion Processes
 in Symbiotic Stars and Related Objects, on December 4-7 at Universidad de La Serena, in Chile.

    In recent years, the Chilean and Korean astronomical communities have begun a path of collaboration that will bring them closer despite the great geographical distance between both countries. Therefore, astronomers based at both sides of the Pacific are fostering several official initiatives to improve partnerships in many aspects of astronomical research among different working groups.

    During the inaugural workshop, participants discussed the process of accretion (the growth of a body by the aggregation of matter to smaller bodies) in symbiotic stars ( a system composed of two stars: a red giant and a small white dwarf star, which are surrounded by a nebula), with the aims of future joint projects in stellar astrophysics.

    The workshop concluded with a visit to the Gemini-South Telescope, in Cerro Pachón, where participants interacted with the observatory staff to learn more about the engineering and technologies that go on “behind the scenes”.

    The organization of this successful meeting was led by astronomers Rodolfo Angeloni (Gemini South) and Hee-Won Lee (Sejong University) and the event was funded by the Gemini Observatory and Korea Astronomy and Space Science Institute (KASI).

    See the full article here .

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

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    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.

     
  • richardmitnick 11:49 am on November 21, 2016 Permalink | Reply
    Tags: , , Gemini Observatory,   

    From Gemini: “Are All Stars Created Equal?” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    November 14, 2016
    Science Contacts:

    Alessio Caratti o Garatti
    Dublin Institute for Advanced Studies
    Email: alessio”at”cp.dias.ie
    Office: +353 1 4406656 ext.342
    Cell: +353 87 1091628

    Bringfried Stecklum
    Thüringer Landessternwarte Tautenburg
    Email: stecklum”at”tls-tautenburg.de
    Office: +49 36427 863
    Cell: +49 179 38088401

    Media Contact:

    Peter Michaud
    Gemini Observatory
    Hilo, Hawai‘i
    Email: pmichaud”at”gemini.edu
    Cell: (808) 936-6643

    1
    Artist’s impression of an accretion burst in a high-mass young stellar object like S255 NIRS 3. Image Credit: Deutsches SOFIA Institut (DSI)

    Astronomers using critical observations from the Gemini Observatory have found the strongest evidence yet that the formation of more massive stars follow a path similar to their lower-mass brethren – but on steroids!

    3
    Pre-outburst (left) and outburst (middle) near-infrared images (K, H, J bands) of the high-mass young stellar object S255IR NIRS 3, taken
    from 2009 UKIDSS archive data and the PANIC camera (Calar Alto Observatory, Man-Planck Society) in 2016, respectively, as well as
    outburst mid-infrared images (right) taken with FORCAST / SOFIA at 7.7, 19.7 and 31.5 microns (2016). Copyright: Caratti o Garatti.

    The new findings, that include data from Gemini, SOFIA, Calar Alto, and the European Southern Observatory, show that the episodic explosive outbursts within what are called accretion disks, known to occur during the formation of average mass stars like our Sun, also happen in the formation of very massive stars.

    “These outbursts, which are several orders of magnitude larger than their lower mass siblings, can release about as much energy as our Sun delivers in over 100,000 years,” said Dr. Alessio Caratti o Garatti of the Dublin Institute for Advanced Studies (Ireland). “Surprisingly, fireworks are observed not just at the end of the lives of massive stars, as supernovae, but also at their birth!”

    The international team of astronomers (led by Caratti o Garatti) published their work in the November 14th issue of the journal Nature Physics, presenting the first clear case that massive stars can form from clumpy disks of material – in much the same way as less massive stars. Previously it was thought that the accretion disks seen around lower mass stars would not survive around stars of higher mass due to their strong radiation pressure. Therefore, some other process would be necessary to account for the existence of more massive stars – which can exceed 50-100 times the mass of our Sun.

    “How accretion disks can survive around these massive stars is still a mystery, but the Gemini spectroscopic observations show the same fingerprints we see in lower mass stars,” said Caratti o Garatti. “Probably the accretion bursts reduce the radiation pressure of the central source and allow the star to form, but we still have a lot of explaining to do in order to account for these observations.”

