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  • richardmitnick 12:36 pm on December 27, 2018 Permalink | Reply
    Tags: APOGEE South spectrograph, , , , , , MaNGA survey,   

    From Science Blog from the SDSS: “SDSS Fifteenth Data Release” 

    SDSS Science blog bloc

    From Science Blog from the SDSS

    On Monday 10 December the Sloan Digital Sky Survey (SDSS) celebrated its fifteenth public data release, DR15. This data release the spotlight was on the MaNGA survey (Mapping Nearby Galaxies at Apache Point Observatory).

    1
    DR15 contains 4621 of the 10,000 galaxies that MaNGA will have observed by summer 2020. To keep up to date with all MaNGA news, you can follow this survey on twitter: @MaNGASurvey. Image credit: Dana Berry / SkyWorks Digital Inc., David Law, and the SDSS collaboration.

    MaNGA observes nearby galaxies using a technique called Integral-Field Spectroscopy. This technique allows them to take many spectra all across the galaxy, and these spectra are then used to map the stars and gas in the galaxy. MaNGA can then find out how the stars and gas move around in the galaxy, and what kind of stellar populations (young? old? metal-rich? metal-poor?) are present in the galaxy. These maps help the MaNGA team understand how galaxies form and evolve over cosmic time. DR15 includes all these maps, that were produced by a special Data Analysis Pipeline, and with Marvin you can now explore these maps yourself!

    2
    Caption: snapshot of Marvin: the new tool to explore MaNGA galaxies. You can find Marvin at https://dr15.sdss.org/marvin/, and you can also follow Marvin on twitter: @Marvin_SDSS. Image taken from Aguado et al. 2018.

    But it was not just galaxies that featured in DR15: MaNGA is running a sub-program called MaStar: the MaNGA Stellar Library.

    3
    Example spectra from the MaStar library.

    This survey observes almost in stealth mode: they use the optical BOSS spectrographs that MaNGA also uses, but only when there is a full moon and the sky is too bright to observe faint galaxies. Bright time is when APOGEE-2 is in charge, using the Sloan telescope to observe Milky Way stars in the infrared.

    4

    But the MaStar and APOGEE-2 teams work together, so that both teams can observe their stars at the same time using two different spectrographs (optical and infrared). The MaStar team is interested in learning more about the properties and physics of their stars, but also want to use their stellar spectra as templates for analyzing MaNGA galaxies.

    All this new data is now freely available, and we have a brand-new portal to show you all the different ways that you can access and interact with SDSS data: https://dr15.sdss.org/. A very big thank you to all the people in SDSS who made DR15 possible, and a special shout-out to all SDSS team members last spring participated in DocuVana, to write all the documentation that goes with this data release!

    What is next? MaNGA’s sibling surveys, APOGEE-2 (APO Galaxy Evolution Experiment 2) and eBOSS (Extended Baryon Oscillation Spectroscopic Survey) took a break during DR15, because they are preparing for a smashing DR16. Next year APOGEE-2 will release lots of new infra-red spectra of stars in the Milky Way, including the very first spectra taken from the Southern hemisphere at Las Campanas Observatory. And eBOSS is currently hard at work putting together new catalogs of the large scale structure of the Universe, that they will release alongside lots of new optical spectra of galaxies and quasars. So stay tuned for DR16!

    6
    The “first light” observations for the APOGEE South spectrograph. The dots show stars whose spectra were observed by APOGEE. Some example spectra are shown (colors are representative only, as APOGEE spectra are in the infrared).

    The first light observations included spectra of supermassive stars in the Tarantula Nebula. This nebula in the Large Magellanic Cloud is forming stars more rapidly than any other region in our Local Group of galaxies. It can only be seen from the Southern Hemisphere, underscoring the importance of APOGEE South’s location. The spectrograph will allow us to study the chemistry and evolution of the stars in the nebula in greater detail than ever before.

    7
    A slice through largest-ever three-dimensional map of the Universe. Earth is at the left, and distances to galaxies and quasars are labelled by the lookback time to the objects (lookback time means how long the light from an object has been traveling to reach us here on Earth). The locations of quasars (galaxies with supermassive black holes) are shown by the red dots, and nearer galaxies mapped by SDSS are also shown (yellow).

