Tagged: Gemini Observatory Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 9:18 am on March 22, 2019 Permalink | Reply
    Tags: , , , , , Gemini Observatory, , HP 1   

    From Gemini Observatory: “Ultra-sharp Images Make Old Stars Look Absolutely Marvelous! “ 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    March 21, 2019

    Media Contact:

    Peter Michaud
    Public Information and Outreach manager
    Gemini Observatory
    Email: pmichaud”at”gemini.edu
    Desk: 808-974-2510
    Cell: 808-936-6643

    Science Contacts:

    Leandro Kerber
    Universidade Estadual de Santa Cruz, Brazil
    Email: lokerber”at”uesc.br
    Cell: +55 11 94724-6073
    Desk: +55 73 3680-5167

    1
    Figure 1. Color composite GSAOI+GeMS image of HP 1 obtained using the Gemini South telescope in Chile. North is up and East to the left. Composite image produced by Mattia Libralato of the Space Telescope Science Institute. Credit: Gemini Observatory/AURA/NSF.

    2
    GSAOI+GeMS color composite image of HP 1 (right image) shown relative to the full field of the cluster obtained by the Visible and Infrared Survey Telescope for Astronomy (left). Credit: Gemini Observatory/NSF/AURA/VISTA/Aladin/CDS.

    Part of ESO’s Paranal Observatory, the VLT Survey Telescope (VISTA) observes the brilliantly clear skies above the Atacama Desert of Chile. It is the largest survey telescope in the world in visible light.
    Credit: ESO/Y. Beletsky, with an elevation of 2,635 metres (8,645 ft) above sea level

    Using high-resolution adaptive optics imaging from the Gemini Observatory, astronomers have uncovered one of the oldest star clusters in the Milky Way Galaxy. The remarkably sharp image looks back into the early history of our Universe and sheds new insights on how our Galaxy formed.

    Just as high-definition imaging is transforming home entertainment, it is also advancing the way astronomers study the Universe.

    “Ultra-sharp adaptive optics images from the Gemini Observatory allowed us to determine the ages of some of the oldest stars in our Galaxy,” said Leandro Kerber of the Universidade de São Paulo and Universidade Estadual de Santa Cruz, Brazil. Kerber led a large international research team that published their results in the April 2019 issue of the Monthly Notices of the Royal Astronomical Society.

    Gemini Observatory Adaptie Optics-Gemini South on the summit of Cerro Pachón in Chile (left) and Gemini North on the summit of Mauna Kea in Hawai’i, USA (right). Image credit Gemini/NSF/AURA

    Using advanced adaptive optics technology at the Gemini South telescope in Chile, the researchers zoomed in on a cluster of stars known as HP 1. “Removing our atmosphere’s distortions to starlight with adaptive optics reveals tremendous details in the objects we study,” added Kerber. “Because we captured these stars in such great detail, we were able to determine their advanced age and piece together a very compelling story.”

    That story begins just as the Universe was reaching its one-billionth birthday.

    “This star cluster is like an ancient fossil buried deep in our Galaxy’s bulge, and now we’ve been able to date it to a far-off time when the Universe was very young,” said Stefano Souza, a PhD student at the Universidade de São Paulo, Brazil, who worked with Kerber as part of the research team. The team’s results date the cluster at about 12.8 billion years, making these stars among the oldest ever found in our Galaxy. “These are also some of the oldest stars we’ve seen anywhere,” added Souza.

    “HP 1 is one of the surviving members of the fundamental building blocks that assembled our Galaxy’s inner bulge,” said Kerber. Until a few years ago, astronomers believed that the oldest globular star clusters — spherical swarms of up to a million stars — were only located in the outer parts of the Milky Way, while the younger ones resided in the innermost Galactic regions. However, Kerber’s study, as well as other recent work based on data from the Gemini Observatory and the Hubble Space Telescope (HST), have revealed that ancient star clusters are also found within the Galactic bulge and relatively close to the Galactic center.

    Globular clusters tell us much about the formation and evolution of the Milky Way. Most of these ancient and massive stellar systems are thought to have coalesced out of the primordial gas cloud that later collapsed to form the spiral disk of our Galaxy, while others appear to be the cores of dwarf galaxies consumed by our Milky Way. Of the roughly 160 globular clusters known in our Galaxy, about a quarter are located within the greatly obscured and tightly packed central bulge region of the Milky Way. This spherical mass of stars some 10,000 light years across forms the central hub of the Milky Way (the yolk if you will) which is made primarily of old stars, gas, and dust. Among the clusters within the bulge, those that are the most metal-poor (lacking in heavier elements) – which includes HP 1 – have long been suspected of being the oldest. HP 1 then is pivotal, as it serves as an excellent tracer of our Galaxy’s early chemical evolution.

    “HP 1 is playing a critical role in our understanding of how the Milky Way formed,” Kerber said. “It is helping us to bridge the gap in our understanding between our Galaxy’s past and its present.”

    Kerber and his international team used the exquisitely deep high-resolution adaptive optics images from Gemini Observatory as well as archival optical images from the HST to identify faint cluster members, which are essential for age determination. With this rich data set they confirmed that HP 1 is a fossil relic born less than a billion years after the Big Bang, when the Universe was in its infancy.

    “These results crown an effort of more than two decades with some of the world’s premier telescopes aimed at determining accurate chemical abundances with high-resolution spectroscopy,” said Beatriz Barbuy of the Universidade de São Paulo, coauthor of this paper and a world-renowned expert in this field. “These Gemini images are the best ground-based photometric data we have. They are at the same level of HST data, allowing us to recover a missing piece in our puzzle: the age of HP 1. From the existence of such old objects, we can attest to the short star formation timescale in the Galactic bulge, as well as its fast chemical enrichment.”

    To determine the cluster’s distance, the team used archival ground-based data to identify 11 RR Lyrae variable stars (a type of “standard candle” used to measure cosmic distances) within HP 1. The observed brightness of these RR Lyrae stars indicate that HP 1 is at a distance of about 21,500 light years, placing it approximately 6,000 light years from the Galactic center, well within the Galaxy’s central bulge region.

    Kerber and his team also used the Gemini data, as well HST, Very Large Telescope, and Gaia mission data, to refine the orbit of HP 1 within our Galaxy. This analysis shows that during HP 1’s history, the cluster came as close as about 400 light years from the Galactic center – less than one-tenth of its current distance.

    NASA/ESA Hubble Telescope

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    ESA/GAIA satellite

    “The combination of high angular resolution and near-infrared sensitivity makes GeMS/GSAOI an extremely powerful tool for studying these compact, highly dust-enshrouded stellar clusters,” added Mattia Libralato of the Space Telescope Science Institute, a coauthor on the study. “Careful characterization of these ancient systems, as we’ve done here, is paramount to refine our knowledge of our Galaxy’s formation.”

    Chris Davis, Program Officer at the National Science Foundation (NSF) for Gemini, commented, “These fabulous results demonstrate why the development of wide-field, high-resolution imaging at Gemini is key to the Observatory’s future. The recent NSF award to support the development of a similar system at Gemini North will make routine super-sharp imaging from both hemispheres a reality. These are certainly exciting times for the Observatory.”

    The Gemini observations resolve stars to about 0.1 arcsecond which is one 36 thousandths of a degree and comparable to separating two automobile headlamps from approximately 1,500 miles, or 2,500 kilometers, away (the distance from Manaus to Sao Paulo in Brazil, or from San Francisco to Dallas in the USA). This resolution was obtained using the Gemini South Adaptive Optics Imager (GSAOI) – a near-infrared adaptive optics camera used with the Gemini Multi-conjugate adaptive optics System (GeMS). GeMS is an advanced adaptive optics system utilizing three deformable mirrors to correct for distortions imparted on starlight by turbulence in layers of our atmosphere.

    See the full article here .


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


    Stem Education Coalition

    NOAO Gemini North on MaunaKea, Hawaii, USA, Altitude 4,213 m (13,822 ft)

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

    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 12:29 pm on February 7, 2019 Permalink | Reply
    Tags: , , , , “When we look at the information ALMA has provided we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chloride coming from the disk", , , Gemini Observatory, Liberal Sprinkling of Salt Discovered around a Young Star, , Orion Source I, , The chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, The Orion Molecular Cloud 1   

    From ALMA: “Liberal Sprinkling of Salt Discovered around a Young Star” 

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

    From ALMA

    7 February, 2019

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory Santiago – Chile
    Phone: +56 2 2467 6258
    Cell phone: +56 9 7587 1963
    Email: valeria.foncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Phone: +1 434 296 0314
    Cell phone: +1 202 236 6324
    Email: cblue@nrao.edu

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: calum.turner@eso.org

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory
, Tokyo – Japan
    Phone: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    1
    Artist impression of Orion Source I, a young, massive star about 1,500 light-years away. New ALMA observations detected a ring of salt — sodium chloride, ordinary table salt — surrounding the star. This is the first detection of salts of any kind associated with a young star. The blue region (about 1/3 the way out from the center of the disk) represents the region where ALMA detected the millimeter-wavelength “glow” from the salts. Credit: NRAO/AUI/NSF; S. Dagnello

    2
    ALMA image of the salty disk surrounding the young, massive star Orion Source I (blue ring). It is shown in relation to the Orion Molecular Cloud 1, a region of explosive starbirth. The background near infrared image was taken with the Gemini Observatory. Credit: ALMA (NRAO/ESO/NAOJ); NRAO/AUI/NSF; Gemini Observatory/AURA

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

    A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula.

    “It’s amazing we’re seeing these molecules at all,” said Adam Ginsburg, a Jansky Fellow of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and lead author of a paper accepted for publication in The Astrophysical Journal. “Since we’ve only ever seen these compounds in the sloughed-off outer layers of dying stars, we don’t fully know what our new discovery means. The nature of the detection, however, shows that the environment around this star is very unusual.”

    To detect molecules in space, astronomers use radio telescopes to search for their chemical signatures – telltale spikes in the spread-out spectra of radio and millimeter-wavelength light. Atoms and molecules emit these signals in several ways, depending on the temperature of their environments.

    The new ALMA observations contain a bristling array of spectral signatures – or transitions, as astronomers refer to them – of the same molecules. To create such strong and varied molecular fingerprints, the temperature differences where the molecules reside must be extreme, ranging anywhere from 100 kelvin to 4,000 kelvin (about -175 Celsius to 3700 Celsius). An in-depth study of these spectral spikes could provide insights about how the star is heating the disk, which would also be a useful measure of the luminosity of the star.

    “When we look at the information ALMA has provided, we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chloride coming from the disk. That is both shocking and exciting,” said Brett McGuire, a chemist at the NRAO in Charlottesville, Virginia, and co-author on the paper.

    The researchers speculate that these salts come from dust grains that collided and spilled their contents into the surrounding disk. Their observations confirm that the salty regions trace the location of the circumstellar disk.

    “Usually when we study protostars in this manner, the signals from the disk and the outflow from the star get muddled, making it difficult to distinguish one from the other,” said Ginsburg. “Since we can now isolate just the disk, we can learn how it is moving and how much mass it contains. It also may tell us new things about the star.”

    The detection of salts around a young star is also of interest to astronomers and astrochemists because some of constituent atoms of salts are metals – sodium and potassium. This suggests there may be other metal-containing molecules in this environment. If so, it may be possible to use similar observations to measure the amount of metals in star-forming regions. “This type of study is not available to us at all presently. Free-floating metallic compounds are generally invisible to radio astronomy,” noted McGuire.

    The salty signatures were found about 30 to 60 astronomical units (AU, or the average distance between the Earth and the Sun) from the host stars. Based on their observations, the astronomers infer that there may be as much as one sextillion (a one with 21 zeros after it) kilograms of salt in this region, which is roughly equivalent to the entire mass of Earth’s oceans.

    “Our next step in this research is to look for salts and metallic molecules in other regions. This will help us understand if these chemical fingerprints are a powerful tool to study a wide range of protoplanetary disks, or if this detection is unique to this source,” said Ginsburg. “In looking to the future, the planned Next Generation VLA would have the right mix of sensitivity and wavelength coverage to study these molecules and perhaps use them as tracers for planet-forming disks.”

    Orion Source I formed in the Orion Molecular Cloud I, a region of explosive starbirth previously observed with ALMA. “This star was ejected from its parent cloud with a speed of about 10 kilometers per second around 550 years ago,”1 said John Bally, an astronomer at the University of Colorado and co-author on the paper. “It is possible that solid grains of salt were vaporized by shock waves as the star and its disk were abruptly accelerated by a close encounter or collision with another star. It remains to be seen if salt vapor is present in all disks surrounding massive protostars, or if such vapor traces violent events like the one we observed with ALMA.”

    1. Light from this object took about 1,500 years to reach Earth. Astronomers are seeing it as if looking through that window of time, which reveals how it looked 550 years after it was ejected from its stellar nursery.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small
    ESO 50 Large
    NAOJ

     
    • iptv 1:43 am on February 13, 2019 Permalink | Reply

      Excellent website. A lot of useful information here. I am sending it to some friends ans also sharing in delicious. And of course, thanks for your sweat!

      Like

  • richardmitnick 10:32 am on January 11, 2019 Permalink | Reply
    Tags: , , , Cosmic Telescope Zooms in on the Beginning of Time, , Gemini Observatory, Quasar known as J0439+1634,   

    From Gemini Observatory: “Cosmic Telescope Zooms in on the Beginning of Time” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    January 9, 2019

    Media Contact:

    Peter Michaud
    Public Information and Outreach manager
    Gemini Observatory
    Email: pmichaud@gemini.edu
    Desk: 808-974-2510
    Cell: 808-936-6643

    Science Contacts:

    Xiaohui Fan
    Regents’ Professor of Astronomy
    Steward Observatory
    University of Arizona
    Email: fan@as.arizona.edu
    Desk: 520-360-0956

    John Blakeslee
    Head Scientist
    Gemini Observatory, La Serena, Chile
    Email: jblakeslee@gemini.edu
    Desk: 56-51-2205-628

    The scientific result described in this release is based on a presentation at the 233rd meeting of the American Astronomical Society in Seattle, Washington and published in The Astrophysical Journal Letters. The research was sponsored by grants from the U.S. National Science Foundation (NSF) Division of Astronomical Sciences and NASA. The National Science Foundation also supports the Gemini Observatory.

    Observations from Gemini Observatory identify a key fingerprint of an extremely distant quasar, allowing astronomers to sample light emitted from the dawn of time. Astronomers happened upon this deep glimpse into space and time thanks to an unremarkable foreground galaxy acting as a gravitational lens, which magnified the quasar’s ancient light.

    Gravitational Lensing NASA/ESA

    The Gemini observations provide critical pieces of the puzzle in confirming this object as the brightest appearing quasar so early in the history of the Universe, raising hopes that more sources like this will be found.

    1
    A number of large telescopes were used to observe quasar J0439+1634 in the optical and infrared light. The 6.5m MMT Telescope was used to discovery this distant quasar.

    CfA U Arizona Fred Lawrence Whipple Observatory Steward Observatory MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA, Altitude 2,616 m (8,583 ft)

    It and the 10m Keck-I Telescope obtained a sensitive spectrum of the quasar in optical light.

    Keck 1 Telescope, Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    The 8.1m Gemini Telescope obtained an infrared spectrum that accurately determined the quasar distance and the mass of its powerful black hole.