    According to team member Dr. Bringfried Stecklum of the Thüringer Landessternwarte Tautenburg (Germany), “Studying the formation of high-mass stars is challenging because they are relatively rare and deeply embedded in their natal cloud, thus not visible in optical, or visible, light. This is why we need infrared instruments like the Near-infrared Integral Field Spectrograph (NIFS) at Gemini North on Maunakea in Hawai‘i.” The outburst events are also very rapid, probably lasting only a few years or less – which, for a star, is the blink of an eye, adding to their rarity.

    “The birth of truly massive stars has been a mystery that astronomers have been studying for decades. Only now, with large, infrared-optimized telescopes like Gemini, are we able to probe the details of this short-lived and, now it seems, rather explosive process,” notes Chris Davis, Program Director at the National Science Foundation which supports the operation of the Gemini Observatory and the development of its instruments. “These NIFS observations represent yet another coup for the Gemini Observatory.”

    The developing star observed in this study, S255IR NIRS 3, is relatively distant, some 6,000 light years away, with a mass estimated at about 20 times the mass of our Sun. The Gemini observations reveal that the source of the explosive outburst is a huge clump of gas, probably about twice the mass of Jupiter, accelerated to supersonic speeds and ingested by the forming star. The team estimates that the outburst began about 16 months ago and according to Caratti o Garatti it appears that the outburst is still active, but much weaker.

    “While low-mass stars, and possible planetary systems, can form basically next door to our Sun, the formation of high-mass stars is a complex and relatively rapid process that tends to happen rather far away in our galaxy, thousands, or even tens of thousands of light years away,” said Caratti o Garatti. He adds that the formation of these massive stars happens on timescales of 100,000 years, whereas it takes hundreds of times longer for lower mass stars like our Sun to form. “When we study the formation of higher mass stars it’s like watching a timelapse move when compared to less massive stars, although the process for massive stars is fast and furious, it still takes tens of thousands of years!”

    “While this research presents the strongest case yet for similar formation processes for low and high mass stars, there is still lots to understand,” concludes Stecklum. “Especially whether planets can form in the same way around stars at both ends of the mass spectrum.”

    Original Publication:
    Disk-mediated accretion burst in a high-mass young stellar object, A. Caratti o Garatti, B. Stecklum, R. Garcia Lopez, J. Eislöffel, T. P. Ray, A. Sanna, R. Cesaroni, C. M.Walmsley, R. D. Oudmaijer,W. J. deWit, L. Moscadelli, J. Greiner, A. Krabbe, C. Fischer, R. Klein and J. M. Ibañez , Nature Physics Journal Nov. 14 th 2016, DOI: 10.1038/NHPYS3942.

    See the full article here .

    Deutsches SOFIA Institute Release

    Please help promote STEM in your local schools.

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    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    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.

     
  • richardmitnick 6:29 pm on October 13, 2016 Permalink | Reply
    Tags: , , Cluster’s Advanced Age in Razor-sharp Focus, Gemini Observatory, NGC 6624   

    From Gemini: “Cluster’s Advanced Age in Razor-sharp Focus” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    October 11, 2016
    Science Contacts:

    Sara Saracino
    Department of Physics and Astronomy
    University of Bologna, Italy
    Email: sara.saracino”at”unibo.it
    Office: +39 051 2095788
    Cell: +39 3201607913

    Douglas Geisler
    Departamento de Astronomia
    Universidad de Concepción, Chile
    Email: dgeisler”at”astroudec.cl
    Office: 56-41-2203092
    Cell: 56-9-93078848

    Media Contacts:

    Peter Michaud
    Gemini Observatory
    Hilo, Hawai‘i
    Email: pmichaud”at”gemini.edu
    Cell: (808) 936-6643

    Manuel Paredes
    Gemini Observatory
    La Serena, Chile
    Email: mparedes”at”gemini.edu
    Phone: +56 (51) 2205671

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    Gemini Observatory GeMS image of NGC 6624 revealing individual stars to the cluster’s core. The Cluster’s age as determined with this study is between 11.5-12.5 billion years old, which confirms that it formed when the Universe was only a fraction of its current age of about 13.8 billion years. Composite color image by Travis Rector, University of Alaska Anchorage. Image Credit: Gemini Observatory/AURA.

