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  • richardmitnick 1:17 pm on January 20, 2019 Permalink | Reply
    Tags: , , , Cosmology, Mantle Neon Illuminates Earth’s Formation, Neon is actually a stand-in for where gases such as water carbon dioxide and nitrogen came from, Neon keeps a memory of where it came from even after four and a half billion years,   

    From UC Davis: “Mantle Neon Illuminates Earth’s Formation” 

    UC Davis bloc

    From UC Davis

    December 5, 2018
    Andy Fell
    530-752-4533
    ahfell@ucdavis.edu

    1
    Artist’s impression of a young star surrounded by a protoplanetary disk in which planets are forming. Based on measures of neon isotopes, UC Davis researchers conclude that the Earth formed relatively quickly from this cloud of dust and gas, collecting water, carbon and nitrogen in the deep Earth. (European Southern Observatory)

    The Earth formed relatively quickly from the cloud of dust and gas around the sun, trapping water and gases in the planet’s mantle, according to research published Dec. 5 in the journal Nature. Apart from settling Earth’s origins, the work could help in identifying extrasolar systems that could support habitable planets.

    Drawing on data from the depths of the Earth to deep space, University of California, Davis, Professor Sujoy Mukhopadhyay and postdoctoral researcher Curtis Williams used neon isotopes to show how the planet formed.

    “We’re trying to understand where and how the neon in Earth’s mantle was acquired, which tells us how fast the planet formed and in what conditions,” Williams said.

    Neon is actually a stand-in for where gases such as water, carbon dioxide and nitrogen came from, Williams said. Unlike these compounds that are essential for life, neon is an inert noble gas, and it isn’t influenced by chemical and biological processes.

    “So neon keeps a memory of where it came from even after four and a half billion years,” Mukhopadhyay said.

    There are three competing ideas about how the Earth formed from a protoplanetary disk of dust and gas over 4 billion years ago and how water and other gases were delivered to the growing Earth. In the first, the planet grew relatively quickly over 2 to 5 million years and captured gas from the nebula, the swirling cloud of dust and gas surrounding the young sun. The second theory suggests dust particles formed and were irradiated by the sun for some time before condensing into miniature objects called planetesimals that were subsequently delivered to the growing planet. In the third option, the Earth formed relatively slowly, and gases were delivered by carbonaceous chondrite meteorites that are rich in water, carbon and nitrogen.

    These different models have consequences for what the early Earth was like, Mukhopadhyay said. If the Earth formed quickly out of the solar nebula, it would have had a lot of hydrogen gas at or near the surface. But if the Earth formed from carbonaceous chondrites, its hydrogen would have come in the more oxidized form, water.

    Neon from ocean floor to deep space

    To figure out which of the three competing ideas on planet formation and delivery of gases was correct, Williams and Mukhopadhyay accurately measured the ratios of neon isotopes that were trapped in the Earth’s mantle when the planet formed. Neon has three isotopes, neon-20, 21 and 22. All three are stable and nonradioactive, but neon-21 is formed by radioactive decay of uranium. So the amounts of neon-20 and 22 in the Earth have been stable since the planet formed and will remain so forever, but neon-21 slowly accumulates over time. The three scenarios for Earth’s formation are predicted to have different ratios of neon-20 to neon-22.

    The closest they could get to the mantle was to look at rocks called pillow basalts on the ocean floor. These glassy rocks are the remains of flows from deep in the Earth that spilled out and cooled in the ocean, later to be collected by a drilling expedition led by the University of Rhode Island, which makes its collection available to other scientists.

    The gases are found in tiny bubbles within the basalt. Using a press, Williams cracked basalt chips in a sealed chamber, allowing the gases to flow into a sensitive mass spectrometer.

    Now for the space part. Previous researchers established the neon isotope ratio for the “solar nebula” (early rapid formation) model with data from the Genesis mission, which captured particles of the solar wind. Data for the “irradiated particles” model came from analyses of lunar soils and of meteorites. Finally, carbonaceous chondrite meteorites provided data for the “late accretion” model.

    Minimum size for a habitable planet

    The isotope ratios they found were well above those for the “irradiated particles” or “late accretion” models, Williams said, and support rapid early formation.

    “This is a clear indication that there is nebular neon in the deep mantle,” Williams said.

    Neon, remember, is a marker for those other volatile compounds. Hydrogen, water, carbon dioxide and nitrogen would have been condensing into the Earth at the same time — all ingredients that, as far as we know, go into making up a habitable planet.

    The results imply that to absorb these vital compounds, a planet must reach a certain size — the size of Mars or a little larger — before the solar nebula dissipates. Observations of other solar systems show that this takes about 2 to 3 million years, Williams said.

    Does the same process happen around other stars? Observations from the Atacama Large Millimeter Array, or ALMA, observatory in Chile suggest that it does, the researchers said.

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

    ALMA uses an array of 66 radiotelescopes working as a single instrument to image dust and gas in the universe. It can see the planet-forming disks of dust and gas around some nearby stars. In some cases, there are dark bands in those disks where dust has been depleted.

    “There are a couple of ways dust could be depleted from the disk, and one of them is that they are forming planets,” Williams said.

