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  • richardmitnick 8:09 pm on December 21, 2014 Permalink | Reply
    Tags: Astronomy, , , , ,   

    From Jodrell Bank: “Giant radio loops: What are they?” 

    Jodrell Bank Lovell Telescope
    Lovell

    Jodrell Bank Centre for Astrophysics

    07 Nov 2014
    Katie Brewin and Aeron Howarth
    Media Relations Officer
    The University of Manchester
    Tel: 0161 275 8387
    Email: katie.brewin@manchester.ac.uk or aeron.howarth@manchester.ac.uk

    The radio sky is full of giant loops and elongated features which have been known since the earliest days of radio astronomy. Using data from the WMAP satellite and reprocessed classic maps of the sky, a team of astronomers at Jodrell Bank suggest these loops may be produced by a nearby expanding shell driven by supernova explosions and the radiation from massive stars.

    NASA WMAP
    NASA WMAP satellite
    NASA/WMAP

    The study of the diffuse Galactic radio emission is nearly as old as radio-astronomy. The first extraterrestrial radio signal detected by Karl [Guth] Jansky in the early 1930s originated from the central region of our Galaxy.

    Later, in the 1950s, maps covering much of the sky were made which showed large elongated features and loops. Various different hypotheses for the origin of these structures are still being discussed today. The emission from the loops is produced by synchrotron radiation, where highly energetic electrons travel spiralling around magnetic field lines at almost the speed of light.

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    The famous 408 MHz map of the radio sky published by Haslam et al (1982). This version has been reprocessed by Remazeilles et al (2014).

    In 1982, Glyn Haslam and colleagues presented a full sky map at a radio frequency of 408 MHz. The map had taken more than a decade to produce and combined data from the Jodrell Bank, Effelsberg and Parkes radio telescopes. This is the most widely used synchrotron template of the sky. In this map, four Loops are visible but they are difficult to isolate from a smooth diffuse component.

    Max Planck Effelberg Radio telescope
    Effelsberg Readio Telescope

    CSIRO Parkes Observatory
    CSIRO/Parks

    Now, using data available from the WMAP satellite, we can see for the first time how the polarised radio sky looks at high radio frequencies (~30 GHz). Surprisingly, the sky is covered by a number of bright filaments, without the uniform smooth background which dominates the radio continuum maps.

    We have catalogued these new filaments and tested a model to explain the origin of some of these features. We believe that they might be caused by the interaction between an expanding shell in the solar vicinity with the magnetic field of the Galaxy. The expanding shell, powered by supernova events and the radiation from massive stars compresses the magnetic field around it, increasing the synchrotron emission from the shell. This simple model reproduces well the data in most of the areas studied.

    See the full article here.

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    Jodrell Bank Centre for Astrophysics comprises research activities in astronomy and astrophysics at The University of Manchester, the world leading facilities of the Jodrell Bank Observatory, the e-MERLIN/VLBI National Facility and the Project Development Office of the Square Kilometre Array.

    Jodrell Bank e-Merlin

    SKA Square Kilometer Array

     
  • richardmitnick 5:49 am on December 21, 2014 Permalink | Reply
    Tags: Astronomy, , , , ,   

    From SPACE.com: “How Was the Moon Formed?” 2013 

    space-dot-com logo

    SPACE.com

    After the sun spun to light, the planets of the solar system began to form. But it took another hundred million years for Earth’s moon to spring into existence. There are three theories as to how our planet’s satellite could have been created: the giant impact hypothesis, the co-formation theory and the capture theory.

    Giant impact hypothesis

    This is the prevailing theory supported by the scientific community. Like the other planets, the Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. According to the giant impact hypothesis, one of these crashed into Earth not long after the young planet was created.

    Known as Theia, the Mars-size body collided with Earth, throwing vaporized chunks of the young planet’s crust into space. Gravity bound the ejected particles together, creating a moon that is the largest in the solar system in relation to its host planet. This sort of formation would explain why the moon is made up predominantly of lighter elements, making it less dense than Earth — the material that formed it came from the crust, while leaving the planet’s rocky core untouched. As the material drew together around what was left of Theia’s core, it would have centered near Earth’s ecliptic plane, the path the sun travels through the sky, which is where the moon orbits today.

    Co-formation theory

    Moons can also form at the same time as their parent planet. Under such an explanation, gravity would have caused material in the early solar system to draw together at the same time as gravity bound particles together to form Earth. Such a moon would have a very similar composition to the planet, and would explain the moon’s present location. However, although Earth and the moon share much of the same material, the moon is much less dense than our planet, which would likely not be the case if both started with the same heavy elements at their core.

    Capture theory

    Perhaps Earth’s gravity snagged a passing body, as happened with other moons in the solar system, such as the Martian moons of Phobos and Deimos. Under the capture theory, a rocky body formed elsewhere in the solar system could have been drawn into orbit around the Earth. The capture theory would explain the differences in the composition of the Earth and its moon. However, such orbiters are often oddly shaped, rather than being spherical bodies like the moon. Their paths don’t tend to line up with the ecliptic of their parent planet, also unlike the moon.

    Although the co-formation theory and the capture theory both explain some elements of the existence of the moon, they leave many questions unanswered. At present, the giant impact hypothesis seems to cover many of these questions, making it the best model to fit the scientific evidence for how the moon was created.
    Conceptual illustrations of the birth of the moon.

    m1

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    m3

    m4

    m5

    m6

    See the full article, with video, here.

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  • richardmitnick 6:04 pm on December 20, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From SPACE.com: “Orion’s Belt: String of Stars & Region of Star Birth” 

    space-dot-com logo

    SPACE.com

    December 20, 2014
    Elizabeth Howell

    Orion’s Belt is an asterism of three stars that appear about midway in the constellation Orion the Hunter. The asterism is so called because it appears to form a belt in the hunter’s outfit. It is one of the most famous asterisms used by amateur astronomers. Asterisms are patterns of stars of similar brightness. The stars may be part of a larger constellation or may be formed from stars in different constellations.

    Spotting the belt is actually one of the easiest ways to find the constellation Orion itself, which is among the brightest and most prominent in the winter sky. The three stars that traditionally make up the belt are, from west to east: Mintaka, Alnilam and Alnitak. The names of the outer two both mean “belt” in Arabic, while Alnilam comes from an Arabis word that mean “string of pearls,” which is the name of the whole asterism in Arabic, according to astronomer Jim Kaler.

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    The stars Alnilam, Mintaka and Alnitak form Orion’s belt.
    Credit: Martin Mutti, Astronomical Image Data Archive

    Hanging down from Orion’s Belt is his sword, which is made up of three fainter stars. The central “star” of the sword is actually the Orion Nebula (M42), a famous region of star birth. The Horsehead Nebula (IC 434), which is a swirl of dark dust in front of a bright nebula, is also nearby.

    o
    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    NASA Hubble Telescope
    NASA Hubble schematic
    Hubble

    Looking north of the belt, Orion’s “shoulders” are marked by Betelgeuse and Bellatrix and south, his “knees” are Saiph and Rigel.

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    Skywatcher Per-Magnus Heden wondered if the Vikings gazed at the same starry sky, which includes the constellation Orion at bottom, when he took this photo in Feb. 2011.
    Credit: P-M Hedén/TWAN

    Cultural references and notable features

    “The only real legend that is sometimes referred to in Western Culture with Orion’s Belt is the Three Kings,” said Tom Kerss, an astronomer with the Royal Observatory Greenwich, in a Space.com interview. This is a direct reference to the Biblical tale of the three kings who offered gifts to the Baby Christ shortly after his birth.

    Because Orion’s Belt is so easy to find in the sky, it can be used as a pointer to bring amateur astronomers to other interesting objects. Move northwest of the star complex and eventually the line will bring you to the Pleiades star cluster, a collection of dozens of stars that are sometimes called the Seven Sisters (after those that are the most easily visible to the naked eye.)

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    The Pleiades, an open cluster consisting of approximately 3,000 stars at a distance of 400 light-years (120 parsecs) from Earth in the constellation of Taurus. It is also known as “The Seven Sisters”, or the astronomical designations NGC 1432/35 and M45.

    http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/

    Following southwest of the stars will lead you to Sirius, the brightest star in the sky in both the Northern and Southern hemispheres. Part of its brightness in the sky comes because it is so close to us, just 8.7 light-years away.

    Kerss said the shape is also interesting astronomically. Some of the stars themselves are physically close together (which is not always true of stars in the sky, which only appear to be nearby.)
    Recent astronomical news

    Although the Orion Nebula has been studied thoroughly by both amateur and professional astronomers, surprises continue with further observations.

    In 2013, a Chilean European Southern Observatory telescope spotted signs of a cosmic “ribbon” in the nebula that is more than 1,000 light-years away. The track contains cold gas and dust, and astronomers also noted they may have found 15 young stars or protostars while making these observations.

    Even closer looks at the nebula have revealed features such as this bow shock from the young star LL Ori, which is sending out wind that strikes gas leaving the heart of the star-forming region.

    See the full article here.

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  • richardmitnick 6:09 am on December 20, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From RAS: “Science and Innovation Strategy: RAS Response” 

    Royal Astronomical Society

    Royal Astronomical Society

    Friday, 19 December 2014
    No Writer Credit

    The UK government published its new Science and Innovation strategy on Wednesday 17 December. The new document, “Our Plan for Growth: science and innovation” includes a number of positive announcements and restatements of support for projects in astronomy and geophysics, such as the capital funding for the Square Kilometre Array (SKA) radio observatory and the Polar Research Ship, and the more recent support for the European Space Agency to develop the ExoMars mission.

    SKA Pathfinder Radio Telescope
    SKA Pathfinder telescope

    ESA ExoMars
    ESA/ExoMars

    The Society welcomes these, along with the statement of support for peer review in investment decisions; the importance of international collaboration, the new targets for the recruitment of maths and physics teachers, the new postgraduate loans scheme, the recognition of the success of the Gaia and Rosetta missions and the opportunities presented by Major Tim Peake’s flight to the International Space Station next year.

    ESA Gaia satellite
    ESA/Gaia

    ESA Rosetta spacecraft
    ESA/Rosetta

    More generally, one of the long-standing concerns of the scientific community has been the low level of public (and private) funding for science compared with other EU and OECD countries. The new strategy explicitly addresses this, with a pledge to examine resource spending in the 2015 Spending Review. The Society welcomes this commitment and the overarching statement that policies for science and innovation should not detract from the importance of fundamental research being carried out for its own sake.

    International collaboration, including UK leadership in European scientific programmes such as Horizon 2020, also has a high prominence. The Society endorses this view and the pledge to use the UK presidency of the EU to support this activity.

    The RAS however remains concerned about several fundamental areas, including the lack of commitment to protect the science ‘ring fence’. This flat cash budget has already been eroded significantly since 2010 and even a low inflation environment will have a serious impact on purchasing power in the years ahead. If this policy continues, the inevitable outcome will be a reduction in the resources (not least postgraduate students and postdoctoral researchers) needed to exploit scientific data. This could greatly hinder the UK’s ability to reap the full benefits of the capital investment in scientific projects. And although there is recognition of the need to recruit the most talented people from across the globe, though there seems no prospect of a loosening of the restrictions on immigration that can make such recruitment almost impossible in practice.

    President of the Royal Astronomical Society Prof Martin Barstow commented: “I am delighted to see that the Government so clearly recognises the importance of scientific research, including the ‘blue skies’ sciences that are so important to the RAS and our Fellows and which are so valued by the wider public. There has though been a hollowing out of the resource budget needed to make the most of our involvement and investment in major scientific programmes, something that will need to be tackled if the UK is to remain a world player in research. As RAS President I will be pressing the Government to tackle this in next year’s Spending Review, in order to deliver the secure environment that will allow our researchers to flourish.”

    See the full article here.

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

     
  • richardmitnick 10:37 pm on December 19, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From Ethan Siegel: “Dark Matter vs. Dark Energy” 

    Starts with a bang
    Starts with a Bang

    Dec 19, 2014
    Ethan Siegel

    “We are incredibly heedless in the formation of our beliefs, but find ourselves filled with an illicit passion for them when anyone proposed to rob us of their companionship.” -James Harvey Robinson

    Sure, most of us have some version in our heads of how this — the Universe — all came to be the way it is. Yet some of the details, no matter how scientifically well-versed we are, have got to seem puzzling. This week’s Ask Ethan comes courtesy of the inquiry of Tom Anderson, who becomes the fourth winner in our Year In Space 2015 calendar giveaway, with his submission:

    [D]ark matter attracts while dark energy repels. Dark energy is continuously driving the expansion of space in between gravitationally bound galaxies/clusters and it seems that the current general consensus is that universe is set to ever expand, cooling and eventually into a “big freeze” scenario. Taking from this, as gravitationally bound systems do not expand, that the combined attraction force of dark matter and ordinary matter is equal or greater to the repelling force of dark energy and ordinary energy. Why then, did the universe expand at all after the Big Bang? [W]hy didn’t the dark matter counteract the force of the dark energy in the universe’s infancy?

    This is a mouthful, so let’s start by breaking this down.

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    Image credit: wiseGEEK, © 2003–2014Conjecture Corporation, via http://www.wisegeek.com/what-is-cosmology.htm#; original from Shutterstock / DesignUA.

    The way the Universe works, and how structures like stars, galaxies, and clusters of galaxies form is a little bit out of the realm of our ordinary experience. To simplify it greatly, our Universe is made of expanding spacetime, where the rate of expansion starts off at some initial value, determined by the physics of cosmic inflation and how that inflationary period ends.

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    Image credit: Don Dixon / Cosmographica, representing cosmic inflation and its end; original from http://www.cosmographica.com/.

    But that expansion rate isn’t constant once inflation does end, because the Universe is filled with all sorts of other forms of energy: radiation, matter, antimatter, neutrinos, dark matter, and a little bit of energy inherent to space itself, known as dark energy. It’s the combination of all these things — which change as the Universe expands — that determine how the expansion rate of the Universe changes as time goes on.

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    Images credit: Pearson / Addison-Wesley ; Quantum Stories, retrieved via http://cuentos-cuanticos.com/.

    So, on a global scale, meaning on the scale of the entire Universe, it’s either going to recollapse entirely, expand forever, or be right on the border between those two cases, depending on what the varying ratios of all the different forms of energy are in the Universe.

    For the one we actually live in, it looks like the Universe will expand forever and ever, as dark energy has come to dominate our Universe at late times.
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    Image credit: Don Dixon, from Scientific American 15, 66–73 (2006) doi:10.1038/scientificamerican0206–66sp.

    But this analysis doesn’t apply to the Universe on all scales; it simply tells us what is happening to the Universe on a global scale, or the scale of the entire Universe! It tells us that now, at late times and on large scales, objects that are not yet gravitationally bound together will begin accelerating away from one another.

    But there are still gravitationally bound systems, and they exist on small scales in great abundance, on medium scales in moderate abundance, and on relatively large scales in sparse but non-zero abundance. And it’s all part of the same cosmic story.

    You see, the Universe didn’t start off perfectly smooth, with exactly equal amounts of matter, radiation, dark matter and dark energy in all locations. If it had, our Universe would be incredibly boring; it would be a perfectly uniform sea where everyplace was exactly average. There would be no stars, galaxies or planets, no voids or places that were empty, no people, animals, life, clusters or filaments.

    Instead, from a very early time, we find that the Universe has slight regions of overdense and underdense regions on all scales: on small, medium and large scales.

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    A cosmological simulation of dark matter growing clumpier over time. Image credit: Andrey Kravtsov.

    Dark matter helps the overdense regions grow over time, and they can grow quickly enough that they will gravitationally collapse, in as little as a few tens of millions of years. It’s as though small regions of the Universe started out, locally, with an overall matter-and-energy density that was great enough so that, if the entire Universe were that way, it would have recollapsed altogether rather quickly!

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    Ned Wright’s Cosmology tutorial, via http://www.astro.ucla.edu/~wright/cosmo_03.htm

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    Ross Church of Jesus College, via http://jcsu.jesus.cam.ac.uk/

    Of course, there are many more regions where the density is less than average, and they tend to give up their matter to the denser regions; if the entire Universe were like those regions, we would have very, very few stars, galaxies and clusters.

    But it’s this very diversity in initial conditions all over the Universe that enables us to wind up with this huge diversity of all that we can see. In the cosmic struggle of dark matter vs. dark energy, of gravitation vs. the expansion, of the great cosmic “pulls” to form structure and the cosmic “pushes” to suppress it, there are both winners and losers.

    We notice the winners far more easily, because they copiously emit and absorb visible light and light from other portions of the electromagnetic spectrum, they gravitationally lens material behind them, and because it’s a lot easier to detect the presence rather than the absence of something.

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    Image credit: NASA; ESA; G. Illingworth, UCO/Lick Observatory and the University of California, Santa Cruz; R. Bouwens, UCO/Lick Observatory and Leiden University; and the HUDF09 Team.

    But the empty regions are there, and they matter, and — in fact — they vastly outnumber the “full” regions! The combined attractive force of dark and normal matter can defeat both the initial expansion and the additional, accelerative force of dark energy, but only on relatively small scales and at relatively early times.

    As we go to larger and larger scales, we find that there are more and more victories for repulsion, and as we reach the largest scales, repulsion always wins.

    The Universe expanded in the beginning because of the initial conditions set up by inflation, and the recollapse option — thanks to the gravitational pull of quantities like normal matter, dark matter, radiation and neutrinos — was only enough to “win” in a few select locations. It didn’t win in all of them, it didn’t win in most of them, and it didn’t win on average.

    And that’s why, when we look out at our Universe today, there are tons of galaxies littered throughout it, many of them clustered together in groups and large collections, and on large scales, aligned along filaments. But these galaxy groups that consist of a few thousand galaxies spanning a few hundred million light-years in size are most likely the largest bound structures we have; on all scales larger than that, alignments are temporary, as the presence of dark energy will eventually drive them apart.

    If the Universe had just the tiniest amount more of dark matter — something like 1 part in 10^24 more — it would have recollapsed billions of years ago. It was very finely balanced for a long time — with gravity winning locally in some spots and losing in others — but now that dark energy has come to dominate it, we’re seeing that its effects are going to win out. It wins in the end, it wins on the largest scales, and it wins for everything that wasn’t already gravitationally bound together after the first seven-or-so billion years of the Universe.

    And that, Tom Anderson, is the answer to your question about the growth, expansion and fate of the Universe! We only have one week left (and one more calendar left) for our Year In Space 2015 calendar giveaway, and if you want a chance to win it, send in (along with your email address) your questions or suggestions for an Ask Ethan column. You could be the year’s final lucky winner!

    See the full article, with video, here.

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    Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible.

     
  • richardmitnick 3:48 pm on December 19, 2014 Permalink | Reply
    Tags: Astronomy, , , Much More,   

    From JPL: “Horsehead of a Different Color” 

    JPL

    December 19, 2014
    No Writer Credit

    Sometimes a horse of a different color hardly seems to be a horse at all, as, for example, in this newly released image from NASA’s Spitzer Space Telescope. The famous Horsehead nebula makes a ghostly appearance on the far right side of the image, but is almost unrecognizable in this infrared view. In visible-light images, the nebula has a distinctively dark and dusty horse-shaped silhouette, but when viewed in infrared light, dust becomes transparent and the nebula appears as a wispy arc.

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    NASA Spitzer Telescope
    NASA Spitzer schematic
    NASA/Spitzer

    NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

    For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer.

    See the full article here.

    Further material

    The Horsehead is only one small feature in the Orion Molecular Cloud Complex, dominated in the center of this view by the brilliant Flame nebula (NGC 2024). The smaller, glowing cavity falling between the Flame nebula and the Horsehead is called NGC 2023. These regions are about 1,200 light-years away.

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    Photo taken by Rogelio Bernal Andreo in October 2010 of the Orion constellation showing the surrounding nebulas of the Orion Molecular Cloud complex. Also captured is the red supergiant Betelgeuse (top left) and the famous belt of Orion composed of the OB stars Altitak, Alnilam and Mintaka. To the bottom right can be found the star Rigel. The red crescent shape is Barnard’s Loop. The photograph appeared as the Astronomy Picture of the Day on October 23, 2010.

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    Flame Nebula
    Stars are often born in clusters, in giant clouds of gas and dust. Astronomers have studied two star clusters using NASA’s Chandra X-ray Observatory and infrared telescopes and the results show that the simplest ideas for the birth of these clusters cannot work, as described in our latest press release. This composite image shows one of the clusters, NGC 2024, which is found in the center of the so-called Flame Nebula about 1,400 light years from Earth. In this image, X-rays from Chandra are seen as purple, while infrared data from NASA’s Spitzer Space Telescope are colored red, green, and blue. A study of NGC 2024 and the Orion Nebula Cluster, another region where many stars are forming, suggest that the stars on the outskirts of these clusters are older than those in the central regions. This is different from what the simplest idea of star formation predicts, where stars are born first in the center of a collapsing cloud of gas and dust when the density is large enough. The research team developed a two-step process to make this discovery. First, they used Chandra data on the brightness of the stars in X-rays to determine their masses. Next, they found out how bright these stars were in infrared light using data from Spitzer, the 2MASS telescope, and the United Kingdom Infrared Telescope.

    2MASS Telescope
    2MASS telescope interior
    2MASS

    UKIRT
    UKIRT interior
    UKIRT

    By combining this information with theoretical models, the ages of the stars throughout the two clusters could be estimated. According to the new results, the stars at the center of NGC 2024 were about 200,000 years old while those on the outskirts were about 1.5 million years in age. In Orion, the age spread went from 1.2 million years in the middle of the cluster to nearly 2 million years for the stars toward the edges.
    Explanations for the new findings can be grouped into three broad categories. The first is that star formation is continuing to occur in the inner regions. This could have happened because the gas in the outer regions of a star-forming cloud is thinner and more diffuse than in the inner regions. Over time, if the density falls below a threshold value where it can no longer collapse to form stars, star formation will cease in the outer regions, whereas stars will continue to form in the inner regions, leading to a concentration of younger stars there. Another suggestion is that old stars have had more time to drift away from the center of the cluster, or be kicked outward by interactions with other stars. Finally, the observations could be explained if young stars are formed in massive filaments of gas that fall toward the center of the cluster. The combination of X-rays from Chandra and infrared data is very powerful for studying populations of young stars in this way. With telescopes that detect visible light, many stars are obscured by dust and gas in these star-forming regions, as shown in this optical image of the region.
    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra’s science and flight operations.
    Date 8 May 2014

    NASA Chandra Telescope
    NASA Chandra schematic
    NASA/Chandra

    The two carved-out cavities of the Flame nebula and NGC 2023 were created by the destructive glare of recently formed massive stars within their confines. They can be seen tracing a spine of glowing dust that runs through the image.

    The Flame nebula sits adjacent to the star Alnitak, the westernmost star in Orion’s belt, seen here as the bright blue dot near the top of the nebula.

    In this infrared image from Spitzer, blue represents light emitted at a wavelength of 3.6-microns, and cyan (blue-green) represents 4.5-microns, both of which come mainly from hot stars. Green represents 8-micron light and red represents 24-micron light. Relatively cooler objects, such as the dust of the nebulae, appear green and red. Some regions along the top and bottom of the image extending beyond Spitzer’s observations were filled in using data from NASA’s Wide-field Infrared Survey Explorer, or WISE, which covered similar wavelengths across the whole sky.

    NASA Wise Telescope
    NASA/WISE

    The visible-light image (see inset), from the European Southern Observatory’s Very Large Telescope facility, can be found online at http://www.eso.org/public/images/eso0202a/.

    ESO VLT Interferometer
    ESO VLT Interior
    ESO/VLT

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 9:07 pm on December 18, 2014 Permalink | Reply
    Tags: AAO, Astronomy, , , ,   

    From NOAO: “NOAO: Compact Galaxy Groups Reveal Details of Their Close Encounters” 

    NOAO Banner

    December 18, 2014
    Dr. David James
    Cerro Tololo Inter-American Observatory
    Casilla 603
    La Serena, CHILE
    E-mail: djj@ctio.noao.edu

    Galaxies – spirals laced with nests of recent star formation, quiescent ellipticals composed mainly of old red stars, and numerous faint dwarfs – are the basic visible building blocks of the Universe. Galaxies are rarely found in isolation, but rather in sparse groups – sort of galactic urban sprawl. But there are occasional dense concentrations, often found in the center of giant clusters, but also, intriguingly, as more isolated compact groups (and yes, called Compact Galaxy Groups or CGs). The galaxies in these Compact Groups show dramatic differences in the way they evolve and change with time compared with galaxies in more isolated surroundings. Why is this? Collisions between galaxies in these dense groups are common, leading to rapid star formation, but there seems to be more to the puzzle.

    A team led by Dr Iraklis Konstantopoulos of the Australian Astronomical Observatory (AAO) has now obtained spectacular images of some CGs with the Dark Energy camera attached to the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). This camera, constructed at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, is able to image large areas of the sky to unprecedented faint limits. The team aims to combine these images with spectroscopic data from the AAO that will reveal the velocities of the galaxies, leading to a much better understanding of their gravitational interactions.

    Dark Energy Camera
    DECam

    CTIO Victor M Blanco 4m Telescope
    CTIO Victor M Blanco 4m Telescope interior
    Blanco 4 meter telescope

    As Dr. David James (CTIO), who planned and obtained the images said, “The new images are absolutely brilliant, and reveal faint streams of gas and stars called tidal tails, created in the mutual gravitational interaction when two galaxies suffer a close encounter.” The tails, one preceding and one trailing the galaxy, persist long after the encounter, and allow the astronomers to calculate how long ago the event took place. The Dark Energy Camera, which can image a field four times the size of the full moon, is able to record these faint tidal tails, and the camera’s wide field will uncover unexpected surprises.

    1
    HCG 07: Galaxies in this cluster are undergoing a burst of star formation, but no tidal tails. How many dwarf galaxies are hidden here? (This image covers an area about a third the size of the full moon.)

    2
    HCG 31: The tidal tails are clues to recent interactions, but no evidence of heated gas between the galaxies, as would be expected.

    3
    HCG 48: This group is dominated by a massive elliptical galaxy that has presumably formed by ingesting (astronomers refer to this as accreting) all of its neighbors.

    4
    HCG 59: Two interacting giants have released a giant stellar stream in this Compact Group, which also hosts a bursting irregular galaxy.

    5
    HCG 62: The brightest Compact Group in the X-ray spectrum, astronomers seek to understand how the galaxies which share a common halo will evolve.

    6
    HCG 79: Known as Seyfert’s Sextet, four of these galaxies are involved in an ongoing interaction. The fifth galaxy is in the background and the sixth is actually material released in the interaction, the best candidate for a tidal dwarf galaxy in the local Universe.

    “The imagery reveals the assembly history of these galaxies living so close to each other via their previous interactions,” Dr Konstantopoulos said. “We look for stretched out tidal debris tails and roughly determine their ages. The time when interactions created the tidal debris and the arrangement of those ‘fossils’ tell us which galaxies interacted, and when.”

    Not all CGs are alike: in some, the gas is contained within the individual galaxies, while in other groups the gas spreads out among the galaxies. These new data will allow astronomers to untangle the physical mechanism that leads to such differences.

    Another new exploration is the census of faint dwarf galaxies. As their name implies, these are minor galaxies in comparison with giant ellipticals and spirals, but they are especially numerous, and the new data will reveal how many are lurking in these Compact Groups.

    The international team consists of astronomers at CTIO (a division of the National Optical Astronomy Observatory), the Australian Astronomical Observatory (the counterpart to the NOAO in Australia), and Monash University in Melbourne.

    See the full article here.

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    NOAO News

    NOAO is the US national research & development center for ground-based night time astronomy. In particular, NOAO is enabling the development of the US optical-infrared (O/IR) System, an alliance of public and private observatories allied for excellence in scientific research, education and public outreach.

    Our core mission is to provide public access to qualified professional researchers via peer-review to forefront scientific capabilities on telescopes operated by NOAO as well as other telescopes throughout the O/IR System. Today, these telescopes range in aperture size from 2-m to 10-m. NOAO is participating in the development of telescopes with aperture sizes of 20-m and larger as well as a unique 8-m telescope that will make a 10-year movie of the Southern sky.

    In support of this mission, NOAO is engaged in programs to develop the next generation of telescopes, instruments, and software tools necessary to enable exploration and investigation through the observable Universe, from planets orbiting other stars to the most distant galaxies in the Universe.

    To communicate the excitement of such world-class scientific research and technology development, NOAO has developed a nationally recognized Education and Public Outreach program. The main goals of the NOAO EPO program are to inspire young people to become explorers in science and research-based technology, and to reach out to groups and individuals who have been historically under-represented in the physics and astronomy science enterprise.

    The National Optical Astronomy Observatory is proud to be a US National Node in the International Year of Astronomy, 2009.

    About Our Observatories:
    Kitt Peak National Observatory (KPNO)

    Kitt Peak

    Kitt Peak National Observatory (KPNO) has its headquarters in Tucson and operates the Mayall 4-meter, the 3.5-meter WIYN , the 2.1-meter and Coudé Feed, and the 0.9-meter telescopes on Kitt Peak Mountain, about 55 miles southwest of the city.

    Cerro Tololo Inter-American Observatory (CTIO)

    NOAO Cerro Tolo

    The Cerro Tololo Inter-American Observatory (CTIO) is located in northern Chile. CTIO operates the 4-meter, 1.5-meter, 0.9-meter, and Curtis Schmidt telescopes at this site.

    The NOAO System Science Center (NSSC)

    Gemini North
    Gemini North

    Gemini South telescope
    Gemini South

    The NOAO System Science Center (NSSC) at NOAO is the gateway for the U.S. astronomical community to the International Gemini Project: twin 8.1 meter telescopes in Hawaii and Chile that provide unprecendented coverage (northern and southern skies) and details of our universe.

    NOAO is managed by the Association of Universities for Research in Astronomy under a Cooperative Agreement with the National Science Foundation.

     
  • richardmitnick 4:45 pm on December 18, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From Chandra: “Chandra Weighs Most Massive Galaxy Cluster in Distant Universe” 

    NASA Chandra

    The most distant massive galaxy cluster, located about 9.6 billion light years from Earth, has been found and studied. Astronomers nicknamed this object the “Gioello” (Italian for “Jewel”) Cluster.
    Using Chandra data, researchers were able to accurately determine the mass and other properties of this cluster. Results like this help astronomers understand how galaxy clusters have evolved over time.

    copm
    Composite

    xray
    X-Ray

    infra
    Infrared

    opt
    Optical
    Credit X-ray: NASA/CXC/INAF/P.Tozzi, et al; Optical: NAOJ/Subaru and ESO/VLT; Infrared: ESA/Herschel
    Release Date December 18, 2014

    A newly discovered galaxy cluster is the most massive one ever detected with an age of 800 million years or younger. Using data from NASA’s Chandra X-ray Observatory, astronomers have accurately determined the mass and other properties of this cluster, as described in our latest press release. This is an important step in understanding how galaxy clusters, the largest structures in the Universe held together by gravity, have evolved over time.

    A composite image shows the distant and massive galaxy cluster that is officially known as XDCP J0044.0-2033. Researchers, however, have nicknamed it “Gioiello”, which is Italian for “jewel”. They chose this name because an image of the cluster contains many sparkling colors from the hot, X-ray emitting gas and various star-forming galaxies within the cluster. Also, the research team met to discuss the Chandra data for the first time at Villa il Gioiello, a 15th century villa near the Observatory of Arcetri, which was the last residence of prominent Italian astronomer Galileo Galilei. In this new image of the Gioiello Cluster, X-rays from Chandra are purple, infrared data from ESA’s Hershel Space Telescope appear as large red halos around some galaxies, and optical data from the Subaru telescope on Mauna Kea in Hawaii are red, green, and blue.

    ESA Herschel
    ESA Herschel schematic
    ESA/Herschel

    NAOJ Subaru Telescope
    NAOJ Subaru Telescope interior

    Astronomers first detected the Gioiello Cluster, located about 9.6 billion light years away, using ESA’s XMM-Newton observatory. They were then approved to study the cluster with Chandra in observations that were equivalent to over four days of time. This is the deepest X-ray observation yet made on a cluster beyond a distance of about 8 billion light years.

    ESA XMM Newton
    ESA XMM-Newton schematc
    ESA/XMM-Newton

    The long observing time allowed the researchers to gather enough X-ray data from Chandra that, when combined with scientific models, provides an accurate weight of the cluster. They determined that the Gioiello Cluster contains a whopping 400 trillion times the mass of the Sun.

    Previously, astronomers had found an enormous galaxy cluster, known as “El Gordo,” at a distance of 7 billion light years away and a few other large, distant clusters. According to the best current model for how the Universe evolved, there is a low chance of finding clusters as massive as the Gioiello Cluster and El Gordo. The new findings suggest that there might be problems with the theory, and are enticing astronomers to look for other distant and massive clusters.

    e
    El Gordo consists of two separate galaxy subclusters colliding at several million
    kilometres per hour.

    These results are being published in The Astrophysical Journal available online. The first author is Paolo Tozzi, from the National Institute for Astrophysics (INAF) in Florence, Italy. The co-authors are Johana Santos, also from INAF in Florence, Italy; James Jee from the University of California in Davis; Rene Fassbender from INAD in Rome, Italy; Piero Rosati from the University of Ferrara in Ferrara, Italy; Alessandro Nastasi from the University of Paris-Sud, in Orsay, France; William Forman from Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA; Barbara Sartoris and Stefano Borgani from the University of Trieste in Trieste, Italy; Hans Boehringer from the Max Planck Institute for Astrophysics in Garching, Germany; Bruno Altieri from the European Space Agency in Madrid, Spain; Gabriel Pratt from CEA Saclay in Cedex, France; Mario Nonino from the University of Trieste in Trieste, Italy and Christine Jones from CfA.

    See the full article here.

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    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

     
  • richardmitnick 3:43 pm on December 18, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From IFA at U Hawaii: “UH Astronomer, Keck Observatory Confirm First Kepler K2 Exoplanet Discovery” 

    U Hawaii

    University of Hawaii

    Institute for Astronomy

    U Hawaii Institute for Astonomy Mauna Kea
    IFA at Manua Kea

    Despite a malfunction that ended its primary mission in May 2013, NASA’s Kepler spacecraft has discovered a new super-Earth using data collected during its “second life,” known as the K2 mission.

    i
    This artist’s conception portrays the first planet discovered by the Kepler spacecraft during its K2 mission. A transit of the planet was teased out of K2’s noisier data using ingenious computer algorithms developed by a researcher at the Harvard-Smithsonian Center for Astrophysics (CfA). The newfound planet, HIP 116454b, has a diameter of 20,000 miles (two and a half times the size of Earth) and weighs 12 times as much. It orbits its star once every 9.1 days. Artwork courtesy CfA.

    University of Hawaii astronomer Christoph Baranec supplied confirming data with his Robo-AO instrument mounted on the Palomar 1.5-meter telescope, and former UH graduate student Brendan Bowler, now a Joint Center for Planetary Astronomy postdoctoral fellow at Caltech, provided additional confirming observations using the Keck II adaptive optics system on Maunakea.

    Caltech Palomar 1.5m 60in telescope
    1.5 meter telescope at Palomar

    Keck Observatory
    Keck

    The Kepler spacecraft detects planets by looking for planets that transit, or cross in front of, their star as seen from the vantage of Earth. During the transit, the star’s light dims slightly. The smaller the planet, the weaker the dimming, so brightness measurements must be exquisitely precise. To enable that precision, the spacecraft must maintain a steady pointing.

    Kepler’s primary mission came to an end when the second of four reaction wheels used to stabilize the spacecraft failed. Without at least three functioning reaction wheels, Kepler couldn’t be pointed accurately.

    Rather than giving up on the plucky spacecraft, a team of scientists and engineers developed an ingenious strategy to use pressure from sunlight as a virtual reaction wheel to help control the spacecraft. The resulting second mission promises to not only continue Kepler’s search for other worlds, but also introduce new opportunities to observe star clusters, active galaxies, and supernovae.

    “Like a phoenix rising from the ashes, Kepler has been reborn and is continuing to make discoveries. Even better, the planet it found is ripe for follow-up studies,” says lead author Andrew Vanderburg of the Harvard-Smithsonian Center for Astrophysics (CfA).

    Due to Kepler’s reduced pointing capabilities, extracting useful data requires sophisticated computer analysis. Vanderburg and his colleagues developed specialized software to correct for spacecraft movements, achieving about half the photometric precision of the original Kepler mission.

    Kepler’s new life began with a nine-day test in February 2014. When Vanderburg and his colleagues analyzed that data, they found that Kepler had detected a single planetary transit.

    The new found planet, HIP 116454b, has a diameter of 20,000 miles, two and a half times the size of Earth, and weighs almost 12 times as much as Earth. This makes HIP 116454b a super-Earth, a class of planets that doesn’t exist in our solar system. The average density suggests that this planet is either a water world (composed of about three-fourths water and one-fourth rock) or a mini-Neptune with an extended, gaseous atmosphere.

    This close-in planet circles its star once every 9.1 days at a distance of 8.4 million miles. Its host star is a type K orange dwarf slightly smaller and cooler than our sun. The system is 180 light-years from Earth in the constellation Pisces.

    During the process of verifying the discovery, Harvard astronomer and co-author John Johnson, a former postdoctoral fellow at the UH Institute for Astronomy, contacted Baranec and the Robo-AO team to obtain high-resolution imaging of HIP 116454 to determine whether it has very nearby stellar companions that could be contaminating the Kepler data, causing a misestimation of the planet’s size and other characteristics.

    “Because of the flexible nature of the Robo-AO system, it was possible to add the target to the Robo-AO intelligent queue, and several observations were carried out within days of the request,” says Baranec.

    While Robo-AO didn’t find any stellar companions, some additional follow-up measurements hinted that there might be a companion that is too close for Robo-AO to see. To be absolutely sure there were no contaminating companions, Bowler was asked to observe HIP 116454 with the Keck II adaptive optics system. He confirmed that HIP 116454 has no close-in stellar companions.

    Since the host star is relatively bright and nearby, follow-up studies will be easier to conduct than for many Kepler planets orbiting fainter, more distant stars. “HIP 116454b will be a top target for telescopes on the ground and in space,” says Johnson.

    The research paper reporting this discovery has been accepted for publication in The Astrophysical Journal.

    See the full article here.

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    System Overview

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

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

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

     
  • richardmitnick 6:28 pm on December 17, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From NASA Goddard: “MESSENGER Data Suggest Recurring Meteor Shower on Mercury “ 

    NASA Goddard Banner

    December 12, 2014
    Nancy Neal-Jones
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039
    nancy.n.jones@nasa.gov

    Elizabeth Zubritsky
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    301-614-5438
    elizabeth.a.zubritsky@nasa.gov

    The closest planet to the sun appears to get hit by a periodic meteor shower, possibly associated with a comet that produces multiple events annually on Earth.

    The clues pointing to Mercury’s shower were discovered in the very thin halo of gases that make up the planet’s exosphere, which is under study by NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft.

    NASA Messenger satellite
    NASA/MESSENGER

    “The possible discovery of a meteor shower at Mercury is really exciting and especially important because the plasma and dust environment around Mercury is relatively unexplored,” said Rosemary Killen, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, available online in Icarus.

    m
    Mercury appears to undergo a recurring meteor shower, perhaps when its orbit crosses the debris trail left by comet Encke. (Artist’s concept.)
    Image Credit: NASA’s Goddard Space Flight Center

    A meteor shower occurs when a planet passes through a swath of debris shed by a comet, or sometimes an asteroid. The smallest bits of dust, rock and ice feel the force of solar radiation, which pushes them away from the sun, creating the comet’s sometimes-dazzling tail. The larger chunks get deposited like a trail of breadcrumbs along the comet’s orbit – a field of tiny meteoroids in the making.

    Earth experiences multiple meteor showers each year, including northern summer’s Perseids, the calling card of comet Swift–Tuttle, and December’s reliable Geminids, one of the few events associated with an asteroid. Comet Encke has left several debris fields in the inner solar system, giving rise to the Southern and Northern Taurids, meteor showers that peak in October and November, and the Beta Taurids in June and July.

    The suggested hallmark of a meteor shower on Mercury is a regular surge of calcium in the exosphere. Measurements taken by MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer have revealed seasonal surges of calcium that occurred regularly over the first nine Mercury years since MESSENGER began orbiting the planet in March 2011.

    The suspected cause of these spiking calcium levels is a shower of small dust particles hitting the planet and knocking calcium-bearing molecules free from the surface. This process, called impact vaporization, continually renews the gases in Mercury’s exosphere as interplanetary dust and meteoroids rain down on the planet. However, the general background of interplanetary dust in the inner solar system cannot, by itself, account for the periodic spikes in calcium. This suggests a periodic source of additional dust, for example, a cometary debris field. Examination of the handful of comets in orbits that would permit their debris to cross Mercury’s orbit indicated that the likely source of the planet’s event is Encke.

    e
    Encke

    “If our scenario is correct, Mercury is a giant dust collector,” said Joseph Hahn, a planetary dynamist in the Austin, Texas, office of the Space Science Institute and coauthor of the study. “The planet is under steady siege from interplanetary dust and then regularly passes through this other dust storm, which we think is from comet Encke.”

    The researchers created detailed computer simulations to test the comet Encke hypothesis. However, the calcium spikes found in the MESSENGER data were offset a bit from the expected results. This shift is probably due to changes in the comet’s orbit over time, due to the gravitational pull of Jupiter and other planets.

    “The variation of Mercury’s calcium exosphere with the planet’s position in its orbit has been known for several years from MESSENGER observations, but the proposal that the source of this variation is a meteor shower associated with a specific comet is novel,” added MESSENGER Principal Investigator Sean Solomon, of the Lamont-Doherty Earth Observatory at Columbia University in New York. “This study should provide a basis for searches for further evidence of the influence of meteor showers on the interaction of Mercury with its solar-system environment.”

    The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA

     
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