    An international team of astronomers, using the Gemini Multi-conjugate adaptive optics System (GeMS) and the high resolution camera GSAOI, brought the ancient globular cluster NGC 6624 into razor-sharp focus and determined its age with very high accuracy - a challenging observation even from space.

    Gemini/GeMS
    Gemini/GeMS

    Gemini GSAOI instrument
    Gemini GSAOI instrument

    In addition to producing a beautiful image, this work ultimately helps astronomers to better understand the formation and evolution of our Galaxy during its earliest development when the Universe was less than two billion years old.

    Researchers using advanced adaptive optics technology at the Gemini South telescope in Chile probed the depths of the highly compact globular cluster NGC 6624, revealing pinpoint images of thousands of stars. The sharpness of the near-infrared images is competitive with that obtained from space with the Hubble Space Telescope in optical light. “With images this sharp, astronomers can do things that we never dreamed were possible from the ground,” says team member Douglas Geisler of the University of Concepción in Chile.

    The team obtained the imaging data using two filters that are sensitive to specific wavelength bands of near-infrared light, then plotted them on a color-magnitude diagram – a technique that reveals details about the evolutionary history of the cluster’s stars. According to first author Sara Saracino from the University of Bologna, this is the most accurate, and deepest, near-infrared color-magnitude diagram ever produced of this cluster and indeed perhaps the best-ever made for any bulge cluster. The results of this research will be published in The Astrophysical Journal.

    The observations provide a clear detection of the so-called “main-sequence knee,” a distinctive bend in the evolutionary track of low mass main-sequence stars (those that burn hydrogen into helium at their cores). This feature is extremely faint and therefore difficult to detect, requiring very precise photometry (measuring the brightness of individual stars). Photometry is generally a problem with most adaptive optics data.

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    The color-magnitude diagrams of NGC6624 obtained from the Gemini observations. All the main evolutionary sequences of the cluster are easily visible. These NIR diagrams turn out to be comparable to the HST optical ones, both in depth and in photometric accuracy. The photometric errors for each bin of Ks and J magnitudes are shown on the right side of the panels.

    This is the first time the main-sequence knee has been identified in this globular cluster. “Analysis of these razor-sharp images, and the very deep color-magnitude diagram, allows us to determine the age of the cluster to extremely high precision,” says Saracino. In turn, this helps to better understand the formation and evolution of our Milky Way bulge, which may well be the oldest component of the Galaxy. The new Gemini data reveal that the age of NGC 6624 is between 11.5-12.5 billion years old, almost as old as the Universe itself - estimated to be about 13.8 billion years old.

    NGC 6624 is also interesting because it has been classified as what astronomers call a post-core collapse cluster, meaning that this is a highly evolved system. The high quality of the data also allowed the researchers to perform a detailed study of the distribution of main-sequence stars of different masses outward from the center. As expected for such a highly evolved system, the team found evidence of a significant increase in low-mass stars at increasing distances from the cluster center.

    This study is part of a much larger research program aimed at shedding new light on the still debated processes that formed the Milky Way’s bulge using its globular cluster population. Due to the large amount of absorption by material between the stars in the Milky Way Galaxy, detailed studies of bulge globular clusters have been severely hampered until now. Geisler notes that the advent of the GeMS instrument now allows astronomers to penetrate the dust and study these clusters in the great detail they deserve. “It will certainly continue to provide us with very important clues about how our Galaxy formed and evolved,” he says.

    The Gemini Multi-conjugate adaptive optics System (GeMS), combined with the Gemini South Adaptive Optics Imager (GSAOI), delivers near diffraction-limited images of near-infrared light (0.9-2.5 microns), over a field nearly as large as the Hubble Space Telescope’s Wide Field Camera 3 (WFC3). Using five artificial laser guide stars, and up to three natural guide stars, GeMS/GSAOI can correct for atmospheric turbulence at an unprecedented level, making it the most powerful wide-field adaptive optics system currently available to astronomers.

    See the full article here .

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    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
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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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