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  • richardmitnick 12:36 pm on May 30, 2017 Permalink | Reply
    Tags: , , , CfA, , Do Stars Fall Quietly into Black Holes, , or Crash into Something Utterly Unknown?,   

    From CfA: “Do Stars Fall Quietly into Black Holes, or Crash into Something Utterly Unknown?” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    May 30, 2017
    Rebecca Johnson
    UT Austin Astronomy Program
    512-475-6763
    rjohnson@astro.as.utexas.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    1

    Astronomers at The University of Texas at Austin and Harvard University have put a basic principle of black holes to the test, showing that matter completely vanishes when pulled in. Their results constitute another successful test for Albert Einstein’s General Theory of Relativity.

    Most scientists agree that black holes, cosmic entities of such great gravity that nothing can escape their grip, are surrounded by a so-called event horizon. Once matter or energy gets close enough to the black hole, it cannot escape — it will be pulled in. Though widely believed, the existence of event horizons has not been proved.

    “Our whole point here is to turn this idea of an event horizon into an experimental science, and find out if event horizons really do exist or not,” said Pawan Kumar, a professor of astrophysics at The University of Texas at Austin.

    Supermassive black holes are thought to lie at the heart of almost all galaxies. But some theorists suggest that there’s something else there instead — not a black hole, but an even stranger supermassive object that has somehow managed to avoid gravitational collapse to a singularity surrounded by an event horizon. The idea is based on modified theories of General Relativity, Einstein’s theory of gravity.

    While a singularity has no surface area, the noncollapsed object would have a hard surface. So material being pulled closer — a star, for instance — would not actually fall into a black hole, but hit this hard surface and be destroyed.

    Kumar, his graduate student Wenbin Lu, and Ramesh Narayan, a theorist from the Harvard-Smithsonian Center for Astrophysics, have come up with a test to determine which idea is correct.

    “Our motive is not so much to establish that there is a hard surface,” Kumar said, “but to push the boundary of knowledge and find concrete evidence that really, there is an event horizon around black holes.”

    The team figured out what a telescope would see when a star hit the hard surface of a supermassive object at the center of a nearby galaxy: The star’s gas would envelope the object, shining for months, perhaps even years.

    Once they knew what to look for, the team figured out how often this should be seen in the nearby universe, if the hard-surface theory is true.

    “We estimated the rate of stars falling onto supermassive black holes,” Lu said. “Nearly every galaxy has one. We only considered the most massive ones, which weigh about 100 million solar masses or more. There are about a million of them within a few billion light-years of Earth.”

    They then searched a recent archive of telescope observations. Pan-STARRS, a 1.8-meter telescope in Hawaii, recently completed a project to survey half of the northern hemisphere sky.

    Pan-STARRS1 located on Haleakala, Maui, HI, USA

    The telescope scanned the area repeatedly during a period of 3.5 years, looking for “transients” — things that glow for a while and then fade. Their goal was to find transients with the expected light signature of a star falling toward a supermassive object and hitting a hard surface.

    “Given the rate of stars falling onto black holes and the number density of black holes in the nearby universe, we calculated how many such transients Pan-STARRS should have detected over a period of operation of 3.5 years. It turns out it should have detected more than 10 of them, if the hard-surface theory is true,” Lu said.

    They did not find any.

    “Our work implies that some, and perhaps all, black holes have event horizons and that material really does disappear from the observable universe when pulled into these exotic objects, as we’ve expected for decades,” Narayan said. “General Relativity has passed another critical test.”

    Now the team is proposing to improve the test with an even larger telescope: the 8.4-meter Large Synoptic Survey Telescope (LSST, now under construction in Chile). Like Pan-STARRS, LSST will make repeated surveys of the sky over time, revealing transients — but with much greater sensitivity.

    This research has been published in the June issue of the journal Monthly Notices of the Royal Astronomical Society.

    See the full article here .

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 10:02 pm on May 26, 2017 Permalink | Reply
    Tags: , , , CfA, , , LHS 1140, MEarth-South telescope array at Cerro Tololo Inter-American Observatory, Planet LHS 1140b   

    From CfA: “Potentially Habitable Super-Earth is a Prime Target for Atmospheric Study” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    April 19, 2017
    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998
    mwatzke@cfa.harvard.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    1
    M. Weiss/CfA

    The study of alien worlds is entering its next phase as astronomers amass the best planets outside our Solar System to look for signs of life. A newly discovered “super-Earth” orbiting in the habitable zone of a nearby small star, has catapulted itself to the top of that list.

    “This is the most exciting exoplanet I’ve seen in the past decade,” said lead author Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (CfA). “We could hardly hope for a better target to perform one of the biggest quests in science − searching for evidence of life beyond Earth.”

    The newfound planet is described in a paper appearing in the April 20th issue of the journal Nature.

    Located just 40 light-years away, the planet was found using the transit method, in which a star dims as a planet crosses in front of it as seen from Earth.

    Planet transit. NASA/Ames

    By measuring how much light this planet blocks, the team determined that it is about 11,000 miles in diameter, or about 40 percent larger than Earth.

