Tagged: NASA ESA Hubble Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:25 pm on March 7, 2019 Permalink | Reply
    Tags: "Not knowing the precise mass of the Milky Way presents a problem for a lot of cosmological questions.", "We know from cosmological simulations the distribution of mass in the galaxies. So we can calculate how accurate this extrapolation is for the Milky Way" said Laura Watkins of the ESO, "We want to know the mass of the Milky Way more accurately so that we can put it into a cosmological context and compare it to simulations of galaxies in the evolving universe" said Roeland van der Ma, "What Does the Milky Way Weigh? Hubble and Gaia Investigate", Although we cannot see it dark matter is the dominant form of matter in the universe and it can be weighed through its influence on visible objects like the globular clusters, Astronomers used Hubble and Gaia to measure the three-dimensional movement of globular star clusters that orbit the center of our galaxy, , , , , Most of the rest of the mass is locked up in dark matter an invisible and mysterious substance that acts like scaffolding throughout the universe and keeps the stars in their galaxies, NASA ESA Hubble, Only a few percent of this is contributed by the approximately 200 billion stars in the Milky Way and includes a 4-million-solar-mass supermassive black hole at the center, The Milky Way weighs in at about 1.5 trillion solar masses (one solar mass is the mass of our Sun), The team of astronomers in this study: Laura Watkins (ESO Garching Germany) Roeland van der Marel (STScI and JHU Center for Astrophysical Sciences Baltimore Maryland) Sangmo Tony Sohn (STScI Baltimore, We can't put the whole Milky Way on a scale. Astronomers have come up with one of the most accurate measurements yet of our galaxy's mass using Hubble Space Telescope and GAIA   

    From NASA/ESA Hubble Telescope: “What Does the Milky Way Weigh? Hubble and Gaia Investigate” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Mar 7, 2019

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Laura Watkins
    European Southern Observatory, Garching, Germany
    011-49-89-3200-6257
    l.watkins@eso.org

    Roeland van der Marel
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4931
    marel@stsci.edu

    1
    NASA, ESA, and A. Feild (STScI)

    We can’t put the whole Milky Way on a scale, but astronomers have been able to come up with one of the most accurate measurements yet of our galaxy’s mass, using NASA’s Hubble Space Telescope and the European Space Agency’s Gaia satellite.

    ESA/GAIA satellite

    The Milky Way weighs in at about 1.5 trillion solar masses (one solar mass is the mass of our Sun), according to the latest measurements. Only a few percent of this is contributed by the approximately 200 billion stars in the Milky Way and includes a 4-million-solar-mass supermassive black hole at the center. Most of the rest of the mass is locked up in dark matter, an invisible and mysterious substance that acts like scaffolding throughout the universe and keeps the stars in their galaxies.

    Earlier research dating back several decades used a variety of observational techniques that provided estimates for our galaxy’s mass ranging between 500 billion to 3 trillion solar masses. The improved measurement is near the middle of this range.

    “We want to know the mass of the Milky Way more accurately so that we can put it into a cosmological context and compare it to simulations of galaxies in the evolving universe,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “Not knowing the precise mass of the Milky Way presents a problem for a lot of cosmological questions.”

    The new mass estimate puts our galaxy on the beefier side, compared to other galaxies in the universe. The lightest galaxies are around a billion solar masses, while the heaviest are 30 trillion, or 30,000 times more massive. The Milky Way’s mass of 1.5 trillion solar masses is fairly normal for a galaxy of its brightness.

    Astronomers used Hubble and Gaia to measure the three-dimensional movement of globular star clusters — isolated spherical islands each containing hundreds of thousands of stars each that orbit the center of our galaxy.

    Although we cannot see it, dark matter is the dominant form of matter in the universe, and it can be weighed through its influence on visible objects like the globular clusters. The more massive a galaxy, the faster its globular clusters move under the pull of gravity. Most previous measurements have been along the line of sight to globular clusters, so astronomers know the speed at which a globular cluster is approaching or receding from Earth. However, Hubble and Gaia record the sideways motion of the globular clusters, from which a more reliable speed (and therefore gravitational acceleration) can be calculated.

    The Hubble and Gaia observations are complementary. Gaia was exclusively designed to create a precise three-dimensional map of astronomical objects throughout the Milky Way and track their motions. It made exacting all-sky measurements that include many globular clusters. Hubble has a smaller field of view, but it can measure fainter stars and therefore reach more distant clusters. The new study augmented Gaia measurements for 34 globular clusters out to 65,000 light-years, with Hubble measurements of 12 clusters out to 130,000 light-years that were obtained from images taken over a 10-year period.

    When the Gaia and Hubble measurements are combined as anchor points, like pins on a map, astronomers can estimate the distribution of the Milky Way’s mass out to nearly 1 million light-years from Earth.

    “We know from cosmological simulations what the distribution of mass in the galaxies should look like, so we can calculate how accurate this extrapolation is for the Milky Way,” said Laura Watkins of the European Southern Observatory in Garching, Germany, lead author of the combined Hubble and Gaia study, to be published in The Astrophysical Journal. These calculations based on the precise measurements of globular cluster motion from Gaia and Hubble enabled the researchers to pin down the mass of the entire Milky Way.

    The earliest homesteaders of the Milky Way, globular clusters contain the oldest known stars, dating back to a few hundred million years after the big bang, the event that created the universe. They formed prior to the construction of the Milky Way’s spiral disk, where our Sun and solar system reside.

    “Because of their great distances, globular star clusters are some of the best tracers astronomers have to measure the mass of the vast envelope of dark matter surrounding our galaxy far beyond the spiral disk of stars,” said Tony Sohn of STScI, who led the Hubble measurements.

    The international team of astronomers in this study are Laura Watkins (European Southern Observatory, Garching, Germany), Roeland van der Marel (Space Telescope Science Institute, and Johns Hopkins University Center for Astrophysical Sciences, Baltimore, Maryland), Sangmo Tony Sohn (Space Telescope Science Institute, Baltimore, Maryland), and N. Wyn Evans (University of Cambridge, Cambridge, United Kingdom).

