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  • richardmitnick 9:23 pm on October 16, 2014 Permalink | Reply
    Tags: , , , , , Radio Astronomy   

    From NRAO: “Milky Way Ransacks Nearby Dwarf Galaxies, Stripping All Traces of Star-Forming Gas” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    October 15, 2014
    Contact: Charles E. Blue, Public Information Officer
    (434) 296-0314; cblue@nrao.edu

    Astronomers using the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia, along with data from other large radio telescopes, have discovered that our nearest galactic neighbors, the dwarf spheroidal galaxies, are devoid of star-forming gas, and that our Milky Way Galaxy is to blame.

    mw

    These new radio observations, which are the highest sensitivity of their kind ever undertaken, reveal that within a well-defined boundary around our Galaxy, dwarf galaxies are completely devoid of hydrogen gas; beyond this point, dwarf galaxies are teeming with star-forming material.

    The Milky Way Galaxy is actually the largest member of a compact clutch of galaxies that are bound together by gravity. Swarming around our home Galaxy is a menagerie of smaller dwarf galaxies, the smallest of which are the relatively nearby dwarf spheroidals, which may be the leftover building blocks of galaxy formation. Further out are a number of similarly sized and slightly misshaped dwarf irregular galaxies, which are not gravitationally bound to the Milky Way and may be relative newcomers to our galactic neighborhood.

    “Astronomers wondered if, after billions of years of interaction, the nearby dwarf spheroidal galaxies have all the same star-forming ‘stuff’ that we find in more distant dwarf galaxies,” said astronomer Kristine Spekkens, assistant professor at the Royal Military College of Canada and lead author on a paper published in the Astrophysical Journal Letters.

    Previous studies have shown that the more distant dwarf irregular galaxies have large reservoirs of neutral hydrogen gas, the fuel for star formation. These past observations, however, were not sensitive enough to rule out the presence of this gas in the smallest dwarf spheroidal galaxies.

    By bringing to bear the combined power of the GBT (the world’s largest fully steerable radio telescope) and other giant telescopes from around the world, Spekkens and her team were able to probe the dwarf galaxies that have been swarming around the Milky Way for billions of years for tiny amounts of atomic hydrogen.

    “What we found is that there is a clear break, a point near our home Galaxy where dwarf galaxies are completely devoid of any traces of neutral atomic hydrogen,” noted Spekkens. Beyond this point, which extends approximately 1,000 light-years from the edge of the Milky Way’s star-filled disk to a point that is thought to coincide with the edge of its dark matter distribution, dwarf spheroidals become vanishingly rare while their gas-rich, dwarf irregular counterparts flourish.

    There are many ways that larger, mature galaxies can lose their star-forming material, but this is mostly tied to furious star formation or powerful jets of material driven by supermassive black holes. The dwarf galaxies that orbit the Milky Way contain neither of these energetic processes. They are, however, susceptible to the broader influences of the Milky Way, which itself resides within an extended, diffuse halo of hot hydrogen plasma.

    The researchers believe that, up to a certain distance from the galactic disk, this halo is dense enough to affect the composition of dwarf galaxies. Within this “danger zone,” the pressure created by the million-mile-per-hour orbital velocities of the dwarf spheroidals can actually strip away any detectable traces of neutral hydrogen. The Milky Way thus shuts down star formation in its smallest neighbors.

    “These observations therefore reveal a great deal about size of the hot halo and about how companions orbit the Milky Way,” concludes Spekkens.

    See the full article here.

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    NRAO ALMA
    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

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  • richardmitnick 6:04 am on October 15, 2014 Permalink | Reply
    Tags: , , , , , Radio Astronomy   

    From ESO: “Construction Secrets of a Galactic Metropolis” 


    European Southern Observatory

    15 October 2014
    Contacts

    Helmut Dannerbauer
    University of Vienna
    Vienna, Austria
    Tel: +43 1 4277 53826
    Email: helmut.dannerbauer@univie.ac.at

    Carlos De Breuck
    ESO APEX Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6613
    Email: cdebreuc@eso.org

    Richard Hook
    ESO, Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Astronomers have used the APEX telescope to probe a huge galaxy cluster that is forming in the early Universe and revealed that much of the star formation taking place is not only hidden by dust, but also occurring in unexpected places. This is the first time that a full census of the star formation in such an object has been possible.

    ESO APEX
    ESO/APEX

    cloud

    Galaxy clusters are the largest objects in the Universe held together by gravity but their formation is not well understood. The Spiderweb Galaxy (formally known as MRC 1138-262 [1]) and its surroundings have been studied for twenty years, using ESO and other telescopes [2], and is thought to be one of the best examples of a protocluster in the process of assembly, more than ten billion years ago.

    But Helmut Dannerbauer (University of Vienna, Austria) and his team strongly suspected that the story was far from complete. They wanted to probe the dark side of star formation and find out how much of the star formation taking place in the Spiderweb Galaxy cluster was hidden from view behind dust.