    The right-hand edge of the map is the limit of the observable Universe, from which we see the Cosmic Microwave Background (CMB) – the light “left over” from the Big Bang. The bulk of the empty space in between the quasars and the edge of the observable universe are from the “dark ages”, prior to the formation of most stars, galaxies, or quasars. Click on the image for a larger version.

    Image Credit: Anand Raichoor (École polytechnique fédérale de Lausanne, Switzerland) and the SDSS collaboration

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft)

    After nearly a decade of design and construction, the Sloan Digital Sky Survey saw first light on its giant mosaic camera in 1998 and entered routine operations in 2000. While the collaboration and scope of the SDSS have changed over the years, many of its key principles have stayed fixed: the use of highly efficient instruments and software to enable astronomical surveys of unprecedented scientific reach, a commitment to creating high quality public data sets, and investigations that draw on the full range of expertise in a large international collaboration. The generous support of the Alfred P. Sloan Foundation has been crucial in all phases of the SDSS, alongside support from the Participating Institutions and national funding agencies in the U.S. and other countries.

    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects.

    In its first five years of operations, the SDSS carried out deep multi-color imaging over 8000 square degrees and measured spectra of more than 700,000 celestial objects. With an ever-growing collaboration, SDSS-II (2005-2008) completed the original survey goals of imaging half the northern sky and mapping the 3-dimensional clustering of one million galaxies and 100,000 quasars. SDSS-II carried out two additional surveys: the Supernova Survey, which discovered and monitored hundreds of supernovae to measure the expansion history of the universe, and the Sloan Extension for Galactic Understanding and Exploration (SEGUE), which extended SDSS imaging towards the plane of the Galaxy and mapped the motions and composition of more than a quarter million Milky Way stars.

    SDSS-III (2008-2014) undertook a major upgrade of the venerable SDSS spectrographs and added two powerful new instruments to execute an interweaved set of four surveys, mapping the clustering of galaxies and intergalactic gas in the distant universe (BOSS), the dynamics and chemical evolution of the Milky Way (SEGUE-2 and APOGEE), and the population of extra-solar giant planets (MARVELS).

    The latest generation of the SDSS (SDSS-IV, 2014-2020) is extending precision cosmological measurements to a critical early phase of cosmic history (eBOSS), expanding its revolutionary infrared spectroscopic survey of the Galaxy in the northern and southern hemispheres (APOGEE-2), and for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies (MaNGA).

    This is the “Science blog” of the SDSS. Here you’ll find short descriptions of interesting scientific research and discoveries from the SDSS. We’ll also update on activities of the collaboration in public engagement and other arenas. We’d love to see your comments and questions about what you read here!

    You can explore more on the SDSS Website.

     
  • richardmitnick 7:08 am on August 1, 2016 Permalink | Reply
    Tags: , , , , MaNGA survey,   

    From SDSS: “THIRTEENTH DATA RELEASE” 

    SDSS Science blog bloc

    Science Blog from the SDSS

    July 31, 2016
    Zheng Zheng

    This weekend, the Sloan Digital Sky Survey (SDSS) is celebrating its thirteenth public data release, or lucky DR13!

    Data releases are an important part of the SDSS. All the data that are observed by the Sloan Telescope for the various surveys that are part of SDSS, get reduced and processed, and eventually are made publicly available. This means that everyone with access to the internet can download the data, use it for their research or teaching, or simply look at all the images and spectra that are available. You just have to go to the SDSS website, and you can start exploring the data for yourself!

    So, what does DR13 have in store for you? Apart from including all the data that was released in previous data releases, there is also lots of new data:

    DR13 is the first data release for the MaNGA survey! MaNGA stands for Mapping Nearby Galaxies at Apache Point Observatory, and it studies galaxies with integral-field spectroscopy. This allows us to study chemical elements and motions of stars and gas not just in the centre of the galaxies, but all over the galaxy outskirts too. MaNGA is releasing its spectra in datacubes for 1351 individual galaxies, making it the biggest integral-field galaxy survey available on-line so far!

    APOGEE, or the APO Galaxy Evolution Experiment is taking infra-red spectra for hundreds of thousands of stars in the Milky Way. For this data release, they have improved the analysis of all their previously released spectra, and measured the abundances of various chemical elements of stars. This will help us understand how the Milky Way formed over time.

    eBOSS, short for extended Baryon Oscillation Spectroscopic Survey, is mapping the structure of the Universe, by taking spectra of more than a million galaxies and quasars. Its goal is to measure the expansion rate of the Universe, and the nature of the mysterious Dark Energy that accelerates this expansion. eBOSS is releasing improved analysis of previously released spectra, as well as several catalogs with information on emission line galaxies and variable quasars.

    Do you want to have a look at all of this data? Here are some places to get started:

    The SDSS SkyServer has several tools to explore the data. You can for instance:
    find stars and galaxies in the Navigate tool
    look at images and spectra of stars and galaxies with the QuickLook tool
    search for a particular sample of galaxies or stars with SQL

    If you are interested in analyzing the data yourself, then you can find more information on how to download the data on the SDSS data access page

    If you are a teacher and interested in activities that will help your students explore the Universe, then have a look at our SDSS education web page, with lots of resources for the class room.

    Anne-Marie Weijmans
    SDSS Data Release Coordinator
    University of St Andrews

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    After nearly a decade of design and construction, the Sloan Digital Sky Survey saw first light on its giant mosaic camera in 1998 and entered routine operations in 2000. While the collaboration and scope of the SDSS have changed over the years, many of its key principles have stayed fixed: the use of highly efficient instruments and software to enable astronomical surveys of unprecedented scientific reach, a commitment to creating high quality public data sets, and investigations that draw on the full range of expertise in a large international collaboration. The generous support of the Alfred P. Sloan Foundation has been crucial in all phases of the SDSS, alongside support from the Participating Institutions and national funding agencies in the U.S. and other countries.

    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects.

    In its first five years of operations, the SDSS carried out deep multi-color imaging over 8000 square degrees and measured spectra of more than 700,000 celestial objects. With an ever-growing collaboration, SDSS-II (2005-2008) completed the original survey goals of imaging half the northern sky and mapping the 3-dimensional clustering of one million galaxies and 100,000 quasars. SDSS-II carried out two additional surveys: the Supernova Survey, which discovered and monitored hundreds of supernovae to measure the expansion history of the universe, and the Sloan Extension for Galactic Understanding and Exploration (SEGUE), which extended SDSS imaging towards the plane of the Galaxy and mapped the motions and composition of more than a quarter million Milky Way stars.

    SDSS-III (2008-2014) undertook a major upgrade of the venerable SDSS spectrographs and added two powerful new instruments to execute an interweaved set of four surveys, mapping the clustering of galaxies and intergalactic gas in the distant universe (BOSS), the dynamics and chemical evolution of the Milky Way (SEGUE-2 and APOGEE), and the population of extra-solar giant planets (MARVELS).

    The latest generation of the SDSS (SDSS-IV, 2014-2020) is extending precision cosmological measurements to a critical early phase of cosmic history (eBOSS), expanding its revolutionary infrared spectroscopic survey of the Galaxy in the northern and southern hemispheres (APOGEE-2), and for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies (MaNGA).

    This is the “Science blog” of the SDSS. Here you’ll find short descriptions of interesting scientific research and discoveries from the SDSS. We’ll also update on activities of the collaboration in public engagement and other arenas. We’d love to see your comments and questions about what you read here!

    You can explore more on the SDSS Website.

     
  • richardmitnick 1:39 pm on January 9, 2016 Permalink | Reply
    Tags: , , MaNGA survey,   

    From SDSS: “Proof That Some Galaxies are LIERs” 

    SDSS Telescope

    Sloan Digital Sky Survey

    January 8, 2016
    Jordan Raddick

    Contacts
    Francesco Belfiore, University of Cambridge / Kavli Institute for Cosmology / Member of the UK Participation Group, fb338@cam.ac.uk, +44 (0)1223 746434
    Roberto Maiolino, University of Cambridge / Kavli Institute for Cosmology / Member of the UK Participation Group, r.maiolino@mrao.cam.ac.uk, +44 (0)1223 761661
    Kevin Bundy, Kavli Institute for the Physics and Mathematics of the Universe, kevin.bundy@ipmu.jp, +81 (0)4-7136-6513

    You might think that astronomers could easily tell the difference between a black hole and a white dwarf – but nature can be deceptive.

    Astronomers from the Sloan Digital Sky Survey (SDSS) this morning announced the results of a new study that reveals the true origin of puzzling light from nearby galaxies. Results were presented at the 227th meeting of the American Astronomical Society in Kissimmee, Florida.

    Temp 1
    This image shows SDSS observations of one of the LIER galaxies used in this study. The underlying image is from the SDSS and includes a scale bar. The pink hexagon shows the size of the MaNGA fiber optic bundle. The region inside the hexagon shows the newly-derived map of interstellar gas from MaNGA.

    The presence of the gas throughout the galaxy eliminates the black hole explanation (pictured at the top left) and favors the white dwarf explanation (bottom right).

    Image Credit: Jennifer Johnson (The Ohio State University) and the SDSS Collaboration
    Black hole: NASA/Dana Berry/SkyWorks Animation
    White dwarf: NASA/JPL (Raghvendra Sahai)

    “We now know that white dwarfs, not central black holes, explain these observations,” says Francesco Belfiore, the lead author of the study and a graduate student at the University of Cambridge. “Because we know that white dwarfs are to blame, we are much closer to understanding how galaxies retire from the star-formation business.”

    To solve the mystery, Belfiore’s team looked at the thin interstellar gas that lies between stars in nearby galaxies. They used information from the emission lines of the spectra of that hot, glowing gas to decode what energy source lights it up. Understanding the origin of these emission lines is far from straightforward. In particular, astronomers have long been puzzled by the energy source for a particular state of gas in galaxies: The source must be hotter than newly formed stars but cooler than the radiation from a violently accreting black hole, like a quasar.

    The leading theory used to be that this gas was lit by a wimpy active galactic nucleus, which is only accreting very small amounts of gas. This idea was supported by the fact that nuclear regions of many galaxies show such Low-Ionization Nuclear Emission-line Regions, which were therefore called LINERs.

    “LINERs are a 35-year-old puzzle,” says Belfiore. “In recent years, several astronomers have argued against the mainstream interpretation and presented evidence that not all LINERs are due to black holes. The new SDSS data gave us a chance to take a new look at this question and evaluate possible alternative theories.

    Previous spectroscopic observations were insufficient because they generally covered only a small portion of a galaxy near its center. A new SDSS instrument, called MaNGA (MApping Nearby Galaxies at Apache Point Observatory), is now capable of obtaining spectroscopic data for the whole galaxy at once.

    Temp 2
    An image of a spiral galaxy with the face of a MaNGA 127 fiber integral field unit (IFU) superimpossed. Galaxies are being selected from the SDSS Main Galaxy Legacy Area, with selection cuts applied to only redshift and a color-based stellar mass estimate.Sloan Digital Sky Survey

    “To get the data we need, we use a simple but innovative design,” says Kevin Bundy from the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), Principal Investigator for the MaNGA survey and co-author of the study. “We tie together a few dozen optical fibers into a large hexagonal bundle and point them at a galaxy. The bundle covers most of the galaxy and each fiber measures the spectrum at a different point.”

    Belfiore and his collaborators used the MaNGA data to map the state of gas and stars throughout more than 600 LINER galaxies. ‘By taking advantage of the fact that MaNGA can get data for an entire galaxy at once, we have revealed that the sources lighting the gas up must be distributed throughout the galaxy, even tens of thousands of light years away from the central black hole. This proves that the emission lines we see cannot all be due to central black holes,” says Belfiore.

    Claudia Maraston of the University of Portsmouth, a co-author of the study, explains the most likely answer to the LINER puzzle. “White dwarfs are revealed as stars lose their outer gas envelopes and expose their hot cores, which still glows at millions of degrees. These newly-exposed white dwarfs are the ideal sources to light up the interstellar gas and produce the emission lines we see,” says Maraston.

    Although this mechanism was originally suggested to be important only in elliptical galaxies, the new MaNGA data reveals that it is in fact common in both elliptical and spiral galaxies. “In the spiral galaxies, the gas shining as LINERs is the dying gasp of star formation being quenched as gas reservoirs are depleted in inner regions and star formation moves to the outer suburbs. In the elliptical galaxies, where almost all star formation occurred rapidly in the early days of the Universe, this glowing gas represents a ‘rejuvenation’ of the dormant galaxy,” says Belfiore. “Donated gas, from dying stars within the galaxy or from a merging galaxy, is now able to intercept the extreme radiation and make the galaxy shine again, albeit only as a LINER.”

    With the extensive mapping of low-ionization emission-line regions outside of the nuclei of galaxies, far removed from central supermassive black holes, but close to newly born white dwarfs, the ‘N’ for ‘nuclear’ in the LINER acronym must disappear.

    The truth, then, is this: many galaxies are LIERs.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects. Learn and explore all phases and surveys—past, present, and future—of the SDSS.

    The SDSS began regular survey operations in 2000, after a decade of design and construction. It has progressed through several phases, SDSS-I (2000-2005), SDSS-II (2005-2008), SDSS-III (2008-2014), and SDSS-IV (2014-). Each of these phases has involved multiple surveys with interlocking science goals. The three surveys that comprise SDSS-IV are eBOSS, APOGEE-2, and MaNGA, described at the links below. You can find more about the surveys of SDSS I-III by following the Prior Surveys link.

    Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS- IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is http://www.sdss.org.

    SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatório Nacional / MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University.

     
  • richardmitnick 12:28 pm on January 5, 2016 Permalink | Reply
    Tags: , , MaNGA survey,   

    From SDSS: “Astronomers studying galaxy mergers using MaNGA data” 

    SDSS Telescope

    Sloan Digital Sky Survey

    January 5, 2016
    Lihwai Lin

    Galaxies are not isolated. During the lifetime of galaxies, they may encounter another galaxy and merge together to become a larger one. Mergers can induce gas to flow toward the inner parts of galaxies through tidal forces, triggering starbursts or even “switching on” a galaxy’s central black hole (the result is called an active galactic nucleus, or AGN). As a result of rapid gas consumption during mergers, a galaxy may lose the majority of its gas and end up as a “dead” system with little on-going star formation. This kind of merger event is rare, but is suggested to be an important process that transforms star-forming galaxies into the quiescent population. One of the key sciences that MaNGA is attempting to address concerns the role of galaxy interactions and mergers in shaping the properties of galaxies. With just one year of the MaNGA survey, we have obtained Integral Field Unit (IFU) observations for ~150 paired galaxies, ranging from early encounters to post-mergers.

    1
    Examples of galaxy pairs selected from the SDSS. The magenta hexagons represent the IFU coverage of MaNGA. (Credit: SDSS)

    In early November of 2015, experts studying galaxy mergers gathered together in Taipei for the “SDSS-IV/MaNGA mini-workshop on galaxy mergers”. This 3-day workshop consists of 6 invited talks, 5 contributed talks, plus 2 discussion sessions devoted to theoretical and observational efforts, chaired by Jennifer Lotz (STScI) and Sara Ellison (University of Victoria) respectively.

    3
    Participants for the MaNGA mini-workshop on galaxy mergers, held at Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA), Taipei, on Nov. 4-6, 2015.

    With MaNGA’s spatially resolved observations for merging galaxies, we can study not only where and when the star formation is triggered and shut down during the process of galaxy interactions, but also how the massive black holes in the center of galaxies can be fueled and grow through galaxy mergers. The observational results from MaNGA will also be compared in great detail with theoretical predictions from state-of-art simulations. Stay tuned for more exciting science that will come from MaNGA!

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects. Learn and explore all phases and surveys—past, present, and future—of the SDSS.

    The SDSS began regular survey operations in 2000, after a decade of design and construction. It has progressed through several phases, SDSS-I (2000-2005), SDSS-II (2005-2008), SDSS-III (2008-2014), and SDSS-IV (2014-). Each of these phases has involved multiple surveys with interlocking science goals. The three surveys that comprise SDSS-IV are eBOSS, APOGEE-2, and MaNGA, described at the links below. You can find more about the surveys of SDSS I-III by following the Prior Surveys link.

    Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS- IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is http://www.sdss.org.

    SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatório Nacional / MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University.

     
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