    The 2×8.4m Large Binocular Telescope captured an adaptive optics corrected image that suggests the quasar is lensed, later confirmed by the sharper Hubble image. Credit: Feige Wang (UCSB), Xiaohui Fan (University of Arizona)

    U Arizona Large Binocular Telescope, Large Binocular Telescope Interferometer, or LBTI, is a ground-based instrument connecting two 8-meter class telescopes on Mount Graham, Arizona, USA, Altitude 3,221 m (10,568 ft.) to form the largest single-mount telescope in the world. The interferometer is designed to detect and study stars and planets outside our solar system. Image credit: NASA/JPL-Caltech.

    Before the cosmos reached its billionth birthday, some of the very first cosmic light began a long journey through the expanding Universe. One particular beam of light, from an energetic source called a quasar, serendipitously passed near an intervening galaxy, whose gravity bent and magnified the quasar’s light and refocused it in our direction, allowing telescopes like Gemini North to probe the quasar in great detail.

    “If it weren’t for this makeshift cosmic telescope, the quasar’s light would appear about 50 times dimmer,” said Xiaohui Fan of the University of Arizona who led the study. “This discovery demonstrates that strongly gravitationally lensed quasars do exist despite the fact that we’ve been looking for over 20 years and not found any others this far back in time.”

    The Gemini observations provided key pieces of the puzzle by filling a critical hole in the data. The Gemini North telescope on Maunakea, Hawai‘i, utilized the Gemini Near-InfraRed Spectrograph (GNIRS) to dissect a significant swath of the infrared part of the light’s spectrum.


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


    Gemini Near-Infrared Spectrograph on Gemini North, Mauna Kea, Hawaii USA

    The Gemini data contained the tell-tale signature of magnesium which is critical for determining how far back in time we are looking. The Gemini observations also led to a determination of the mass of the black hole powering the quasar. “When we combined the Gemini data with observations from multiple observatories on Maunakea, the Hubble Space Telescope, and other observatories around the world, we were able to paint a complete picture of the quasar and the intervening galaxy,” said Feige Wang of the University of California, Santa Barbara, who is a member of the discovery team.

    That picture reveals that the quasar is located extremely far back in time and space – shortly after what is known as the Epoch of Reionization — when the very first light emerged from the Big Bang.

    Reionization era and first stars, Caltech

    “This is one of the first sources to shine as the Universe emerged from the cosmic dark ages,” said Jinyi Yang of the University of Arizona, another member of the discovery team. “Prior to this, no stars, quasars, or galaxies had been formed, until objects like this appeared like candles in the dark.”

    The foreground galaxy that enhances our view of the quasar is especially dim, which is extremely fortuitous. “If this galaxy were much brighter, we wouldn’t have been able to differentiate it from the quasar,” explained Fan, adding that this finding will change the way astronomers look for lensed quasars in the future and could significantly increase the number of lensed quasar discoveries. However, as Fan suggested, “We don’t expect to find many quasars brighter than this one in the whole observable Universe.”

    The intense brilliance of the quasar, known as J0439+1634 (J0439+1634 for short), also suggests that it is fueled by a supermassive black hole at the heart of a young forming galaxy. The broad appearance of the magnesium fingerprint captured by Gemini also allowed astronomers to measure the mass of the quasar’s supermassive black hole at 700 million times that of the Sun. The supermassive black hole is most likely surrounded by a sizable flattened disk of dust and gas. This torus of matter — known as an accretion disk — most likely continually spirals inward to feed the black hole powerhouse. Observations at submillimeter wavelengths with the James Clerk Maxwell Telescope on Maunakea suggest that the black hole is not only accreting gas but may be triggering star birth at a prodigious rate — which appears to be up to 10,000 stars per year; by comparison, our Milky Way Galaxy makes one star per year. However, because of the boosting effect of gravitational lensing, the actual rate of star formation could be much lower.

    Quasars are extremely energetic sources powered by huge black holes thought to have resided in the very first galaxies to form in the Universe. Because of their brightness and distance, quasars provide a unique glimpse into the conditions in the early Universe. This quasar has a redshift of 6.51, which translates to a distance of 12.8 billion light years, and appears to shine with a combined light of about 600 trillion Suns, boosted by the gravitational lensing magnification. The foreground galaxy which bent the quasar’s light is about half that distance away, at a mere 6 billion light years from us.

    Fan’s team selected J0439+1634 as a very distant quasar candidate based on optical data from several sources: the Panoramic Survey Telescope and Rapid Response System1 (Pan-STARRS1; operated by the University of Hawai‘i’s Institute for Astronomy), the United Kingdom Infra-Red Telescope Hemisphere Survey (conducted on Maunakea, Hawai‘i), and NASA’s Wide-field Infrared Survey Explorer (WISE) space telescope archive.

    Pann-STARSR1 Telescope, U Hawaii, Mauna Kea, Hawaii, USA, Altitude 3,052 m (10,013 ft)


    UKIRT, located on Mauna Kea, Hawai’i, USA as part of Mauna Kea Observatory,4,207 m (13,802 ft) above sea level

    NASA Wise Telescope

    The first follow-up spectroscopic observations, conducted at the Multi-Mirror Telescope in Arizona, confirmed the object as a high-redshift quasar. Subsequent observations with the Gemini North and Keck I telescopes in Hawai‘i confirmed the MMT’s finding, and led to Gemini’s detection of the crucial magnesium fingerprint — the key to nailing down the quasar’s fantastic distance. However, the foreground lensing galaxy and the quasar appear so close that it is impossible to separate them with images taken from the ground due to blurring of the Earth’s atmosphere. It took the exquisitely sharp images by the Hubble Space Telescope to reveal that the quasar image is split into three components by a faint lensing galaxy.r.

    The quasar is ripe for future scrutiny. Astronomers also plan to use the Atacama Large Millimeter/submillimeter Array, and eventually NASA’s James Webb Space Telescope, to look within 150 light-years of the black hole and directly detect the influence of the gravity from black hole on gas motion and star formation in its vicinity.

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

    NASA/ESA/CSA Webb Telescope annotated

    Any future discoveries of very distant quasars like J0439+1634 will continue to teach astronomers about the chemical environment and the growth of massive black holes in our early Universe.

    See the full article here .


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


    Stem Education Coalition

    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

    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 3:22 pm on November 5, 2018 Permalink | Reply
    Tags: , , , , , Gemini Observatory, Tiny Old Star Has Huge Impact   

    From Gemini Observatory: “Tiny Old Star Has Huge Impact” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    November 5th, 2018

    Media Contacts:

    Peter Michaud
    Public Information and Outreach manager
    Gemini Observatory
    Email: pmichaud”at”gemini.edu
    Phone: 808-974-2510
    Cell: 808-936-6643

    Jill Rosen
    Senior Media Relations Representative
    Johns Hopkins University
    Email: jrosen”at”jhu.edu
    Desk: 443-997-9906
    Cell: 443-547-8805

    Science Contact:

    Kevin Schlaufman
    Assistant Professor of Physics and Astronomy
    Johns Hopkins University
    Email: kschlaufman”at”jhu.edu
    Office Phone: 410-516-3295
    Cell Phone: 814-490-9177

    1
    The new discovery is only 14% the size of the Sun and is the new record holder for the star with the smallest complement of heavy elements. It has about the same heavy element proportion as Mercury, the smallest planet in our solar system. Credit: Kevin Schlaufman.

    Astronomers use the Gemini Observatory to investigate a tiny star that is likely the oldest known star in the disk of our galaxy. The diminutive star could have a disproportionate impact on our understanding of the age and history of our Milky Way Galaxy. It also provides a unique glimpse into the conditions present in the young Universe shortly after the Big Bang.