    The researchers have also weighed the planet to be 6.6 times the mass of Earth, showing that it is dense and likely has a rocky composition. Small, potentially habitable planets have been found in the TRAPPIST-1 system, located a similar distance from Earth, but only one of those worlds has had its density measured accurately, showing that it isn’t rocky. Therefore, some or all of the others also might not be rocky.

    Since this planet transits its star, unlike the closest world to the solar system Proxima Centauri b, it can be examined for the presence of air. As the planet moves in front of the star, the star’s light will be filtered through any atmosphere and leave an imprint. Large, next-generation telescopes will be needed to tease out these subtle signals.

    “This planet will be an excellent target for the James Webb Space Telescope when it launches in 2018, and I’m especially excited about studying it with the ground-based Giant Magellan Telescope, which is under construction,” said co-author David Charbonneau of the CfA.

    NASA/ESA/CSA Webb Telescope annotated

    Giant Magellan Telescope, to be at Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

    The planet orbits a tiny, faint star known as LHS 1140, which is only one-fifth the size of the Sun. Since the star is so dim and cool, its habitable zone (the distance at which a planet might be warm enough to hold liquid water) is very close. This planet, designated LHS 1140 b, orbits its star every 25 days. At that distance, it receives about half as much sunlight from its star as Earth.

    Although the planet is potentially habitable now, it might have faced a hellish past. When the star was young, it would have bathed the planet in a harsh ultraviolet glare that could have stripped any water from the atmosphere, leading to a runaway greenhouse effect like we see on Venus.

    However, since the planet is larger than Earth, it might have possessed a magma ocean on its surface for millions of years. Powered by heat from naturally radioactive elements, that churning ocean of lava may have fed steam into the atmosphere long after the star calmed to its current, steady glow. This process could have replenished the planet with water, making it suitable for life as we know it.

    “Right now we’re just making educated guesses about the content of this planet’s atmosphere,” said Dittmann. “Future observations might enable us to detect the atmosphere of a potentially habitable planet for the first time. We plan to search for water, and ultimately molecular oxygen.”

    In contrast with the TRAPPIST-1 star, LHS 1140 spins slowly and does not emit much high-energy radiation, which also may help the likelihood of life on its planet.

    LHS 1140 b was discovered using the MEarth-South telescope array at Cerro Tololo Inter-American Observatory.

    2
    MEarth-South telescope array at Cerro Tololo Inter-American Observatory

    This collection of eight telescopes, with its companion facility MEarth-North, studies faint, red stars known as M dwarfs to locate orbiting planets using the transit method.

    In follow-up work the team was able to detect LHS 1140 wobbling as the planet orbits it, using the High Accuracy Radial velocity Planet Searcher (HARPS) installed on the European Southern Observatory’s 3.6m telescope at La Silla Observatory in Chile.

    ESO/HARPS at La Silla


    ESO 3.6m telescope & HARPS at LaSilla

    This information was combined with data from the transit method, allowing the team to make good measurements of the planet’s size, mass and density.

    The MEarth Project is supported by the National Science Foundation, the David and Lucile Packard Foundation, and the John Templeton Foundation.

    See the full article here .

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 9:12 pm on May 21, 2017 Permalink | Reply
    Tags: , , , CfA, , Star Forming Filaments   

    From CfA: “Star Forming Filaments” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    May 19, 2017
    No writer credit found

    1
    A false-color image map of the gas density in the Musca star-forming filament (the highest densities are shown in red). New theoretical work on the structure of these long filaments proposes several kinds of star-forming zones along the length and successfully reproduces many of the features seen in filaments like this one in Musca. Kainulainen, 2016

    Interstellar molecular clouds are often seen to be elongated and “filamentary” in shape, and come in a wide range of sizes. In molecular clouds, where stars form, the filamentary structure is thought to play an important role in star formation as the matter collapses to form protostars. Filamentary clouds are detected because the dust they contain obscures the optical light of background stars while emitting at infrared and submillimeter wavelengths. Observations of some filaments indicate that they are themselves composed of bundles of closely spaced fibers with distinct physical properties. Computer simulations are able to reproduce some of these filamentary structures, and astronomers generally agree that turbulence in the gas combined with gravitational collapse can lead to filaments and protostars within them, but the exact ways in which filaments form, make stars, and finally dissipate are not understood. The number of new stars that develop, for example, varies widely between filaments for reasons that are not known.

    The usual model for a star forming filament is a cylinder whose density increases towards the axis according to a specific profile, but which otherwise is uniform along its length. CfA astronomer Phil Myers has developed a variant of this model in which the filament has a star-forming zone along its length where the density and diameter are higher, with three generic profiles to describe their shapes. Besides being a more realistic description of a filament’s structure, the different density profiles develop different strength gravitational “wells” naturally leading to different numbers of stars forming within them.

    Myers compares the star formation properties of these three kinds of zones with the properties of observed star formation filaments, with excellent results. The filament in the molecular cloud in Musca has relatively little star formation, and can be reasonably well explained with one of the three profiles indicative of an early stage of evolution. A small cluster of young stars in the Corona Australis constellation fits a second model that has evolved for longer, while Ophiuchus hosts a filament that may be near the end of its star forming lifetime and resembles the third type. The three profiles so far seem able to account for the full range of conditions. The new results are an important step in bringing more sophistication and realism to the theory of star forming filaments. Future work will probe the specific processes that fragment the various star-forming zones into their stars.