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 4:42 pm on February 20, 2019 Permalink | Reply
    Tags: , , , , , NASA ESA Hubble,   

    From NASA/ESA Hubble Telescope: Women in STEM- “Hubblecast 116: Henrietta Leavitt — ahead of her time” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Hubblecast 116: Henrietta Leavitt — ahead of her time

    Born in 1868, Henrietta Leavitt was an astronomer ahead of her time, whose work helped to revolutionise our understanding of the Universe. While working at Harvard Observatory, she began to study stars of fluctuating brightness. She made a crucial observation about these objects, which gave astronomers a new way to measure distances, ultimately leading to such impactful discoveries as the expansion of the Universe.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 12:29 pm on January 31, 2019 Permalink | Reply
    Tags: , , , Bedin 1 in NGC 6752-Isolated star-city is a fossil from the early universe, , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Accidentally Discovers a New Galaxy in Cosmic Neighborhood” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Jan 31, 2019

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Luigi Bedin
    INAF-Astronomical Observatory of Padua, Italy
    011-49-829-3413
    luigi.bedin@oapd.inaf.it

    1
    Featured Image: Bedin 1 in NGC 6752
    Isolated star-city is a fossil from the early universe.

    2
    Bedin 1 Pullout

    The universe is very cluttered. Myriad island cities of stars, the galaxies, form a backdrop tapestry. Much closer to home are nebulae, star clusters, and assorted other foreground celestial objects that are mostly within our Milky Way galaxy. Despite the vastness of space, objects tend to get in front of each other.

    This happened when astronomers used the Hubble Space Telescope to photograph the globular star cluster NGC 6752 (located 13,000 light-years away in our Milky Way’s halo). In a celestial game of “Where’s Waldo?”, Hubble’s sharp vision uncovered a never-before-seen dwarf galaxy located far behind the cluster’s crowded stellar population. The loner galaxy is in our own cosmic backyard, only 30 million light-years away (approximately 2,300 times farther than the foreground cluster).

    The object is classified as a dwarf spheroidal galaxy because it measures only around 3,000 light-years at its greatest extent (barely 1/30th the diameter of the Milky Way), and it is roughly a thousand times dimmer than the Milky Way.

    Because of its 13-billion-year-old age, and its isolation — which resulted in hardly any interaction with other galaxies — the dwarf is the astronomical equivalent of a living fossil from the early universe.

    The international team of astronomers that carried out this study consists of L. Bedin (INAF-Astronomical Observatory of Padua, Italy), M. Salaris (Liverpool John Moores University, Liverpool, England, UK), R. Rich (University of California, Los Angeles, California, USA), H. Richer (University of British Columbia, Vancouver, British Columbia, Canada), J. Anderson (Space Telescope Science Institute, Baltimore, Maryland, USA), B. Bettoni (INAF-Astronomical Observatory of Padua, Italy), D. Nardiello, A. Milone, and A. Marino (University of Padua, Italy), M. Libralato and A. Bellini (Space Telescope Science Institute, Baltimore, Maryland, USA), A. Dieball (University of Bonn, Bonn, Germany), P. Bergeron (University of Montreal, Quebec, Canada), A. Burgasser (University of California, San Diego, California, USA), and D. Apai (University of Arizona, Tucson, Arizona, USA).

    The science team’s results will be published online January 31, 2019, in the Monthly Notices of the Royal Astronomical Society: Letters.

    From ESA/Hubble

    In the outer fringes of the area observed with Hubble’s Advanced Camera for Surveys a compact collection of stars was visible. After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster — which is part of the Milky Way — but rather they are millions of light-years more distant.

    Our newly discovered cosmic neighbour, nicknamed Bedin 1 by the astronomers, is a modestly sized, elongated galaxy. It measures only around 3000 light-years at its greatest extent — a fraction of the size of the Milky Way. Not only is it tiny, but it is also incredibly faint. These properties led astronomers to classify it as a dwarf spheroidal galaxy.

    Dwarf spheroidal galaxies are defined by their small size, low-luminosity, lack of dust and old stellar populations [1]. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.

    While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Not only is it one of just a few dwarf spheroidals that have a well established distance but it is also extremely isolated. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744. This makes it possibly the most isolated small dwarf galaxy discovered to date.

    From the properties of its stars, astronomers were able to infer that the galaxy is around 13 billion years old — nearly as old as the Universe itself. Because of its isolation — which resulted in hardly any interaction with other galaxies — and its age, Bedin 1 is the astronomical equivalent of a living fossil from the early Universe.

    The discovery of Bedin 1 was a truly serendipitous find. Very few Hubble images allow such faint objects to be seen, and they cover only a small area of the sky. Future telescopes with a large field of view, such as the WFIRST telescope, will have cameras covering a much larger area of the sky and may find many more of these galactic neighbours.
    Notes

    [1] While similar to dwarf elliptical galaxies in appearance and properties, dwarf spheroidal galaxies are in general approximately spherical in shape and have a lower luminosity.

    See the full INBOX ASTRONOMY article here .
    See the full ESA/Hubble article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 11:03 am on January 28, 2019 Permalink | Reply
    Tags: , , , , NASA ESA Hubble, Pan-STARRS releases 1.6 petabytes of data from its four-year survey, , The survey data resides in the Mikulski Archive for Space Telescopes (MAST) which serves as NASA's repository for all of its optical and ultraviolet-light observations, University of Hawai’i Institute for Astronomy in Honolulu Hawaii USA, World's Largest Digital Sky Survey Issues Biggest Astronomical Data Release Ever   

    From NASA/ESA Hubble Telescope: “World’s Largest Digital Sky Survey Issues Biggest Astronomical Data Release Ever” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Jan 28, 2019

    Media Contact:
    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4366
    cpulliam@stsci.edu

    Science Contacts:
    Marc Postman
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4340
    postman@stsci.edu

    Armin Rest
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4358
    arest@stsci.edu

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

    2
    Pan-STARRS releases 1.6 petabytes of data from its four-year survey

    Data from the world’s largest digital sky survey is being publicly released today by the Space Telescope Science Institute (STScI) in Baltimore, Maryland, in conjunction with the University of Hawai’i Institute for Astronomy in Honolulu, Hawaii. Data from the Pan-STARRS1 Surveys will allow anyone to access millions of images and use the database and catalogs containing precision measurements of billions of stars and galaxies. This data release contains over 1.6 petabytes of data (a petabyte is one million gigabytes), making it the largest volume of astronomical information ever released. The survey data resides in the Mikulski Archive for Space Telescopes (MAST), which serves as NASA’s repository for all of its optical and ultraviolet-light observations.

    The Space Telescope Science Institute (STScI) in Baltimore, Maryland, in conjunction with the University of Hawai’i Institute for Astronomy (IfA), is releasing the second edition of data from Pan-STARRS — the Panoramic Survey Telescope & Rapid Response System — the world’s largest digital sky survey. This second release contains over 1.6 petabytes of data (a petabyte is 1015 bytes or one million gigabytes), making it the largest volume of astronomical information ever released. The amount of imaging data is equivalent to two billion selfies, or 30,000 times the total text content of Wikipedia. The catalog data is 15 times the volume of the Library of Congress.

    The Pan-STARRS observatory consists of a 1.8-meter telescope equipped with a 1.4-billion-pixel digital camera, located at the summit of Haleakalā, on Maui. Conceived and developed by the IfA, it embarked on a digital survey of the sky in visible and near-infrared light in May 2010. Pan-STARRS was the first survey to observe the entire sky visible from Hawai’i multiple times in many colors of light. One of the survey’s goals was to identify moving, transient, and variable objects, including asteroids that could potentially threaten the Earth. The survey took approximately four years to complete, scanning the sky 12 times in five filters. This second data release provides, for the first time, access to all of the individual exposures at each epoch of time. This will allow astronomers and public users of the archive to search the full survey for high-energy explosive events in the cosmos, discover moving objects in our own solar system, and explore the time domain of the universe.

    Dr. Heather Flewelling, a researcher at the Institute for Astronomy in Hawai’i, and a key designer of the PS1 database, stated that “Pan-STARRS DR2 represents a vast quantity of astronomical data, with many great discoveries already unveiled. These discoveries just barely scratch the surface of what is possible, however, and the astronomy community will now be able to dig deep, mine the data, and find the astronomical treasures within that we have not even begun to imagine.”

    “We put the universe in a box and everyone can take a peek,” said database engineer Conrad Holmberg.

    The four years of data comprise 3 billion separate sources, including stars, galaxies, and various other objects. This research program was undertaken by the PS1 Science Consortium — a collaboration among 10 research institutions in four countries, with support from NASA and the National Science Foundation (NSF). Consortium observations for the sky survey were completed in April 2014. The initial Pan-STARRS public data release occurred in December 2016, but included only the combined data and not the individual exposures at each epoch of time.

    “The Pan-STARRS1 Survey allows anyone access to millions of images and catalogs containing precision measurements of billions of stars, galaxies, and moving objects,” said Dr Ken Chambers, Director of the Pan-STARRS Observatories. “While searching for Near Earth Objects, Pan-STARRS has made many discoveries from ‘Oumuamua passing through our solar system to lonely planets between the stars; it has mapped the dust in three dimensions in our galaxy and found new streams of stars; and it has found new kinds of exploding stars and distant quasars in the early universe. We hope people will discover all kinds of things we missed in this incredibly large and rich dataset.”

    The Space Telescope Science Institute hosts the storage hardware, the computers that handle the database queries, and the user-friendly interfaces to access the data. The survey data resides in the Mikulski Archive for Space Telescopes (MAST), which serves as NASA’s repository for all of its optical and ultraviolet-light observations, some of which date to the early 1970s. It includes all of the observational data from such space astrophysics missions as Hubble, Kepler, GALEX, and a wide variety of other telescopes, as well as several all-sky surveys. Pan-STARRS marks the nineteenth mission to be archived in MAST.

    The Pan-STARRS1 Surveys and its science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawai’i, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, the Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Center for Astrophysics | Harvard and Smithsonian (CfA), the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, and the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eōtvōs Loránd University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 1:48 pm on January 26, 2019 Permalink | Reply
    Tags: , , , , Dark Matter missing in galaxies?, , Keck 2 Cosmic Web Imager, NASA ESA Hubble, NGC 1052-DF2, NGC 1052-DF4, , U Toronto Dunlap Dragonfly telescope Array   

    From Scientific American: “Ghostly Galaxies Hint at Dark Matter Breakthrough” 

    Scientific American

    From Scientific American

    January 25, 2019
    Rebecca Boyle

    Two newfound galaxies appear to be devoid of the mysterious substance, paradoxically providing more proof dark matter exists.

    1
    The bizarre galaxy NGC 1052-DF2, a diffuse collection of stars, gas and dust that is apparently devoid of dark matter. Credit: NASA, ESA, and P. van Dokkum (Yale University)

    Much as a ripple in a pond reveals a thrown stone, the existence of the mysterious stuff known as dark matter is inferred via its wider cosmic influence. Astronomers cannot see it directly, but its gravity sculpts the birth, shape and movement of galaxies. This makes a discovery from last year all the more unexpected: a weirdly diffuse galaxy that seemed to harbor no dark matter at all.

    Even as some researchers hailed the finding, others aired their doubts, criticizing measurements of the galaxy’s distance and motion. The stakes are high: If the galaxy does in fact lack dark matter, that would paradoxically bolster the case for the material’s existence. Now the original team is back with additional evidence confirming their initial discovery, plus a newfound second galaxy that appears to show the same thing—or, rather, the lack thereof. Where once there was but one ultradiffuse galaxy seemingly free of dark matter, now, it seems, there are two. “One object, you can always write off as a unicorn, but once you find two unicorns, you start thinking unicorns exist, maybe,” says Michael Boylan-Kolchin, an astronomer at The University of Texas at Austin who was not involved in the research. “Then you have to start worrying about how they got there, what are their properties and how common are they?”

    Finding the Unicorns

    The two galaxies are very faint and far away from Earth: Photons from their smatterings of stars began traveling to Earth in the last days of the dinosaurs’ reign, some 65 million years ago. The original galaxy, called NGC 1052-DF2 [above], is the size of the Milky Way but contains just 1 percent of our galaxy’s stars. The new one, NGC 1052-DF4, is in the same patch of sky and has roughly the same size and mass.

    2
    NGC 1052-DF4

    (The name “DF” comes from their discovery using the Dragonfly Telephoto Array, which specializes in detecting faint objects.)

    U Toronto Dunlap Dragonfly telescope Array at its home at high-altitude observing location New Mexico Skies hosting facility at 7300′ altitude

    Last March researchers led by Shany Danieli and Pieter van Dokkum of Yale University published a study that sized up NGC 1052-DF2 by observing its starlight as well as the movements of star clusters that surround it. If DF2 contained as much dark matter as astronomers would normally expect for such a galaxy, the dark matter would boost the orbital speeds of those star clusters. But they move sluggishly, which suggests dark matter is absent. Critics countered these star cluster speeds had not been calculated correctly—and, even if the calculations were correct, argued the sample size of just 10 star clusters was too modest for making reliable determinations of DF2’s dark matter inventory.

    Next, in October, Danieli set out to settle the question using a different technique. She used the Keck Cosmic Web Imager, a new instrument freshly installed behind the giant 10-meter primary mirror of the Keck 2 telescope in Hawaii.

    Keck Cosmic Web Imager on Keck 2 schematic

    Keck Cosmic Web Imager on Keck 2

    Keck 2 telescope Maunakea Hawaii USA, 4,207 m (13,802 ft)

    The instrument can measure the light from very faint objects at extremely high resolution, making it an ideal instrument for scrutinizing ultradiffuse galaxies such as NGC 1052-DF2. The instrument was so good, in fact, that Danieli no longer needed to study the star cluster motions to infer the galaxy’s mass. Instead, she could get at the mass more directly, using the galaxy’s starlight.

    In terms of information, starlight contains multitudes. By splitting light into its constituent colors, a practice called spectroscopy, scientists can determine a star’s makeup, age, direction through the cosmos and speed. Much of that information is conveyed in spectral lines—linear features embedded in a star’s spectrum due to the emission or absorption of various chemical elements. The Keck instrument measured the spectra for roughly 10 million stars in the DF2 galaxy. The size of the spread between the fastest and slowest stars in the galaxy gives an idea of how much matter interacts with them. The more matter present—dark or otherwise—the greater the spread in the stellar velocities. “To our own surprise, we measured extremely narrow [spectral] lines, which leaves very little room for more mass other than the mass contributed by the stars in the galaxy,” Danieli says. No room for dark matter.

    Meanwhile, Eric Emsellem of the European Southern Observatory and colleagues were scrutinizing the galaxy using the Very Large Telescope in Chile’s Atacama desert.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    They also found a low-velocity dispersion, which supports the missing dark matter scenario.

    Nicolas Martin, an astronomer at the University of Strasbourg in France, was among the critics of the original paper. In subsequent work published last year, he argued it is too difficult to estimate the DF2 galaxy’s mass based on surrounding star cluster motions. But Martin says he was reassured by the latest results from Danieli and Emsellem. “This is only thanks to brand-new instruments that arrived on the biggest telescopes on the planet that this is feasible. And to be entirely honest, it wasn’t clear to me a year ago that it would be feasible,” he notes. “A year ago I wasn’t ready to say the system was necessarily weird, because I felt the measurement wasn’t entirely supported by the data. But now that there are two different teams that have measured the range of velocities of the stars themselves, I think it’s clear that this is an oddball.”

    Danieli presented her new findings at a dark matter conference last week at Princeton University, and has submitted them to The Astrophysical Journal Letters for peer-reviewed publication.

    In a separate paper she describes the DF4 galaxy, which she and several colleagues observed with the Hubble Space Telescope last year.

    NASA/ESA Hubble Telescope

    Examining seven star clusters orbiting DF4, Danieli and her co-workers found they are moving languidly, suggesting there is very little or no dark matter in the galaxy. Taken together, the near back-to-back discovery of DF2 and DF4 lurking in the same patch of sky implies a whole class of such dark matter–poor galaxies exists, she says.

    In Search of Missing Matter

    Several astronomers are scratching their heads over how such galaxies could form in the first place, and where the dark matter went. One possibility is the gravitational pull of a much larger galaxy nearby stripped off the dark matter, Boylan-Kolchin says. Or DF2 and DF4 may not be galaxies after all, just modest collections of stars masquerading as such; in that case, these isolated groups of stars may have formed from colliding jets of gas streaming from another location. Or there could be more humdrum scenarios such as the galaxies’ orientation with respect to Earth being unfavorable for obtaining accurate spectral measurements of their motions, according to Martin. “I’m a little torn about the system. It’s certainly intriguing and it needs to be explained, but it could well be that the explanation is quite mundane, and it’s just the wrong angle or something like that,” he says.

    One thing is clear: If confirmed beyond a reasonable doubt, the galaxies’ lack of dark matter would conclusively show the stuff is separable from stars, gas, dust and other regular matter, and would further bolster the case for dark matter’s existence.

    To date, nobody has definitively detected dark matter despite decades of ardent searching. The absence of evidence has led some astrophysicists to search for alternative ways to sculpt galaxies and dictate their motions by developing classes of hypotheses with names like “emergent gravity” and “modified Newtonian dynamics.” Proponents of such ideas argue the sculpting most astronomers attribute to dark matter may actually be a phenomenon that arises from physics we cannot yet comprehend. But if that were the case, those conditions would obtain everywhere. Galaxies like NCG 1052 DF2 and DF4 would be subject to those alternative gravities, too—and those theories would need to somehow explain such galactic oddities (which they presently do not). And so the galaxies’ sheer peculiarity suggests these alternatives are wrong, and dark matter must indeed be the cause.

    Stacy McGaugh, an astronomer at Case Western Reserve University and a proponent of some dark matter alternatives, notes Emsellem’s velocity-dispersion measurement is almost twice as high as Danieli’s. “The statement one is obliged to make is that we are still waiting for this to settle out. I would like to see the data be consistent,” he says. “But it is consistent with stars only and no dark matter, and that makes it really interesting. The next thing you have to ask is: How did that come to be? Is it an intrinsic property, there are just galaxies like this? My own feeling is no.”

    More definitive answers could come soon; Danieli says the team is now looking for other dark matter–free dwarf galaxies. “It may be that these objects tell us something about the nature of dark matter, but it’s too soon to tell. That’s certainly our hope, but we first need to find more objects and study them in greater detail,” she says.

    See the full article here .


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

    Stem Education Coalition

    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 2:02 pm on January 24, 2019 Permalink | Reply
    Tags: , , , , D100 being stripped of its gas as it plunges toward the cluster’s center, Hubble Sees Plunging Galaxy Losing Its Gas, NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Sees Plunging Galaxy Losing Its Gas” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Jan 24, 2019

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    William Cramer
    Yale University, New Haven, Connecticut
    william.cramer@yale.edu

    Jeffrey Kenney
    Yale University, New Haven, Connecticut
    203-432-3013
    jeff.kenney@yale.edu

    1
    D100

    2
    H-alpha Tail of D100

    3
    Compass Image for D100

    The rough-and-tumble environment near the center of the massive Coma galaxy cluster is no match for a wayward spiral galaxy. New images from NASA’s Hubble Space Telescope show a spiral galaxy being stripped of its gas as it plunges toward the cluster’s center. A long, thin streamer of gas and dust stretches like taffy from the galaxy’s core and on into space. Eventually, the galaxy, named D100, will lose all of its gas and become a dead relic, deprived of the material to create new stars and shining only by the feeble glow of old, red stars.

    “This galaxy stands out as a particularly extreme example of processes common in massive clusters, where a galaxy goes from being a healthy spiral full of star formation to a ‘red and dead galaxy,'” said William Cramer of Yale University in New Haven, Connecticut, leader of the team using the Hubble observations. “The spiral arms disappear, and the galaxy is left with no gas and only old stars. This phenomenon has been known about for several decades, but Hubble provides the best imagery of galaxies undergoing this process.”

    Called “ram pressure stripping,” the process occurs when a galaxy, due to the pull of gravity, falls toward the dense center of a massive cluster of thousands of galaxies, which swarm around like a hive of bees. During its plunge, the galaxy plows through intergalactic material, like a boat moving through water. The material pushes gas and dust from the galaxy. Once the galaxy loses all of its hydrogen gas — fuel for starbirth — it meets an untimely death because it can no longer create new stars. The gas-stripping process in D100 began roughly 300 million years ago.

    In the massive Coma cluster this violent gas-loss process occurs in many galaxies.

    But D100 is unique in several ways. Its long, thin tail is its most unusual feature. The tail, a mixture of dust and hydrogen gas, extends nearly 200,000 light-years, about the width of two Milky Way galaxies. But the pencil-like structure is comparatively narrow, only 7,000 light-years wide.

    “The tail is remarkably well-defined, straight and smooth, and has clear edges,” explained team member Jeffrey Kenney, also of Yale University. “This is a surprise because a tail like this is not seen in most computer simulations. Most galaxies undergoing this process are more of a mess. The clean edges and filamentary structures of the tail suggest that magnetic fields play a prominent role in shaping it. Computer simulations show that magnetic fields form filaments in the tail’s gas. With no magnetic fields, the tail is more clumpy than filamentary.”

    The researchers’ main goal was to study star formation along the tail. Hubble’s sharp vision uncovered the blue glow of clumps of young stars. The brightest clump in the middle of the tail contains at least 200,000 stars, triggered by the ongoing gas loss from the galaxy. However, based on the amount of glowing hydrogen gas contained in the tail, the team had expected Hubble to uncover three times more stars than it detected.

    The Subaru Telescope in Hawaii observed the glowing tail in 2007 during a survey of the Coma cluster’s galaxies.


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level

    But the astronomers needed Hubble observations to confirm that the hot hydrogen gas contained in the tail was a signature of star formation.

    “Without the depth and resolution of Hubble, it’s hard to say if the glowing hydrogen-gas emission is coming from stars in the tail or if it’s just from the gas being heated,” Cramer said. “These Hubble visible-light observations are the first and best follow-up of the Subaru survey.”

    The Hubble data show that the gas-stripping process began on the outskirts of the galaxy and is moving in towards the center, which is typical in this type of mass loss. Based on the Hubble images, the gas has been cleared out all the way down to the central 6,400 light-years.

    Within that central region, there is still a lot of gas, as seen in a burst of star formation. “This region is the only place in the galaxy where gas exists and star formation is taking place,” Cramer said. “But now that gas is being stripped out of the center, forming the long tail.”

    Adding to this compelling narrative is another galaxy in the image that foreshadows D100’s fate. The object, named D99, began as a spiral galaxy similar in mass to D100. It underwent the same violent gas-loss process as D100 is now undergoing, and is now a dead relic. All of the gas was siphoned from D99 between 500 million and 1 billion years ago. Its spiral structure has mostly faded away, and its stellar inhabitants consist of old, red stars. “D100 will look like D99 in a few hundred million years,” Kenney said.

    The Coma cluster is located 330 million light-years from Earth.

    Coma cluster via NASA/ESA Hubble

    The team’s results appear online in the January 8, 2019, issue of The Astrophysical Journal.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 2:38 pm on January 10, 2019 Permalink | Reply
    Tags: , , , , , , , NASA ESA Hubble, PHANGS-ALMA   

    From ALMA: “What 100,000 Star Factories in 74 Galaxies Tell Us about Star Formation across the Universe” 

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

    From ALMA

    9 January, 2019

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Phone: +1 434 296 0314
    Cell phone: +1 202 236 6324
    Email: cblue@nrao.edu

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: calum.turner@eso.org

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

    1

    Galaxies come in a wide variety of shapes and sizes. Some of the most significant differences among galaxies, however, relate to where and how they form new stars. Compelling research to explain these differences has been elusive, but that is about to change. The Atacama Large Millimeter/submillimeter Array (ALMA) is conducting an unprecedented survey of nearby disk galaxies to study their stellar nurseries. With it, astronomers are beginning to unravel the complex and as-yet poorly understood relationship between star-forming clouds and their host galaxies.

    A vast, new research project with ALMA, known as PHANGS-ALMA (Physics at High Angular Resolution in Nearby GalaxieS), delves into this question with far greater power and precision than ever before by measuring the demographics and characteristics of a staggering 100,000 individual stellar nurseries spread throughout 74 galaxies.

    PHANGS-ALMA, an unprecedented and ongoing research campaign, has already amassed a total of 750 hours of observations and given astronomers a much clearer understanding of how the cycle of star formation changes, depending on the size, age, and internal dynamics of each individual galaxy. This campaign is ten- to one-hundred-times more powerful (depending on your parameters) than any prior survey of its kind.

    “Some galaxies are furiously bursting with new stars while others have long ago used up most of their fuel for star formation. The origin of this diversity may very likely lie in the properties of the stellar nurseries themselves,” said Erik Rosolowsky, an astronomer at the University of Alberta in Canada and a co-Principal Investigator of the PHANGS-ALMA research team.

    He presented initial findings of this research at the 233rd meeting of the American Astronomical Society being held this week in Seattle, Washington. Several papers based on this campaign have also been published in The Astrophysical Journal and the Astrophysical Journal Letters [Papers are listed below].

    “Previous observations with earlier generations of radio telescopes provide some crucial insights about the nature of cold, dense stellar nurseries,” Rosolowsky said. “These observations, however, lacked the sensitivity, fine-scale resolution, and power to study the entire breadth of stellar nurseries across the full population of local galaxies. This severely limited our ability to connect the behavior or properties of individual stellar nurseries to the properties of the galaxies that they live in.”

    For decades, astronomers have speculated that there are fundamental differences in the way disk galaxies of various sizes convert hydrogen into new stars. Some astronomers theorize that larger, and generally older galaxies, are not as efficient at stellar production as their smaller cousins. The most logical explanation would be that these big galaxies have less efficient stellar nurseries. But testing this idea with observations has been difficult.

    For the first time, ALMA is allowing astronomers to conduct the necessary wide-ranging census to determine how the large-scale properties (size, motion, etc.) of a galaxy influence the cycle of star formation on the scale of individual molecular clouds. These clouds are only about a few tens to a few hundreds of light-years across, which is phenomenally small on the scale of an entire galaxy, especially when seen from millions of light-years away.

    “Stars form more efficiently in some galaxies than others, but the dearth of high-resolution, cloud-scale observations meant our theories were weakly tested, which is why these ALMA observations are so critical,” said Adam Leroy, an astronomer at The Ohio State University and co-Principal Investigator on the PHANGS-ALMA team.

    Part of the mystery of star formation, the astronomers note, has to do with the interstellar medium – all the matter and energy that fills the space between the stars.

    Astronomers understand that there is an ongoing feedback loop in and around the stellar nurseries. Within these clouds, pockets of dense gas collapse and form stars, which disrupts the interstellar medium.

    “Indeed, comparing early PHANGS observations with the locations of newly formed stars shows that the newly formed stars quickly destroy their birth clouds,” said Rosolowsky. “The PHANGS team is studying how this disruption plays out in different types of galaxies, which may be a key factor in star-forming efficiency.”

    For this research, ALMA is observing molecules of carbon monoxide (CO) from all relatively massive, generally face-on spiral galaxies visible from the Southern Hemisphere. Molecules of CO naturally emit the millimeter-wavelength light that ALMA can detect. They are particularly effective at highlighting the location of star-forming clouds.

    “ALMA is a stunningly efficient machine to map carbon monoxide over large areas in nearby galaxies,” said Leroy. “It was able to perform this survey because of the combined power of the 12-meter dishes, which study fine-scale features, and the smaller, 7-meter dishes at the center of the array, which are sensitive to large-scale features, essentially filling in the gaps.”

    A companion survey, PHANGS-MUSE, is using the Very Large Telescope to obtain optical imaging of the first 19 galaxies observed by ALMA.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo, with an elevation of 2,635 metres (8,645 ft) above sea level,

    MUSE stands for the Multi-Unit Spectroscopic Explorer.

    ESO MUSE on the VLT on Yepun (UT4)

    Another survey, PHANGS-HST uses the Hubble Space Telescope to survey 38 of these galaxies to find their youngest stellar clusters.

    NASA/ESA Hubble Telescope

    Together, these three surveys give a startlingly complete picture of how well galaxies form stars by probing cold molecular gas, its motion, the location of ionized gas (regions where stars are already forming), and the galaxies’ complete stellar populations.

    “In astronomy, we have no ability to watch the cosmos change over time; the timescales simply dwarf human existence,” noted Rosolowsky. “We can’t watch one object forever, but we can observe hundreds of thousands of star-forming clouds in galaxies of different sizes and ages to infer how galactic evolution works. That is the real value of the PHANGS-ALMA campaign.”

    “We also look at thousands to tens of thousands of star-forming regions within each galaxy, catching them across their life cycle. This lets us build a picture of the birth and death of stellar nurseries across galaxies, something almost impossible before ALMA,” added Leroy.

    So far, PHANGS-ALMA has studied about 100,000 Orion Nebula-like objects in the nearby universe. It is expected that the campaign will eventually observe around 300,000 star-forming regions.

    These results are being published in a series of papers in The Astrophysical Journal and the Astrophysical Journal Letters. Already accepted and published:

    “Cloud-scale Molecular Gas Properties in 15 Nearby Galaxies,” J. Sun, et al., 2018 June. 25, The Astrophysical Journal [http://iopscience.iop.org/article/10.3847/1538-4357/aac326]

    “Star Formation Efficiency per Free-fall Time in nearby Galaxies,” D. Utomo, et al., 2018 July 11, Astrophysical Journal Letters [http://iopscience.iop.org/article/10.3847/2041-8213/aacf8f/meta]

    “A 50 pc Scale View of Star Formation Efficiency across NGC 628,” K. Kreckel, et al., 2018 August 14, Astrophysical Journal Letters [http://iopscience.iop.org/article/10.3847/2041-8213/aad77d]

    IMAGES

    1
    Six ALMA-imaged galaxies out of a collection of the 74. The images were taken as part of the PHANGS-ALMA survey to study the properties of star-forming clouds in disk galaxies. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

    2
    ALMA image of galaxy NGC 4321, also known as Messier 100, an intermediate spiral galaxy located about 55 million light-years from Earth in the constellation Coma Berenices. It is imaged as part of the PHANGS-ALMA survey to study the properties of star-forming clouds in disk galaxies. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

    3
    ALMA image of NGC 628, also known as Messier 74, a spiral galaxy in the constellation Pisces, located approximately 32 million light-years from Earth. It is imaged as part of the PHANGS-ALMA survey to study the properties of star-forming clouds in disk galaxies. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

    4
    Composite ALMA (orange) and Hubble (blue) image of NGC 628, also known as Messier 74, a spiral galaxy in the constellation Pisces, located approximately 32 million light-years from Earth. It is imaged as part of the PHANGS-ALMA survey to study the properties of star-forming clouds in disk galaxies. Credit: NRAO/AUI/NSF, B. Saxton: ALMA (ESO/NAOJ/NRAO); NASA/Hubble

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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
    ESO 50 Large
    NAOJ

     
  • richardmitnick 9:28 pm on January 9, 2019 Permalink | Reply
    Tags: , , , , NASA ESA Hubble, NASA's Hubble Helps Astronomers Uncover the Brightest Quasar in the Early Universe, Super-bright quasar cataloged as J043947.08+163415.7   

    From NASA/ESA Hubble Telescope: “NASA’s Hubble Helps Astronomers Uncover the Brightest Quasar in the Early Universe” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Jan 9, 2019

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Xiaohui Fan
    University of Arizona, Tucson, Arizona
    520-360-0956 (cell)
    520-626-7558 (office)
    fan@as.arizona.edu

    1
    Zoom Lens in Space Gives Hubble a Peek into the Era of Galaxy Birth

    Less than a billion years after the big bang, a monster black hole began devouring anything within its gravitational grasp. This triggered a firestorm of star formation around the black hole. A galaxy was being born. A blowtorch of energy, equivalent to the light from 600 trillion Suns, blazed across the universe. Now, 12.8 billion years later, the Hubble Space Telescope captured the beacon from this event. But Hubble astronomers needed help to spot it. The gravitational warping of space by a comparatively nearby intervening galaxy greatly amplified and distorted the quasar’s light, making it the brightest such object seen in the early universe. It offers a rare opportunity to study a zoomed-in image of how supermassive black holes accompanied star formation in the very early universe and influenced the assembly of galaxies.

    Astronomers have discovered the brightest object ever seen at a time when the universe was less than one billion years old, with the help of NASA’s Hubble Space Telescope. The brilliant beacon is a quasar, the core of a galaxy with a black hole ravenously eating material surrounding it.

    Though the quasar is very far away — 12.8 billion light-years — astronomers can detect it because a galaxy closer to Earth acts as a lens and makes the quasar look extra bright. The gravitational field of the closer galaxy warps space itself, bending and amplifying the distant quasar’s light. This effect is called gravitational lensing.

    Gravitational Lensing NASA/ESA

    Though researchers have searched for these very remote quasars for over 20 years, a rare and fortuitous celestial alignment made this one visible to them. “We don’t expect to find many quasars brighter than that in the whole observable universe,” said lead investigator Xiaohui Fan of the University of Arizona, in Tucson.

    The super-bright quasar, cataloged as J043947.08+163415.7, could hold the record of being the brightest in the early universe for some time, making it a unique object for follow-up studies.

    Shining with light equivalent to 600 trillion Suns, the quasar is fueled by a supermassive black hole at the heart of a young galaxy in the process of forming. An immense amount of energy is emitted as the black hole consumes material around it. The detection provides a rare opportunity to study a zoomed-in image of how such black holes accompanied star formation in the very early universe and influenced the assembly of galaxies.

    Besides being bright in visible and infrared wavelengths, the lensed quasar is also bright in submillimeter wavelengths, where it was observed with the James Clerk Maxwell Telescope on Mauna Kea, Hawaii.

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    This is due to hot dust heated by intense star formation in the galaxy hosting the lensed quasar. The formation rate is estimated to be up to 10,000 stars per year (by comparison, our Milky Way galaxy makes one star per year).

    “Clearly, this black hole is not only accreting gas, but has a lot of star formation around it,” said team member Jinyi Yang at the University of Arizona. “However, because of the boosting effect of gravitational lensing, the actual rate of star formation could be much lower than the observed brightness suggests,” she added.

    The quasar existed at a transitional period in the universe’s evolution, called reionization, where light from young galaxies and quasars reheated the obscuring hydrogen that cooled off not long after the big bang.

    The quasar would have gone undetected if not for the power of gravitational lensing, which boosted its brightness by a factor of 50.

    However, because very distant quasars are identified by their red color (due to absorption by diffuse gas in intergalactic space), sometimes their light is “contaminated,” and looks bluer because of the starlight of an intervening galaxy. As a result, they may be overlooked in quasar searches because their color is diluted to resemble that of a normal galaxy. Fan proposes that many other remote quasars have been missed due to this light contamination.

    His team got lucky with finding J043947.08+163415.7, because the quasar is so bright it drowns out the starlight from the especially faint foreground lensing galaxy. “Without this high level of magnification, it would make it impossible for us to see the galaxy,” said team member Feige Wang of the University of California, Santa Barbara. “We can even look for gas around the black hole and what the black hole may be influencing in the galaxy.”

    The object was selected by its color by combining photometric data from the United Kingdom Infrared Telescope Hemisphere Survey, the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) at optical wavelengths, and NASA’s Wide-field Infrared Survey Explorer archive in the mid-infrared.


    UKIRT, located on Mauna Kea, Hawai’i, USA as part of Mauna Kea Observatory,4,207 m (13,802 ft) above sea level

    Pann-STARSR1 Telescope, U Hawaii, Mauna Kea, Hawaii, USA, Altitude 3,052 m (10,013 ft)

    NASA Infrared Telescope facility Mauna Kea, Hawaii, USA, 4,207 m (13,802 ft) above sea level

    Follow-up spectroscopic observations were conducted by the University of Arizona’s Multi-Mirror Telescope, the Gemini Observatory and the Keck Observatory. These observations revealed the signature of a very faint foreground galaxy directly between the quasar and Earth that is magnifying the quasar image. However, because the source looks fuzzy in the ground-based observations (and so could be mistaken for only a galaxy), the researchers used Hubble’s exquisite imaging capabilities to confirm it is a lensed quasar.

    CfA U Arizona Fred Lawrence Whipple Observatory Steward Observatory MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA, Altitude 2,616 m (8,583 ft)


    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    “It’s a hard system to photograph because it turns out to be so compact, which requires the sharpest view from Hubble,” Fan said.

    The quasar is ripe for future scrutiny. Fan’s team is analyzing a detailed 20-hour spectrum from the European Southern Observatory’s Very Large Telescope, which would show gas absorption features to identify chemical composition and temperatures of intergalactic gas in the early universe. Astronomers also will use the Atacama Large Millimeter/submillimeter Array, and eventually NASA’s James Webb Space Telescope, to look within 150 light-years of the black hole to directly detect the influence of the black hole’s gravity on gas motion and star formation in its vicinity.

    Fan will present the team’s results at a press conference Jan. 9, 2019, at the 233rd meeting of the American Astronomical Society in Seattle, Washington. The team’s science paper is available online in The Astrophysical Journal Letters.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
  • richardmitnick 1:55 pm on January 9, 2019 Permalink | Reply
    Tags: , , , , Hubble telescope camera is broken — and US government shutdown could delay repairs, NASA ESA Hubble, Wide Field Camera 3   

    From Nature: “Hubble telescope camera is broken — and US government shutdown could delay repairs” 

    Nature Mag
    From Nature

    09 January 2019

    NASA/ESA Hubble Telescope

    Ageing telescope’s wide-field camera fails while key NASA staff are on involuntary, indefinite leave due to political impasse.

    NASA/ESA Hubble WFC3

    One of the Hubble Space Telescope’s main instruments stopped working on 8 January because of an unspecified hardware problem, NASA says. Engineers are unlikely to be able to fix the ageing telescope until the ongoing US government shutdown ends — whenever that might be.

    Hubble’s mission operations are based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where most employees are on involuntary leave during the shutdown. A few people who operate spacecraft that are actively flying, including Hubble, have been allowed to keep working.

    But fixing the problem with Hubble, which is almost 30 years old, will almost certainly involve additional government employees who are forbidden to work during the shutdown. NASA has formed an investigative team, composed primarily of contractors and experts from its industry partners, to examine the technical troubles.

    Federal law allows agencies to keep some personnel working during a shutdown if they are deemed necessary to protect life and property. It is not clear whether NASA might request an emergency exception to allow repairs to Hubble before the shutdown — now in its 19th day — ends.

    An e-mail to a NASA press officer seeking comment prompted this automatic reply: “I am in furlough status and unable to respond to your message at this time.”

    Camera trouble

    The instrument that broke is Hubble’s Wide Field Camera 3, one of its scientific workhorses. The telescope has one other camera and two spectrographs that remain operational and will keep collecting data, NASA said in an 8 January announcement.

    In October, Hubble stopped working entirely for three weeks after the failure of one of the gyroscopes that it uses to orient itself in space. Engineers fixed the problem, but the rescue effort required input from experts from across NASA, including many who are currently furloughed.

    The Space Telescope Science Institute in Baltimore, Maryland, which runs Hubble’s science operations, remains open for now, using money it received from NASA before the shutdown started. But many of Hubble’s technical experts are based at Goddard, which is closed.

    Hubble launched in 1990 and has been upgraded and updated five times by visiting astronauts, the last time in 2009. The Wide Field Camera 3 was installed during that final servicing mission. It has a back-up set of electronics that can be used if something has gone permanently wrong with the main set — but engineers won’t know that until they are allowed to work on it.

    The risk of not being able to fix Hubble if something broke is one of the impacts scientists were worried about as the government shutdown began on 22 December.

    The shutdown, which affects roughly 75% of the government, is now in its third week with no end in sight. If it persists until 12 January, it will break the record for longest shutdown, which was set by a 21-day event that began on 16 December 1995.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Natureis a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 2:12 pm on January 8, 2019 Permalink | Reply
    Tags: , , , , NASA ESA Hubble, Water and organic compounds essential for life as we know it may get blown away before they can reach the surface of young planets, Young Planets Orbiting Red Dwarfs May Lack Ingredients for Life   

    From NASA/ESA Hubble Telescope: “Young Planets Orbiting Red Dwarfs May Lack Ingredients for Life” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    Jan 8, 2019

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Carol Grady
    Eureka Scientific, Oakland, California
    carol.a.grady@nasa.gov

    Glenn Schneider
    Steward Observatory, Tucson, Arizona
    gschneider@as.arizona.edu

    John Wisniewski
    University of Oklahoma, Norman, Oklahoma
    wisniewski@ou.edu

    1
    AU Microscopii. Release type: American Astronomical Society Meeting.

    Rocky planets orbiting red dwarf stars may be bone dry and lifeless, according to a new study using NASA’s Hubble Space Telescope. Water and organic compounds, essential for life as we know it, may get blown away before they can reach the surface of young planets.

    This hypothesis is based on surprising observations of a rapidly eroding dust-and-gas disk encircling the young, nearby red dwarf star AU Microscopii (AU Mic) by Hubble and the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    Red dwarfs, which are smaller and fainter than our Sun, are the most abundant and longest-lived stars in the galaxy.

    Fast-moving blobs of material appear to be ejecting particles from the AU Mic disk. If the disk continues to dissipate at this rapid pace, it will be gone in about 1.5 million years. In that short time, icy material from comets and asteroids could be cleared out of the disk. Comets and asteroids are important because they are believed to have seeded rocky planets such as Earth with water and organic compounds, the chemical building blocks for life. If this same transport system is needed for planets in the AU Mic system, then they may end up “dry” and dusty — inhospitable for life as we know it.

    “The Earth, we know, formed ‘dry,’ with a hot, molten surface, and accreted atmospheric water and other volatiles for hundreds of millions of years, being enriched by icy material from comets and asteroids transported from the outer solar system,” said co-investigator Glenn Schneider of Steward Observatory in Tucson, Arizona.

    The observations are led by John Wisniewski of the University of Oklahoma in Norman, whose team is composed of 14 astronomers from the U.S. and Europe.

    If the activity around AU Mic is typical of the planet-birthing process among red dwarfs, it could further reduce prospects of habitable worlds across our galaxy. Previous observations suggest that a torrent of ultraviolet light from young red dwarf stars quickly strips away the atmosphere of any orbiting planets. This particular star is only 23 million years old.

    Surveys have shown that terrestrial planets are common around red dwarfs. In fact, they should contain the bulk of our galaxy’s planet population, which could number tens of billions of worlds. Planets have been found within the habitable zone of several nearby red dwarfs, but their physical characteristics are largely unknown.

    Blown Out by Blobs

    Observations by Hubble’s Space Telescope Imaging Spectrograph (STIS) and the VLT show that the AU Mic circumstellar disk is being excavated by fast-moving blobs of circumstellar material, which are acting like a snowplow by pushing small particles — possibly containing water and other volatiles — out of the system. Researchers don’t yet know how the blobs were launched. One theory is that powerful mass ejections from the turbulent star expelled them. Such energetic activity is common among young red dwarfs.

    “These observations suggest that water-bearing planets might be rare around red dwarfs because all the smaller bodies transporting water and organics are blown out as the disk is excavated,” explained Carol Grady of Eureka Scientific in Oakland, California, co-investigator on the Hubble observations.

    Conventional theory holds that billions of years ago Earth formed as a comparatively dry planet. Gravitationally perturbed asteroids and comets, rich in water from the cooler outer solar system, bombarded Earth and seeded the surface with ice and organic compounds. “However, this process may not work in all planetary systems,” Grady said.

    The team determined the disk’s lifespan by using an estimated mass of the disk from an independent study, as well as calculating the mass of the escaping blobs in their STIS visible-light data. The mass of each blob is about four ten-millionths the mass of Earth. The disk’s mass — about 1.7 times more massive than Earth — is based on data taken by the Atacama Large Millimeter/submillimeter Array (ALMA).

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

    Although the mass of the wayward blobs seems tiny, the diameter of each blob could stretch at least from the Sun to Jupiter. At present, the team has spotted six outbound blobs, but it is possible that there is a continuous stream of them. Groups of blobs careening through the disk could sweep out material fairly quickly.

    “The fast dissipation of the disk is not something I would have expected,” Grady said. “Based on the observations of disks around more luminous stars, we had expected disks around fainter red dwarf stars to have a longer time span. In this system, the disk will be gone before the star is 25 million years old.” She added that AU Mic likely started out with an outer rim of small icy bodies, like the Kuiper belt found within our own solar system. If the disk weren’t being eroded, it would have provided ices to any dry inner planets.

    Probing the Blob Mystery

    Hubble astronomers spotted the blobs in STIS visible-light images taken in 2010-2011. As a follow-up to the Hubble study, the SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument mounted on the European Southern Observatory’s Very Large Telescope in Chile, made near-infrared observations.

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT MELIPAL UT3, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    Features in the disk were hinted at in observations taken in 2004 by ground-based telescopes and Hubble’s Advanced Camera for Surveys.

    So far, the team has uncovered blobs on the disk’s southeast side, with estimated ejection speeds between 9,000 miles per hour and 27,000 miles per hour, fast enough to escape the star’s gravitational clutches. They currently range in distance from roughly 930 million miles to more than 5.5 billion miles from the star.

    Hubble is also showing that these blobs may not just be giant balls of dusty debris. The telescope has resolved substructure in one of the blobs, including a mushroom-shaped cap above the plane of the disk itself and a complex “loop-like” structure below the disk. “These structures could yield clues to the mechanisms that drive these blobs,” Schneider said.

    The system resides 32 light-years away in the southern constellation Microscopium.

    “AU Mic is ideally placed,” Schneider said. “But it is only one of about three or four red-dwarf systems with known starlight-scattering disks of circumstellar debris. The other known systems are typically about six times farther away, so it’s challenging to conduct a detailed study of the types of features in those disks that we see in AU Mic.”

    However, astronomers are beginning to identify some possibly similar activity in these other systems. “It shows that AU Mic is not unique,” Grady said. “In fact, you could argue that because it is one of the nearest systems of this type, it would be unlikely that it would be unique.”

    The AU Mic observations show the importance of a star’s disk environment on planet formation and evolution. “What we have learned is that disks seem to be a normal part of the history of planetary systems,” Grady said. “If you don’t understand a star’s disk, you don’t have a good understanding of the resulting planetary system.”

    Grady will present the team’s results at a press conference Jan. 8, 2019, at the 233rd meeting of the American Astronomical Society in Seattle, Washington.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large

    AURA Icon

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: