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  • richardmitnick 11:37 am on January 26, 2021 Permalink | Reply
    Tags: "Astronomers Detect a Surprisingly Huge Galactic Birthplace in The Early Universe", , , , , , LAGER-z7od1 protocluster, Laniakea supercluster, Lyman Alpha Galaxies in the Epoch of Reionization survey, , This research can reveal clues about one of the most mysterious stages in the history of the Universe: the Epoch of Reionization.,   

    From University of Science and Technology [中国科学技术大学] (CN) via Science Alert (AU): “Astronomers Detect a Surprisingly Huge Galactic Birthplace in The Early Universe” 

    From University of Science and Technology [中国科学技术大学] (CN)

    via

    ScienceAlert

    Science Alert (AU)

    25 JANUARY 2021
    MICHELLE STARR

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    Artist’s impression of LAGER-z7od1 protocluster. Credit: ESO/M. Kornmesser.

    Back at the dawn of the Universe, astronomers have found a stacks on of cosmic proportions. At least 21 galaxies, forming stars at a tremendous rate, are merging together in the early stages of the formation of a galaxy cluster. And it’s all happening 13 billion light-years away – just 770 million years after the Big Bang itself.

    This is the earliest protocluster discovered yet, named LAGER-z7OD1, and today it has probably evolved into a group of galaxies 3.7 quadrillion times the mass of the Sun.

    Such a large protocluster, so early in the Universe – barely a cosmic eye blink since the curtain was raised on life, the Universe and everything – could contain some vital clues as to how the primordial smoke cleared and the lights switched on, sending light streaming freely through space.

    Our Universe is a massively interconnected place. Galaxies may seem relatively self-contained, but more than half of all galaxies are gravitationally bound together in clusters or groups, huge structures of hundreds to thousands of galaxies.

    Laniakea supercluster. From Nature: The Laniakea supercluster of galaxies Credit:R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    The beginnings of such clusters are not unknown in the early Universe. Protoclusters have been found nearly as far as LAGER-z7OD1, some even much bigger, suggesting that clusters could begin assembling much faster than previously thought possible.

    But LAGER-z7OD1, according to a team of researchers led by astronomer Weida Hu of the University of Science and Technology of China, is special. It can reveal clues about one of the most mysterious stages in the history of the Universe: the Epoch of Reionization.

    Epoch of Reionization and first stars. Credit: Caltech.

    “The total volume of the ionised bubbles generated by its member galaxies is found to be comparable to the volume of the protocluster itself, indicating that we are witnessing the merging of the individual bubbles and that the intergalactic medium within the protocluster is almost fully ionised,” they wrote in their paper.

    “LAGER-z7OD1 thus provides a unique natural laboratory to investigate the reionization process.”

    Space, you see, wasn’t always the lovely, see-through place it is today. For the first 370 million years or so, it was filled with a hot murky fog of ionised gas. Light was unable to travel freely through this fog; it scattered off free electrons and that was that.

    Once the Universe cooled down enough, protons and electrons started to recombine into neutral hydrogen atoms. This meant that light – not that there was much, yet – could finally travel through space.

    As the first stars and galaxies began to form, their ultraviolet light reionized the neutral hydrogen ubiquitous throughout the Universe: first in localised bubbles around the ultraviolet sources, and then larger and larger areas as the ionized bubbles connected and overlapped, allowing the entire spectrum of electromagnetic radiation to stream freely.

    By about 1 billion years after the Big Bang, the Universe was completely re-ionized. This means that it’s more challenging to probe beyond this point (about 12.8 light-years away), but it also means that the reionization process itself is tricky to understand.

    Ideally, you need really bright objects whose ionizing radiation could cut through the neutral hydrogen, and that’s what Hu and his team were looking for with the Lyman Alpha Galaxies in the Epoch of Reionization survey. These are small, early-Universe galaxies forming stars at an insane rate, which means they can be detected at quite large distances, well inside the Epoch of Reionization. This makes them useful probes of the period.

    In their search, the researchers found LAGER-z7OD1, an over dense region of galaxies in a three-dimensional volume of space measuring 215 million by 98 million by 85 million light-years. This volume contained two distinct subprotoclusters merging together into one larger one, with at least 21 galaxies, 16 of which have been confirmed.

    The total volume of ionized space around the galaxies was slightly larger than the volume of LAGER-z7OD1.

    “This demonstrates substantial overlaps between individual bubbles, indicating that the individual bubbles are in the act of merging into one or two giant bubbles,” the researchers wrote.

    So not only does the protocluster represent an excellent example of its kind, providing a new datapoint for studying how these structures form and emerge, as well as star formation in the early Universe, it offers a one-of-a-kind window into the formation and combination of ionised bubbles in the middle of the Epoch of Reionization.

    What insights will emerge are yet to be discovered, though. As the researchers note, that will be the work of future, more powerful telescopes that will better be able to observe the finer details of the reionization process.

    The team’s research has been published in Nature Astronomy.

    See the full article here.

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    University of Science and Technology of China [中国科学技术大学] (CN)

    “The Cradle Of Scientists” In China

    The University of Science and Technology of China [中国科学技术大] (CN) is a prominent university in China and enjoys an excellent reputation worldwide. It was established by the Chinese Academy of Sciences (CAS) in 1958 in Beijing, as a strategic action by the Chinese government, to meet China’s science and technology needs and increases the country’s international competitiveness. CAS integrated its resources with USTC, with the aim of educating top talent in cutting-edge, interdisciplinary science and technology. The establishment of USTC was hailed as “a great event in the history of education and science of China”. In 1970, USTC moved to its current location in Hefei, the capital of Anhui Province.

     
  • richardmitnick 1:39 pm on August 18, 2020 Permalink | Reply
    Tags: "Meet the Andromeda galaxy, , , , , , Laniakea supercluster, the closest large spiral", ,   

    From EarthSky: “Meet the Andromeda galaxy, the closest large spiral” 

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    From EarthSky

    Originally August 18, 2019
    Re-presented August 18, 2020

    Bruce McClure

    The Andromeda galaxy is the closest big galaxy to our Milky Way. At 2.5 million light-years, it’s the most distant thing you can see with the eye alone. Now is the time to look for it.

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    The Andromeda Galaxy with 2 of its satellite galaxies, via Flickr user Adam Evans.

    Although several dozen minor galaxies lie closer to our Milky Way, the Andromeda galaxy is the closest large spiral galaxy to ours. Excluding the Large and Small Magellanic Clouds, which can’t be seen from northerly latitudes, the Andromeda galaxy – also known as Messier 31 – is the brightest galaxy you can see. At 2.5 million light-years, it’s also the most distant thing visible to your unaided eye.

    Magellanic Clouds ESO S. Brunier

    To the eye, this galaxy appears as a smudge of light larger than a full moon.

    When to look for the Andromeda Galaxy. From mid-northern latitudes, you can see Messier 31 – also called the Andromeda galaxy – for at least part of every night, all year long. But most people see the galaxy first around northern autumn, when it’s high enough in the sky to be seen from nightfall until daybreak.

    In late August and early September, begin looking for the galaxy in mid-evening, about midway between your local nightfall and midnight.

    In late September and early October, the Andromeda galaxy shines in your eastern sky at nightfall, swings high overhead in the middle of the night, and stands rather high in the west at the onset of morning dawn.

    Winter evenings are also good for viewing the Andromeda galaxy.

    If you are far from city lights, and it’s a moonless night – and you’re looking on a late summer, autumn or winter evening – it’s possible you’ll simply notice the galaxy in your night sky. It looks like a hazy patch in the sky, as wide across as a full moon.

    But if you look, and don’t see the galaxy – yet you know you’re looking at a time when it’s above the horizon – you can star-hop to find the galaxy in one of two ways. The easiest way is to use the constellation Cassiopeia. You can also use the Great Square of Pegasus.

    History of our knowledge of the Andromeda galaxy. At one time, the Andromeda galaxy was called the Great Andromeda Nebula. Astronomers thought this patch of light was composed of glowing gases, or was perhaps a solar system in the process of formation.

    It wasn’t until the 20th century that astronomers were able to resolve the Andromeda spiral nebula into individual stars. This discovery lead to a controversy about whether the Andromeda spiral nebula and other spiral nebulae lie within or outside the Milky Way.

    In the 1920s Edwin Hubble finally put the matter to rest, when he used Cepheid variable stars within the Andromeda galaxy to determine that it is indeed an island universe residing beyond the bounds of our Milky Way galaxy.

    Andromeda and Milky Way in context. The Andromeda galaxy and our Milky Way galaxy reign as the two most massive and dominant galaxies within the Local Group of Galaxies.

    Local Group. Andrew Z. Colvin 3 March 2011

    The Andromeda Galaxy is the largest galaxy of the Local Group, which, in addition to the Milky Way, also contains the Triangulum Galaxy and about 30 other smaller galaxies.

    Both the Milky Way and the Andromeda galaxies lay claim to about a dozen satellite galaxies. Both are some 100,000 light-years across, containing enough mass to make billions of stars.

    Astronomers have discovered that our Local Group is on the outskirts of a giant cluster of several thousand galaxies, which astronomers call the Virgo Cluster.

    Virgo Supercluster NASA

    We also know of an irregular supercluster of galaxies, which contains the Virgo Cluster, which in turn contains our Local Group, which in turn contains our Milky Way galaxy and the nearby Andromeda galaxy. At least 100 galaxy groups and clusters are located within this Virgo Supercluster. Its diameter is thought to be about 110 million light-years.

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    The Virgo Supercluster is thought to be one of millions of superclusters in the observable universe.

    See the full article here .


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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 10:39 am on July 13, 2020 Permalink | Reply
    Tags: "Astronomers map massive structure beyond Laniakea Supercluster", , , , , Laniakea supercluster, , ,   

    From U Hawaii at Manoa: “Astronomers map massive structure beyond Laniakea Supercluster” 

    From U Hawaii at Manoa

    July 10, 2020

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    For the past decade, an international team of astronomers, led in part by Brent Tully at the University of Hawaiʻi Institute for Astronomy, has been mapping the distribution of galaxies around the Milky Way. They have discovered an immense structure beyond Laniakea, an immense supercluster of galaxies, including our own. Astronomers have dubbed the newly identified structure the South Pole Wall.

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    South Pole Wall. https://wordlesstech.com/astronomers-discover-south-pole-wall/

    The South Pole Wall lies immediately beyond the Laniakea Supercluster, wrapping the region like an arm. The densest part of it lies in the direction of the Earth’s South Pole, inspiring the name. It extends in a great arc of 200 degrees—more than a semicircle—reaching well into the northern sky. The concentration at the South Pole lies at a distance of 500 million light years. Following the arm north, it folds inward to within 300 million light years of the Milky Way. Along the arm, galaxies are slowly moving toward the South Pole, and from there, across a part of the sky obscured from Earth by the Milky Way toward the dominant structure in the nearby universe, the Shapley connection.

    Shapely Supercluster from Richard Powell

    “We wonder if the South Pole Wall is much bigger than what we see. What we have mapped stretches across the full domain of the region we have surveyed. We are early explorers of the cosmos, extending our maps into unknown territory,” described Tully.

    The team’s research was published in The Astrophysical Journal.

    Throughout the last 40 years, there has been a growing appreciation of patterns in the distribution of galaxies in the Universe, reminiscent of geographic features like mountain ranges and island archipelagos. The Milky Way galaxy, with its 100 billion stars, is part of the small Local Group of galaxies, which in turn is a suburb of the Virgo cluster with thousands of galaxies.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt. The bar is visible in this image

    Local Group. Andrew Z. Colvin 3 March 2011

    Virgo Supercluster NASA

    The Virgo cluster in turn is an outer component of an even larger conglomeration of many rich clusters of galaxies, collectively called the “Great Attractor” because of its immense gravitational pull. In 2014, the team mapped out the Laniakea Supercluster, the bundling of a hundred thousand galaxies over an even larger region, spanning 500 million light years.

    The South Pole Wall is as large as the Sloan Great Wall, one of the largest structures known in the Universe, but the new discovery is much closer. University of Paris-Saclay cosmic cartographer Daniel Pomarede, one of the study’s lead authors, explained “One might wonder how such a large and not-so distant structure remained unnoticed. This is due to its location in a region of the sky that has not been completely surveyed, and where direct observations are hindered by foreground patches of galactic dust and clouds. We have found it thanks to its gravitational influence, imprinted in the velocities of a sample of galaxies.”

    Heléne Courtois from the University of Lyon (UDL) led the observing campaign in the collaborative investigation. Romain Graziani from UDL and Yehuda Hoffman of Hebrew University in Jerusalem built the descriptive models.

    See the full article here .

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

    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth.

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    Pann-STARS 1 Telescope, U Hawaii, situated at Haleakala Observatories near the summit of Haleakala , on the island of Maui in Hawaii, USA, Pann-STARS 1 Telescope, U Hawaii, situated at Haleakala Observatories near the summit of Haleakala in Hawaii, USA, altitude 3,052 m (10,013 ft)altitude 3,052 m (10,013 ft)


    System Overview

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

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

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

     
  • richardmitnick 4:24 pm on July 10, 2020 Permalink | Reply
    Tags: "Beyond the Milky Way a Galactic Wall", Bootes Void, Dr. Pomarède and his colleagues were able to observe their gravitational effects by assembling data from telescopes around the world., Hercules-Corona Borealis Great Wall, Laniakea supercluster, Sloan Great Wall, , The galaxies between Earth and the South Pole Wall are sailing away from us slightly faster than they otherwise should be by about 30 miles per second drawn outward by the enormous blob of matter in t, The Great Attractor, The Great Wall, , ,   

    From The New York Times: “Beyond the Milky Way, a Galactic Wall” 

    From The New York Times

    July 10, 2020
    Dennis Overbye

    Astronomers have discovered a vast assemblage of galaxies hidden behind our own, in the “zone of avoidance.”

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    The starry core of our spiral Milky Way galaxy, in an infrared image from NASA Spitzer Space Telescope. Obscured behind it is the South Pole Wall, a curtain of thousands of galaxies across at least 700 million light-years of space.Credit…NASA

    The South Pole Wall, as it is known, consists of thousands of galaxies — beehives of trillions of stars and dark worlds, as well as dust and gas — aligned in a curtain arcing across at least 700 million light-years of space.

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    A visualization showing the South Pole Wall, a large cluster of galaxies near the southernmost part of the sky. (Image: © D. Pomarede, R. B. Tully, R. Graziani, H. Courtois, Y. Hoffman, J. Lezmy.)

    It winds behind the dust, gas and stars of our own galaxy, the Milky Way, from the constellation Perseus in the Northern Hemisphere to the constellation Apus in the far south. It is so massive that it perturbs the local expansion of the universe.

    But don’t bother trying to see it. The entire conglomeration is behind the Milky Way, in what astronomers quaintly call the zone of avoidance.

    An international team of astronomers led by Daniel Pomarède of Paris-Saclay University and R. Brent Tully of the University of Hawaii announced this new addition to the local universe on Friday in a paper in The Astrophysical Journal. The paper is festooned with maps and diagrams of blobby and stringy features of our local universe as well as a video tour of the South Pole Wall.

    It is the latest installment of an ongoing mission to determine where we are in the universe — to fix our neighborhood among the galaxies and the endless voids — and where we are going.

    “The surprise for us is that this structure is as big as the Sloan Great Wall and twice as close, and remained unnoticed, being hidden in an obscured sector of the southern sky,” Dr. Pomarède said in an email.

    “The discovery is a wonderful poster child for the power of visualizations in research,” Dr. Tully said.

    The new wall joins a host of other cosmographic features: arrangements of galaxies, or a lack of them, that astronomers have come to know and love over the last few decades, with names like the Great Wall, the Sloan Great Wall, the Hercules-Corona Borealis Great Wall and the Bootes Void.

    The new paper was based on measurements, performed by Dr. Tully and his colleagues, of the distances of 18,000 galaxies as far away as 600 million light-years. By comparison, the most distant objects we can see — quasars and galaxies that formed shortly after the Big Bang — are about 13 billion light years away.

    The galaxies in the wall cannot be seen, but Dr. Pomarède and his colleagues were able to observe their gravitational effects by assembling data from telescopes around the world.

    In the expanding universe, as described in 1929 by the astronomer Edwin Hubble and confirmed for almost a century, distant galaxies are flying away from us as if they were dots on an inflating balloon; the farther they are, the faster they recede from us, according to a relation called the Hubble law.

    That motion away from Earth causes their light to be shifted to longer, redder wavelengths and lower frequencies, like retreating ambulance sirens. Astronomers use this “redshift,” which is easily measured, as a proxy for relative distance in the universe. By measuring the galaxy distances independently, the “Cosmicflows” team, as Dr. Pomarède and his colleagues call themselves, was able to distinguish the motion caused by the cosmic expansion from motions caused by gravitational irregularities.

    As a result, they found that the galaxies between Earth and the South Pole Wall are sailing away from us slightly faster than they otherwise should be, by about 30 miles per second, drawn outward by the enormous blob of matter in the wall. And galaxies beyond the wall are moving outward more slowly than they otherwise should be, reined in by the gravitational drag of the wall.

    One astonishing aspect of the wall is how big it is compared to the volume that the team was surveying: a contiguous filament of light 1.4 billion light-years long, packed into a cloud maybe 600 million in radius. “There is hardly room in the volume for anything bigger!” Dr. Tully said in an email. “We’d have to anticipate that our view of the filament is clipped; that it extends beyond our survey horizon.”

    And yet the South Pole Wall is nearby in cosmological terms. “One might wonder how such a large and not-so-distant structure remained unnoticed,” Dr. Pomarède mused in a statement issued by his university.

    But in the expanding universe, there is always something more to see.

    On the largest scales, cosmologists attest, the universe should be expanding smoothly, and the galaxies should be evenly distributed. But on smaller, more local scales, the universe appears lumpy and gnarled. Astronomers have found that galaxies are gathered, often by the thousands, in giant clouds called clusters and that these are connected to one another in lacy, luminous chains and filaments to form superclusters extending across billions of light-years. In between are vast deserts of darkness called voids.

    From all of this has emerged what some astronomers call our “long address”: We live on Earth, which is in the solar system, which is in the Milky Way galaxy. The Milky Way is part of a small cluster of galaxies called the Local Group, which is on the edge of the Virgo cluster, a conglomeration of several thousand galaxies.

    In 2014, Dr. Tully suggested that these features were all connected, as part of a giant conglomeration he called Laniakea — Hawaiian for “open skies” or “immense heaven.” It consists of 100,000 galaxies spread across 500 million light-years.

    All this lumpiness has distorted the expansion of the universe. In 1986, a group of astronomers who called themselves the Seven Samurai announced that the galaxies in a huge swath of the sky in the direction of the constellation Centaurus were flying away much faster than the Hubble law predicted, as if being pulled toward something — something the astronomers called the Great Attractor. It was the beginning of something big.

    “We now see the Great Attractor as the downtown region of the supercluster that we live in — an overall entity that our team has called the Laniakea Supercluster,” Dr. Tully said. All the different parts of this supercluster are tugging on us, he added.

    Great Attractor galaxies

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    As a result, the Great Attractor and its relatives are shedding light on another enduring cosmic mystery — namely, where we are headed.

    Astronomers discovered in 1965 that space is suffused with microwave radiation, a bath of heat — with a temperature of 2.7 degrees Kelvin, or minus 455 degrees Fahrenheit — left over from the birth of the universe 14 billion years ago. Subsequent observations revealed that this bath is not uniform: It is slightly warmer in one direction, suggesting that we — Earth, our galaxy and the Local Group — are moving through the microwaves, like a goldfish in a fishbowl, at about 400 miles per second in the approximate direction of Centaurus, but aiming far beyond.

    Local Group. Andrew Z. Colvin 3 March 2011

    Why? What is over there, on the other side of the fishbowl, compelling us? That is the kind of question that would come up in an Arthur C. Clarke novel, where humanity is always gearing up for some definitive expedition around the curve of the universe.

    “A major goal in cosmology is to explain this motion,” Dr. Tully said in a series of emails. In theory, the motion arises from the lumpy distribution of matter that grew out of tiny ripples in the density of the early universe.

    “The Great Attractor is certainly an important part of the cause of our motion,” Dr. Tully said. “The South Pole Wall also contributes but, again, only in part,” he added, listing more local galaxy clusters and voids. “Every hill and valley in the density distribution makes itself felt.”

    Most of that is stuff that we cannot see directly. According to the prevailing theory of a confoundingly preposterous universe, the cosmos contains about five times as much invisible dark matter as luminous atomic matter.

    Nobody knows exactly what dark matter is made of, but according to cosmologists it provides the gravitational scaffolding for the luminous structures in the universe — galaxies, galaxy clusters, superclusters, voids and chains like the South Pole Wall, all connected by spidery filaments in what’s known as the cosmic web. The visible universe of stars and galaxies, cosmologists like to say, is like snow on mountaintops or lights on dark, distant Christmas trees.

    But by following the lights and how they are moving, astronomers like Dr. Tully and his cosmographers have now been able to probe the shadows on which they sit: galumphing clouds of mass whose gravity shapes the destiny of the visible cosmos, arranging it into shapes and neighborhoods, walls, valleys and voids.

    “It’s just dark matter having its way,” Dr. Tully said.

    “We are like swimmers attempting to swim upstream but being carried downstream faster.”

    See the full article here .

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  • richardmitnick 12:31 pm on December 20, 2019 Permalink | Reply
    Tags: "These are the stars the Pioneer and Voyager spacecraft will encounter", , , , , , , Laniakea supercluster, , , , NASA Pioneer 10 and 11,   

    From MIT Technology Review: “These are the stars the Pioneer and Voyager spacecraft will encounter” 

    MIT Technology Review
    From MIT Technology Review

    Dec 20, 2019
    Emerging Technology from the arXiv

    As four NASA spacecraft exit our solar system, a 3D map [below] of the Milky Way reveals which others they’re likely to visit tens of thousands of years on.

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt. The bar is visible in this image

    NASA Pioneer 10

    NASA Pioneer 11

    NASA/Voyager 1

    NASA/Voyager 2

    During the 1970s, NASA launched four of the most important spacecraft ever built. When Pioneer 10 began its journey to Jupiter, astronomers did not even know whether it was possible to pass through the asteroid belt unharmed.

    The inner Solar System, from the Sun to Jupiter. Also includes the asteroid belt (the white donut-shaped cloud), the Hildas (the orange “triangle” just inside the orbit of Jupiter), the Jupiter trojans (green), and the near-Earth asteroids. The group that leads Jupiter are called the “Greeks” and the trailing group are called the “Trojans” (Murray and Dermott, Solar System Dynamics, pg. 107)
    This image is based on data found in the en:JPL DE-405 ephemeris, and the en:Minor Planet Center database of asteroids (etc) published 2006 Jul 6. The image is looking down on the en:ecliptic plane as would have been seen on 2006 August 14. It was rendered by custom software written for Wikipedia. The same image without labels is also available at File:InnerSolarSystem.png. Mdf at English Wikipedia

    Only after it emerged safe was Pioneer 11 sent on its way.

    Both sent back the first close-up pictures of Jupiter, with Pioneer 11 continuing to Saturn. Voyager 1 and 2 later took even more detailed measurements, and extended the exploration of the solar system to Uranus and Neptune.

    All four of these spacecraft are now on their way out of the solar system, heading into interstellar space at a rate of about 10 kilometers per second. They will travel about a parsec (3.26 light-years) every 100,000 years, and that raises an important question: What stars will they encounter next?

    This is harder to answer than it seems. Stars are not stationary but moving rapidly through interstellar space. Without knowing their precise velocity, it’s impossible to say which ones our interstellar travelers are on course to meet.

    Enter Coryn Bailer-Jones at the Max Planck Institute for Astronomy in Germany and Davide Farnocchia at the Jet Propulsion Laboratory in Pasadena, California. These guys have performed this calculation using a new 3D map of star positions and velocities throughout the Milky Way.

    Max Planck Institute for Astronomy


    Max Planck Institute for Astronomy campus, Heidelberg, Baden-Württemberg, Germany

    NASA JPL


    NASA JPL-Caltech Campus

    This has allowed them to work out for the first time which stars the spacecraft will rendezvous with in the coming millennia. “The closest encounters for all spacecraft take place at separations between 0.2 and 0.5 parsecs within the next million years,” they say.

    Their results were made possible by the observations of a space telescope called Gaia.

    ESA/GAIA satellite

    Since 2014, Gaia has sat some 1.5 million from Earth recording the position of 1 billion stars, planets, comets, asteroids, quasars, and so on. At the same time, it has been measuring the velocities of the brightest 150 million of these objects.

    The result is a three-dimensional map of the Milky Way and the way astronomical objects within it are moving. It is the latest incarnation of this map, Gaia Data Release 2 or GDR2, that Bailer-Jones and Farnocchia have used for their calculations.

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    ESA/Gaia/DPAC

    The map makes it possible to project the future positions of stars in our neighborhood and to compare them with the future positions of the Pioneer and Voyager spacecraft, calculated using their last known positions and velocities.

    This information yields a list of stars that the spacecraft will encounter in the coming millennia. Bailer-Jones and Farnocchia define a close encounter as flying within 0.2 or 0.3 parsecs.

    The first spacecraft to encounter another star will be Pioneer 10 in 90,000 years. It will approach the orange-red star HIP 117795 in the constellation of Cassiopeia at a distance of 0.231 parsecs. Then, in 303,000 years, Voyager 1 will pass a star called TYC 3135-52-1 at a distance of 0.3 parsecs. And in 900,000 years, Pioneer 11 will pass a star called TYC 992-192-1 at a distance of 0.245 parsecs.

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    These fly-bys are all at a distance of less than one light-year and in some cases might even graze the orbits of the stars’ most distant comets.

    Voyager 2 is destined for a more lonely future. According to the team’s calculations, it will never come within 0.3 parsecs of another star in the next 5 million years, although it is predicted to come within 0.6 parsecs of a star called Ross 248 in the constellation Andromeda in 42,000 years.

    Andromeda Galaxy Messier 31 with Messier32 -a satellite galaxy copyright Terry Hancock.

    Milkdromeda -Andromeda on the left-Earth’s night sky in 3.75 billion years-NASA

    These interstellar explorers will eventually collide with or be captured by other stars. It’s not possible yet to say which ones these will be, but Bailer-Jones and Farnocchia have an idea of the time involved. “The timescale for the collision of a spacecraft with a star is of order 10^20 years, so the spacecraft have a long future ahead of them,” they conclude.

    The Pioneer and Voyager spacecraft will soon be joined by another interstellar traveler. The New Horizons spacecraft that flew past Pluto in 2015 is heading out of the solar system but may yet execute a maneuver so that it intercepts a Kuiper Belt object on its way.

    NASA/New Horizons spacecraft

    Kuiper Belt. Minor Planet Center

    After that last course correction takes place, Bailer-Jones and Farnocchia will be able to work out its final destination.

    Ref: arxiv.org/abs/1912.03503 : Future stellar flybys of the Voyager and Pioneer spacecraft

    See the full article here .


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    The mission of MIT Technology Review is to equip its audiences with the intelligence to understand a world shaped by technology.

     
  • richardmitnick 1:51 pm on March 2, 2019 Permalink | Reply
    Tags: "Discovery of Many New Ultra-Diffuse Galaxies in Galaxy Clusters", , , , , Galaxies like our Milky Way can live in large groups with many others the so-called galaxy clusters, , KIWICS-The Kapteyn IAC WEAVE INT Clusters Survey, Laniakea supercluster,   

    From Isaac Newton Group of Telescopes: “Discovery of Many New Ultra-Diffuse Galaxies in Galaxy Clusters” 

    Isaac Newton Group of Telescopes Logo
    From Isaac Newton Group of Telescopes

    In preparation for the new multi-object survey spectrograph, WEAVE, on the 4.2m William Herschel Telescope, the astronomical community is working on deep imaging surveys to identify the astronomical objects which will be studied later in more detail with WEAVE.

    WEAVE will allow astronomers to take optical spectra of up to ~1000 targets at the same time in a single exposure, or to carry out integral-field spectroscopy using 20 deployable mini integral-field units or one large integral-field unit.

    Galaxies, like our Milky Way, can live in large groups with many others, the so-called galaxy clusters.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Local Group. Andrew Z. Colvin 3 March 2011

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    Such associations contain a potpourri of galaxies with many different properties such as colours, ages, morphologies and brightness. Among this broad diversity there exists a bewildering population of large but extremely faint galaxies, called “ultra diffuse galaxies” (see e.g., news release “The Puzzle of Ultra-Diffuse Galaxies”), and understanding their properties is important to understand how the environment of galaxies affects their evolution. Since they are so faint, they are easily perturbed by the cluster environment, and therefore are ideal probes to study what happens with galaxies in the dense cluster environment.

    Using the capabilities of the WFC at the Isaac Newton Telescope (INT) to explore large areas of the sky and detect faint ultra-diffuse galaxies (UDGs), a collaboration of astronomers in the Netherlands and Spain performed a study to investigate these galaxies in detail, the Kapteyn IAC WEAVE INT Clusters Survey (KIWICS).

    ING Wide Field Camera on the Isaac Newton Telescope

    2
    Figure 1. Map of the sky showing the clusters surveyed in KIWICS, and the eight clusters that have been already analysed. Credit: Pavel Mancera Piña.

    When finished, the KIWICS survey will contain 48 X-ray selected clusters. The results for 8 clusters have recently been published in the journal Monthly Notices of the Royal Astronomical Society, and Monthly Notices of the Royal Astronomical Society

    By analysing the general properties of about 500 newly-found UDGs at different distances from the centres of the clusters the researchers found several signs of environmental effects. The first result was that the larger clusters show a lack of UDGs in their centres. This is proof that the enormous gravitational forces present there are tearing these fluffy galaxies apart.

    Moreover they also found that UDGs away from the cluster centre are generally younger and have less concentrated stellar distributions, showing that the gravitational potential of the cluster, which is stronger close to the cluster centre, is changing the structure of galaxies, and is removing the interstellar gas, so that no new stars are being formed in the centres of clusters.

    In addition, they see that, as UDGs approach the centres of their host clusters, their morphologies are transformed from irregular discs to more spheroidal systems. In fact, for dwarf galaxies, which are similar to UDGs, but much smaller, observations in the literature give the same results.

    3
    Figure 2. Left panel: Example of UDGs found in different clusters, the white lines show a scale of 5 arcsec. Upper right panel: The Sérsic index distribution (a measure of the light concentration of a galaxy) for central (red) and outer (blue) UDGs, showing that the galaxies in the central regions are more concentrated. Lower right panel: Axis ratio distribution of the two samples, showing that galaxies in the central regions are rounder. Credit: Pavel Mancera Piña.

    It is expected that the whole KIWICS survey will be finished at the end of 2019, just before WEAVE will be installed on the William Herschel Telescope.

    See the full article here .

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

    Please help promote STEM in your local schools.

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    Isaac Newton Group of Telescopes located at Roque de los Muchachos Observatory on La Palma in the Canary Islands, Altitude 2,344 m (7,690 ft)

    Isaac Newton Group telescopes


    ING 4 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands, 2,396 m (7,861 ft)


    ING Isaac Newton 2.5m telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands, Spain, Altitude 2,344 m (7,690 ft)

    ING Isaac Newton 2.5m telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands, Spain, Altitude 2,344 m (7,690 ft)

     
  • richardmitnick 1:53 pm on December 16, 2018 Permalink | Reply
    Tags: , , , , Laniakea supercluster, , ,   

    From EarthSky: “What is the Local Group?” 

    1

    From EarthSky

    How many galaxies are now known to lie within our Local Group of galaxies? How does our Milky Way rank, size-wise? And what about the vast superclusters beyond?

    1
    One view of the Local Group- a bit to constricted.The 3 largest galaxies in the Local Group are, in descending order, Messier 31 the Andromeda galaxy, the Milky Way, and Messier 33 also known as the Triangulum Galaxy

    Iconic view of the Local Group. Andrew Z. Colvin 3 March 2011

    We know where our galaxy is located, but only locally speaking. The Milky Way galaxy is one of more than 54 galaxies known as the Local Group. The three largest members of the group are our Milky Way (second-biggest), the Andromeda galaxy (biggest) and the Triangulum Galaxy. The other galaxies in the Local Group are dwarf galaxies, and they’re mostly clustered around the three larger galaxies.

    The Local Group does have a gravitational center. It’s somewhere between the Milky Way and the Andromeda Galaxy.

    The Local Group has a diameter of about 10 million light-years.

    Astronomers have also discovered that our Local Group is on the outskirts of a giant supercluster of galaxies, known as the Virgo Supercluster.

    Virgo Supercluster NASA

    Virgo Supercluster, NASA, Wikipedia

    At least 100 galaxy groups and clusters are located within the Virgo Supercluster. Its diameter is thought to be about 110 million light-years.

    The Virgo Supercluster may be part of an even-larger structure that astronomers call the Laniakea Supercluster.

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    It consists of perhaps 100,000 galaxies stretched out over some 520 million light-years.

    See the full article here .


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

    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.orgin 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
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