    “We can observe planet formation in a gas disk in other solar systems, and there is a similar record of our own solar system preserved in Earth’s interior,” Mukhopadhyay said. “This might be a common way for planets to form elsewhere.”

    The work was funded by the National Science Foundation.

    See the full article here .

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    UC Davis Campus

    The University of California, Davis, is a major public research university located in Davis, California, just west of Sacramento. It encompasses 5,300 acres of land, making it the second largest UC campus in terms of land ownership, after UC Merced.

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  • richardmitnick 12:15 pm on January 20, 2019 Permalink | Reply
    Tags: , , , , , Cosmology, , KAGRA,   

    From Science News: “A new gravitational wave detector is almost ready to join the search” 

    From Science News

    January 18, 2019
    Emily Conover

    Japan’s KAGRA experiment tests new techniques for spotting ripples in spacetime.

    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    KAGRA tunnel

    In the quest for better gravitational wave detectors, scientists are going cold.

    An up-and-coming detector called KAGRA aims to spot spacetime ripples by harnessing advanced technological twists: chilling key components to temperatures hovering just above absolute zero, and placing the ultrasensitive setup in an enormous underground cavern.

    Scientists with KAGRA, located in Kamioka, Japan, now have results from their first ultrafrigid tests. Those experiments suggest that the detector should be ready to start searching for gravitational waves later in 2019, the team reports January 14 at arXiv.org.

    The new detector will join similar observatories in the search for the minute cosmic undulations, which are stirred up by violent events like collisions of black holes. The Laser Interferometer Gravitational-Wave Observatory, LIGO, has two detectors located in Hanford, Wash., and Livingston, La. Another observatory, Virgo, is located near Pisa, Italy.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


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

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

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

    ESA/eLISA the future of gravitational wave research

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

    Those detectors sit above ground, and don’t use the cooling technique, making KAGRA the first of its kind.

    KAGRA consists of two 3-kilometer-long arms, arranged in an “L” shape. Within each arm, laser light bounces back and forth between two mirrors located at both ends. The light acts like a giant measuring stick, capturing tiny changes in the length of each arm, which can be caused by a passing gravitational wave stretching and squeezing spacetime.

    2
    FREEZE UP KAGRA’s mirrors (one shown) are cooled to very low temperatures to prevent jiggling that could hamper the search for gravitational waves.

    Because gravitational wave detectors measure length changes tinier than the diameter of a proton, minuscule effects like the jiggling of molecules on the mirrors’ surfaces can interfere with the measurements. Cooling the mirrors to about 20 kelvins (–253° Celsius) limits that jiggling.

    In the new tests, performed in spring 2018, researchers cooled only one of KAGRA’s four mirrors, says KAGRA leader Takaaki Kajita of the University of Tokyo. When the detector starts up for real, the others will be chilled too.

    Having the detector underground also helps keep the mirrors from vibrating due to activity on Earth’s surface. LIGO is so sensitive that it can be affected by rumbling trucks, a stiff breeze or even mischievous wildlife (SN Online: 4/18/18). KAGRA’s underground lair should be significantly quieter.

    Building underground and going cold required years of effort from KAGRA’s researchers. “They’ve taken on these two great challenges, which are both important to the long-term future of the field,” says LIGO spokesperson David Shoemaker of MIT. In the future, even more advanced gravitational wave detectors could build on KAGRA’s techniques.

    For now, adding KAGRA to the existing observatories should help scientists improve their studies of where gravitational wiggles come from. Once scientists detect a gravitational wave signal, they alert astronomers, who search for light from the cataclysm that generated the waves in the hope of better understanding the event (SN: 11/11/17, p. 6). Having an additional gravitational wave detector in a different part of the world will help better triangulate wave sources. “This feature is very important,” Kajita says, “because telescopes can only see a small part of the sky at a time.”

    See the full article here .


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  • richardmitnick 2:38 pm on January 19, 2019 Permalink | Reply
    Tags: , , , Cosmology, Disentangling starlight,   

    From ESOblog: “Disentangling starlight” 

    ESO 50 Large

    From ESOblog

    1

    Although they look like fuzzy patches of light, distant galaxies are actually made up of billions of stars and other astronomical intricacies. Telescopes are rarely powerful enough to study the individual stars in galaxies except for those closest to the Milky Way, but a team of scientists has now used the MUSE instrument on ESO’s Very Large Telescope to resolve the stars in the spiral galaxy NGC 300.

    ESO MUSE on the VLT on Yepun (UT4)

    By telling the story of how astronomy has reached this point, team member Martin M. Roth from the Leibniz Institute for Astrophysics Potsdam helps us understand why this result is so exciting.

    Four hundred years ago, Galileo Galilei became the first person to point a telescope at the sky and prove that the hazy band of the Milky Way is actually composed of billions of individual stars. Astronomy has come a long way since then, and nowadays astronomers do not merely look at the stars, but also analyse their chemical composition, measure their rotation and velocity in space, and determine many other physical parameters to find out more about the Universe — all using a technique called spectroscopy, which is the study of the interaction of matter and light.

    Stellar spectroscopy really started taking speed with the emergence of a technique called integral field spectroscopy, around the same time that I joined Leibniz Institute for Astrophysics Potsdam (AIP) as a young astronomer in the early 1990s. This technique allows astronomers to obtain a 3D view of a galaxy in just one shot. It uses an Integral Field Unit (IFU) to divide the field of view into many segments — or pixels — to obtain a more comprehensive overview of the whole. The signal from each pixel is fed into a spectrograph which generates a light spectrum for each one. The pixels in this case are rather lovingly named “spaxels”.

    Even all those years ago it occurred to me that such a device could be used to disentangle the stars in crowded fields, such as in star clusters and distant galaxies, where the light from stars blends together to become a blurry blob. So by 1996, our team at Potsdam had begun to develop our own integral field spectrograph. We called it PMAS — the Potsdam Multi-Aperture Spectrophotometer.

    1
    How integral field spectroscopy works. Credit: ESO

    Several research groups were developing integral field spectrographs at the same time, but the main drawback to all of them was the number of spaxels. PMAS, for example, hosted a mere 256 of them — compare this to your phone camera, which probably has something like 10–15 million pixels. This all changed dramatically with the arrival of MUSE, the Multi Unit Spectroscopic Explorer, on ESO’s Very Large Telescope (VLT). MUSE hosts an incredible 90 000 spaxels and boasts superb sensitivity.

    The primary raison d’etre of MUSE is to study the origin and development of the Universe as a whole, but when ESO invited proposals for MUSE pilot studies almost five years ago, I applied to use the new instrument to try to resolve stars in the nearby spiral galaxy NGC 300. This had already been done for very nearby galaxies in what is called the Local Group but never for galaxies further afield.

    Thankfully, my proposal to observe NGC 300 was chosen as one of the MUSE pilot studies, and we were given observing time! At a distance of six million light-years from the Milky Way, NGC 300 is just outside the Local Group and is what I would describe as a very “typical” spiral galaxy; finding out more about it should help us find out more about how spiral galaxies work in general.

    2
    The intricate network of pipes surrounding the 24 spectrographs of the MUSE instrument on the VLT. The instruments complexity is equaled by its power and productivity. Credit: A. Tudorica/ESO

    But it wasn’t enough just to observe the galaxy using MUSE, it was also necessary to develop some software that could help us visually separate the stars in the MUSE data. A talented doctoral student within our research group created a novel tool to do this. To test the tool, we used our old PMAS spectrograph on a telescope at the Calar Alto Observatory in Spain to measure the speed of some stars in Milky Way star clusters. The tool worked perfectly!

    Calar Alto Observatory located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres

    We then tried out the tool with MUSE images of a cluster of Milky Way stars before the real test — would it work on NGC 300, a galaxy 800 times further away than this star cluster?

    The results turned out to be better than we could have ever imagined! We could see individual stars with incredible clarity and gaseous regions, such as supernova remnants, planetary nebulae, and ionised hydrogen regions were revealed. Amazingly, we could even see dim background galaxies through NGC 300! MUSE is special because it can look at light with a wide range of wavelengths, making many different objects and colours visible.

    4
    This picture of the spectacular southern spiral galaxy NGC 300 was taken using the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile.

    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres

    It was assembled from many individual images through a large set of different filters over many observing nights, spanning several years. The main purpose of this extensive observational campaign was to get an unusually thorough census of the stars in the galaxy, counting both the number and varieties of stars and marking regions, or even individual stars, that warrant deeper and more focussed investigation. But such a rich data collection will also have many other uses for years to come.

    The images were mostly taken through filters that transmit red, green or blue light. These were supplemented by images through special filters that allow through only the light from ionised hydrogen or oxygen gas and highlight the glowing clouds in the galaxy’s spiral arms. The total exposure time amounted to around 50 hours.

    Credit: ESO

    5
    The new MUSE images of NGC 300 laid over the WFI image, with individual stars clearly visible. Credit: ESO

    After so many years of preparation, involving the hard work of so many individuals, it’s fair to say that we were overwhelmed when we received the NGC 300 data. But we have merely scratched the surface of a gold mine. We have so much more data to analyse that we have gathered a team of enthusiastic astronomers to go through it, all keen to discover what lies beyond what we once thought was impossible. And through it all, I keep reminding myself that this was a pilot study.

    Not only do we hope to use MUSE to look at even more galaxies, ESO is currently building an instrument called 4MOST that will be dedicated to disentangling starlight and imaging up to 2400 individual stars per single exposure in the Milky Way. The goal is to study millions of stars in the attempt to unravel our galaxy’s formation history and evolution, as part of a vibrant field of research called “galactic archaeology”.

    But MUSE is already enabling “extragalactic archaeology” for the first time ever. With its ability to collect huge amounts of light and create incredibly sharp images, ESO’s Extremely Large Telescope will be able to take extragalactic archaeology even further, investigating individual stars in other galaxies to help us find out more about the Universe.

    See the full article here .


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    Visit ESO in Social Media-

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

    ESO 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,

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

    ESO VLT 4 lasers on Yepun


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

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

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

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

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


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

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

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

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

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

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

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

     
  • richardmitnick 1:54 pm on January 19, 2019 Permalink | Reply
    Tags: Active galaxies nuclei, , , , Cosmology, Galaxy ESO 428-G14,   

    From Instituto de Astrofísica de Canarias – IAC: “A faint galaxy that outshines the others” 

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    19.1.19
    Manu Astrónomus

    Contacts:
    Almudena Prieto: aprieto@iac.es
    Alberto Ardila Rodríguez: aardila@lna.br

    1
    Image of the active galaxy ESO little light LLAGN 428-G14.

    According to an international investigation which involved scientists from the Institute of Astrophysics of the Canary Islands (IAC) , luminous galaxies with active nuclei have little enough to expel gas quantities similar to those removed galaxies with bright nuclei much energy.

    The gas is essential in the process of formation of a galaxy. During the early stages, the amount of gas present determines the number of stars that will be in it. Active galaxies nucleus (AGN, for its acronym in English) they are those that have a higher brightness region in its center. This bright area is caused by the presence of a massive black hole, the effect of its gravity, accumulated material around a process known as accretion.

    Supermassive black holes heat the surrounding gas and pushing part of it to the outside Galaxy (feedback effect). It was thought that AGN lower luminosity did not have enough to expel large amounts of gas energy. But an international study, in which two researchers from the Institute of Astrophysics of the Canary Islands (IAC) involved, proves otherwise.

    2
    The red dots represent the spatial distribution and morphology due to high
    ionization of the gas cloud, due to the strong emission of the jets hole
    black of this active galaxy. Credit: D.May et al.

    In the article, recently published in the journal Monthly Notices of the Royal Astronomical Society, they analyzed the galaxy ESO 428-G14, which has a slightly luminous AGN. Thanks to the data obtained with integral field spectrograph SINFONI the Very Large Telescope (VLT) , the European Southern Observatory (ESO) detected that this galaxy has the strongest feedback effect seen in one of its class.

    ESO SINFONI

    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,

    “In this galaxy dim glow explains Daniel May, researcher at the Institute of Astronomy, Geophysics and Atmospheric Sciences at the University of Sao Paulo and first author of the publication-, the jet is responsible for carrying out the work of expulsion gas. However, in the most luminous active nuclei, this task is performed by the radiation emitted by the nucleus itself.”

    3
    a): Image HI Brγ λ21661 Å emission (total flow 24 ± 1 × 10-15 erg s-1 cm-2)
    the dashed ellipses highlight the ‘helix’ into two substructures, b1 and b2. (B): The line
    of [Si VI] of all cubes combined data (DS2), with a smaller FOV and
    greater signal / noise ratio. The contrast shows the fainter structures and b4 b3.
    The cross marks the position of the AGN. The flow bar is in units of
    10 -19 erg s-1 cm-2 A-1. Credit: D.May et al.

    Radio galaxies, which are AGN with powerful jets, expels the material at rates between 1 and 50 solar masses per year. ESO 428-G14, which has a modest jet, it is in the range of 3 to 8 solar masses per year. “With these data -comenta Almudena Prieto, IAC researcher and co-author of the study, is the least luminous galaxy with the strongest feedback observed to date.”

    “Our findings open a debate on the role of supermassive black holes as efficient in the heart of galaxies, regardless of its brightness engines,” says Alberto Ardila Rodríguez, a visiting researcher and co-author IAC.

    Through further studies, the team of scientists attempt to discover the nature of the process makes it possible as little light as ESO 428-G14, core so efficiently removing gaseous matter. “He’s probably related to own source of gas in the galaxy,” said May.

    See the full article here.


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    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.



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

     
  • richardmitnick 5:47 pm on January 18, 2019 Permalink | Reply
    Tags: , , , , Can Blue Stragglers Be Used to Tell Time?, Cosmology, Gyrochronology   

    From AAS NOVA: “Can Blue Stragglers Be Used to Tell Time?” 

    AASNOVA

    From AAS NOVA

    18 January 2019
    Kerry Hensley

    1
    This Hubble image of the center of globular cluster NGC 6362 shows an impressive spectrum of stellar colors. Particularly interesting are the bright blue stars in this image, which should have left the main sequence already. [ESA/Hubble & NASA]

    NASA/ESA Hubble Telescope

    As stars age, they gradually lose angular momentum and spin more slowly. This process occurs so predictably for normal, solar-type stars that we can treat them as cosmic clocks using a technique called gyrochronology. But could the same strategy be applied to an unusual type of main-sequence star called blue stragglers?

    2
    The blue stragglers in globular cluster M55 are easily identified in a color-magnitude diagram (cyan circle). [Adapted from B.J. Mochejska, J. Kaluzny (CAMK), 1-m Swope Telescope]


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

    Stars That Linger

    Based on their mass and age, we would expect blue-straggler stars to have exhausted their core hydrogen and evolved off the main sequence already. Instead, these oddball objects have managed to loiter long past their time by gaining mass — either by siphoning it from a binary companion star or by consuming another star altogether through a collision.

    Blue stragglers are easy to pick out in a star cluster, where they are bluer and brighter than the main-sequence turnoff point on a color–magnitude diagram. Post-mass-transfer stars like blue stragglers also exist outside of clusters, where they can be identified by abnormal chemical abundances or the presence of a white-dwarf companion.

    To better understand post-mass-transfer stars like blue stragglers, we would like to know how long ago they accreted mass from their companions. We know that these stars experience a jump in spin rate immediately after mass accretion — but what happens after that point? Do they undergo predictable spin-down like normal, solar-type stars, allowing us to use gyrochronology to determine their post-mass-transfer ages?

    Going for a Spin

    To explore this question, a team led by Emily Leiner (Northwestern University) studied the rotation-rate slowdown of blue-straggler and other post-mass-transfer stars. Leiner and collaborators compiled a sample of post-mass-transfer binaries of varying ages by selecting stars with spectral types F, G, and K with white-dwarf companions in close orbits. Here, age doesn’t refer to time since the star formed, but rather time since the mass transfer took place.

    The very young systems were selected by direct detection of the white-dwarf companion in the extreme ultraviolet. In older systems, the white-dwarf companion is too cool to be visible but can be detected by gravitational microlensing.

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    Leiner and collaborators combined the age estimates from white-dwarf cooling models with rotation periods derived from photometric or spectral measurements. The authors found that the stars spin faster after the mass transfer, then steadily slow down after about 100 million years since the mass transfer have passed.

    3
    Ages and rotation periods for this sample of post-mass-transfer systems. The purple and gold lines are single-star models, while the red and cyan lines are collisional-product models.

    A Model for Spin-down

    To understand the physics of post-mass-transfer star spin-down, the authors compared the observed spin-down to models for single solar-type stars and stellar collision products. They found that the models for the stellar collision products showed distinctly different behavior; the collision products maintained their rapid rotation rates far longer than the single stars or post-mass-transfer stars.

    Leiner and collaborators attributed this to the possibility that the collision products don’t form normal stellar magnetic fields and can’t lose angular momentum through magnetic braking the way single main-sequence stars do.

    On the other hand, the models for spin-down of single solar-type stars matched the blue-straggler observations well. This suggests that blue stragglers and other post-mass-transfer stars have a promising future as gyrochronometers!

    Citation

    “Observations of Spin-down in Post-mass-transfer Stars and the Possibility for Blue Straggler Gyrochronology,” Emily Leiner, Robert D. Mathieu, Natalie M. Gosnell, and Alison Sills 2018 ApJL 869 L29. http://iopscience.iop.org/article/10.3847/2041-8213/aaf4ed/meta

    See the full article here .


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    Stem Education Coalition

    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Societyis to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 5:21 pm on January 18, 2019 Permalink | Reply
    Tags: , , , Cosmology, , , , The observation of a rare hypernova   

    From Instituto de Astrofísica de Canarias – IAC: “The observation of a rare hypernova, complete the story of the death of the most massive stars. 

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    8/1/19
    Manu Astrónomus

    Contact:
    Institute of Astrophysics of Andalusia (IAA-CSIC)
    Dissemination and Communication Unit
    Silbia Lopez de Lacalle – sll@iaa.es – 958230676
    https://www.iaa.csic.es
    https://divulgacion.iaa.csic.es

    [I have done my best to correct the translation.]

    1
    Explosion image obtained by the Gran Telescopio Canarias in the period of maximum brightness of the event.

    A study led by the Institute of Astrophysics of Andalusia (IAA-CSIC) and published in Nature, studied in detail to the life of a star, which produces a gamma – ray burst (GRB) and a hypernovae.

    The end of the life of stars holds placid scenarios in the case of low-mass stars like the sun. Not so in the case of very massive stars, which undergo explosive events so intense that they can get to outshine all the galaxy that hosts. An international group of astronomers has studied in detail the end of a massive star that has been a gamma-ray burst (GRB) and hypernovae, which has detected a new component in this type of phenomena. The study, published in the journal Nature [above], provides the link to complete the story that links hypernovae with GRBs.

    “In 1998 the first hypernovae was detected, a version of the very energy supernovae, which followed a burst of gamma rays and which was the first evidence of the connection between the two phenomena” says Luca Izzo Institute investigator Andalusia Astrophysics (IAA-CSIC) headed the study.

    The proposed scenario to explain the phenomenon involved a star of more than twenty solar masses, to exhaust their fuel undergoes a process of core collapse. To collapse on itself, the core generates a black hole or neutron stars, while two polar jets of matter that cross the outer layers of the star and, emerging into the medium, produce gamma ray bursts occur ( GRBs). Hypernovae finally burst, which can be tens of times more intense than a supernova occurs.

    2
    Hypernovae artistic representation. The interaction of the jet
    with the outer layers of the star forms a sheath around
    the jet head and begins to spread laterally with respect
    to the jet direction. The jet is able to completely pierce the
    shell of the parent star, issue the issuance of a type of high – energy,
    responsible for GRB. Source: Anna Serena Esposito.

    But, even after twenty years of studying the relationship between GRBs and hypernovae seems clear, it is not met in the opposite direction, as they have detected several hypernovae not have associated gamma-ray bursts. “This work has allowed us to identify the missing link between these two subtypes hypernovae in the form of a new component: a kind of hot envelope is formed around the jet according propagates through the parent star -apunta Izzo (IAA CSIC) -. The jet transfers a significant part of its energy to the shell and, if it goes through the surface of the star will produce gamma ray emission we identify as GRB “.

    However, the jet may spoil within the star and not emerge to medium lacking sufficient energy, a circumstance occurs hypernovae but not a GRB. Thus, the casing detected in this investigation represents the link between the two subtypes hypernovae studied so far, and these “jets damped” (English choked-jets) naturally explain the differences.

    EVENT HISTORY

    On December 5 the GRB171205A outbreak was detected in a galaxy located just five hundred million light years from Earth, making it the fourth GRB nearest known. “Phenomena of this kind occur on average once every ten years, so immediately began an intense campaign observation with the Gran Telescopio Canarias to observe the emerging hypernovae from the early stages -apunta Christina Thöne, researcher at the Institute of Astrophysics of Andalusia ( IAA-CSIC) participating in the hallazgo-. In fact, it is the earliest detection of a hypernovae to date, less than a day after the collapse of the star. ”

    And indeed, once the first evidence of the presence of a hypernovae were observed. “This was possible because the luminosity of the jets was much weaker than normal because usually outshine the emission of the supernova He points during the first week Antonio de Ugarte Postigo, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) participating in the hallazgo-. However, a peculiar hypernovae, was already showing very high growth rates and a different chemical abundances to those recorded in similar events “.

    This unique chemical composition and velocities associated fit the existence of a jet surrounded by an envelope that cuts on the surface of the star, which had been predicted earlier but had not yet observed. Sheath accompanying the jet during the first days drag material from the interior of the star, and in the case study allowed us to determine its chemical structure. After a few days, this comoponent disappeared and hypernovae evolved similarly to those observed previously.

    The total energy emitted by the envelope was higher than the GRB, which implies that the jet deposited much of its energy in it. But also it shows that the energy of GRB depends on the interaction of the jet with stellar material and this new component, the wrapper. And also highlights the need to review the model: “While the standard model supernovae core collapse leads to nearly spherical explosions, evidence of such energy emission produced by a sheath of this type suggests that the jet plays an important role in central collapse supernovae, and we need to take into account the role of the jet explosion models of supernovae, “says Izzo (IAA-CSIC).

    This study was coordinated by researchers from the group Phenomena Transients High Energy and Environment (High-Energy Transients and Their Hosts, HETH) of the IAA-CSIC. Christina headed by Thöne, studying the physics of transient astronomical phenomena, the environment in which they occur and the galaxies that host them.

    See the full article here.


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    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.



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

     
  • richardmitnick 1:21 pm on January 18, 2019 Permalink | Reply
    Tags: , , , Cosmology, , , When New Horizons Met Ultima Thule   

    From SETI Institute: “When New Horizons Met Ultima Thule” Video 

    SETI Logo new
    From SETI Institute


    43 minutes

    1
    Ultima Thule

    NASA New Horizons spacecraft

    Kuiper Belt. Minor Planet Center

    CEO Bill Diamond is joined by New Horizons Hazard team lead and SETI Institute Senior Scientist, Mark Showalter to discuss the spacecraft’s flyby of Ultima Thule, what it’s like working on the Hazards team, and even the naming of some of Pluto’s surface features.

    See the full article here .

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    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
    Privacy PolicyQuestions and Comments

     
  • richardmitnick 2:33 pm on January 17, 2019 Permalink | Reply
    Tags: , , , Cosmology, , prototype Schwarzschild-Couder Telescope (pSCT), ,   

    From UC Santa Cruz: “Scientists to inaugurate a new type of gamma ray telescope at Whipple Observatory” 

    UC Santa Cruz

    From UC Santa Cruz

    January 16, 2019
    Tim Stephens
    stephens@ucsc.edu

    1
    The prototype Schwarzschild-Couder Telescope (pSCT) is a novel type of gamma-ray telescope designed for the Cherenkov Telescope Array (CTA). (Photo by Amy Oliver, Fred Lawrence Whipple Observatory, Center for Astrophysics, Harvard & Smithsonian)

    A new type of gamma-ray telescope will be unveiled January 17 in an inauguration event at the Fred Lawrence Whipple Observatory in Amado, Arizona. Expected to see first light in early 2019, the telescope is a prototype Schwarzschild-Couder Telescope (pSCT) designed for the Cherenkov Telescope Array (CTA), the next generation ground-based observatory for gamma-ray astronomy at very high energies.

    David Williams, adjunct professor of physics at UC Santa Cruz, chairs the CTA-US Consortium.

    “The inauguration of the pSCT is an exciting moment for the institutions involved in its development and construction,” Williams said. “The first of its kind in the history of gamma-ray telescopes, the SCT design is expected to boost CTA performance towards the theoretical limit of the technology.”

    The CTA Observatory, for which construction will begin in 2019, will be the world’s largest and most sensitive high-energy gamma-ray observatory, with more than 100 telescopes located in the northern and southern hemispheres.

    The 9.7-meter aperture pSCT is a pathfinder telescope for use in the CTA and exploits a novel optical design. Its complex dual-mirror optical system improves on the single-mirror designs traditionally used in gamma-ray telescopes by dramatically enhancing the optical quality of their focused light over a large region of the sky, and by enabling the use of compact, highly-efficient photo-sensors in the telescope camera.

    “Ultimately, the SCT is designed to improve CTA’s ability to detect very-high-energy gamma-ray sources, which may also be sources of neutrinos and gravitational waves,” said Vladimir Vassiliev, principal investigator of the pSCT. “Once the SCT technology is demonstrated at FLWO, it is hoped that SCTs will become a part of at least one of the two CTA arrays, located in each of the northern and southern hemispheres.”

    The CTA Observatory (CTAO) will consist of 118 telescopes of three different sizes and is expected to detect sources of gamma rays in the energy range 20 GeV to 300 TeV, with about ten times increased sensitivity compared to any current observatory. Notable for providing improved gamma-ray angular resolution and its very-high-resolution camera (more than 11,000 pixels), the SCT is proposed for the medium-sized CTA telescopes and will primarily contribute to the middle of CTA’s energy range (80 GeV to 50 TeV).

    “The SCT and other telescopes at CTA will greatly improve upon current gamma-ray research being conducted at HAWC, HESS, MAGIC, and VERITAS, the last of which is located at the Fred Lawrence Whipple Observatory,” said VERITAS Director Wystan Benbow.

    HAWC High Altitude Cherenkov Experiment, located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays

    HESS Cherenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg searches for cosmic rays, altitude, 1,800 m (5,900 ft)

    MAGIC Cherenkov telescopes at the Observatorio del Roque de los Muchachos (Garfia, La Palma, Spain))

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

    “Gamma-ray observatories like VERITAS have been operating for 12 to 16 years, and their many successes have brought very-high-energy gamma-ray astronomy into the mainstream, and have made many exciting discoveries. We hope CTA will supersede VERITAS around 2023, and it will be used to continue to build upon the 50 years of gamma-ray research at the Whipple Observatory and elsewhere.”

    The Whipple Observatory is operated by the Harvard-Smithsonian Center for Astrophysics.

    The SCT optical design was first conceptualized by U.S. members of CTA in 2006, and the construction of the pSCT was funded in 2012. Preparation of the pSCT site at the base of Mt. Hopkins in Amado, AZ, began in late 2014, and the steel structure was assembled on site in 2016. The installation of pSCT’s 9.7-meter primary mirror surface, consisting of 48 aspheric mirror panels, occurred in early 2018, and was followed by the camera installation in June 2018 and the 5.4-meter secondary mirror surface installation, consisting of 24 aspheric mirror panels, in August 2018.

    Leading up to the inauguration and in preparation for first light, scientists opened the telescope’s optical surfaces in January 2019. The SCT is based on a 114-year-old dual-mirror optical system first proposed by Karl Schwarzschild in 1905. It became possible to construct only recently as a result of critical research and development progress made at both the Brera Astronomical Observatory and Media Lario Technologies Incorporated in Italy.

    The pSCT was made possible by funding through the U.S. National Science Foundation Major Research Instrumentation program and by the contributions of thirty institutions and five critical industrial partners across the United States, Italy, Germany, Japan, and Mexico.

    More information about the pSCT is available online at http://www.cta-observatory.org/project/technology/sct.

    See the full article here .


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    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    .

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

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

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

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

    UCSC is the home base for the Lick Observatory.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

     
  • richardmitnick 10:13 am on January 17, 2019 Permalink | Reply
    Tags: , Are Fast Radio Bursts from Flaring Magnetars?, , , , Cosmology,   

    From AAS NOVA: “Are Fast Radio Bursts from Flaring Magnetars?” 

    AASNOVA

    From AAS NOVA

    16 January 2019
    Susanna Kohler

    1
    Artist’s impression of a magnetized neutron star. Could these objects be responsible for fast radio bursts? [ESO/L. Calçada]

    Could the mysterious fast-radio-burst signal FRB 121102 be emitted from a flaring, strongly magnetic neutron star? In a new study, two scientists explore the evidence.

    Mysterious Signals

    More than a decade ago, a powerful burst of coherent radio emission lasting only a few milliseconds mystified astronomers. The dispersion of the signal — the delay of its component frequencies by different amounts of time, depending on the wavelength — indicated that this pulse came from beyond our galaxy. But what was it?

    2
    Artist’s impression of a fast radio burst observed by the Parkes Radio Telescope. [Swinburne Astronomy Productions]

    Today, we’ve detected many dozens of these odd fast radio bursts (FRBs), including two sources that appear to repeat. The repetition has allowed scientists to learn more about the best studied of these, FRB 121102: this burst has been localized to a star-forming dwarf galaxy that lies three billion light-years from Earth. Upon closer inspection of the region, scientists found that in addition to FRB 121102’s repeating bursts, a dim and steady source of radio emission lies nearby.

    These accumulating clues all address a broad mystery: what object could be responsible for the bursting and steady emission we observe? What is the source of an FRB?

    A Magnetized Solution

    Two scientists at Columbia University, former graduate student Ben Margalit (now a NASA Einstein Postdoctoral Fellow at UC Berkeley) and advisor Brian Metzger, recently proposed an explanation for FRB 121102: perhaps this source is a young, flaring, highly magnetized neutron star that is embedded in a decades-old supernova remnant.

    Neutron stars are dense cores left behind after a star’s spectacular death in a supernova or a gamma-ray burst. In particular, a magnetar is a type of neutron star with an extremely powerful magnetic field that causes flares and bursts early in the object’s life. Such flares from a distant young magnetar, Margalit and Metzger argue, could explain the FRB signals we observe.

    3
    Schematic of the authors’ model, in which a young, flaring magnetar is embedded in a magnetized nebula trapped behind the shell of supernova ejecta. Electrons in the magnetized nebula emit the persistent radio radiation, and the nebula leaves an imprint on the burst emission — which originates from the magnetar — as well. [Margalit & Metzger 2018]

    In addition, the newly-formed magnetar may rest in the center of a compact, magnetized nebula that’s trapped behind the expanding shell of supernova ejecta created when the magnetar was born. This magnetized nebula could power persistent radio emission like what we observed near FRB 121102.

    As a final piece of the puzzle, the authors point out that the identified home for FRB 121102 is consistent with the type of galaxy in which magnetars often form. Such small galaxies with high specific star formation rates are known to preferentially host long gamma-ray bursts and superluminous supernovae, events in which magnetars are born.

    Predicting the Future

    To test their theory, Margalit and Metzger develop a detailed time-dependent model of an expanding, magnetized electron-ion nebula inflated by a flaring, young magnetar. They then show that the energetics of their model beautifully match the properties of both the bursting and persistent radio emission from FRB 121102.

    Does this mean the mystery’s solved? We can’t say for sure yet — but the authors make specific predictions for future observations of FRB 121102 that will provide a robust test of their model. In addition, the very recent discovery of a second repeating burst, FRB 180814.J0422+73, will hopefully allow us to further explore these mysterious sources and confirm their origin.

    Citation

    “A Concordance Picture of FRB 121102 as a Flaring Magnetar Embedded in a Magnetized Ion–Electron Wind Nebula,” Ben Margalit and Brian D. Metzger 2018 ApJL 868 L4.
    http://iopscience.iop.org/article/10.3847/2041-8213/aaedad/meta

    See the full article here .


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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Societyis to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 12:57 pm on January 16, 2019 Permalink | Reply
    Tags: , , , Cosmology, , ESO's M2 secondary mirror   

    From European Southern Observatory: “World’s largest convex mirror blank ready for final touches” 

    ESO 50 Large

    From European Southern Observatory

    16 January 2019

    Calum Turner
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6670
    Email: pio@eso.org

    The ELT’s M2 blank is being shipped to France for fine polishing.

    1

    Work on the elaborate optics of ESO’s 39-metre Extremely Large Telescope (ELT) has taken a major step forwards following the successful casting, annealing, ceramization, machining and acid-etching of the substrate for the ELT’s secondary mirror, M2. This massive 3-ton mirror blank has been successfully machined from a slab of the low-expansion ceramic material ZERODURⓇ into its near-final form by the German company SCHOTT [1]. The creation of this technological masterpiece was a challenging process, requiring state-of-the-art CNC machines to correctly grind the mirror blank. Now, safely stowed in an extra-large transport box, the blank is being shipped to France for final grinding and polishing by Safran Reosc.

    Despite being the ELT’s secondary mirror, M2 still has an impressive diameter of 4.25 meters — larger than the primary mirror of many astronomical telescopes operating today. Following sixteen months of precision manufacturing at SCHOTT, M2 will now receive its final touches — more precisely, fine polishing — at Safran Reosc. The French company will polish the mirror to a precision of 15 nanometres across its entire optical surface, and a final layer of reflective silver and a wafer-thin protective layer of silicon oxide will be applied by ESO at a coating facility at ESO’s Paranal Observatory in Chile.

    M2 will be the largest ever secondary mirror employed on a telescope, as well as the largest convex mirror ever produced. Fabricating this highly convex, aspherical mirror is a considerable challenge — and the result will be a truly remarkable example of pioneering optical engineering. The secondary mirror and its support system — weighing 12 tonnes — will hang upside-down high above the 39-metre primary mirror.

    Notes

    [1] ZERODURⓇ ceramic glass was originally developed for astronomical telescopes in the late 1960s. It has almost no thermal expansion, which means that even in the case of large temperature fluctuations, the material does not expand. Chemically, the material is very resistant and can be polished to a high standard of finish. The reflective layer, made of aluminium or silver, is usually vaporised onto the extremely smooth surface shortly before the telescope is put into operation. Many well-known telescopes with ZERODURⓇ mirrors have been operating reliably for decades, including ESO’s Very Large Telescope atop Cerro Paranal in Chile.

    Links

    The ELT
    SCHOTT
    Safran Reosc

    See the full article here .


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    Visit ESO in Social Media-

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

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

    ESO/HARPS at La Silla

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

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

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

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


    ESO VLT 4 lasers on Yepun

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

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



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

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

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

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

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

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

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

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

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

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

     
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