    Reference(s):

    “Star-forming Filament Models,” Philip C. Myers, ApJ 838, 10, 2017.

    See the full article here .

    Please help promote STEM in your local schools.

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 1:36 pm on March 30, 2017 Permalink | Reply
    Tags: , , CfA, , Draper,   

    From CfA: “Next Stop: A Trip Inside the Sun’s Atmosphere” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    March 29, 2017
    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998
    mwatzke@cfa.harvard.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    Dan Dent
    Draper Laboratory
    ddent@draper.com
    +1 617-258-2464

    1
    NASA’s Solar Probe Plus will enter the sun’s corona to understand space weather using a Faraday cup developed by the Smithsonian Astrophysical Observatory and Draper.
    NASA/Johns Hopkins University Applied Physics Laboratory

    Every so often the sun emits an explosive burst of charged particles that makes its way to Earth and often wreaks havoc on power grids, aircraft and satellite systems. When clouds of high-speed charged particles come racing off the sun, they can bathe spacecraft, astronauts and planetary surfaces in damaging radiation. Understanding why the sun occasionally emits these high-energy particles can help scientists predict space weather. Knowing when solar energetic particles may hit Earth can help people on the planet take precautions.

    Now, Draper and the Smithsonian Astrophysical Observatory (SAO) are addressing these challenges, and hoping to untangle these unsolved science mysteries, by developing sophisticated sensors for a new NASA mission. Launching in 2018, NASA’s Solar Probe Plus spacecraft, which is being designed and built by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., will make 24 solar flybys over nearly seven years, setting a new record for the fastest moving man-made object as it zips 37.6 million kilometers closer to the sun than any spacecraft that has ever studied this star, and be exposed to temperatures exceeding 2500 degrees Fahrenheit.

    NASA’s Solar Probe Plus—the first mission that will fly into the sun’s upper atmosphere and “touch” the sun—will collect data on the mechanisms that heat the corona and accelerate the solar wind, a constant flow of charged particles from the sun. These are two processes with fundamental roles in the complex interconnected system linking the sun and near-Earth space—a system that can drive changes in our space weather and impact our satellites.

    To capture the velocity and direction of the positively-charged particles, Solar Probe Plus will be equipped with a Faraday cup, built by the Smithsonian Astrophysical Observatory, with technical support from Draper, and operated by SAO and the University of Michigan in Ann Arbor. The Faraday cup, which is capable of measuring the full force of supersonic solar particles and radiation, is one of only two instruments riding outside the protective sunshield of NASA’s Solar Probe Plus. The challenge will be to capture the data while operating at extreme temperatures on the fastest moving manmade spacecraft ever created—it will achieve a velocity of close to 200 km/sec—and do it with accuracy.

    For years, astronomers have studied the sun, but never from inside the sun’s atmosphere, according to Seamus Tuohy, Director of the Space Systems Program Office at Draper. “Such a mission would require a spacecraft and instrumentation capable of withstanding extremes of radiation, high velocity travel and the harsh solar condition—and that is the kind of program deeply familiar to Draper and the Smithsonian Astrophysical Observatory.”

    The investigation will specifically track the most abundant particles in the solar atmosphere and wind—electrons, protons and helium ions–“in addition to answering fundamental science questions, the intent is to better understand the risks space weather poses to the modern communication, aviation and energy systems we all rely on,” said Justin C. Kasper, principal investigator at the Smithsonian Astrophysical Observatory and University of Michigan Professor in Space Science. “Many of the systems we in the modern world rely on—our telecommunications, GPS, satellites and power grids—could be disrupted for an extended period of time if a large solar storm were to happen today. Solar Probe Plus will help us predict and manage the impact of space weather on society.”

    Draper

    At Draper, we believe exciting things happen when new capabilities are imagined and created. Whether formulating a concept and developing each component to achieve a field-ready prototype or combining existing technologies in new ways, Draper engineers apply multidisciplinary approaches that deliver new capabilities to customers. As a not-for-profit research and development company, Draper focuses on the design, development and deployment of advanced technological solutions for the world¹s most challenging and important problems. We provide engineering solutions directly to government, industry and academia; work on teams as prime contractor or subcontractor; and participate as a collaborator in consortia. We provide unbiased assessments of technology or systems designed or recommended by other organizations—custom designed, as well as commercial-off-the-shelf.

    See the full article here .

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 5:21 pm on March 22, 2017 Permalink | Reply
    Tags: , , , , , CfA, , Dark Energy Spectroscopic Instrument (DESI), , , New Study Maps Space Dust in 3-D, Pan-STARRS,   

    From LBNL: “New Study Maps Space Dust in 3-D” 

    Berkeley Logo

    Berkeley Lab

    March 22, 2017
    Glenn Roberts Jr
    geroberts@lbl.gov
    510-486-5582


    Access mp4 video here .
    This animation shows a 3-D rendering of space dust, as viewed in a several-kiloparsec (thousands of light years) loop through and out of the Milky Way’s galactic plane. The animation uses data for hundreds of millions of stars from Pan-STARRS1 and 2MASS surveys, and is made available through a Creative Commons License. (Credit: Gregory M. Green/SLAC, KIPAC)

    Consider that the Earth is just a giant cosmic dust bunny—a big bundle of debris amassed from exploded stars. We Earthlings are essentially just little clumps of stardust, too, albeit with very complex chemistry.

    And because outer space is a very dusty place, that makes things very difficult for astronomers and astrophysicists who are trying to peer farther across the universe or deep into the center of our own galaxy to learn more about their structure, formation and evolution.

    Building a better dust map

    Now, a new study led by Edward F. Schlafly, a Hubble Fellow in the Physics Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), is providing a detailed, 3-D look at dust on a scale spanning thousands of light-years in our Milky Way galaxy. The study was published today in The Astrophysical Journal.

    This dust map is of critical importance for the Dark Energy Spectroscopic Instrument (DESI), a Berkeley Lab-led project that will measure the universe’s accelerating expansion rate when it starts up in 2019. DESI will build a map of more than 30 million distant galaxies, but that map will be distorted if this dust is ignored.

    “The light from those distant galaxies travels for billions of years before we see it,” according to Schlafly, “but in the last thousand years of its journey toward us a few percent of that light is absorbed and scattered by dust in our own galaxy. We need to correct for that.”

    Just as airborne dust in Earth’s sky contributes to the atmospheric haze that gives us brilliant oranges and reds in sunrises and sunsets, dust can also make distant galaxies and other space objects appear redder in the sky, distorting their distance and in some cases concealing them from view.

    Scientists are constantly developing better ways to map out this interstellar dust and understand its concentration, composition, and common particle sizes and shapes.

    1
    The dark regions show very dense dust clouds. The red stars tend to be reddened by dust, while the blue stars are in front of the dust clouds. These images are part of a survey of the southern galactic plane. (Credit: Legacy Survey/NOAO, AURA, NSF)

    Once we can solve the dust problem by creating better dust maps and learning new details about the properties of this space dust, this can give us a much more precise gauge of distances to faraway stars in the Milky Way, like a galactic GPS. Dust maps can also help to better gauge the distance to supernovae events by taking into account the effects of dust in reddening their light.

    “The overarching aim of this project is to map dust in three dimensions—to find out how much dust is in any 3-D region in the sky and in the Milky Way galaxy,” Schlafly said.

    Combined data from sky surveys shed new light on dust

    Taking data from separate sky surveys conducted with telescopes on Maui and in New Mexico, Schlafly’s research team composed maps that compare dust within one kiloparsec, or 3,262 light-years, in the outer Milky Way—including collections of gas and dust known as molecular clouds that can contain dense star- and planet-forming regions known as nebulae—with more distant dust in the galaxy.

    2
    Pan-STARRS2 and PanSTARS1 telescopes atop Haleakalā on the island of Maui, Hawaii. (Credit: Pan-STARRS)

    The resolution of these 3-D dust maps is many times better than anything that previously existed,” said Schlafly.

    This undertaking was made possible by the combination of a very detailed multiyear survey known as Pan-STARRS that is powered by a 1.4-gigapixel digital camera and covers three-fourths of the visible sky, and a separate survey called APOGEE that used a technique known as infrared spectroscopy.

    3
    A compressed view of the entire sky visible from Hawaii by the Pan-STARRS1 Observatory. The image is a compilation of half a million exposures, each about 45 seconds in length, taken over a period of four years. The disk of the Milky Way looks like a yellow arc, and the dust lanes show up as reddish-brown filaments. The background is made up of billions of faint stars and galaxies. (Credit: D. Farrow/Pan-STARRS1 Science Consortium, and Max Planck Institute for Extraterrestrial Physics)

    Infrared measurements can effectively cut through the dust that obscures many other types of observations and provides a more precise measurement of stars’ natural color. The APOGEE experiment focused on the light from about 100,000 red giant stars across the Milky Way, including those in its central halo.


    SDSS Telescope at Apache Point Observatory, NM, USA

    What they found is a more complex picture of dust than earlier research and models had suggested. The dust properties within 1 kiloparsec of the sun, which scientists measure with a light-obscuring property known as its “extinction curve,” is different than that of the dust properties in the more remote galactic plane and outer galaxy.

    New questions emerge on the makeup of space dust

    The results, researchers found, appear to be in conflict with models that expect dust to be more predictably distributed, and to simply exhibit larger grain sizes in areas where more dust resides. But the observations find that the dust properties vary little with the amount of dust, so the models may need to be adjusted to account for a different chemical makeup, for example.

    “In denser regions, it was thought that dust grains will conglomerate, so you have more big grains and fewer small grains,” Schlafly said. But the observations show that dense dust clouds look much the same as less concentrated dust clouds, so that variations in dust properties are not just a product of dust density: “whatever is driving this is not just conglomeration in these regions.”

    He added, “The message to me that we don’t yet know what’s going on. I don’t think the existing (models) are correct, or they are only right at the very highest densities.”

    Accurate measures of the chemical makeup of space dust are important, Schlafly said. “A large amount of chemistry takes place on dust grains, and you can only form molecular hydrogen on the surface of dust grains,” he said—this molecular hydrogen is essential in the formation of stars and planets.


    Access mp4 video here .
    This animation shows a 3-D rendering of dust, as viewed from a 50-parsec (163-light-year) loop around the sun. The animation uses data for hundreds of millions of stars from Pan-STARRS1 and 2MASS surveys, and is made available through a Creative Commons License: https://creativecommons.org/licenses/by-sa/4.0/. (Credit: Gregory M. Green/SLAC, KIPAC)

    Even with a growing collection of dust data, we still have an incomplete dust map of our galaxy. “There is about one-third of the galaxy that’s missing,” Schlafly said, “and we’re working right now on imaging this ‘missing third’ of the galaxy.” A sky survey that will complete the imaging of the southern galactic plane and provide this missing data should wrap up in May, he said.

    APOGEE-2, a follow-up survey to APOGEE, for example, will provide more complete maps of the dust in the local galaxy, and other instruments are expected to provide better dust maps for nearby galaxies, too.

    While the density of dust shrouds our view of the center of the Milky Way, Schlafly said there will be progress, too, in seeing deeper and collecting better dust measurements there as well.

    Researchers at the Harvard-Smithsonian Center for Astrophysics and Harvard University also participated in this work.

    4
    The planned APOGEE-2 survey area overlain on an image of the Milky Way. Each dot shows a position where APOGEE-2 will obtain stellar spectra. (Credit: APOGEE-2)

    APOGEE is a part of the Sloan Digital Sky Survey III (SDSS-III), with participating institutions including Berkeley Lab, the Alfred P. Sloan Foundation, and the National Science Foundation. PanSTARRS1 surveys are supported by the University of Hawaii Institute for Astronomy; the Pan-STARRS Project Office; the Max-Planck Society and its participating institutes in Germany; the Johns Hopkins University; the University of Durham, the University of Edinburgh, and the Queen’s University Belfast in the U.K.; the Harvard-Smithsonian Center for Astrophysics; the Las Cumbres Observatory Global Telescope Network Inc.; and the National Central University of Taiwan. Pan-STARRS is supported by the U.S. Air Force.

    See the full article here .

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  • richardmitnick 12:50 pm on March 22, 2017 Permalink | Reply
    Tags: , Astronomy Rewind, , , CfA, , ,   

    From CfA: “With Astronomy Rewind, Citizen Scientists Will Bring Zombie Astrophotos Back to Life” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    March 22, 2017
    Rick Fienberg / Julie Steffen
    AAS Press Officer / AAS Director of Publishing
    +1 202-328-2010 x116 / +1 202-328-2010 x125
    rick.fienberg@aas.org / julie.steffen@aas.org

    Rob Bernstein
    Publisher, IOP Publishing
    +1 202-747-1807
    rob.bernstein@iop.org

    Megan Watzke / Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998 / +1 617-571-7279
    mwatzke@cfa.harvard.edu / pedmonds@cfa.harvard.edu

    Alyssa Goodman
    Professor of Astronomy, Harvard University
    Harvard-Smithsonian Center for Science
    agoodman@cfa.harvard.edu

    Laura Trouille
    Director of Citizen Science, Adler Planetarium
    Co-Investigator, Zooniverse
    +1 312-322-0820
    trouille@zooniverse.org

    1

    A new citizen-science project will rescue tens of thousands of potentially valuable cosmic images that are mostly dead to science and bring them fully back to life. Called Astronomy Rewind, the effort, which launches today (22 March 2017), will take photographs, radio maps, and other telescopic images that have been scanned from the pages of dusty old journals and place them in context in digital sky atlases and catalogs. Anyone will then be able to find them online and compare them with modern electronic data from ground- and space-based telescopes, making possible new studies of short- and long-term changes in the heavens.

    “There’s no telling what discoveries await,” says Alyssa Goodman (Harvard-Smithsonian Center for Astrophysics, CfA), one of the project’s founders. “Turning historical scientific literature into searchable, retrievable data is like turning the key to a treasure chest.”

    Astronomy Rewind is the latest citizen-science program on the Zooniverse platform, which debuted at Oxford University a decade ago with Galaxy Zoo and now hosts more than 50 active “people-powered” projects across a variety of scientific disciplines. After going through a short exercise to learn what they’re looking for, users will view scanned pages from the journals of the American Astronomical Society (AAS) dating from the 19th century to the mid-1990s, when the Society began publishing electronically. Volunteers’ first task will be to determine what types of images the pages contain: photos of celestial objects with (or without) sky coordinates? maps of planetary surfaces with (or without) grids of latitude and longitude? graphs or other types of diagrams?

    The images of most interest are ones whose scale, orientation, and sky position can be nailed down by some combination of labels on or around the images plus details provided in the text or captions. Pictures that lack such information but clearly show recognizable stars, galaxies, or other celestial objects will be sent to Astrometry.net, an automated online service that compares astrophotos to star catalogs to determine what areas of sky they show.

    Modern electronic astronomical images often include information about where they fit on the sky, along with which telescope and camera were used and many other details. But such “metadata” are useful to researchers only if the original image files are published along with the journal articles in which they’re analyzed and interpreted. This isn’t always the case — though it’s becoming more common with encouragement by the AAS — so some electronic journal pages will eventually be run through Astronomy Rewind and Astrometry.net too.

    Thanks to these human-assisted and automated efforts, many thousands of “new old” images will ultimately end up in NASA’s and others’ data repositories alongside pictures from the Hubble Space Telescope. They will also be incorporated into the Astronomy Image Explorer, a service of the AAS and its journal-publishing partner, the UK Institute of Physics (IOP) Publishing, and viewable in WorldWide Telescope, a powerful data-visualization tool and digital sky atlas originally developed by Microsoft Research and now managed by the AAS.

    The scans of pages from the AAS journals — the Astronomical Journal (AJ), Astrophysical Journal (ApJ), ApJ Letters, and the ApJ Supplement Series — are being provided by the Astrophysics Data System (ADS), a NASA-funded bibliographic service and archive at the Smithsonian Astrophysical Observatory (SAO), part of the CfA.

    Astronomy Rewind is built on a foundation laid by the ADS All-Sky Survey, an earlier effort to extract scientifically valuable images from old astronomy papers using computers. “It turns out that machines aren’t very good at recognizing celestial images on digitized pages that contain a mixture of text and graphics,” says Alberto Accomazzi (SAO/ADS). “And they really get confused with multiple images of the sky on the same page. Humans do much better.”

    Accomazzi’s CfA colleague Goodman, who runs a collaboration called Seamless Astronomy to develop, refine, and share tools that accelerate the pace of astronomical research, helped bring ADS and Zooniverse together. According to Zooniverse co-investigator Laura Trouille (Adler Planetarium), 1.6 million volunteers have made about 4 billion image classifications or other contributions using the platform over the last 10 years. “This isn’t just busywork,” says Trouille. “Zooniverse projects have led to many surprising discoveries and to more than 100 peer-reviewed scientific publications.”

    If Astronomy Rewind attracts volunteers in numbers comparable to other astronomy projects on Zooniverse, Trouille estimates that at least 1,000 journal pages will be processed daily. Each page will be examined by five different citizen scientists; the more of them agree on what a given page shows, the higher the confidence that they’re right. It shouldn’t take more than a few months to get through the initial batch of pages from the AAS journals and move most of them on to the next stage, where the celestial scenes they contain will be annotated with essential information, extracted into digital images, mapped onto the sky, and made available to anyone who wants access to them.

    “You simply couldn’t do a project like this in any reasonable amount of time without ‘crowdsourcing,'” says Julie Steffen, AAS Director of Publishing. “Astronomy Rewind will breathe new life into old journal articles and put long-lost images of the night sky back into circulation, and that’s exciting. But what’s more exciting is what happens when a volunteer on Zooniverse looks at one of our journal pages and goes, ‘Hmm, that’s odd!’ That’ll be the first step toward learning something new about the universe.”

    This video provides a quick demonstration of the value of placing “antique” astronomy images back on the sky in WorldWide Telescope through the project called Astronomy Rewind.

    Astronomy Rewind and its partners and precursors have received funding from NASA’s Astrophysics Data Analysis Program, Microsoft Research, Astrometry.net, Centre de Données astronomiques de Strasbourg (CDS), IOP Publishing, and the American Astronomical Society (AAS).

    The American Astronomical Society (AAS), established in 1899, is the major organization of professional astronomers in North America. The membership (approx. 8,000) also includes physicists, mathematicians, geologists, engineers, and others whose research interests lie within the broad spectrum of subjects now comprising contemporary astronomy. The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the universe, which it achieves through publishing, meeting organization, education and outreach, and training and professional development.

    IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide. Beyond IOP’s core journals program of more than 70 publications, high-value scientific information is made easily accessible through an ever-evolving portfolio of community websites, magazines, open-access conference proceedings, and a multitude of electronic services. The company is focused on making the most of new technologies and continually improving electronic interfaces to make it easier for researchers to find exactly what they need, when they need it, in the format that suits them best. IOP Publishing is part of the Institute of Physics (IOP), a leading scientific society with more than 50,000 international members. The Institute aims to advance physics for the benefit of all by working to advance physics research, application, and education; and engaging with policymakers and the public to develop awareness and understanding of physics. Any financial surplus earned by IOP Publishing goes to support science through the activities of the Institute.

    Zooniverse is the world’s largest and most popular platform for people-powered research. This research is made possible by volunteers — hundreds of thousands of people around the world who come together to assist professional researchers. Its goal is to enable research that would not otherwise be possible or practical. Zooniverse research results in new discoveries, datasets useful to the wider research community, and many refereed publications.

    See the full article here .

    Please help promote STEM in your local schools.

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 1:57 pm on March 10, 2017 Permalink | Reply
    Tags: , , , CfA, ,   

    From CfA: “Superluminous Supernovae” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    March 10, 2017

    1
    Wikipedia

    Supernovae, the explosive deaths of massive stars, are among the most momentous events in the cosmos because they disburse into space all of the chemical elements that were produced inside their progenitor stars, including the elements essential for making planets and life. Their bright emission also enables them to be used as probes of the very distant universe. Not least, supernovae are astrophysical laboratories for the study of very energetic phenomena. One class of supernovae consists of single stars whose mass is at least eight solar masses as they finish their lives.

    A typical supernova shines about as brightly as ten billion Suns at its peak. In the last decade, a new type of supernova was discovered that is ten to one hundred times more luminous than a normal massive stellar collapse supernova, and today over a dozen of these superluminous supernovae (SLSN) have been seen. Astronomers are in agreement that these objects come from the collapse of massive stars, but their tremendous luminosities cannot be explained by the usual physical mechanisms invoked. Instead, the debate has centered on whether the excess emission results from an external source, for example the interaction of material ejected from the explosion with a circumstellar shell, or instead by some kind of powerful internal engine such as a highly magnetized, spinning neutron star.

    The SLSN “Gaia6apd” was discovered by the European Gaia satellite, and at a distance of about one and one-half billion light-years it is the second-closest SLSN discovered to date.


    ESA/GAIA

    It is also special in another way: it is extraordinarily bright in the ultraviolet, nearly four times brighter than the next nearest known SLSN despite the fact that in the optical both have comparable luminosities. CfA astronomers Matthew Nicholl, Edo Berger, Peter Blanchard, Dan Milisavljevic, and Peter Challis and their colleagues used facilities at the CfA’s MMT and Fred Lawrence Whipple Observatory to track the changing emission of this source from immediately after its discovery and continuing for one hundred and fifty days.


    CfA MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA


    CfA Whipple Observatory, near Amado, Arizona on the slopes of Mount Hopkins

    The long time coverage revealed that the UV emission eventually faded to a level typical for normal supernovae, providing some clues to the mechanisms responsible. The scientists review all the known data and conclude that the most likely source is an internal central engine like a rapidly spinning neutron star. They also emphasize the key role that UV wavelengths played in diagnosing the mechanisms and urge that future studies of SLSN include UV coverage.

    Reference(s):

    “An Ultraviolet Excess in the Superluminous Supernova Gaia16apd Reveals a Powerful Central Engine,” M. Nicholl, E. Berger, R. Margutti, P. K. Blanchard, D. Milisavljevic, P. Challis, B. D. Metzger, and R. Chornock, ApJLett 835, 8, 2017.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 12:39 pm on March 9, 2017 Permalink | Reply
    Tags: , , , CfA, , FRB's - Powering Alien Probes?   

    From CfA: “Could Fast Radio Bursts Be Powering Alien Probes? 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    March 9, 2017
    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998
    mwatzke@cfa.harvard.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    1
    An artist’s illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. The leakage from such beams as they sweep across the sky would appear as Fast Radio Bursts (FRBs), similar to the new population of sources that was discovered recently at cosmological distances. M. Weiss/CfA

    The search for extraterrestrial intelligence has looked for many different signs of alien life, from radio broadcasts to laser flashes, without success. However, newly published research in the Astrophysical Journal Letters suggests that mysterious phenomena called fast radio bursts could be evidence of advanced alien technology. Specifically, these bursts might be leakage from planet-sized transmitters powering interstellar probes in distant galaxies.

    “Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” said theorist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “An artificial origin is worth contemplating and checking.”

    As the name implies, fast radio bursts are millisecond-long flashes of radio emission. First discovered in 2007, fewer than two dozen have been detected by gigantic radio telescopes like the Parkes Observatory in Australia or the Arecibo Observatory in Puerto Rico.


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    NAIC/Arecibo Observatory, Puerto Rico, USA

    They are inferred to originate from distant galaxies, billions of light-years away.

    Loeb and his co-author Manasvi Lingam (Harvard University) examined the feasibility of creating a radio transmitter strong enough for it to be detectable across such immense distances. They found that, if the transmitter were solar powered, the sunlight falling on an area of a planet twice the size of the Earth would be enough to generate the needed energy. Such a vast construction project is well beyond our technology, but within the realm of possibility according to the laws of physics.

    Lingam and Loeb also considered whether such a transmitter would be viable from an engineering perspective, or whether the tremendous energies involved would melt any underlying structure. Again, they found that a water-cooled device twice the size of Earth could withstand the heat.

    They then asked, why build such an instrument in the first place? They argue that the most plausible use of such power is driving interstellar light sails. The amount of power involved would be sufficient to push a payload of a million tons, or about 20 times the largest cruise ships on Earth.

    “That’s big enough to carry living passengers across interstellar or even intergalactic distances,” added Lingam.

    To power a light sail, the transmitter would need to focus a beam on it continuously. Observers on Earth would see a brief flash because the sail and its host planet, star and galaxy are all moving relative to us. As a result, the beam sweeps across the sky and only points in our direction for a moment. Repeated appearances of the beam, which were observed but cannot be explained by cataclysmic astrophysical events, might provide important clues about its artificial origin.

    Loeb admits that this work is speculative. When asked whether he really believes that any fast radio bursts are due to aliens, he replied, “Science isn’t a matter of belief, it’s a matter of evidence. Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 1:41 pm on February 14, 2017 Permalink | Reply
    Tags: CfA, ,   

    From CfA: “Astronomers Propose a Cell Phone Search for Galactic Fast Radio Bursts” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    February 14, 2017
    Christine Pulliam
    Media Relations Manager
    Harvard-Smithsonian Center for Astrophysics
    617-495-7463
    cpulliam@cfa.harvard.edu

    1

    Fast radio bursts (FRBs) are brief spurts of radio emission, lasting just one-thousandth of a second, whose origins are mysterious. Fewer than two dozen have been identified in the past decade using giant radio telescopes such as the 1,000-foot dish in Arecibo, Puerto Rico.

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    Of those, only one has been pinpointed to originate from a galaxy about 3 billion light-years away.

    The other known FRBs seem to also come from distant galaxies, but there is no obvious reason that, every once in a while, an FRB wouldn’t occur in our own Milky Way galaxy too. If it did, astronomers suggest that it would be “loud” enough that a global network of cell phones or small radio receivers could “hear” it.

    “The search for nearby fast radio bursts offers an opportunity for citizen scientists to help astronomers find and study one of the newest species in the galactic zoo,” says theorist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA).

    Previous FRBs were detected at radio frequencies that match those used by cell phones, Wi-Fi, and similar devices. Consumers could potentially download a free smartphone app that would run in the background, monitoring appropriate frequencies and sending the data to a central processing facility.

    “An FRB in the Milky Way, essentially in our own back yard, would wash over the entire planet at once. If thousands of cell phones picked up a radio blip at nearly the same time, that would be a good sign that we’ve found a real event,” explains lead author Dan Maoz of Tel Aviv University.

    Finding a Milky Way FRB might require some patience. Based on the few, more distant ones, that have been spotted so far, Maoz and Loeb estimate that a new one might pop off in the Milky Way once every 30 to 1,500 years. However, given that some FRBs are known to burst repeatedly, perhaps for decades or even centuries, there might be one alive in the Milky Way today. If so, success could become a yearly or even weekly event.

    A dedicated network of specialized detectors could be even more helpful in the search for a nearby FRB. For as little as $10 each, off-the-shelf devices that plug into the USB port of a laptop or desktop computer can be purchased. If thousands of such detectors were deployed around the world, especially in areas relatively free from Earthly radio interference, then finding a close FRB might just be a matter of time.

    This work has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 1:46 pm on February 8, 2017 Permalink | Reply
    Tags: , CfA,   

    From CfA: “A Middleweight Black Hole is Hiding at the Center of a Giant Star Cluster” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    February 8, 2017
    Christine Pulliam
    Media Relations Manager
    Harvard-Smithsonian Center for Astrophysics
    617-495-7463
    cpulliam@cfa.harvard.edu

    1
    In this artist’s illustration, an intermediate-mass black hole in the foreground distorts light from the globular star cluster in the background. New research suggests that a 2,200 solar-mass black hole resides at the center of the globular cluster 47 Tucanae. CfA / M. Weiss

    2
    This artist’s conception shows another representation of the intermediate-mass black hole that may lurk in the center of the globular cluster 47 Tucanae. B. Kızıltan & T. Karacan

    All known black holes fall into two categories: small, stellar-mass black holes weighing a few Suns, and supermassive black holes weighing millions or billions of Suns. Astronomers expect that intermediate-mass black holes weighing 100 – 10,000 Suns also exist, but so far no conclusive proof of such middleweights has been found. Today, astronomers are announcing new evidence that an intermediate-mass black hole (IMBH) weighing 2,200 Suns is hiding at the center of the globular star cluster 47 Tucanae.

    “We want to find intermediate-mass black holes because they are the missing link between stellar-mass and supermassive black holes. They may be the primordial seeds that grew into the monsters we see in the centers of galaxies today,” says lead author Bulent Kiziltan of the Harvard-Smithsonian Center for Astrophysics (CfA).

    This work appears in the Feb. 9, 2017, issue of the prestigious science journal Nature.

    47 Tucanae is a 12-billion-year-old star cluster located 13,000 light-years from Earth in the southern constellation of Tucana the Toucan. It contains hundreds of thousands of stars in a ball only about 120 light-years in diameter. It also holds about two dozen pulsars that were important targets of this investigation.

    47 Tucanae has been examined for a central black hole before without success. In most cases, a black hole is found by looking for X-rays coming from a hot disk of material swirling around it. This method only works if the black hole is actively feeding on nearby gas. The center of 47 Tucanae is gas-free, effectively starving any black hole that might lurk there.

    The supermassive black hole at the center of the Milky Way also betrays its presence by its influence on nearby stars. Years of infrared observations have shown a handful of stars at our galactic center whipping around an invisible object with a strong gravitational tug. But the crowded center of 47 Tucanae makes it impossible to watch the motions of individual stars.

    The new research relies on two lines of evidence. The first is overall motions of stars throughout the cluster. A globular cluster’s environment is so dense that heavier stars tend to sink to the center of the cluster. An IMBH at the cluster’s center acts like a cosmic “spoon” and stirs the pot, causing those stars to slingshot to higher speeds and greater distances. This imparts a subtle signal that astronomers can measure.

    By employing computer simulations of stellar motions and distances, and comparing them with visible-light observations, the team finds evidence for just this sort of gravitational stirring.

    The second line of evidence comes from pulsars, compact remnants of dead stars whose radio signals are easily detectable. These objects also get flung about by the gravity of the central IMBH, causing them to be found at greater distances from the cluster’s center than would be expected if no black hole existed.

    Combined, this evidence suggests the presence of an IMBH of about 2,200 solar masses within 47 Tucanae.

    Since this black hole has eluded detection for so long, similar IMBHs may be hiding in other globular clusters. Locating them will require similar data on the positions and motions of both the stars and any pulsars within the clusters.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
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