    A tiny star found in our galactic neighborhood is presenting astronomers with a compelling glimpse into the history of our galaxy and the early Universe. The star has some very interesting characteristics: it’s small, it’s old, and most significantly it’s made of material very similar to that spewed by the Big Bang. To host a star like this suggests that the disk of our galaxy could be up to three billion years older than previously thought.

    “Our Sun likely descended from thousands of generations of short-lived massive stars that have lived and died since the Big Bang,” said Kevin Schlaufman of Johns Hopkins University, leader of this study published in the November 5th issue of The Astrophysical Journal. “However, what’s most interesting about this star is that it had perhaps only one ancestor separating it and the beginnings of everything,” Schlaufman adds.

    The Big Bang theory dates our Universe at about 13.7 billion years and suggests that the first stars were made almost exclusively of hydrogen and helium. As stars die and gradually recycle their materials into new stars, heavier elements formed. Astronomers refer to stars which lack heavier elements as low metallicity stars. “But this one has such low metallicity,” said Schlaufman, “it’s known as an ultra metal poor star – this star may be one in ten million.”

    The star, which goes by the designation 2MASS J18082002-5104378 B, also challenges the assumption that the first stars in the Universe were large, exclusively high-mass and short-lived stars. In addition, its location within the usually active and crowded disk of our galaxy is unexpected.

    2MASS J18082002–5104378 B is a part of a binary star system. It is the smaller companion to a larger low-metallicity star observed in 2014 and 2015 by the European Southern Observatory’s Very Large Telescope UT2.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    Before the discovery of the tiny star, astronomers mistakenly believed that this binary system might contain a black hole or neutron star. From April 2016 to July 2017, Schlaufman and his team used both the Gemini Multi-Object Spectrograph (GMOS) on the Gemini South telescope in Chile and the Magellan Clay Telescope at Las Campanas Observatory to dissect the star system’s light and measure the object’s relative motions, thus discovering the tiny star by detecting its gravitational tug on its partner.

    Las Campanas Clay Magellan telescope, located at Carnegie’s Las Campanas Observatory, Chile, approximately 100 kilometres (62 mi) northeast of the city of La Serena, over 2,500 m (8,200 ft) high

    Gemini Observatory GMOS on Gemini South

    “Gemini was critical to this discovery, as its flexible observing modes enabled weekly check-ins on the system over six months,” Schlaufman confirms.

    “Understanding the history of our own galaxy is critical for humanity to understand the broader history of the entire Universe,” said Chris Davis of the United State’s National Science Foundation (NSF). NSF funds the Gemini Observatory on behalf of the United States, additional international partners are listed at the end of this release.

    2MASS J18082002–5104378 B has only about 14% the mass of our Sun making it a red dwarf star. While average-sized stars like our Sun live for approximately 10 billion years before extinguishing their nuclear fuel, low-mass stars can burn for trillions of years.

    “Diminutive stars like these tend to shine for a very long time,” said Schlaufman. “This star has aged well. It looks exactly the same today as it did when it formed 13.5 billion years ago.”

    The discovery of 2MASS J18082002–5104378 B gives astronomers hope for finding more of these old stars which provide a glimpse at the very early Universe. Only about 30 ultra metal poor stars have been identified. “Observations such as these are paving the way to perhaps one day finding that ever elusive first generation star,” concludes Schlaufman.

    See the full article here.
    See also the Monash University article here .


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


    Stem Education Coalition

    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

    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 9:29 pm on October 17, 2018 Permalink | Reply
    Tags: , , , , Gemini Near-Infrared Spectrograph on Gemini North, , Gemini Observatory, Hawaii USA, , Sierra Remote Observatory, The core-collapse supernova 2017eaw   

    From Gemini Observatory: “Nearby Supernova Sheds Light on Ancient Dust” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    October 16, 2018

    Thanks to two allocations of Director’s Discretionary Time and a successful Fast-Turnaround program, an international team (including Gemini Emeritus Astronomer Tom Geballe, who wrote this summary on behalf of the team) used Gemini North/GNIRS to follow the evolution of the near-infrared spectrum of the core-collapse supernova 2017eaw (ccSN 2017eaw) over three semesters.

    Gemini Near-Infrared Spectrograph on Gemini North, Mauna Kea, Hawaii USA

    The data obtained from this relatively nearby event may help us to better understand the existence of dusty galaxies in the early, much more distant Universe.

    One of the unexpected discoveries in studies of the very early Universe is that many high redshift galaxies are “dusty.” These dusty galaxies exist as recently as several hundred million to a billion years after the Big Bang. The origin of this dust is somewhat of a mystery, because stars with masses similar to the Sun, which constitute the vast majority of stars in a galaxy, would not have evolved to the dust-producing stage in such a short time. Thus, there must be another source of dust in these very distant and very young galaxies.

    __________________________________________________
    Where Does Interstellar Dust Originate?

    Interstellar dust constitutes about 1% of the mass of interstellar matter in our Milky Way and in many other galaxies. It is generally understood that the origin of most of that dust is stars with masses roughly similar to that of our Sun, that became red giants and ejected their outer layers into space. Although initially almost entirely hydrogen and helium, during the red giant phase the outer layers of those stars are polluted by heavier elements such as carbon, nitrogen, oxygen, silicon, magnesium, and many others that are produced by thermonuclear reactions deep inside the stars and then mixed into the outer layers. Once the ejecta cool to temperatures lower than about 2,000 K, dust particles inevitably start to form out of these heavy elements. However, it is billions of years after these stars formed when this happens. On the other hand, core collapse supernovae live only a few millions to a few tens of millions of years before they explode, during which time they turn most of their hydrogen-rich and helium-rich interiors into vast reservoirs of heavy elements. Thus, unlike stars like the Sun, massive stars are potential dust-producers in the early Universe.
    __________________________________________________

    One possible source is the ejecta from massive stars that explode after only a few millions to a few tens of millions of years after they form, the so-called core-collapse supernovae (ccSNe).

    1
    Figure 1. Image of spiral galaxy NGC 6946 and SN 2017eaw indicated by arrow. Photo courtesy of Damian Peach, obtained on May 28th, 2017, at 10:31 UTC from the Sierra Remote Observatory, California.

    Sierra Remote Observatory in the Sierra Nevada Mountains, a mountain range in the Western United States, between the Central Valley of California and the Great Basin

    2
    The Great Basin is the largest area of contiguous endorheic watersheds in North America. It spans nearly all of Nevada, much of Oregon and Utah, and portions of California, Idaho, and Wyoming.

    While we cannot study individual supernovae in such distant galaxies, we can find examples of them in the nearby Universe. Infrared- and millimeter-wave observations of several “local” examples have revealed that ccSNe can produce copious amounts of dust — up to one solar mass for each event. Until now, however, detailed evolution of dust production in such supernovae, which can take place over several years, has only been followed in one object: the very nearby, famous, and rather unusual ccSN 1987A in the Large Magellanic Cloud. Fortuitously, our recent observations of ccSN 2017eaw in the nearby galaxy NGC 6946 provided another rare opportunity to follow that evolution in detail over an extended period. NGC 6946 is located about 7 megaparsecs away and is popularly known as the Fireworks Galaxy, because it is a prodigious supplier of supernovae (see Figure 1 and a pre-SN 2017eaw Gemini Legacy Image of NGC 6946).

    SN 2017eaw was discovered on May 14, 2017, just as its host galaxy, NGC 6946, became observable in the eastern sky before dawn. Because of its high northerly location, we saw an opportunity to follow SN 2017eaw continuously from May until December (before it became too low in the western sky to observe from Maunakea) and proposed the idea to Gemini Observatory. Thanks to two allocations of Director’s Discretionary Time and a successful Fast-Turnaround program, the team led by Jeonghee Rho (SETI Institute) was able to follow the evolution of the supernova’s near-infrared (0.84-2.52 micron) spectrum in Semesters 2017A, 2017B, and 2018A. The team also includes Tom Geballe (Gemini Observatory), Dipankar Banerjee and Vishal Joshi (Physical Research Laboratory, Ahmedabad, India), Nye Evans (Keele University, U.K.), and Luc Dessart (Universidad de Chile).

    During 2017-18, we obtained Gemini North/GNIRS (Gemini Near-InfraRed Spectrometer) data on ten dates between 22 and 387 days after the discovery. It is believed that these data represent the highest quality and most extensive near-infrared time-sequence of spectra ever obtained for a Type II-P SN, the most common type of ccSN, whose light curve has a distinctive flat stretch (called a plateau).

    The first nine of these spectra, obtained in 2017, are shown in Figure 2. While they are a goldmine of information — revealing details on elemental abundances, nucleosynthesis, changes in ionization, and velocities of the ejecta — our major goal was to witness and model the formation of the molecule carbon monoxide (CO) and dust, which is quite hot when it forms. Information on these species is contained only at the long wavelength end of the spectra, from 2.0 to 2.5 microns.

    CO is important because it is a powerful coolant of the ejecta, which aids in making dust formation possible. Its presence is clearly detected on day 124 by the sharp increase in signal near 2.30 microns, and we think it was already marginally present at day 107. The dust signature also begins at day 124, and is the flattening slope of the continuum from 2.1 microns to longer wavelengths, compared to the steadily decreasing continuum signal at shorter wavelengths, and across the entire spectrum at earlier times.

    We have used the spectra to estimate the CO mass produced by SN 2017eaw and find that it is qualitatively matched by models in the literature of a progenitor star of mass roughly 15 times that of the Sun. Fits to the continuum indicate that the temperature of the dust emitting at 2.1-2.5 microns is ~ 1,300 K and that the dust is mainly graphitic, which, unlike amorphous carbon, can condense at higher temperatures than this. Discussion of these and other results and analysis are reported in Rho et al., The Astrophysical Journal Letters, 864: L20, 2018.

    We are continuing our monitoring of SN 2017eaw in Semester 2018B; thereafter it will be too faint. In future semesters, we hope to measure additional nearby ccSNe that occur in order to estimate the frequency of CO and dust production by such SNe, as well as the masses of CO and dust produced by each.

    See the full article here .


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


    Stem Education Coalition

    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

    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 2:56 pm on September 21, 2018 Permalink | Reply
    Tags: , , , , Gemini Observatory, , GeMS “SERVS” Up Sharp Views of Young Galaxies in Early Universe, GeMS-Gemini Multi-Conjugate Adaptive Optics System, GSAOI-Gemini South Adaptive Optics Imager   

    From Gemini Observatory: “GeMS “SERVS” Up Sharp Views of Young Galaxies in Early Universe” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    1
    GeMS/GSAOI K-band image of one of the three fields targeted from the Spitzer Extragalactic Representative Volume Survey. The insets show detailed views of several distant galaxies in this field.

    Multi-conjugate adaptive optics technology at Gemini South reveals that young galaxies, with large amounts of star formation, and actively growing central black holes, were relatively compact in the early Universe.

    Gemini South Adaptive Objects laser guide star

    A team of astronomers led by Dr. Mark Lacy (National Radio Astronomy Observatory, USA) used advanced adaptive optics on the Gemini South telescope in Chile to obtain high-resolution near-infrared images of three fields from the Spitzer Extragalactic Representative Volume Survey (SERVS). Their sample includes several ultra-luminous infrared galaxies (ULIRGs) which the Herschel Space Observatory found to be undergoing large bursts of star formation within the first few billion years of the Big Bang.

    ESA/Herschel spacecraft active from 2009 to 2013

    Such galaxies have hundreds of times the infrared luminosity of a normal galaxy such as the Milky Way.

    The high-resolution GeMS images reveal that the ULIRGs have messy, irregular structures indicating that they are the product of recent galactic interactions and mergers. Lacy explains, “The fact that the disturbed morphologies of these galaxies persist into the infrared suggests that their appearance is not dominated by clumpy extinction from dust, but reflects the irregular distribution of stellar light.” Dust is highly effective at obscuring ultraviolet and blue light, but effects red and infrared light less. “These GeMS observations help reveal the physical mechanisms by which massive galaxies evolve into the objects we see today,” added Lacy.

    The team used the Gemini South Adaptive Optics Imager (GSAOI) with the Gemini Multi-Conjugate Adaptive Optics System (GeMS) to obtain K-band observations. Lacy’s team combined these Gemini data with other multiwavelength data at optical, far-infrared, and radio wavelengths to study the masses, morphologies, and star formation rates of the galaxies.

    The results of the GeMS study support previous results using the Hubble Space Telescope indicating that massive compact galaxies were more common in the early Universe than they are today.

    NASA/ESA Hubble Telescope

    The fraction of galaxies with compact structures is even higher in the GeMS data, but it is unclear whether this is due to improved resolution with GeMS or a tendency to miss the more diffuse galaxies in ground-based images that must contend with the infrared glow from the Earth’s atmosphere.

    Some of the galaxies in the study also harbor active galactic nuclei (AGN), luminous central engines powered by supermassive black holes that are actively accreting mass. The researchers found that star-forming galaxies with AGN tend to have more compact structures than ULIRGs that lack active nuclei. The team also found what appears to be a rare triple AGN system, a close grouping of three galaxies with actively growing supermassive black holes that may be headed for an imminent collision.

    “Among the sources that we examined, we have one close pair, one candidate triple black hole, and other objects with disturbed morphologies that might be late-stage mergers,” said Lacy. “Observations such as theses can therefore significantly improve the constraints on galaxy and supermassive black hole merger rates.”

    In the future, the James Webb Space Telescope (JWST) will enable studies at similar angular resolution and very high sensitivity at near-infrared wavelengths of large numbers of galaxies at these early cosmic times. However, the recent delays, and anticipated high demand for JWST, means that ground-based Multi-Conjugate Adaptive Optics systems like GeMS will continue to play an important role in targeted studies of rare infrared-bright objects in the early Universe.

    This work is published in arXiv.org.

    See the full article here .


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


    Stem Education Coalition

    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

    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 7:26 am on August 8, 2018 Permalink | Reply
    Tags: , , , , Elusive Intermediate Mass Black Hole Revealed by Cosmic Belch, Gemini Observatory   

    From Gemini Observatory: “Elusive Intermediate Mass Black Hole Revealed by Cosmic Belch” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    July 9, 2018

    1
    Gemini South GMOS spectrum (black line) of the nuclear region of the host galaxy of the observed off-center tidal disruption event, believed to be caused by an intermediate mass black hole. The best-fit model of the spectrum is shown in green, with the contribution from the stars alone indicated in red. The gray areas mark regions where the spectrum was affected by atmospheric absorption and the GMOS CCD gap. This Gemini spectrum was used to extract the stellar population properties and kinematics of the galaxy in which this unusual event occurred.

    Gemini Observatory GMOS on Gemini South

    The frustrating search for intermediate mass black holes is advancing thanks to Gemini observations of a “belch” which escaped when a black hole devoured a star. The black hole powering the blast weighed in at a few tens of thousand solar masses and is quite possibly a missing link between supermassive and stellar mass black holes.

    After 10 years of searching, an international team of astronomers used Gemini South, and space-based telescopes, to probe a luminous X-ray outburst unlike any seen before. The outburst was unusual because it appears to be the result of a “tidal disruption event” (TDE), in which a massive black hole slurps up an entire star, but this particular event did not occur within the center of a galaxy, where the most massive black holes reside.

    In their investigation, the researchers measured the mass of the black hole that powered the outburst and found it was a likely Intermediate Mass Black Hole (IMBH) candidate. IMBHs are black holes with masses between that of supermassive black holes (millions of solar masses) and stellar mass black holes (a few to tens of solar masses). Astronomers continue to argue if IMBHs exist and therefore this finding will undoubtedly undergo intense scrutiny.

    The paper, “A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster” is accepted in Nature Astronomy.

    “This is a dramatic demonstration that detecting IMBHs through X-ray flares produced by tidal disruption events in star clusters is extremely effective in looking for IMBHs,” points out Rodrigo Carrasco, an astronomer at Gemini South and a co-author of the paper.

    Dacheng Lin (University of New Hampshire) led the research and adds that previous strong TDE candidates were found in the centers of galaxies. “However, here we discovered a luminous X-ray outburst from a massive star cluster about 40,000 light years from the center of a large lenticular galaxy where it can be studied in relative isolation.” The host galaxy is about 780 million light years away and goes by the designation 6dFGS gJ215022.2-055059.

    These circumstances allowed the team to study the X-ray flare emission as the black hole devoured a star far from the center of a galaxy and away from dense stellar regions where these events are generally found. “We had a nice clean laboratory in which to study this event,” said Carrasco. “That’s what allowed us to measure this black hole so confidently and conclude that this is very likely an IMBH revealing its secrets.”

    The team used the Gemini Multi-Object Spectrograph on the Gemini South telescope in Chile with data obtained in late 2016, to determine the distance of the host galaxy and the off-centered star cluster.

    IMBHs are significantly more massive than stellar black holes – produced when massive stars die – but much less massive than supermassive black holes – which are found in the centers of most massive galaxies. The existence of IMBHs continues as an ongoing debate among astronomers since they are so difficult to find and measure.

    See the full article here .


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


    Stem Education Coalition

    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

    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 1:36 pm on August 2, 2018 Permalink | Reply
    Tags: , Gemini Observatory, , The Star that Wouldn’t Die   

    From NASA/ESA Hubble Telescope and Gemini Observatory: “Astronomers Uncover New Clues to the Star that Wouldn’t Die”(Hubble) and “Astronomers Blown Away by Historic Stellar Blast” (Gemini) 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Aug 2, 2018

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Nathan Smith
    University of Arizona, Tucson
    520-621-4513
    nathans@as.arizona.edu

    Armin Rest
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4358
    arest@stsci.edu

    1
    Brawl Among Three Rowdy Stellar Siblings May Have Triggered Eruption

    It takes more than a massive outburst to destroy the mammoth star Eta Carinae, one of the brightest known stars in the Milky Way galaxy. About 170 years ago, Eta Carinae erupted, unleashing almost as much energy as a standard supernova explosion.

    Yet that powerful blast wasn’t enough to obliterate the star, and astronomers have been searching for clues to explain the outburst ever since. Although they cannot travel back to the mid-1800s to witness the actual eruption, they can watch a rebroadcast of part of the event — courtesy of some wayward light from the explosion. Rather than heading straight toward Earth, some of the light from the outburst rebounded or “echoed” off of interstellar dust, and is just now arriving at Earth. This effect is called a light echo.

    The surprise is that new measurements of the 19th-century eruption, made by ground-based telescopes, reveal material expanding with record-breaking speeds of up to 20 times faster than astronomers expected. The observed velocities are more like the fastest material ejected by the blast wave in a supernova explosion, rather than the relatively slow and gentle winds expected from massive stars before they die.

    Based on the new data, researchers suggest that the 1840s eruption may have been triggered by a prolonged stellar brawl among three rowdy sibling stars, which destroyed one star and left the other two in a binary system. This tussle may have culminated with a violent explosion when Eta Carinae devoured one of its two companions, rocketing more than 10 times the mass of our Sun into space. The ejected mass created gigantic bipolar lobes resembling the dumbbell shape seen in present-day images.

    The Full Story

    What happens when a star behaves like it exploded, but it’s still there?

    About 170 years ago, astronomers witnessed a major outburst by Eta Carinae, one of the brightest known stars in the Milky Way galaxy. The blast unleashed almost as much energy as a standard supernova explosion.

    Yet Eta Carinae survived.

    Eta Carinae Image Credit: N. Smith, J. A. Morse (U. Colorado) et al., NASA

    An explanation for the eruption has eluded astrophysicists. They can’t take a time machine back to the mid-1800s to observe the outburst with modern technology.

    However, astronomers can use nature’s own “time machine,” courtesy of the fact that light travels at a finite speed through space. Rather than heading straight toward Earth, some of the light from the outburst rebounded or “echoed” off of interstellar dust, and is just now arriving at Earth. This effect is called a light echo. The light is behaving like a postcard that got lost in the mail and is only arriving 170 years later.

    By performing modern astronomical forensics of the delayed light with ground-based telescopes, astronomers uncovered a surprise. The new measurements of the 1840s eruption reveal material expanding with record-breaking speeds up to 20 times faster than astronomers expected. The observed velocities are more like the fastest material ejected by the blast wave in a supernova explosion, rather than the relatively slow and gentle winds expected from massive stars before they die.

    Based on this data, researchers suggest that the eruption may have been triggered by a prolonged stellar brawl among three rowdy sibling stars, which destroyed one star and left the other two in a binary system. This tussle may have culminated with a violent explosion when Eta Carinae devoured one of its two companions, rocketing more than 10 times the mass of our Sun into space. The ejected mass created gigantic bipolar lobes resembling the dumbbell shape seen in present-day images.

    The results are reported in a pair of papers by a team led by Nathan Smith of the University of Arizona in Tucson, Arizona, and Armin Rest of the Space Telescope Science Institute in Baltimore, Maryland.

    The light echoes were detected in visible-light images obtained since 2003 with moderate-sized telescopes at the Cerro Tololo Inter-American Observatory in Chile. Using larger telescopes at the Magellan Observatory and the Gemini South Observatory, both also located in Chile, the team then used spectroscopy to dissect the light, allowing them to measure theejecta’s expansion speeds. They clocked material zipping along at more than 20 million miles per hour (fast enough to travel from Earth to Pluto in a few days).

    The observations offer new clues to the mystery surrounding the titanic convulsion that, at the time, made Eta Carinae the second-brightest nighttime star seen in the sky from Earth between 1837 and 1858. The data hint at how it may have come to be the most luminous and massive star in the Milky Way galaxy.

    “We see these really high velocities in a star that seems to have had a powerful explosion, but somehow the star survived,” Smith explained. “The easiest way to do this is with a shock wave that exits the star and accelerates material to very high speeds.”

    Massive stars normally meet their final demise in shock-driven events when their cores collapse to make a neutron star or black hole. Astronomers see this phenomenon in supernova explosions where the star is obliterated. So how do you have a star explode with a shock-driven event, but it isn’t enough to completely blow itself apart? Some violent event must have dumped just the right amount of energy onto the star, causing it to eject its outer layers. But the energy wasn’t enough to completely annihilate the star.

    One possibility for just such an event is a merger between two stars, but it has been hard to find a scenario that could work and match all the data on Eta Carinae.

    The researchers suggest that the most straightforward way to explain a wide range of observed facts surrounding the eruption is with an interaction of three stars, where the objects exchange mass.

    If that’s the case, then the present-day remnant binary system must have started out as a triple system. “The reason why we suggest that members of a crazy triple system interact with each other is because this is the best explanation for how the present-day companion quickly lost its outer layers before its more massive sibling,” Smith said.

    In the team’s proposed scenario, two hefty stars are orbiting closely and a third companion is orbiting farther away. When the most massive of the close binary stars nears the end of its life, it begins to expand and dumps most of its material onto its slightly smaller sibling.

    The sibling has now bulked up to about 100 times the mass of our Sun and is extremely bright. The donor star, now only about 30 solar masses, has been stripped of its hydrogen layers, exposing its hot helium core.

    Hot helium core stars are known to represent an advanced stage of evolution in the lives of massive stars. “From stellar evolution, there’s a pretty firm understanding that more massive stars live their lives more quickly and less massive stars have longer lifetimes,” Rest explained. “So the hot companion star seems to be further along in its evolution, even though it is now a much less massive star than the one it is orbiting. That doesn’t make sense without a transfer of mass.”

    The mass transfer alters the gravitational balance of the system, and the helium-core star moves farther away from its monster sibling. The star travels so far away that it gravitationally interacts with the outermost third star, kicking it inward. After making a few close passes, the star merges with its heavyweight partner, producing an outflow of material.

    In the merger’s initial stages, the ejecta is dense and expanding relatively slowly as the two stars spiral closer and closer. Later, an explosive event occurs when the two inner stars finally join together, blasting off material moving 100 times faster. This material eventually catches up with the slow ejecta and rams into it like a snowplow, heating the material and making it glow. This glowing material is the light source of the main historical eruption seen by astronomers a century and a half ago.

    Meanwhile, the smaller helium-core star settles into an elliptical orbit, passing through the giant star’s outer layers every 5.5 years. This interaction generates X-ray emitting shock waves.

    A better understanding of the physics of Eta Carinae’s eruption may help to shed light on the complicated interactions of binary and multiple stars, which are critical for understanding the evolution and death of massive stars.

    The Eta Carinae system resides 7,500 light-years away inside the Carina nebula, a vast star-forming region seen in the southern sky.

    The team published its findings in two papers, which appear online Aug. 2 in The Monthly Notices of the Royal Astronomical Society.

    The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

    The science paper by N. Smith et al. MNRAS

    The science paper by N. Smith et al. MNRAS

    Gemini Observatory’s Release

    August 2nd, 2018
    Gemini Observatory Press Release
    Astronomers Blown Away by Historic Stellar Blast

    3
    This sequence of images show’s an artist’s conception of the expanding blast wave from Eta Carinae’s 1843 eruption. The first image shows the star as it may have appeared before the eruption, as a hot blue supergiant star surrounded by an older shell of gas that was ejected in a previous outburst about 1,000 years ago. Then in 1843, Eta Carinae suffered its explosive giant outburst, which created the well-known two-lobed “Homunculus” nebula, plus a fast shock wave porpagating ahead of the Homunculus. New evidence for this fast material is reported here. As time procedes, both the faster shock wave and the denser Homunculus nebula expand and fill the interior of the old shell. Eventually, we see that the faster blast wave begins to catch-up with and overtake parts of the older shell, producing a bright fireworks display that heats the older shell. See: https://www.gemini.edu/node/11120 for more images.

    Media Contact:

    Peter Michaud
    Public Information and Outreach manager
    Gemini Observatory
    Email: pmichaud”at”gemini.edu
    Phone: 808-974-2510
    Cell: 808-936-6643

    Science Contacts

    Nathan Smith
    Associate Professor
    Department of Astronomy and Steward Observatory
    University of Arizona
    E-mail: nathans”at”as.arizona.edu
    Desk: 520-621-4513

    Armin Rest
    Associate Astronomer
    Space Telescope Science Institute
    E-mail: arest”at”stsci.edu
    Desk: 410-338-4358
    Cell: 443-794-4838

    Observations from the Gemini South and other telescopes in Chile played a critical role in understanding light echoes from a stellar eruption which occurred almost 200 years ago. Gemini spectroscopy shows that ejected material from the blast is the fastest ever seen from a star that remained intact.


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

    Imagine traveling to the Moon in just 20 seconds! That’s how fast material from a 170 year old stellar eruption sped away from the unstable, eruptive, and extremely massive star Eta Carinae.

    Astronomers conclude that this is the fastest jettisoned gas ever measured from a stellar outburst that didn’t result in the complete annihilation of the star.

    The blast, from the most luminous star known in our galaxy, released almost as much energy as a typical supernova explosion that would have left behind a stellar corpse. However, in this case a double-star system remained and played a critical role in the circumstances that led to the colossal blast.

    Over the past seven years a team of astronomers led by Nathan Smith, of the University of Arizona, and Armin Rest, of the Space Telescope Science Institute, determined the extent of this extreme stellar blast by observing light echoes from Eta Carinae and its surroundings.

    Light echos occur when the light from bright, short-lived events are reflected off of clouds of dust, which act like distant mirrors redirecting light in our direction. Like an audio echo, the arriving signal of the reflected light has a time delay after the original event due to the finite speed of light. In the case of Eta Carinae, the bright event was a major eruption of the star that expelled a huge amount of mass back in the mid-1800s during what is known as the “Great Eruption.” The delayed signal of these light echoes allowed astronomers to decode the light from the eruption with modern astronomical telescopes and instruments, even though the original eruption was seen from Earth back in the mid-19th century. That was a time before modern tools like the astronomical spectrograph were invented.

    “A light echo is the next best thing to time travel,” Smith said. “That’s why light echoes are so beautiful. They give us a chance to unravel the mysteries of a rare stellar eruption that was witnessed 170 years ago, but using our modern telescopes and cameras. We can also compare that information about the event itself with the 170-year old remnant nebula that was ejected. This was a behemoth stellar explosion from a very rare monster star, the likes of which has not happened since in our Milky Way Galaxy.”

    The Great Eruption temporarily promoted Eta Carinae to the second brightest star visible in our nighttime sky, vasty outshining the energy output every other star in the Milky Way, after which the star faded from naked eye visibility. The outburst expelled material (about 10 times more than the mass of our Sun) that also formed the bright glowing gas cloud known as the Homunculus. This dumbbell-shaped remnant is visible surrounding the star from within a vast star-forming region. The eruptive remnant can even be seen in small amateur telescopes from the Earth’s Southern Hemisphere and equatorial regions, but is best seen in images obtained with the Hubble Space Telescope.

    The team used instruments on the 8-meter Gemini South telescope, Cerro Tololo Inter-American Observatory 4-meter Blanco telescope, and the Magellan Telescope at Las Campanas Observatory to decode the light from these light echoes and to understand the expansion speeds in the historical explosion.


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

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high

    “Gemini spectroscopy helped pin down the unprecedented velocities we observed in this gas, which clocked in at between about 10,000 to 20,000 kilometers per second,” according to Rest. The research team, Gemini Observatory, and Blanco telescope are all supported by the U.S. National Science Foundation (NSF).

    “We see these really high velocities all the time in supernova explosions where the star is obliterated.” Smith notes. However, in this case the star survived, and explaining that led the researchers into new territory. “Something must have dumped a lot of energy into the star in a short amount of time,” said Smith. The material expelled by Eta Carinae is travelling up to 20 times faster than expected for typical winds from a massive star so, according to Smith and his collaborators, enlisting the help of two partner stars might explain the extreme outflow.

    The researchers suggest that the most straightforward way to simultaneously explain a wide range of observed facts surrounding the eruption and the remnant star system seen today is with an interaction of three stars, including a dramatic event where two of the three stars merged into one monster star. If that’s the case, then the present-day binary system must have started out as triple system, with one of those two stars being the one that swallowed its sibling.

    “Understanding the dynamics and environment around the largest stars in our galaxy is one of the most difficult areas of astronomy,” said Richard Green, Director of the Division of Astronomical Sciences at NSF, the major funding agency for Gemini. “Very massive stars live short lives compared to stars like our Sun, but nevertheless catching one in the act of a major evolutionary step is statistically unlikely. That’s why a case like Eta Carinae is so critical, and why NSF supports this kind of research.”

    Chris Smith, Head of Mission at the AURA Observatory in Chile and also part of the research team adds a historical perspective. “I’m thrilled that we can see light echoes coming from an event that John Herschel observed in the middle of the 19th century from South Africa,” he said. “Now, over 150 years later we can look back in time, thanks to these light echoes, and unveil the secrets of this supernova wannabe using the modern instrumentation on Gemini to analyze the light in ways Hershel couldn’t have even imagined!”

    Eta Carinae is an unstable type of star known as a Luminous Blue Variable (LBV), located about 7,500 light years from Earth in a young star forming nebula found in the southern constellation of Carinae. The star is one of the intrinsically brightest in our galaxy and shines some five million times brighter than our Sun with a mass about one hundred times greater. Stars like Eta Carinae have the greatest mass-loss rates prior to undergoing supernova explosions, but the amount of mass expelled in Eta Carinae’s 19th century Great Eruption exceeds any others known.

    Eta Carinae will probably undergo a true supernova explosion sometime within the next half-million years at most, but possibly much sooner. Some types of supernovae have been seen to experience eruptive blasts like that of Eta Carinae in only the few years or decades before their final explosion, so some astronomers speculate that Eta Carinae might blow sooner rather than later.

    The Gemini Observations utilized the Gemini Multi-Object Spectrograph on the Gemini South telescope in Chile and used a powerful technique called Nod and Shuffle that enables greatly improved spectroscopic measurements of extremely faint sources by reducing the contaminating effects of the night sky.

    Gemini Observatory GMOS on Gemini South

    The new results are presented in two papers accepted for publication in the Monthly Notices of the Royal Astronomical Society.

    See the full Hubble article here .
    See the full Gemini article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

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

    ESA50 Logo large

    AURA Icon

    NASA image

     
  • richardmitnick 5:05 pm on June 4, 2018 Permalink | Reply
    Tags: , , , Can Exoplanets Form in a Binary Star System?, , Gemini Observatory,   

    From Gemini Observatory: “Can Exoplanets Form in a Binary Star System?” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    May 31, 2018

    1
    Artist interpretation of a close binary star system in which several planets orbit the brighter star. The fainter companion star looms brightly in the sky (upper right). A recent investigation confirms that the presence of a stellar pair does not interfere in planet formation. The study finds that approximately half of the stars harboring exoplanets are binary. Image credit: Robin Dienel, courtesy of the Carnegie Institution for Science.

    A new study using Gemini data reveals that the ratio of binary stars in Kepler’s K2 exoplanet host stars is similar to that found elsewhere in our neighborhood of the Milky Way. According to lead author Dr. Rachel Matson of NASA’s Ames Research Center, “While we have known that about 50% of all stars are binary, to confirm a similar ratio in exoplanet host stars helps set some important constraints on the formation of potential exoplanets seen by Kepler.”

    Until recently, astronomers generally focused on single exoplanet host stars, believing that planets form primarily around lone stars like our Sun. However, the research led by Matson, who’s team observed 206 star systems, demonstrates that the influence of a neighboring star does not appear to deter planet formation. The presence of a very close neighboring star produces enormous collateral effects on a planetary system, possibly ejecting planets into interstellar space, or gravitationally interfering with their formation and orbits.

    “In our sample we did not find evidence that the proximity of a companion star suppresses the formation of exoplanets, even at distances as small as 50 Astronomical Units, which is similar to the distance between the Sun and the edge of the Kuiper belt,” explained Matson.

    Dr. Steve Howell, Space Science & Astrobiology Division Chief at NASA Ames Research Center, a co-author of the study and leader of the Gemini Observatory high-resolution imaging effort, said, “We now have found that about half of the stars that host exoplanets are binary, both in the Kepler sample and now in the K2 sample, telling us we cannot ignore such systems and need to take them into account in our exoplanet studies.“

    The researchers used observations from the Gemini North and South telescopes, and the WIYN telescope using the Differential Speckle Survey Instrument (DSSI), for the high-resolution imaging of the K2 stars.

    NOAO WIYN telescope DSSI Differential Speckle Survey Instrument


    NOAO WIYN 3.5 meter telescope at Kitt Peak, AZ, USA, Altitude 2,096 m (6,877 ft)

    The paper is accepted for publication in The Astrophysical Journal.

    A preprint of the paper can be found here.

    See the full article here .


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


    Stem Education Coalition

    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

    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 7:44 am on May 10, 2018 Permalink | Reply
    Tags: , , , , Gemini Observatory, Massive Cluster Galaxies Move in Unexpected Ways   

    From Gemini Observatory: “Massive Cluster Galaxies Move in Unexpected Ways” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    1
    Figure 1. MS0440+02 galaxy cluster. The central galaxy is a multi-component BCG formed by six bright elliptical spheroids, all at the same redshift. This is a color composite GMOS South image (g, r, i) of the clusters. The size of the image is 2.6 x 2.6 arcmin2 (N up, E left). Credit: R. Carrasco (Gemini Observatory/AURA) and Tomás Verdugo (UNAM).

    2
    Figure 2. The slope η of the velocity dispersion profile is plotted against the central velocity dispersion σ0 for galaxies in multiple different samples. The blue points represent brightest galaxies in groups (BGGs) of high (square) and low (circles) density, while the green, red, and yellow points represent brightest cluster galaxies (BCGs) in various samples of galaxy clusters. The grey points indicate generic “early-type galaxies” (ETGs). The slope η is negative if the velocity dispersion decreases with radius and positive if it rises. Thus, massive BCGs tend to have rising profiles, with the stellar velocities responding to the cluster potential at larger radii. [Reproduced from Loubser et al. 2018, MNRAS, in press.]

    Astronomers using data from both of the Gemini Multi-Object Spectrographs (GMOS – North and South) measured the motions of stars within a sample of 32 massive elliptical cluster galaxies and found the stellar motions inconsistent with these galaxies’ solitary cousins.

    Gemini Observatory GMOS on Gemini South


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

    GEMINI/North GMOS


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

    The galaxies chosen are known as brightest cluster galaxies (BCGs) because they are the brightest members of large galaxy clusters. The international team of astronomers obtained Gemini spectra to find the relative velocities of stars within each galaxy and then determine the central stellar velocity dispersions and radial dispersion profiles for each galaxy. “This is similar to what we see in our own Solar System with the different velocities of the planets around the Sun,” said John Blakeslee, Gemini Observatory’s Head of Science. “We use the planets’ velocities to determine our Solar System’s mass distribution and it is also how we know the Sun’s mass accurately.”

    The researchers discovered a surprising variety in the shapes of the velocity dispersion profiles for the BCGs, with a large fraction showing rising dispersion profiles (Figure 2). A rising velocity dispersion profile means that the stars within these galaxies are moving faster as you look further from the galaxy’s core in response to an increasing gravitational force. In comparison, rising velocity dispersion profiles are much rarer in other massive ellipticals that are not BCGs, including many brightest galaxies in groups (BGGs).

    “You would naively think that massive elliptical galaxies are a homogeneous, well-behaved class of objects, but the most massive beasts, those in the centers of groups and clusters, continue to surprise us,” said Ilani Loubser, an astronomer at North-West University in South Africa and the lead author of the study, which has been accepted for publication in Monthly Notices of the Royal Astronomical Society. She also noted, “The quality, and the wealth of information we can measure from the GMOS spectra (even in poor weather), is remarkable!”

    BCGs tend to reside near the centers of their respective clusters, and are therefore generally embedded within extended distributions of both light and dark matter. The sample of BCGs in this study included some of the most massive known galaxies in the Universe out to a distance of about 3.2 billion light years (z ~ 0.3).

    The study also found that the slopes of the velocity dispersion profiles correlate with the galaxy luminosity, in the sense that the increase in the speed of the stars is greater in brighter BCGs, as well as BGGs. Whether the full diversity in the observed velocity dispersion profiles is consistent with standard models for the growth of massive galaxies is not yet clear. More detailed comparisons with velocity dispersion profiles in cosmological simulations are needed.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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

    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.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: