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  • richardmitnick 1:07 pm on May 17, 2018 Permalink | Reply
    Tags: , , , , HubbleSite, LEGUS survey, , spacetelescope.org   

    From NASA/ESA Hubble Telescope: “Astronomers Release Most Complete Ultraviolet-Light Survey of Nearby Galaxies” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    May 17, 2018

    Donna Weaver /
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493 / 410-338-4514
    dweaver@stsci.edu / villard@stsci.edu

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

    Daniela Calzetti
    University of Massachusetts, Amherst, Massachusetts
    413-545-3556
    calzettii@astro.umass.edu

    Elena Sabbi
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4732 / 410-338-4926
    sabbi@stsci.edu

    Linda Smith
    ESA/Space Telescope Science Institute, Baltimore, Maryland
    410-338-4926
    lsmith@stsci.edu

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Cell: +49 176 62397500
    Email: mjaeger@partner.eso.org

    1
    Hubble samples 50 star-forming spiral and dwarf galaxies

    2
    LEGUS Galaxies

    From HubbleSite [NASA]

    Much of the light in the universe comes from stars, and yet, star formation is still a vexing question in astronomy.

    To piece together a more complete picture of star birth, astronomers have used the Hubble Space Telescope to look at star formation among galaxies in our own cosmic back yard. The survey of 50 galaxies in the local universe, called the Legacy ExtraGalactic UV Survey (LEGUS), is the sharpest, most comprehensive ultraviolet-light look at nearby star-forming galaxies.

    The LEGUS survey combines new Hubble observations with archival Hubble images for star-forming spiral and dwarf galaxies, offering a valuable resource for understanding the complexities of star formation and galaxy evolution. Astronomers are releasing the star catalogs for each of the LEGUS galaxies and cluster catalogs for 30 of the galaxies, as well as images of the galaxies themselves. The catalogs provide detailed information on young, massive stars and star clusters, and how their environment affects their development.

    The local universe, stretching across the gulf of space between us and the great Virgo cluster of galaxies, is ideal for study because astronomers can amass a big enough sample of galaxies, and yet, the galaxies are close enough to Earth that Hubble can resolve individual stars. The survey will also help astronomers understand galaxies in the distant universe, where rapid star formation took place.

    __________________________________________________________

    Capitalizing on the unparalleled sharpness and spectral range of NASA’s Hubble Space Telescope, an international team of astronomers is releasing the most comprehensive, high-resolution ultraviolet-light survey of nearby star-forming galaxies.

    The researchers combined new Hubble observations with archival Hubble images for 50 star-forming spiral and dwarf galaxies in the local universe, offering a large and extensive resource for understanding the complexities of star formation and galaxy evolution. The project, called the Legacy ExtraGalactic UV Survey (LEGUS), has amassed star catalogs for each of the LEGUS galaxies and cluster catalogs for 30 of the galaxies, as well as images of the galaxies themselves. The data provide detailed information on young, massive stars and star clusters, and how their environment affects their development.

    “There has never before been a star cluster and a stellar catalog that included observations in ultraviolet light,” explained survey leader Daniela Calzetti of the University of Massachusetts, Amherst. “Ultraviolet light is a major tracer of the youngest and hottest star populations, which astronomers need to derive the ages of stars and get a complete stellar history. The synergy of the two catalogs combined offers an unprecedented potential for understanding star formation.”

    How stars form is still a vexing question in astronomy. “Much of the light we get from the universe comes from stars, and yet we still don’t understand many aspects of how stars form,” said team member Elena Sabbi of the Space Telescope Science Institute in Baltimore, Maryland. “This is even key to our existence — we know life wouldn’t be here if we didn’t have a star around.”

    The research team carefully selected the LEGUS targets from among 500 galaxies, compiled in ground-based surveys, located between 11 million and 58 million light-years from Earth. Team members chose the galaxies based on their mass, star-formation rate, and abundances of elements that are heavier than hydrogen and helium. The catalog of ultraviolet objects collected by NASA’s Galaxy Evolution Explorer (GALEX) spacecraft also helped lay the path for the Hubble study.

    The team used Hubble’s Wide Field Camera 3 and the Advanced Camera for Surveys over a one-year period to snap visible- and ultraviolet-light images of the galaxies and their most massive young stars and star clusters.

    NASA/ESA Hubble WFC3

    NASA/ESA Hubble ACS

    The researchers also added archival visible-light images to provide a complete picture.

    The star cluster catalogs contain about 8,000 young clusters whose ages range from 1 million to roughly 500 million years old. These stellar groupings are as much as 10 times more massive than the largest clusters seen in our Milky Way galaxy.

    The star catalogs comprise about 39 million stars that are at least five times more massive than our Sun. Stars in the visible-light images are between 1 million and several billion years old; the youngest stars, those between 1 million and 100 million years old, shine prominently in ultraviolet light.

    The Hubble data provide all of the information to analyze these galaxies, the researchers explained. “We also are offering computer models to help astronomers interpret the data in the star and cluster catalogs,” Sabbi said. “Researchers, for example, can investigate how star formation occurred in one specific galaxy or a set of galaxies. They can correlate the properties of the galaxies with their star formation. They can derive the star-formation history of the galaxies. The ultraviolet-light images may also help astronomers identify the progenitor stars of supernovas found in the data.”

    One of the key questions the survey may help astronomers answer is the connection between star formation and the major structures, such as spiral arms, that make up a galaxy.

    “When we look at a spiral galaxy, we usually don’t just see a random distribution of stars,” Calzetti said. “It’s a very orderly structure, whether it’s spiral arms or rings, and that’s particularly true with the youngest stellar populations. On the other hand, there are multiple competing theories to connect the individual stars in individual star clusters to these ordered structures.

    “By seeing galaxies in very fine detail — the star clusters — while also showing the connection to the larger structures, we are trying to identify the physical parameters underlying this ordering of stellar populations within galaxies. Getting the final link between gas and star formation is key for understanding galaxy evolution.”

    Team member Linda Smith of the European Space Agency (ESA) and the Space Telescope Science Institute, added: “We’re looking at the effects of the environment, particularly with star clusters, and how their survival is linked to the environment around them.”

    The LEGUS survey will also help astronomers interpret views of galaxies in the distant universe, where the ultraviolet glow from young stars is stretched to infrared wavelengths due to the expansion of space. “The data in the star and cluster catalogs of these nearby galaxies will help pave the way for what we see with NASA’s upcoming infrared observatory, the James Webb Space Telescope, developed in partnership with ESA and the Canadian Space Agency (CSA),” Sabbi said.

    Webb observations would be complementary to the LEGUS views. The space observatory will penetrate dusty stellar cocoons to reveal the infrared glow of infant stars, which cannot be seen in visible- and ultraviolet-light images. “Webb will be able to see how star formation propagates over a galaxy,” Sabbi continued. “If you have information on the gas properties, you can really connect the points and see where, when, and how star formation happens.”

    The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

    Credits
    NASA, ESA, and D. Calzetti (University of Massachusetts) and the LEGUS team

    Related Links

    LEGUS Team Members
    NASA’s Hubble Portal
    LEGUS Project Portal

    From ESA/Hubble’s Release

    From spacetelescope.org [ESA]

    3
    Using the unparalleled sharpness and ultraviolet observational capabilities of the NASA/ESA Hubble Space Telescope, an international team of astronomers has created the most comprehensive high-resolution ultraviolet-light survey of star-forming galaxies in the local Universe. The catalogue contains about 8000 clusters and 39 million hot blue stars.

    Ultraviolet light is a major tracer of the youngest and hottest stars. These stars are short-lived and intensely bright. Astronomers have now finished a survey called LEGUS (Legacy ExtraGalactic UV Survey) that captured the details of 50 local galaxies within 60 million light-years of Earth in both visible and ultraviolet light.

    The LEGUS team carefully selected its targets from among 500 candidate galaxies compiled from ground-based surveys. They chose the galaxies based on their mass, star-formation rate, and their abundances of elements heavier than hydrogen and helium. Because of the proximity of the selected galaxies, Hubble was able to resolve them into their main components: stars and star clusters. With the LEGUS data, the team created a catalogue with about 8000 young clusters and it also created a star catalogue comprising about 39 million stars that are at least five times more massive than our Sun.

    The data, gathered with Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys, provide detailed information on young, massive stars and star clusters, and how their environment affects their development. As such, the catalogue offers an extensive resource for understanding the complexities of star formation and galaxy evolution.

    One of the key questions the survey may help astronomers answer is the connection between star formation and the major structures, such as spiral arms, that make up a galaxy. These structured distributions are particularly visible in the youngest stellar populations.

    By resolving the fine details of the studied galaxies, while also studying the connection to larger galactic structures, the team aims to identify the physical mechanisms behind the observed distribution of stellar populations within galaxies.

    Figuring out the final link between gas and star formation is key to fully understanding galaxy evolution. Astronomers are studying this link by looking at the effects of the environment on star clusters, and how their survival is linked to their surroundings.

    LEGUS will not only allow astronomers to understand the local Universe. It will also help interpret views of distant galaxies, where the ultraviolet light from young stars is stretched to infrared wavelengths due to the expansion of space. The NASA/ESA/CSA James Webb Space Telescope and its ability to observe in the far infrared will complement the LEGUS views.

    See the full Hubblesite article here .
    See the full ESA/Hubble spacetelescope.org article here .

    Please help promote STEM in your local schools.

    stem

    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.

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    AURA Icon

    NASA image

     
  • richardmitnick 11:00 am on November 13, 2017 Permalink | Reply
    Tags: , , , , HubbleSite, , The Space Telescope Science Institute is announcing some of the first science programs NASA's James Webb Space Telescope will conduct following its launch and commissioning   

    From James Webb Space Telescope via HubbleSite: “NASA’s James Webb Space Telescope Early Science Observations Revealed” 

    NASA Webb Header

    NASA Webb Telescope

    James Webb Space Telescope

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Nov 13, 2017
    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4366
    cpulliam@stsci.edu

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

    1
    First Publicly Available Science Observations for Webb Announced
    The Space Telescope Science Institute is announcing some of the first science programs NASA’s James Webb Space Telescope will conduct following its launch and commissioning. These specific observations are part of a program of Director’s Discretionary Early Release Science (DD-ERS), which will provide the scientific community with immediate access to Webb data. These data will help inform proposals for observations in the second year of Webb operations. The 13 ERS programs will address a broad variety of science areas, from black hole growth and the assembly of galaxies to star formation and the study of exoplanets.

    Astronomers around the world will have immediate access to early data from specific science observations from NASA’s James Webb Space Telescope, which will be completed within the first five months of Webb’s science operations. These observing programs were chosen from a Space Telescope Science Institute call for early release science proposals, and include examining Jupiter and its moons, searching for organic molecules forming around infant stars, weighing supermassive black holes lurking in galactic cores, and hunting for baby galaxies born in the early universe.

    “I’m thrilled to see the list of astronomers’ most fascinating targets for the Webb telescope, and extremely eager to see the results. We fully expect to be surprised by what we find,” said Dr. John C. Mather, Senior Project Scientist for the Webb telescope and Senior Astrophysicist at NASA’s Goddard Space Flight Center, Greenbelt, Maryland.

    The resulting observations will comprise the Director’s Discretionary Early Release Science (DD-ERS), and cover the gamut of Webb science targets, from planets in our solar system to the most distant galaxies. The program provides the entire scientific community with immediate access to Webb data so they have the opportunity to analyze the data and plan follow-up observations.

    “We were impressed by the high quality of the proposals received,” said Dr. Ken Sembach, Director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “These observing programs not only will generate great science, but also will be a unique resource for demonstrating the investigative capabilities of this extraordinary observatory to the worldwide scientific community.”

    The observations will also exercise all four of Webb’s science instruments, so that the astronomical community can explore Webb’s full potential. Webb has a minimum scientific lifetime of five years, so the scientific community will have to rapidly learn to use its advanced capabilities.

    “We want the research community to be as scientifically productive as possible, as early as possible, which is why I am so pleased to be able to dedicate nearly 500 hours of director’s discretionary time to these ERS observations,” said Sembach.

    One of the most widely anticipated areas of research by Webb is to study planets orbiting other stars. When such an exoplanet passes in front of its host star, starlight filters through the planet’s atmosphere, which absorbs certain colors of light depending on the chemical composition. Webb will measure this absorption, using its powerful infrared spectrographs, to look for the chemical fingerprints of the atmosphere’s gasses. Astronomers initially will train their gaze onto gaseous Jupiter-sized worlds like WASP-39b and WASP-43b because they are easier targets on which to apply this technique. The results will help guide observing strategies for smaller, mostly rocky and more Earth-like super-Earths, where atmospheric composition may give hints of a planet’s potential habitability.

    Webb also will peer into the distant universe, examining galaxies whose light has been stretched into infrared wavelengths by the expansion of space. This infrared region is beyond what Hubble can detect. Galaxy clusters are particularly rich sources of targets, since a cluster’s gravity can magnify light from more distant background galaxies. DD-ERS observations will target regions of the sky already examined by Hubble’s Frontier Fields program, such as the galaxy cluster MACS J0717.5+3745. Webb data will complement Hubble’s, giving astronomers new insights into these cornucopias of galaxies.

    Since Webb must remain shielded from sunlight, its field of view is limited to specific areas of the sky at certain times of year. As a result, the potential targets listed above may shift depending on the launch date.

    More than 100 proposals for DD-ERS observations were submitted in August 2017. Of those, 13 programs requesting 460 hours of telescope time were selected following review by panels of subject matter experts and the STScI director.

    Additional information about the selected DD-ERS proposals is available online.

    The James Webb Space Telescope, the scientific complement to NASA’s Hubble Space Telescope, will be the premier space observatory of the next decade.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

    Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

    NASA image

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    Canadian Space Agency

     
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