    The team used the LABOCA camera on the APEX telescope in Chile to make 40 hours of observations of the Spiderweb Cluster at millimetre wavelengths — wavelengths of light that are long enough to peer right through most of the thick dust clouds. LABOCA has a wide field and is the perfect instrument for this survey.

    ESO LABOCA
    ESO/ LABOCA Camera on APEX

    Carlos De Breuck (APEX project scientist at ESO, and a co-author of the new study) emphasises: “This is one of the deepest observations ever made with APEX and pushes the technology to its limits — as well as the endurance of the staff working at the high-altitude APEX site, 5050 metres above sea level.”

    The APEX observations revealed that there were about four times as many sources detected in the area of the Spiderweb compared to the surrounding sky. And by carefully comparing the new data with complementary observations made at different wavelengths they were able to confirm that many of these sources were at the same distance as the galaxy cluster itself and must be parts of the forming cluster.

    Helmut Dannerbauer explains: “The new APEX observations add the final piece needed to create a complete census of all inhabitants of this mega star city. These galaxies are in the process of formation so, rather like a construction site on Earth, they are very dusty.”

    But a surprise awaited the team when they looked at where the newly detected star formation was taking place. They were expecting to find this star formation region on the large filaments connecting galaxies. Instead, they found it concentrated mostly in a single region, and that region is not even centred on the central Spiderweb Galaxy in the protocluster [3].

    Helmut Dannerbauer concludes: “We aimed to find the hidden star formation in the Spiderweb cluster — and succeeded — but we unearthed a new mystery in the process; it was not where we expected! The mega city is developing asymmetrically.”

    To continue the story further observations are needed — and ALMA will be the perfect instrument to take the next steps and study these dusty regions in far greater detail.

    ALMA Array
    ALMA
    Notes

    [1] The Spiderweb Galaxy contains a supermassive black hole and is a powerful source of radio waves — which is what led astronomers to notice it in the first place.

    [2] This region had been intensively observed by a variety of ESO telescopes since the mid-1990s. The redshift (and hence the distance) of the radio galaxy MRC1138-262 (the Spiderweb Galaxy) was first measured at La Silla. The first visitor mode FORS observations on the VLT discovered the protocluster and afterwards further observations were made with ISAAC, SINFONI, VIMOS and HAWK-I. The APEX LABOCA data complement optical and near-infrared datasets from ESO telescopes. The team also used a 12-hour VLA image to cross-identify the LABOCA sources in the optical images.

    ESO LaSilla Long View
    ESO/LaSilla

    ESO FORS1
    ESO/FORS

    ESO VLT Interferometer
    ESO/VLT

    ESO ISAAC
    ESO/ISAAC

    ESO SINFONI
    ESO/SINFONI

    ESO VIMOS
    ESO VIMOS

    ESO HAWK-I
    ESO HAWK-I

    [3] These dusty starbursts are thought to evolve into elliptical galaxies like those seen around us today in nearby galaxy clusters.
    More information

    This research was presented in a paper, An excess of dusty starbursts related to the Spiderweb galaxy, by Dannerbauer, Kurk, De Breuck et al., to appear online in the journal Astronomy & Astrophysics on 15 October 2014.

    APEX is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. Operation of APEX at Chajnantor is entrusted to ESO.

    The team is composed of H. Dannerbauer (University of Vienna, Austria), J. D. Kurk (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), C. De Breuck (ESO, Garching, Germany), D. Wylezalek (ESO, Garching, Germany), J. S. Santos (INAF–Osservatorio Astrofisico di Arcetri, Florence, Italy), Y. Koyama (National Astronomical Observatory of Japan, Tokyo, Japan [NAOJ]; Institute of Space Astronomical Science, Kanagawa, Japan), N. Seymour (CSIRO Astronomy and Space Science, Epping, Australia), M. Tanaka (NAOJ; Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, Japan), N. Hatch (University of Nottingham, United Kingdom), B. Altieri (Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Cañada, Spain [HSC]), D. Coia (HSC), A. Galametz (INAF–Osservatorio di Roma, Italy), T. Kodama (NAOJ), G. Miley (Leiden Observatory, the Netherlands), H. Röttgering (Leiden Observatory), M. Sanchez-Portal (HSC), I. Valtchanov (HSC), B. Venemans (Max-Planck Institut für Astronomie, Heidelberg, Germany) and B. Ziegler (University of Vienna).

    See the full article here.

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    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.

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  • richardmitnick 2:12 pm on October 14, 2014 Permalink | Reply
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    From Daily Galaxy: “Astrophysicists Take Pulse of Milky Way’s Supermassive Black Hole” 

    Daily Galaxy
    The Daily Galaxy

    October 14, 2014
    Julie Cohen/ucsb.edu

    Is matter falling into the massive black hole at the center of the Milky Way or being ejected from it? No one knows for sure, but a UC Santa Barbara astrophysicist is searching for an answer. Carl Gwinn, a professor in UCSB’s Department of Physics, and colleagues have analyzed images collected by the Russian spacecraft RadioAstron that was launched into orbit from Baikonur, Kazakhstan, in July 2011 with several missions, one of which was to investigate the scattering of pulsars — the cores of dead stars — by interstellar gas. What the team found led them to examine additional observations of Sagittarius A-Star (A*), the source that marks the Milky Way’s central black hole. Sagittarius A* is visible at radio, infrared and X-ray wavelengths.

    sag a
    This image was taken with NASA’s Chandra X-Ray Observatory.

    NASA Chandra Telescope
    NASA/Chandra

    This massive black hole — which contains 4 million solar masses — does not emit radiation but is visible from the gas around it. The gas is being acted upon by the black hole’s very strong gravitational field. The wavelengths that make Sagittarius A* visible are scattered by interstellar gas along the line of sight in the same way that light is scattered by fog on Earth.

    “The theory and observations allow us to make statements about the interstellar gas responsible for the scattering, and about the emission region around the black hole,” said Michael Johnson, at the Harvard-Smithsonian Center for Astrophysics. “It turns out that the size of that emission region is only 20 times the diameter of the event horizon as it would be seen from Earth. With additional observations, we can begin to understand the behavior in this extreme environment.”

    Gwinn and his colleagues found that the images taken by RadioAstron contained small spots. “I was quite surprised to find that the effect of scattering produced images with small lumps in the overall smooth image,” explained Gwinn. “We call these substructure. Some previous theories had predicted similar effects in the 1980s, and a quite controversial observation in the 1970s had hinted at their presence.”

    In order to better understand the substructure, Johnson, conducted theoretical research. He realized that the anomalies could be used to infer the actual size of the underlying source.

    Additional observations made using the Very Long Baseline Array — an interferometer consisting of 10 identical antennas distributed across the United States — and the 100-meter Green Bank Telescope in West Virginia showed the presence of lumps in the image of Sagittarius A*. Recent upgrades have greatly increased the sensitivity of these telescopes. Even so, evidence of the lumps, or substructure, remained extremely faint.

    VLBA
    VBLA

    NRAO GBT
    GBT

    While no scientific team has been able to produce a complete image of the black hole’s emission, astronomers have drawn inferences about scattering properties from observations at longer wavelengths. “From these they can extrapolate those properties to 1 centimeter and use that to make a rough estimate of the size of the source,” Gwinn said. “We seem to agree quite well with that estimate.”

    Not only did Gwinn and his colleagues directly confirm these indirect inferences about the size of Sagittarius A*, they were also able to provide new information about fluctuations in the interstellar gas that cause scattering. Their work shows that the spectrum of interstellar turbulence is shallow.

    sag
    Sag A-Star (1)

    “There are different ways of interpreting observations of the scattering, and we showed that one of them is right and the others are wrong,” said co-investigator Yuri Kovalev, the RadioAstron project scientist. “This will be important for future research on the gas near this black hole. This work is a good example of the synergy between different modern research infrastructures, technologies and science ideas.”

    A friendly international race is going on to see who will be the first to image the black hole’s emissions and thereby determine whether gas falls into the black hole or is being ejected in the form of a jet.

    “The character of the substructure seems to be random, so we are keen to go back and confirm the statistics of our sample with more data,” Gwinn said. “We’re also interested in looking at shorter wavelengths where we think the emission region may be smaller and we can get closer to the black hole. We may be able to extract more information than just the size of the emission region. We might possibly be able to make a simple image of how matter falls into a black hole or is ejected from it. It would be very exciting to produce such an image.”

    In 2009, calculations by scientists suggest that hundreds of rogue black holes should be traveling the Milky Way’s outskirts, each containing the mass of 1,000 to 100,000 suns left over from the galaxy-building days of the early universe, may wander the Milky Way.The calculations have been made by Ryan O’Leary and Avi Loeb from the Harvard-Smithsonian Center for Astrophysics. Though the research indicates that rogue black holes may roam the Milky Way, the good news is that the Earth is safe, as the closest rogue black hole should reside thousands of light-years away.

    “These black holes are relics of the Milky Way’s past,” said Loeb. “You could say that we are archaeologists studying those relics to learn about our galaxy’s history and the formation history of black holes in the early universe,” he added.

    According to theory, rogue black holes originally lurked at the centers of tiny, low-mass galaxies. Over billions of years, those dwarf galaxies smashed together to form full-sized galaxies like the Milky Way. Each time two proto-galaxies with central black holes collided, their black holes merged to form a single, “relic” black hole.

    The UCSB findings appear in the current issue of The Astrophysical Journal Letters.

    See the full article here.

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  • richardmitnick 7:35 am on October 10, 2014 Permalink | Reply
    Tags: , , , Radio Astronomy,   

    From SKA via VB News: “How big data is fueling a new age in space exploration” 

    SKA Square Kilometer Array

    SKA

    Untitled

    October 5, 2014
    Ilya Golubovich

    In 2018, a group of organizations from all of the world will begin construction of the largest radio telescope ever built, the Square Kilometre Array (SKA).

    scopes

    With one million square meters of collecting area and enough optical fiber to wrap around the Earth twice, this marvel of modern engineering will be sensitive enough to detect airport radar on a planet 50 light years away. SKA will also generate 700 terabytes of data every second, equivalent to roughly 35 times the data stored in the Library of Congress. At full capacity, the SKA’s aperture arrays are expected to produce 100 times more data than the entire Internet. It doesn’t take a rocket scientist to realize that such a deluge of information creates a big data problem, perhaps the biggest we have ever encountered.

    Solving this big data problem for the space industry requires innovation in the data storage, processing, and access (or visualization) technologies, which, in turn, creates ample opportunities for startups and large data crunching companies to take advantage of.

    A few major factors will drive exponential growth in the amount of terabytes falling on us from the skies over the next couple of decades: the increasing speed of commercial satellite deployment, implementation of faster communication technology, and the onset of interplanetary missions.

    The Growing “Orbital Economy” and Deep Space Exploration

    The dwindling cost of launches and the democratization of the satellite market are going to result in an unprecedented growth of orbital activity. Based on announced plans by various companies and space programs, between 2,000 and 2,750 cube- and nano-sats will be launched by the end of this decade — the Goddard Space Flight Center lists 2,271 satellites currently in orbit. Most of the new spacecraft will have commercial applications, particularly in Earth observation. Earth observation means images and video, often multi-spectral or even 3D, which are some of the heaviest “packages” in terms of data units involved.

    SKA Murchison Widefield Array
    A small portion of the Murchison Widefield Array, a SKA component

    Historically, the single largest barrier that has kept the space data floodgates closed was the ability to transmit the collected information back to Earth. Most current space missions use radio frequency to transfer data, which is a relatively slow approach. NASA’s typical deep space explorer would send back data on the order of megabytes per second, while earth orbiting spacecraft are typically doing so in gigabytes per second. In the future, however, the space industry is expected to start switching to new type of optical (or laser) communications that will significantly increase the download speed and mean a 1,000-multiple surge in the volume of data.

    SKA ASKAP
    SKA ASKAP

    In the last few years, both national space programs and private companies have made a number of big announcements regarding their plans for ambitious interplanetary missions: China is reportedly plotting a moon colony, SpaceX is well on track for a manned mission to Mars — especially given the latest contract award from NASA — and Planetary Resources is planning to prospect and mine near-earth asteroids for water and platinoid group metals by the end of this decade. (Disclosure: Planetary Resources is one of my portfolio companies.)

    Eric Anderson, the co-founder of Planetary Resources, estimates that the “planetographic” data available just in our own solar system dwarfs the amount of geographical data we have on Earth by three orders of magnitude.

    Data Storage and Management

    Amazon and NASA have recently launched the NASA Earth Exchange (NEX) platform, a collaboration and analytical tool that combines state-of-the-art supercomputing, Earth system modeling, workflow management and NASA remote-sensing data. With NEX, users can explore and analyze large earth science data sets, run and share modeling algorithms, collaborate on new or existing projects, and exchange workflows and results within and among other science communities. For now, NEX works primarily with data sets for climate, vegetation, and Landsat global land survey. However the platform ultimately serves as a strong showcase for what cloud computing technologies can do for the space industry.

    In the meantime, we see a number of players testing new business models by bringing the concepts of sharing economy into the geo-business by mobilizing underused assets — satellite constellations, UAVs, and other aerial imaging platforms — and essentially creating a new revenue channel for data owners. The concepts of “virtual satellite constellation” and “geo-AppStore” are becoming more and more a reality. In the past year, we have seen a number of cloud-based platforms such as ArcGIS by Esri and CloudEO Store that bring together data providers, software developers, and service providers in an online marketplace where customers can search for geospatial products to fit their needs in safe SaaS-based environments. (Disclosure: CloudEO is one of my portfolio companies.)

    Even hardware innovators are recognizing the importance of opening up their platforms to greater collaboration. Silicon Valley based Planet Labs — which raised more than $60 million from groups like DFJ, OATV, and Yuri Milner — is promising to release its developer API (application-programming interface) by the end of this year.

    Visualization

    Visualization is the other important aspect of making geospatial data useful to the end customer. Whether you are a farmer looking to assess how soil moisture content affects vegetation levels across your fields or a government agency trying to identify deforestation patterns and illegal logging operations, the way data is analyzed and presented can be partial to the end result.

    inter
    SKA Interferometer

    Spanish startup CartoDB recently offered a unique approach to visualization. Instead of focusing on the base maps like Google Earth does, it focuses on the data and application layers on top. Moreover, by using an open-source approach, CartoDB has attracted more than 50,000 users to its platform, and they are constantly contributing to the quality and quantity of available data and applications on the platform. The result has been thousands of beautiful maps that are useful across a number of industries, from real estate and banking to healthcare and natural resources. Investors showed their confidence in the company’s approach with an $8 million Series A round earlier this month.

    The market for geographic information systems (GIS) is estimated at $2.5 billion, the data visualization market stands at $4.2 billion, and location-based services stand at $7.5 billion. No wonder Google has been actively building on top of its platform by acquiring complementary assets such as Skybox Imaging and Titan Aerospace earlier this year. By combining satellite and drone imagery with its computing power and content delivery capabilities, Google has a chance to build the first fully vertically integrated GIS service and perhaps take Google Earth platform LIVE someday.

    While it does seem more glamorous to be launching rockets and building space stations, the truth of the matter is that major dollars will still be made on Earth by data crunchers converting space bytes into beautiful maps and infographics that anyone of us can use.

    See the full article here.

    SKA Banner

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

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  • richardmitnick 3:28 pm on October 8, 2014 Permalink | Reply
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    From Astronomy: “Radio telescopes unravel mystery of nova gamma rays” 

    Astronomy magazine

    Astronomy Magazine

    October 08, 2014
    NRAO, Socorro, New Mexico

    The discovery revealed a probable mechanism for the gamma-ray emissions, which mystified astronomers when first observed in 2012.

    Highly detailed radio-telescope images have pinpointed the locations where a stellar explosion called a nova emitted gamma rays, the most energetic form of electromagnetic waves. The discovery revealed a probable mechanism for the gamma-ray emissions, which mystified astronomers when first observed in 2012.

    three
    A nova does not explode like an expanding ball, but instead throws out gas in different directions at different times and different speeds. When this gas inevitably crashes together, it produces shocks and high-energy gamma-ray photons. The complex explosion and gas collisions in nova V959 Mon is illustrated here. In the first days of the nova explosion, dense, relatively slow-moving material is expelled along the binary star system’s equator (yellow material in left panel). Over the next several weeks, fast winds pick up and are blown off the binary, but they are funneled along the binary star system’s poles (blue material in central panel). The equatorial and polar material crashes together at their intersection, producing shocks and gamma-ray emission (red regions in central panel). Finally, at later times, the nova stops blowing a wind, and the material drifts off into space, the fireworks finished (right panel).
    Bill Saxton, NRAO/AUI/NSF

    “We not only found where the gamma rays came from, but also got a look at a previously unseen scenario that may be common in other nova explosions,” said Laura Chomiuk of Michigan State University in East Lansing.

    A nova occurs when a dense white dwarf star pulls material onto itself from a companion star, triggering a thermonuclear explosion that blows debris into interstellar space. Astronomers did not expect this scenario to produce high-energy gamma rays. However, in June 2012, NASA’s Fermi spacecraft detected gamma rays coming from a nova called V959 Mon, some 6,500 light-years from Earth.

    NASA Fermi Telescope
    NASA/Fermi

    At the same time, observations with the Karl G. Jansky Very Large Array (VLA) indicated that radio waves coming from the nova probably were caused by subatomic particles moving at nearly the speed of light interacting with magnetic fields. The high-energy gamma-ray emission, the astronomers noted, also required such fast-moving particles.

    NRAO VLA
    VLA

    Later observations with the extremely sharp radio “vision” of the Very Long Baseline Array (VLBA) and the European VLBI network revealed two distinct knots of radio emission. These knots then were seen to move away from each other. This observation, along with studies made with e-MERLIN in the United Kingdom, and another round of VLA observations in 2014 provided the scientists with information that allowed them to put together a picture of how the radio knots and the gamma rays were produced.

    NRAO VLBA
    VLBA

    evlbi
    European VLBI network

    emerlin
    e-MERLIN

    In the first stage of this scenario, the white dwarf and its companion give up some of their orbital energy to boost some of the explosion material, making the ejected material move outward faster in the plane of their orbit. Later, the white dwarf blows off a faster wind of particles moving mostly outward along the poles of the orbital plane. When the faster-moving polar flow hits the slower-moving material, the shock accelerates particles to the speeds needed to produce the gamma rays and the knots of radio emission.

    “By watching this system over time and seeing how the pattern of radio emission changed, then tracing the movements of the knots, we saw the exact behavior expected from this scenario,” Chomiuk said.

    Since the 2012 outburst of V959 Mon, Fermi has detected gamma rays from three additional nova explosions.

    “This mechanism may be common to such systems. The reason the gamma rays were first seen in V959 Mon is because it’s close,” Chomiuk said.

    Because the type of ejection seen in V959 Mon also is seen in other binary-star systems, the new insights may help astronomers understand how those systems develop. This “common envelope” phase occurs in all close binary stars and is poorly understood.

    “We may be able to use novae as a “test bed” for improving our understanding of this critical stage of binary evolution,” Chomiuk said.

    See the full article here.

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  • richardmitnick 7:12 pm on October 6, 2014 Permalink | Reply
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    From SPACE.com: “Aliens May Be Out There, But Too Distant for Contact” 

    space-dot-com logo

    SPACE.com

    October 06, 2014
    Irene Klotz

    The Milky Way may be home to some 3,000 extraterrestrial civilizations but the vast distances between our galactic cousins will make contact extremely rare, a new study concludes.

    Data collected by NASA’s Kepler space telescope and other observatories scouting for planets beyond the solar system indicate Earth is one of some 40 billion potentially habitable worlds in the galaxy, with about one new life-friendly planet forming every year, astronomer Michael Garrett, head of the Dutch astronomy research foundation ASTRON, said at the International Astronomical Congress in Toronto.

    NASA Kepler Telescope
    NASA/Kepler

    Sounds promising, until you consider the sheer size of the Milky Way, which spans more than 100,000 light-years in diameter. Light travels at about 186,000 miles per second, but a signal will still take more than 4 years to reach neighboring system Alpha Centauri and 100,000 years to travel from one end of the galaxy to the other.

    “On average, you’d expect the civilizations to be separated by at least 1,000 light-years in the Milky Way. That’s a large distance, and for communication purposes you need to allow for twice the travel distance, so you’re talking about civilizations that have to be around for at least a few thousand years in order to have the opportunity to talk to each other,” Garrett said.

    “We don’t really know the time scales in which civilizations persist,” he added.

    The one example available — Earth — indicates that life essentially developed as soon as the conditions were right, but intelligent life arose comparatively late.

    “It’s really just essentially in the last few minutes of the overall evolution of life on the planet,” Garrett said. “I don’t want to be too negative about this, but … my basic conclusion is that SETI signals will be rare in the Milky Way.”

    That doesn’t mean astronomers shouldn’t look, he added. Quite the contrary, given the huge technological leaps in radio astronomy and in data processing techniques compared to what was available for Search for Extraterrestrial Intelligence, or SETI, programs 60 years ago.

    SETI also is benefitting from sister radio astronomy projects, such as the ongoing quest to find the source of mysterious transient radio bursts.

    SETI@home screensaver
    SETI@home from Space Science LabSpaceScienceLabs at UC Berkeley

    “SETI is not easy, but it’s a pursuit that is well worth doing. The question is so important,” Garrett said. “Everyone is interested, not just scientists and space enthusiasts. People in the street are interested to know what else is out there.”

    See the full article, with added material, here.

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  • richardmitnick 7:50 pm on September 30, 2014 Permalink | Reply
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    From Astronomy: “New molecule found in space connotes life origins” 

    Astronomy magazine

    Astronomy Magazine

    September 29, 2014
    No Writer Credit
    Cornell University, Ithaca, New York

    Like finding a molecular needle in a cosmic haystack, astronomers have detected radio waves emitted by isopropyl cyanide.

    Hunting from a distance of 27,000 light-years, astronomers have discovered an unusual carbon-based molecule — one with a branched structure — contained within a giant gas cloud in interstellar space. Like finding a molecular needle in a cosmic haystack, astronomers have detected radio waves emitted by isopropyl cyanide. The discovery suggests that the complex molecules needed for life may have their origins in interstellar space.

    cyan
    Dust and molecules in the central region of our galaxy: The background image shows the dust emission in a combination of data obtained with the APEX telescope and the Planck space observatory at a wavelength around 860 micrometers. The organic molecule iso-propyl cyanide with a branched carbon backbone (i-C3H7CN, left) as well as its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right) were both detected with the Atacama Large Millimeter/submillimeter Array in the star-forming region Sgr B2, about 300 light years away from the galactic center Sgr A*.
    MPIfR/A. Weiß (background image); University of Cologne/M. Koerber (molecular models); MPIfR/A. Belloche (montage)

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), researchers studied the gaseous star-forming region Sagittarius B2.

    ALMA Array
    ALMA

    Organic molecules usually found in these star-forming regions consist of a single “backbone” of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making it the first interstellar detection of such a molecule, said Rob Garrod from Cornell University in Ithaca, New York.

    This detection opens a new frontier in the complexity of molecules that can be formed in interstellar space and that might ultimately find their way to the surfaces of planets, said Garrod. The branched carbon structure of isopropyl cyanide is a common feature in molecules that are needed for life — such as amino acids, which are the building blocks of proteins. This new discovery lends weight to the idea that biologically crucial molecules, like amino acids that are commonly found in meteorites, are produced early in the process of star formation — even before planets such as Earth are formed.

    Garrod, along with Arnaud Belloche and Karl Menten, both of the Max Planck Institute for Radio Astronomy, and Holger Müller of the University of Cologne, sought to examine the chemical makeup of Sagittarius B2, a region close to the Milky Way’s galactic center and an area rich in complex interstellar organic molecules.

    With ALMA, the group conducted a full spectral survey looking for fingerprints of new interstellar molecules — with sensitivity and resolution 10 times greater than previous surveys.

    The purpose of the ALMA Observatory is to search for cosmic origins through an array of 66 sensitive radio antennas from the high elevation and dry air of northern Chile’s Atacama Desert. The array of radio telescopes works together to form a gigantic “eye” peering into the cosmos.

    “Understanding the production of organic material at the early stages of star formation is critical to piecing together the gradual progression from simple molecules to potentially life-bearing chemistry,” said Belloche.

    About 50 individual features for isopropyl cyanide and 120 for normal-propyl cyanide — its straight-chain sister molecule — were identified in the ALMA spectrum of the Sagittarius B2 region. The two molecules — isopropyl cyanide and normal-propyl cyanide — are also the largest molecules yet detected in any star-forming region.

    See the full article here..

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  • richardmitnick 4:24 pm on September 25, 2014 Permalink | Reply
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    From SPACE.com: “Newfound Molecule in Space Dust Offers Clues to Life’s Origins” 

    space-dot-com logo

    SPACE.com

    September 25, 2014
    Megan Gannon

    The discovery of a strangely branched organic molecule in the depths of interstellar space has capped a decades-long search for the carbon-bearing stuff.

    life
    The organic molecule iso-propyl cyanide has a branched carbon backbone (i-C3H7CN, left), unlike its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right). Both molecules were detected with ALMA in Sagittarius B2. Credit: MPIfR/A. Weiss, University of Cologne/M. Koerber, MPIfR/A. Belloche

    The molecule in question — iso-propyl cyanide (i-C3H7CN) — was spotted in Sagittarius B2, a huge star-making cloud of gas and dust near the center of the Milky Way, about 27,000 light-years from the sun. The discovery suggests that some of the key ingredients for life on Earth could have originated in interstellar space.

    A specific molecule emits light at a particular wavelength and in a telltale pattern, or spectrum, which scientists can detect using radio telescopes. For this study, astronomers used the enormous Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the Chilean desert, which went online last year and combines the power of 66 radio antennas.

    ALMA Array
    ALMA Array

    Iso-propyl cyanide joins a long list of molecules detected in interstellar space. But what makes this discovery significant is the structure of iso-propyl cyanide. All other organic molecules that have been detected in space so far (including normal-propyl cyanide, the sister of i-C3H7CN) are made of a straight chain with a carbon backbone. Iso-propyl cyanide, however, has a “branched” structure. This same type of branched structure is a key characteristic of amino acids.

    “Amino acids are the building blocks of proteins, which are important ingredients of life on Earth,” the study’s lead author, Arnaud Belloche, of the Max Planck Institute for Radio Astronomy, told Space.com in an email. “We are interested in the origin of amino acids in general and their distribution in our galaxy.”

    alma
    The central region of the Milky Way can be seen above the antennas of the ALMA observatory in Chile.

    Scientists have previously found amino acids in meteorites that fell to Earth, and the composition of these chemicals suggested they had an interstellar origin. The researchers in this new study did not find amino acids, but their discovery adds an “additional piece of evidence that the amino acids found in meteorites could have been formed in the interstellar medium,” Belloche wrote.

    “The detection of a molecule with a branched carbon backbone in interstellar space, in a region where stars are being formed, is interesting because it shows that interstellar chemistry is indeed capable of producing molecules with such a complex, branched structure,” Belloche added.

    It was first suggested in the 1980s that branched molecules could form on the surface of dust grains in interstellar space. But this is the first time such compounds have been detected. What’s more, iso-propyl cyanide seemed to be plentiful — it was almost half as abundant of its more common sister variant in Sagittarius B2, the study found. This means that branched molecules could actually be quite ordinary in interstellar space, the researchers said.

    The research is detailed in the Sept. 26 edition of the journal Science.

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  • richardmitnick 2:33 pm on September 24, 2014 Permalink | Reply
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    From ALMA: “ALMA Extends Its Arms” 

    ESO ALMA Array
    ALMA

    Wednesday, 24 September 2014

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Richard Hook
    Public Information Officer, ESO
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

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

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    Email: cblue@nrao.edu

    The Atacama Large Millimeter/submillimeter Array (ALMA) has successfully tested an antenna in the most extended configuration of the array yet, producing the longest baseline ever achieved by ALMA. This advance became possible once the first of ALMA’s three extended arms was successfully powered up for the first time, and opens up the possibility of greatly extending ALMA’s capabilities. With longer baselines, the ability of a radio telescope to see fine detail increases, allowing astronomers to uncover much more information about objects observed in the Universe.

    alma extend
    This image by ESO, no image credit

    truck
    ALMA transporter moving a distant antenna Lore, one of ALMA’s two tailor-made antenna transporters, made its first journey along the Pampa la Bola arm and relocated an antenna to a distant pad. Engineers had to design vehicles rugged and durable enough to carry the antennas safely through the hostile desert environment. | ALMA (ESO/NAOJ/NRAO), P. Carrillo Download image

    Lore, one of ALMA’s two tailor-made antenna transporters, made its first journey along the Pampa la Bola arm and for the first time relocated an antenna to a position seven kilometers away from its furthest neighbour. This marks a major new technical achievement in the Atacama Desert in Chile, at more than 5000 metres above sea level. This new baseline is more than four times longer than is currently available to the ALMA scientific community, and tests of even longer baselines are in progress.

    Catherine Vlahakis, Program Scientist for the ALMA Long Baseline Campaign says that: “successfully powering up an antenna for the first time over these long distances marks an important technical step towards increasing ALMA’s ability to see objects in the Universe in fine detail”.

    antenna
    A distant ALMA antenna This image shows an ALMA antenna on a distant pad in the Pampa la Bola branch, with Japanese ASTE and NANTEN2 telescopes in the background. | ALMA (ESO/NAOJ/NRAO), T. Sawada Download image

    Ed Fomalont, Lead Scientist for the ALMA Long Baseline Campaign, explains that “the combination of the signals from the antennas produces patterns called fringes. The fringes measured from the antenna seven kilometres away were as pure and strong as will be needed to obtain high quality images when additional antennas are moved to these long baselines.”

    Catherine Vlahakis, adds that “this is the first step in a process of moving several antennas out to these longer distances. Once the rest of the antennas are also in place we will be able to begin test observations of astronomical objects at higher angular resolution, and therefore in more exquisite detail, than ALMA has yet achieved.”

    Observations that will further test baselines as long as nearly 11 kilometers will continue over the next two months. If all goes as intended, this process will provide ALMA astronomers with the knowledge needed to offer long-baseline observations to the scientific community.

    See the full article here.

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

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

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  • richardmitnick 6:20 pm on September 22, 2014 Permalink | Reply
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    From ALMA: “ALMA Studies Infant Sun-like Solar System to Try and Catch the Wind” 

    ESO ALMA Array
    ALMA

    Monday, 22 September 2014

    Contacts

    Dr. Colette Salyk
    National Optical Astronomy Observatory
    950 N Cherry Ave, Tucson AZ 85719 USA
    E-mail: csalyk@noao.edu

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    Email: cblue@nrao.edu

    Richard Hook
    Public Information Officer, ESO
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

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

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have studied a special kind of young star, a T Tauri star, to understand why some have disks that glow weirdly in infrared light while others shine in a more predictable fashion. The answer, researchers speculate, may be due to differences in the wind around these stars.

    tt

    T Tauri stars are the infant versions of stars like our Sun. They are relatively normal, medium size-stars that are surrounded by the raw materials to build both rocky and gaseous planets. Though nearly invisible in optical light, these disks shine in both infrared and millimeter-wavelength light.

    “The material in the disk of a T Tauri star usually, but not always, emits infrared radiation with a predictable energy distribution,” said Colette Salyk, an astronomer with the National Optical Astronomical Observatory (NOAO) and lead author on a paper published in the Astrophysical Journal, “some T Tauri stars, however, like to act up by emitting infrared radiation in unexpected ways.”

    To account for the different infrared signature around such similar stars, astronomers propose that winds may be emanating from within some T Tauri stars’ protoplanetary disks. These winds could have important implications for planet formation, potentially robbing the disk of some of the gas required for the formation of giant Jupiter-like planets, or stirring up the disk and causing the building blocks of planets to change location entirely. These winds have been predicted by astronomers, but have never been clearly detected.

    Using ALMA, Salyk and her colleagues looked for evidence of a possible wind in AS 205 N, a T Tauri star located 407 light-years away at the edge of a star-forming region in the constellation Ophiuchus, the Snake Bearer. This star seemed to exhibit the characteristically uneven infrared signature that had intrigued astronomers.

    With ALMA’s exceptional resolution and sensitivity, the researchers were able to study the distribution of carbon monoxide around the star. Carbon monoxide is an excellent tracer for the molecular gas that makes up stars and their planet-forming disks. These studies confirmed that there was indeed gas leaving the disk surface, as would be expected if a wind were present. The properties of the wind, however, did not exactly match expectations.

    This different between observations and expectations could be due to the fact that AS 205 N is actually part of a multiple star system – with a companion dubbed AS 205 S, that is itself a binary star.

    This multiple star arrangement may suggest that the gas is leaving the disk surface because it’s being pulled away by the binary companion star rather than ejected by a wind.

    “We are hoping these new ALMA observations help us better understand winds, but they have also left us with a new mystery,” said Salyk, “Are we seeing winds, or interactions with the companion star?”

    The study’s authors are not pessimistic, however. They plan to continue their research with more ALMA observations, targeting other unusual T Tauri stars, with and without companions, to see whether they show these same features.

    T Tauri stars are named after their prototype star, discovered in 1852 – the third star in the constellation Taurus whose brightness was found to vary erratically. At one point, some 4.5 billion years ago, our Sun was a T Tauri star.

    This work is published in the Astrophysical Journal: other authors include Klaus Pontoppidan, Space Telescope Science Institute; Stuartt Corder, Joint ALMA Observatory; Diego Muñoz, Center for Space Research, Department of Astronomy, Cornell University; and Ke Zhang and Geoffrey Blake, Division of Geological & Planetary Sciences, California Institute of Technology.

    See the full article here.

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

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

    NRAO Small

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    NAOJ

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