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  • richardmitnick 8:30 am on May 18, 2015 Permalink | Reply
    Tags: , , ESA Planck   

    From ESA: “Star formation and magnetic turbulence in the Orion Molecular Cloud” 

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    European Space Agency

    18/05/2015
    No Writer Credit

    Temp 1
    ESA and the Planck Collaboration

    With blue hues suggestive of marine paradises and a texture evoking the tranquil flow of sea waves, this image might make us daydream of sandy beaches and exotic holiday destinations. Instead, the subject of the scene is intense and powerful, because it depicts the formation of stars in the turbulent billows of gas and dust of the Orion Molecular Cloud.

    The image is based on data from ESA’s Planck satellite, which scanned the sky between 2009 and 2013 to study the cosmic microwave background [CMB], the most ancient light in the Universe’s history.

    ESA Planck
    Planck

    Cosmic Microwave Background  Planck
    CMB per Planck

    While doing so, Planck also detected foreground emission from material in the Milky Way, as well as from other galaxies.

    Our Galaxy is pervaded by a diffuse mixture of gas and dust that occasionally becomes denser, creating giant gas clouds where stars can form. While present only in traces, dust is a crucial ingredient in these interstellar clouds. It also shines brightly at some of the wavelengths that were probed by Planck, so astronomers can use these data to learn more about the cradles of star formation.

    In addition, dust grains have elongated shapes and tend to align their longest axis at right angles to the direction of the Galaxy’s magnetic field. This makes their emission partly ‘polarised’ – it vibrates in a preferred direction. Since Planck was equipped with polarisation-sensitive detectors, its scans also contain information about the direction of the magnetic field threading the Milky Way.

    This image combines a visualisation of the total intensity of dust emission, shown in the colour scale, with an indication of the magnetic field’s orientation, represented by the texture. Blue hues correspond to regions with little dust, while the yellow and red areas reflect denser (and mostly hotter) clouds containing larger amounts of dust, as well as gas.

    The red clumps at the centre of the image are part of the Orion Molecular Cloud Complex, one of the closest large regions of star formation, only about 1300 light-years from the Sun.

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    Part of the Orion Molecular Cloud Complex, with the Great Nebula in Orion near the center, along with the Belt of Orion, and Barnard’s Loop curling around the image

    The most prominent of the red clumps, to the lower left of centre, is the famous Orion Nebula, also known as M42.

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    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    This is visible to the naked eye in the constellation Orion, just below the three stars forming the ‘belt’ of the mythological hunter. An annotated version of the image can be found here.

    The magnetic field appears regular and organised in almost parallel lines in the upper part of the image: this is a result of the large-scale arrangement of the magnetic field along the Galactic plane, which is located above the top of this image. However, the field becomes less regular in the central and lower parts of the image, in the region of the Orion Molecular Cloud. Astronomers believe that the turbulent structure of the magnetic field observed in this and other star-forming clouds is related to the powerful processes taking place when stars are being born.

    The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz. The image spans about 40º across.

    See the full article here.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 11:43 am on March 31, 2015 Permalink | Reply
    Tags: , , , ESA Planck, Galaxy clusters   

    From ESA: Herschel and Planck Find Missing Clue to Galaxy Cluster Formation 

    ESASpaceForEuropeBanner
    European Space Agency

    31 March 2015

    Markus Bauer

    ESA Science and Robotic Exploration Communication Officer

    Tel: +31 71 565 6799; +34 91 8131 199

    Mob: +31 61 594 3954

    Email: Markus.Bauer@esa.int

    Hervé Dole
    Institut d’Astrophysique Spatiale (CNRS & Univ. Paris-Sud) and Institut Universitaire de France Orsay, France

    Tel: +33 1 69 85 85 72
    Email: Herve.Dole@ias.u-psud.fr

    Ludovic Montier
    Institut de Recherche en Astrophysique et Planétologie (CNRS & Univ. Paul Sabatier Toulouse III), Toulouse, France
    Tel: +33 5 61 55 65 51
    Email: Ludovic.Montier@irap.omp.eu

    Jan Tauber

    ESA Planck Project Scientist

    Tel: +31 71 565 5342

    Email: Jan.Tauber@esa.int

    Göran Pilbratt

    ESA Herschel Project Scientist

    Tel: +31 71 565 3621

    Email: gpilbratt@cosmos.esa.int

    1
    Proto-cluster candidates

    By combining observations of the distant Universe made with ESA’s Herschel and Planck space observatories, cosmologists have discovered what could be the precursors of the vast clusters of galaxies that we see today.

    ESA Herschel
    Herschel

    ESA Planck
    Planck

    Galaxies like our Milky Way with its 100 billion stars are usually not found in isolation. In the Universe today, 13.8 billion years after the Big Bang, many are in dense clusters of tens, hundreds or even thousands of galaxies.

    However, these clusters have not always existed, and a key question in modern cosmology is how such massive structures assembled in the early Universe.

    Pinpointing when and how they formed should provide insight into the process of galaxy cluster evolution, including the role played by dark matter in shaping these cosmic metropolises.

    Now, using the combined strengths of Herschel and Planck, astronomers have found objects in the distant Universe, seen at a time when it was only three billion years old, which could be precursors of the clusters seen around us today.

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    The history of the Universe

    Planck’s main goal was to provide the most precise map of the relic radiation of the Big Bang, the cosmic microwave background [CMB].

    Cosmic Microwave Background  Planck
    CMB per Planck

    To do so, it surveyed the entire sky in nine different wavelengths from the far-infrared to radio, in order to eliminate foreground emission from our galaxy and others in the Universe.

    But those foreground sources can be important in other fields of astronomy, and it was in Planck’s short wavelength data that scientists were able to identify 234 bright sources with characteristics that suggested they were located in the distant, early Universe.

    Herschel then observed these objects across the far-infrared to submillimetre wavelength range, but with much higher sensitivity and angular resolution.

    Herschel revealed that the vast majority of the Planck-detected sources are consistent with dense concentrations of galaxies in the early Universe, vigorously forming new stars.

    Each of these young galaxies is seen to be converting gas and dust into stars at a rate of a few hundred to 1500 times the mass of our Sun per year. By comparison, our own Milky Way galaxy today is producing stars at an average rate of just one solar mass per year.

    While the astronomers have not yet conclusively established the ages and luminosities of many of these newly discovered distant galaxy concentrations, they are the best candidates yet found for ‘proto-clusters’ – precursors of the large, mature galaxy clusters we see in the Universe today.

    “Hints of these kinds of objects had been found earlier in data from Herschel and other telescopes, but the all-sky capability of Planck revealed many more candidates for us to study,” says Hervé Dole of the Institut d’Astrophysique Spatiale, Orsay, lead scientist of the analysis published today in Astronomy & Astrophysics.

    “We still have a lot to learn about this new population, requiring further follow-up studies with other observatories. But we believe that they are a missing piece of cosmological structure formation.”

    “We are now preparing an extended catalogue of possible proto-clusters detected by Planck, which should help us identify even more of these objects,” adds Ludovic Montier, a CNRS researcher at the Institut de Recherche en Astrophysique et Planétologie, Toulouse, who is the lead scientist of the Planck catalogue of high-redshift source candidates, which is about to be delivered to the community.

    “This exciting result was possible thanks to the synergy between Herschel and Planck: rare objects could be identified from the Planck data covering the entire sky, and then Herschel was able to scrutinise them in finer detail,” says ESA’s Herschel Project Scientist, Göran Pilbratt.

    “Both space observatories completed their science observations in 2013, but their rich datasets will be exploited for plentiful new insights about the cosmos for years to come.”

    Notes for Editors

    High-redshift infrared galaxy overdensity candidates and lensed sources discovered by Planck and confirmed by Herschel-SPIRE, is authored by the Planck Collaboration.

    Planck detected the sky at nine frequencies, from 30 GHz to 857 GHz. The Planck frequencies used to detect the candidate proto-clusters in this study were 857 GHz, 545 GHz and 353 GHz. The follow-up observations made by Herschel’s SPIRE instrument were at 250, 350 and 500 microns. The SPIRE 350 micron and 500 micron bands overlap with Planck’s High Frequency Instrument (HFI) at 857 GHz and 545 GHz.

    ESA Herschel SPIRE
    SPIRE on Herschel

    The Planck Scientific Collaboration consists of all the scientists who have contributed to the development of the mission, and who participate in the scientific exploitation of the data during the proprietary period. These scientists are members of one or more of four consortia: the LFI Consortium, the HFI Consortium, the DK-Planck Consortium and ESA’s Planck Science Office. The two European-led Planck Data Processing Centres are located in Paris, France and Trieste, Italy. The LFI consortium is led by N. Mandolesi, ASI, Italy (deputy PI: M. Bersanelli, Universita’ degli Studi di Milano, Italy), and was responsible for the development and operation of LFI. The HFI consortium is led by J.L. Puget, Institut d’Astrophysique Spatiale in Orsay, France (deputy PI: F. Bouchet, Institut d’Astrophysique de Paris, France), and was responsible for the development and operation of HFI.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 8:31 pm on February 6, 2015 Permalink | Reply
    Tags: , , ESA Planck   

    From Space.com: “Gallery: Planck Spacecraft Sees Big Bang Relics” 

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    SPACE.com

    ESA’s Planck Spacecraft
    1
    Credit: ESA – C. Carreau
    The European Space Agency’s Planck observatory peered back into the universe’s history to study the cosmic microwave background, the oldest light in the universe. See images from Planck’s prolific mission in this Space.com gallery. Here: An artist’s view of Planck with the cosmic microwave background as a backdrop.

    Milky Way Galaxy in Microwaves
    temp0
    Credit: ESA/NASA/JPL-Caltech
    A view of the Milky Way galaxy in microwaves, captured by the European Space Agency’s Planck satellite. The different colors correspond to different elements, including gas, dust, and energetic particles.

    Milky Way Dust – Planck Map
    3
    Credit: ESA/NASA/JPL-Caltech
    This map of the Milky Way shows the distribution of interstellar dust across the galaxy as seen by the Planck space observatory, a mission by the European Space Agency. ESA and NASA unveiled the image on Feb. 5, 2015.

    A View of the Milky Way in Microwaves
    4
    Credit: ESA/NASA/JPL-Caltech
    Each of the four bottom) show a specific subset of Planck observations that make up the combined view (top). Of the subsets, they show: Top left is dust, top right is gas, bottom right is light from charged particle interactions, and bottom right shows charged particles moving along the galaxy’s magnetic field.

    All the Matter in the Universe by Planck
    5
    Credit: ESA/NASA/JPL-Caltech
    All of the matter between Earth and the edge of the observable universe is shown in this image based on data from the European Space Agency’s Planck space observatory. This map was released on Feb. 5, 2015.

    Planck’s All-Sky Map: Cosmic Microwave Background
    6
    Credit: ESA and the Planck Collaboration
    This image unveiled March 21, 2013, shows the cosmic microwave background (CMB) as observed by the European Space Agency’s Planck space observatory. The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380 000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.

    Planck’s Ingredients of the Universe
    7
    Credit: ESA and the Planck Collaboration
    This European Space Agency graphic depicts the most refined values yet of the Universe’s ingredients, based on the first all-sky map of the cosmic microwave background by the Planck space observatory unveiled on March 21, 2013. Normal matter that makes up stars and galaxies contributes 4.9 percent of the Universe’s mass/energy inventory. Dark matter occupies 26.8 percent, while dark energy accounts for 68.3 percent.

    Planck’s All-Sky Map: Cosmic Microwave Background Anomalies
    8
    Credit: ESA and the Planck Collaboration
    Two Cosmic Microwave Background anomalies hinted at by the Planck observatory’s predecessor, NASA’s WMAP, are confirmed in new high-precision data revealed on March 21, 2013. In this image, the two anomalous regions have been enhanced with red and blue shading to make them more clearly visible.

    Planck’s All-Sky Map vs. Standard Model
    9
    This European Space Agency graphic shows a map of the universe that depicts the anomalies seen when comparing the Planck space observatory’s map of the universe’s cosmic microwave background and the standard model of the cosmos. Image released March 21, 2013.

    Planck All-Sky Image of Carbon Monoxide
    10
    Credit: ESA/Planck Collaboration
    This all-sky image shows the distribution of carbon monoxide (CO), a molecule used by astronomers to trace molecular clouds across the sky, as seen by Planck. Image released February 13, 2012.

    Galactic Haze Seen by Planck and Galactic ‘Bubbles’ Seen by Fermi
    11
    Credit: ESA/Planck Collaboration (microwave); NASA/DOE/Fermi LAT/D. Finkbeiner et al. (gamma rays)
    This all-sky image shows the distribution of the galactic haze seen by ESA’s Planck mission at microwave frequencies…

    Galactic Haze Seen by Planck
    12
    Credit: ESA/Planck Collaboration
    his all-sky image shows the spatial distribution over the whole sky of the galactic haze at 30 and 44 GHz, extracted from the Planck observations. Image released February 13, 2012.

    Planck All-Sky Image Superimposition
    13
    Credit: ESA/Planck Collaboration; T. Dame et al.
    This all-sky image shows the distribution of carbon monoxide (CO), a molecule used by astronomers to trace molecular clouds across the sky, as seen by Planck (blue). A compilation of previous surveys (Dame et al. (2001)), which left large areas of the sky unobserved, has been superimposed for comparison (red). The outlines identify the portions of the sky covered by these surveys. Image released February 13, 2012.

    Cepheus Molecular Cloud Complex
    14
    Credit: ESA/Planck Collaboration; T. Dame et al., 2001
    This image shows the Cepheus molecular cloud complex as seen through the glow of carbon monoxide (CO) with Planck (blue). The same region is shown as imaged by previous CO surveys (Dame et al., 2001) for comparison (red). Image released February 13, 2012.

    All-Sky Distribution of Carbon Monoxide
    15
    Credit: ESA/Planck Collaboration
    This all-sky image shows the distribution of carbon monoxide (CO), a molecule used by astronomers to trace molecular clouds across the sky, as seen by Planck. The inserts provide a zoomed-in view onto three individual regions on the sky where Planck has detected concentrations of CO: Cepheus, Taurus and Pegasus, respectively. Image released February 13, 2012.

    All-sky Distribution of Carbon Monoxide (CO).
    16
    Credit: ESA/Planck Collaboration; T. Dame et al., 2001
    This all-sky image shows the distribution of carbon monoxide (CO), a molecule used by astronomers to trace molecular clouds across the sky, as seen by Planck (blue). A compilation of previous surveys (Dame et al. (2001)), which left large areas of the sky unobserved, is shown for comparison (red). Image released February 13, 2012.

    Taurus Molecular Cloud Complex
    17
    Credit: ESA/Planck Collaboration; T. Dame et al., 2001
    This image shows the Taurus molecular cloud complex as seen through the glow of carbon monoxide (CO) with Planck (blue). The same region is shown as imaged by previous CO surveys (Dame et al., 2001) for comparison (red). Image released February 13, 2012.

    Molecular Clouds in the Pegasus Region
    18
    Credit: ESA/Planck Collaboration
    This image shows molecular clouds in the Pegasus region as seen through the glow of carbon monoxide (CO) with Planck (blue). Image released February 13, 2012.

    Planck’s Microwave Sky
    19
    Credit: ESA/ LFI & HFI Consortia
    This multi-frequency all-sky image of the microwave sky has been composed using data from Planck covering the electromagnetic spectrum from 30 GHz to 857 GHz. This image was released on July 5, 2010. The mottled structure of the cosmic microwave background, with its tiny temperature fluctuations reflecting the primordial density variations from which today’s cosmic structure originated, is clearly visible in the high-latitude regions of the map. The central band is the plane of our Galaxy. A large portion of the image is dominated by the diffuse emission from its gas and dust. The image was derived from data collected by Planck during its first all-sky survey and comes from observations taken between August 2009 and June 2010. This image is a low- resolution version of the full data set.

    Planck’s Orbit at L2
    20
    Credit: ESA
    Planck’s orbit around L2, the second Lagrange point of the Sun-Earth system.

    Sky Tapestry by Planck Spacecraft
    21
    Credit: ESA and the HFI Consortium, IRAS
    The image spans about 50 degrees of the sky. It is a three-colour combination constructed from Planck’s two highest frequency channels (557 and 857 GHz, corresponding to wavelengths of 540 and 350 micrometres), and an image at the shorter wavelength of 100 micrometres made by the IRAS satellite. It was released on March 17, 2010.

    Planck’s View of Orion Nebula (Close-Up)
    27
    Credit: ESA/LFI & HFI Consortia
    An active star-formation region in the Orion Nebula, as seen By Planck. This image covers a region of 13×13 degrees. It is a three-colour combination constructed from three of Planck’s nine frequency channels: 30, 353 and 857 GHz. This image was released on April 26, 2010.

    New Sky Map Could Help Reveal How Universe Formed
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    Credit: ESA/ LFI & HFI Consortia
    The microwave sky as seen by ESA’s Planck satellite. Light from the main disk of the Milky Way is seen across the center band, while radiation left over from the Big Bang is visible on the outskirts of the image.

    Planck View of Milky Way – Jan. 11, 2011
    29
    Credit: ESA/Planck Collaboration
    This image shows the location of the first six fields used to detect and study the Cosmic Infrared Background. The fields, named N1, AG, SP, LH2, Boötes 1 and Boötes 2, respectively, are all located at a relatively high galactic latitude, where the foreground contamination due to the Milky Way’s diffuse emission is less dramatic. It was released on Jan. 11, 2011.

    Clumps of Star-forming Cores Across the Sky
    30
    Credit: ESA/NASA/JPL-Caltech
    This map illustrates the numerous star-forming clouds, called cold cores, that Planck observed throughout our Milky Way galaxy. Planck, a European Space Agency mission with significant NASA participation, detected around 10,000 of these cores, thousands of which had never been seen before.

    32
    Credit: ESA/LFI & HFI Consortia
    Star-formation Region in the Constellation Perseus

    See the full article here.

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  • richardmitnick 1:11 pm on February 5, 2015 Permalink | Reply
    Tags: , , , ESA Planck   

    From ESA: “Planck reveals first stars were born late” 

    ESASpaceForEuropeBanner
    European Space Agency

    5 February 2015
    Markus Bauer
    ESA Science and Robotic Exploration Communication Officer
    Tel: +31 71 565 6799; +34 91 8131 199
    Mob: +31 61 594 3954
    Email: Markus.Bauer@esa.int

    Jan Tauber
    ESA Planck Project Scientist
    Tel: +31 71 565 5342
    Email: Jan.Tauber@esa.int

    François Bouchet
    Institut d’Astrophysique de Paris (CNRS/UPMC), France
    Tel: +33 1 4432 8095
    Email: bouchet@iap.fr

    Marco Bersanelli
    Università degli Studi di Milano, Italy
    Tel: +39 02 50317264
    Email: marco.bersanelli@mi.infn.it

    George Efstathiou
    University of Cambridge, UK
    Tel: +44 1223 337530
    Email: gpe@ast.cam.ac.uk

    1
    Polarisation of the Cosmic Microwave Background

    5 February 2015

    New maps from ESA’s Planck satellite uncover the ‘polarised’ light from the early Universe across the entire sky, revealing that the first stars formed much later than previously thought.

    The history of our Universe is a 13.8 billion-year tale that scientists endeavour to read by studying the planets, asteroids, comets and other objects in our Solar System, and gathering light emitted by distant stars, galaxies and the matter spread between them.

    A major source of information used to piece together this story is the Cosmic Microwave Background, or CMB, the fossil light resulting from a time when the Universe was hot and dense, only 380 000 years after the Big Bang.

    Thanks to the expansion of the Universe, we see this light today covering the whole sky at microwave wavelengths.

    Between 2009 and 2013, Planck surveyed the sky to study this ancient light in unprecedented detail. Tiny differences in the background’s temperature trace regions of slightly different density in the early cosmos, representing the seeds of all future structure, the stars and galaxies of today.

    Scientists from the Planck collaboration have published the results from the analysis of these data in a large number of scientific papers over the past two years, confirming the standard cosmological picture of our Universe with ever greater accuracy.

    “But there is more: the CMB carries additional clues about our cosmic history that are encoded in its ‘polarisation’,” explains Jan Tauber, ESA’s Planck project scientist.

    “Planck has measured this signal for the first time at high resolution over the entire sky, producing the unique maps released today.”

    2
    History of the Universe

    Light is polarised when it vibrates in a preferred direction, something that may arise as a result of photons – the particles of light – bouncing off other particles. This is exactly what happened when the CMB originated in the early Universe.

    Initially, photons were trapped in a hot, dense soup of particles that, by the time the Universe was a few seconds old, consisted mainly of electrons, protons and neutrinos. Owing to the high density, electrons and photons collided with one another so frequently that light could not travel any significant distant before bumping into another electron, making the early Universe extremely ‘foggy’.

    Slowly but surely, as the cosmos expanded and cooled, photons and the other particles grew farther apart, and collisions became less frequent.

    This had two consequences: electrons and protons could finally combine and form neutral atoms without them being torn apart again by an incoming photon, and photons had enough room to travel, being no longer trapped in the cosmic fog.

    3
    CMB polarisation: full sky and details

    Once freed from the fog, the light was set on its cosmic journey that would take it all the way to the present day, where telescopes like Planck detect it as the CMB. But the light also retains a memory of its last encounter with the electrons, captured in its polarisation.

    “The polarisation of the CMB also shows minuscule fluctuations from one place to another across the sky: like the temperature fluctuations, these reflect the state of the cosmos at the time when light and matter parted company,” says François Bouchet of the Institut d’Astrophysique de Paris, France.

    “This provides a powerful tool to estimate in a new and independent way parameters such as the age of the Universe, its rate of expansion and its essential composition of normal matter, dark matter and dark energy.”

    Planck’s polarisation data confirm the details of the standard cosmological picture determined from its measurement of the CMB temperature fluctuations, but add an important new answer to a fundamental question: when were the first stars born?

    4
    CMB polarisation: zoom

    “After the CMB was released, the Universe was still very different from the one we live in today, and it took a long time until the first stars were able to form,” explains Marco Bersanelli of Università degli Studi di Milano, Italy.

    “Planck’s observations of the CMB polarisation now tell us that these ‘Dark Ages’ ended some 550 million years after the Big Bang – more than 100 million years later than previously thought.

    “While these 100 million years may seem negligible compared to the Universe’s age of almost 14 billion years, they make a significant difference when it comes to the formation of the first stars.”

    The Dark Ages ended as the first stars began to shine. And as their light interacted with gas in the Universe, more and more of the atoms were turned back into their constituent particles: electrons and protons.

    This key phase in the history of the cosmos is known as the ‘epoch of reionisation’.

    5
    CMB polarisation: finer detail

    The newly liberated electrons were once again able to collide with the light from the CMB, albeit much less frequently now that the Universe had significantly expanded. Nevertheless, just as they had 380 000 years after the Big Bang, these encounters between electrons and photons left a tell-tale imprint on the polarisation of the CMB.

    “From our measurements of the most distant galaxies and quasars, we know that the process of reionisation was complete by the time that the Universe was about 900 million years old,” says George Efstathiou of the University of Cambridge, UK.

    “But, at the moment, it is only with the CMB data that we can learn when this process began.”

    Planck’s new results are critical, because previous studies of the CMB polarisation seemed to point towards an earlier dawn of the first stars, placing the beginning of reionisation about 450 million years after the Big Bang.

    This posed a problem. Very deep images of the sky from the NASA–ESA Hubble Space Telescope have provided a census of the earliest known galaxies in the Universe, which started forming perhaps 300–400 million years after the Big Bang.

    However, these would not have been powerful enough to succeed at ending the Dark Ages within 450 million years.

    “In that case, we would have needed additional, more exotic sources of energy to explain the history of reionisation,” says Professor Efstathiou.

    The new evidence from Planck significantly reduces the problem, indicating that reionisation started later than previously believed, and that the earliest stars and galaxies alone might have been enough to drive it.

    This later end of the Dark Ages also implies that it might be easier to detect the very first generation of galaxies with the next generation of observatories, including the James Webb Space Telescope.

    NASA Webb Telescope
    NASA/Webb

    6
    Galactic dust

    But the first stars are definitely not the limit. With the new Planck data released today, scientists are also studying the polarisation of foreground emission from gas and dust in the Milky Way to analyse the structure of the Galactic magnetic field.

    The data have also enabled new important insights into the early cosmos and its components, including the intriguing dark matter and the elusive neutrinos, as described in papers also released today.

    The Planck data have delved into the even earlier history of the cosmos, all the way to inflation – the brief era of accelerated expansion that the Universe underwent when it was a tiny fraction of a second old. As the ultimate probe of this epoch, astronomers are looking for a signature of gravitational waves triggered by inflation and later imprinted on the polarisation of the CMB.

    No direct detection of this signal has yet been achieved, as reported last week. However, when combining the newest all-sky Planck data with those latest results, the limits on the amount of primordial gravitational waves are pushed even further down to achieve the best upper limits yet.

    “These are only a few highlights from the scrutiny of Planck’s observations of the CMB polarisation, which is revealing the sky and the Universe in a brand new way,” says Jan Tauber.

    “This is an incredibly rich data set and the harvest of discoveries has just begun.”

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 1:52 pm on January 30, 2015 Permalink | Reply
    Tags: , , ESA Planck, keck Array South Pole   

    From ESA- “Planck: gravitational waves remain elusive” 

    ESASpaceForEuropeBanner
    European Space Agency

    30 January 2015
    Markus Bauer
    ESA Science and Robotic Exploration Communication Officer
    Tel: +31-71-565-6799
    Mob: +31-61-594-3-954
    Email: Markus.Bauer@esa.int

    Jan Tauber
    ESA Planck Project Scientist
    Tel: +31-71-565-5342
    Email: Jan.Tauber@esa.int

    1
    Planck view of BICEP2 field

    Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves.

    ESA Planck
    ESA/Planck

    BICEP 2
    BICEP2

    Keck Array
    Keck Array

    The Universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today.

    An extraordinary source of information about the Universe’s history is the Cosmic Microwave Background, or CMB, the legacy of light emitted only 380 000 years after the Big Bang.

    Cosmic Background Radiation Planck
    CMB per Planck

    ESA’s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early Universe has already been revealed over the past two years.

    But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic ‘inflation’ – a very brief accelerated expansion that, according to current theory, the Universe experienced when it was only the tiniest fraction of a second old.

    This signature would be seeded by gravitational waves, tiny perturbations in the fabric of space-time, that astronomers believe would have been generated during the inflationary phase.

    Gravitational Wave Background
    Theorized gravitational wave pattern

    Interestingly, these perturbations should leave an imprint on another feature of the cosmic background: its polarisation.

    When light waves vibrate preferentially in a certain direction, we say the light is polarised.

    The CMB is polarised, exhibiting a complex arrangement across the sky. This arises from the combination of two basic patterns: circular and radial (known as E-modes), and curly (B-modes).

    Different phenomena in the Universe produce either E- or B-modes on different angular scales and identifying the various contributions requires extremely precise measurements. It is the B-modes that could hold the prize of probing the Universe’s early inflation.

    “Searching for this unique record of the very early Universe is as difficult as it is exciting, since this subtle signal is hidden in the polarisation of the CMB, which itself only represents only a feeble few percent of the total light,” says Jan Tauber, ESA’s project scientist for Planck.

    Planck is not alone in this search. In early 2014, another team of astronomers presented results based on observations of the polarised CMB on a small patch of the sky performed 2010–12 with BICEP2, an experiment located at the South Pole. The team also used preliminary data from another South Pole experiment, the Keck Array.

    They found something new: curly B-modes in the polarisation observed over stretches of the sky a few times larger than the size of the full Moon.

    The BICEP2 team presented evidence favouring the interpretation that this signal originated in primordial gravitational waves, sparking an enormous response in the academic community and general public.

    However, there is another contender in this game that can produce a similar effect: interstellar dust in our Galaxy, the Milky Way.

    3
    Planck view of Galactic dust

    The Milky Way is pervaded by a mixture of gas and dust shining at similar frequencies to those of the CMB, and this foreground emission affects the observation of the most ancient cosmic light. Very careful analysis is needed to separate the foreground emission from the cosmic background.

    Critically, interstellar dust also emits polarised light, thus affecting the CMB polarisation as well.

    “When we first detected this signal in our data, we relied on models for Galactic dust emission that were available at the time,” says John Kovac, a principal investigator of BICEP2 at Harvard University, in the USA.

    “These seemed to indicate that the region of the sky chosen for our observations had dust polarisation much lower than the detected signal.”

    The two ground-based experiments collected data at a single microwave frequency, making it difficult to separate the emissions coming from the Milky Way and the background.

    On the other hand, Planck observed the sky in nine microwave and sub-millimetre frequency channels, seven of which were also equipped with polarisation-sensitive detectors. By careful analysis, these multi-frequency data can be used to separate the various contributions.

    The BICEP2 team had chosen a field where they believed dust emission would be low, and thus interpreted the signal as likely to be cosmological.

    However, as soon as Planck’s maps of the polarised emission from Galactic dust were released, it was clear that this foreground contribution could be much higher than previously expected.

    In fact, in September 2014, Planck revealed for the first time that the polarised emission from dust is significant over the entire sky, and comparable to the signal detected by BICEP2 even in the cleanest regions.

    So, the Planck and BICEP2 teams joined forces, combining the satellite’s ability to deal with foregrounds using observations at several frequencies – including those where dust emission is strongest – with the greater sensitivity of the ground-based experiments over limited areas of the sky, thanks to their more recent, improved technology. By then, the full Keck Array data from 2012 and 2013 had also become available.

    “This joint work has shown that the detection of primordial B-modes is no longer robust once the emission from Galactic dust is removed,” says Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d’Astrophysique Spatiale in Orsay, France.

    “So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation.”

    Deflecting light from the Big Bang

    Another source of B-mode polarisation, dating back to the early Universe, was detected in this study, but on much smaller scales on the sky.

    This signal, first discovered in 2013, is not a direct probe of the inflationary phase but is induced by the cosmic web of massive structures that populate the Universe and change the path of the CMB photons on their way to us.

    This effect is called ‘gravitational lensing’, since it is caused by massive objects bending the surrounding space and thus deflecting the trajectory of light much like a magnifying glass does. The detection of this signal using Planck, BICEP2 and the Keck Array together is the strongest yet.

    As for signs of the inflationary period, the question remains open.

    “While we haven’t found strong evidence of a signal from primordial gravitational waves in the best observations of CMB polarisation that are currently available, this by no means rules out inflation,” says Reno Mandolesi, principal investigator of the LFI instrument on Planck at University of Ferrara, Italy.

    In fact, the joint study sets an upper limit on the amount of gravitational waves from inflation, which might have been generated at the time but at a level too low to be confirmed by the present analysis.

    “This analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal,” says Clem Pryke, a principal investigator of BICEP2 at University of Minnesota, in the USA.

    “The new upper limit on the signal due to gravitational waves agrees well with the upper limit that we obtained earlier with Planck using the temperature fluctuations of the CMB,” says Brendan Crill, a leading member of both the Planck and BICEP2 teams from NASA’s Jet Propulsion Laboratory in the USA.

    “The gravitational wave signal could still be there, and the search is definitely on.”

    “A Joint Analysis of BICEP2/Keck Array and Planck Data” by the BICEP2/Keck and Planck collaboration has been submitted to the journal Physical Review Letters.
    The study combines data from ESA’s Planck satellite and from the US National Science Foundation ground-based experiments BICEP2 and the Keck Array, at the South Pole.

    The analysis is based on observations of the CMB polarisation on a 400 square degree patch of the sky. The Planck data cover frequencies between 30 GHz and 353 GHz, while the BICEP2 and Keck Array data were taken at a frequency of 150 GHz.

    A public release of Planck data products will follow next week.

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 1:13 pm on January 18, 2015 Permalink | Reply
    Tags: , , , ESA Planck   

    From ESA: “The magnetic field along the Galactic plane” 

    ESASpaceForEuropeBanner
    European Space Agency

    15/12/2014
    No Writer Credit

    1

    While the pastel tones and fine texture of this image may bring to mind brush strokes on an artist’s canvas, they are in fact a visualisation of data from ESA’s Planck satellite. The image portrays the interaction between interstellar dust in the Milky Way and the structure of our Galaxy’s magnetic field.

    ESA Planck
    Planck

    Between 2009 and 2013, Planck scanned the sky to detect the most ancient light in the history of the Universe – the cosmic microwave background. It also detected significant foreground emission from diffuse material in our Galaxy which, although a nuisance for cosmological studies, is extremely important for studying the birth of stars and other phenomena in the Milky Way.

    Cosmic Background Radiation Planck
    CMB per Planck

    Among the foreground sources at the wavelengths probed by Planck is cosmic dust, a minor but crucial component of the interstellar medium that pervades the Galaxy. Mainly gas, it is the raw material for stars to form.

    Interstellar clouds of gas and dust are also threaded by the Galaxy’s magnetic field, and dust grains tend to align their longest axis at right angles to the direction of the field. As a result, the light emitted by dust grains is partly ‘polarised’ – it vibrates in a preferred direction – and, as such, could be caught by the polarisation-sensitive detectors on Planck.

    Scientists in the Planck collaboration are using the polarised emission of interstellar dust to reconstruct the Galaxy’s magnetic field and study its role in the build-up of structure in the Milky Way, leading to star formation.

    In this image, the colour scale represents the total intensity of dust emission, revealing the structure of interstellar clouds in the Milky Way. The texture is based on measurements of the direction of the polarised light emitted by the dust, which in turn indicates the orientation of the magnetic field.

    This image shows the intricate link between the magnetic field and the structure of the interstellar medium along the plane of the Milky Way. In particular, the arrangement of the magnetic field is more ordered along the Galactic plane, where it follows the spiral structure of the Milky Way. Small clouds are seen just above and below the plane, where the magnetic field structure becomes less regular.

    From these and other similar observations, Planck scientists found that filamentary interstellar clouds are preferentially aligned with the direction of the ambient magnetic field, highlighting the strong role played by magnetism in galaxy evolution.

    The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 3:32 pm on December 15, 2014 Permalink | Reply
    Tags: , , , , , ESA Planck   

    From ESA: “The magnetic field along the Galactic plane” 

    ESASpaceForEuropeBanner
    European Space Agency

    15/12/2014

    ESA/Planck Collaboration

    i

    While the pastel tones and fine texture of this image may bring to mind brush strokes on an artist’s canvas, they are in fact a visualisation of data from ESA’s Planck satellite.

    ESA Planck
    ESA Planck schematic
    ESA/Planck

    The image portrays the interaction between interstellar dust in the Milky Way and the structure of our Galaxy’s magnetic field.

    Between 2009 and 2013, Planck scanned the sky to detect the most ancient light in the history of the Universe – the cosmic microwave background. It also detected significant foreground emission from diffuse material in our Galaxy which, although a nuisance for cosmological studies, is extremely important for studying the birth of stars and other phenomena in the Milky Way.

    Cosmic Microwave Background  Planck
    CMB per ESA/Planck

    Among the foreground sources at the wavelengths probed by Planck is cosmic dust, a minor but crucial component of the interstellar medium that pervades the Galaxy. Mainly gas, it is the raw material for stars to form.

    Interstellar clouds of gas and dust are also threaded by the Galaxy’s magnetic field, and dust grains tend to align their longest axis at right angles to the direction of the field. As a result, the light emitted by dust grains is partly ‘polarised’ – it vibrates in a preferred direction – and, as such, could be caught by the polarisation-sensitive detectors on Planck.

    Scientists in the Planck collaboration are using the polarised emission of interstellar dust to reconstruct the Galaxy’s magnetic field and study its role in the build-up of structure in the Milky Way, leading to star formation.

    In this image, the colour scale represents the total intensity of dust emission, revealing the structure of interstellar clouds in the Milky Way. The texture is based on measurements of the direction of the polarised light emitted by the dust, which in turn indicates the orientation of the magnetic field.

    This image shows the intricate link between the magnetic field and the structure of the interstellar medium along the plane of the Milky Way. In particular, the arrangement of the magnetic field is more ordered along the Galactic plane, where it follows the spiral structure of the Milky Way. Small clouds are seen just above and below the plane, where the magnetic field structure becomes less regular.

    From these and other similar observations, Planck scientists found that filamentary interstellar clouds are preferentially aligned with the direction of the ambient magnetic field, highlighting the strong role played by magnetism in galaxy evolution.

    The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz.

    Acknowledgment: M.-A. Miville-Deschênes, >CNRS – Institut d’Astrophysique Spatiale, Université Paris-XI, Orsay, France

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 12:25 pm on December 5, 2014 Permalink | Reply
    Tags: , , , , , , , ESA Planck,   

    From physicsworld: “Planck offers another glimpse of the early universe” 

    physicsworld
    physicsworld.com

    Dec 4, 2014
    Tushna Commissariat

    Results of four years of observations made by the Planck space telescope provide the most precise confirmation so far of the Standard Model of cosmology, and also place new constraints on the properties of potential dark-matter candidates. That is the conclusion of astronomers working on the €700m mission of the European Space Agency (ESA). Planck studies the intensity and the polarization of the cosmic microwave background (CMB), which is the thermal remnant of the Big Bang. These latest results will no doubt frustrate cosmologists, because Planck has so far failed to shed much light on some of the biggest mysteries of physics, including what constitutes the dark matter and dark energy that appears to dominate the universe.

    e
    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe)

    ESA Planck
    ESA Planck schematic
    ESA/Planck

    Cosmic Background Radiation Planck
    Cosmic Background Radiation per Planck

    WMAP
    NASA/WMAP spacecraft

    Cosmic Background Radiation per WMAP
    Cosmic Background Radiation per WMAP

    Planck ran from 2009–2013, and the first data were released in March last year, comprising temperature data taken during the first 15 months of observations. A more complete data set from Planck will be published later this month, and is being previewed this week at a conference in Ferrara, Italy (Planck 2014 – The microwave sky in temperature and polarization). So far, Planck scientists have revealed that a previous disagreement of 1–1.5% between Planck and its predecessor – NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) – regarding the mission’s “absolute-temperature” measurements has been reduced to 0.3%.

    Winnowing dark matter

    Planck’s latest measurement of the CMB polarization rules out a class of dark-matter models involving particle annihilation in the early universe. These models were developed to explain excesses of cosmic-ray positrons that have been measured by three independent experiments – the PAMELA mission, the Alpha Magnetic Spectrometer and the Fermi Gamma-Ray Space Telescope.

    INFN PAMELA spacecraft
    PAMELA

    AMS-02
    AMS-02

    NASA Fermi Telescope
    NASA/Fermi

    The Planck collaboration also revealed that it has, for the first time, “detected unambiguously” traces left behind by primordial neutrinos on the CMB. Such neutrinos are thought to have been released one second after the Big Bang, when the universe was still opaque to light but already transparent to these elusive particles. Planck has set an upper limit (0.23 eV/c2) on the sum of the masses of the three types of neutrinos known to exist. Furthermore, the new data exclude the existence of a fourth type of neutrino that is favoured by some models.

    Planck versus BICEP2

    Despite the new data, the collaboration did not give any insights into the recent controversy surrounding the possible detection of primordial “B-mode” polarization of the CMB by astronomers working on the BICEP2 telescope.

    BICEP 2
    BICEP 2 interior
    BICEP 2 with South Pole Telescope

    If verified, the BICEP2 observation would be “smoking-gun” evidence for the rapid “inflation” of the early universe – the extremely rapid expansion that cosmologists believe the universe underwent a mere 10–35 s after the Big Bang. A new analysis of polarized dust emission in our galaxy, carried out by Planck earlier in September, showed that the part of the sky observed by BICEP2 has much more dust than originally anticipated, and while this did not completely rule out BICEP2’s original claim, it established that the dust emission is nearly as big as the entire BICEP2 signal. Both Planck and BICEP2 have since been working together on joint analysis of their data, but a result is still forthcoming.

    [THIS IS THE BEST WE CAN DO UNTIL ESA RELEASES THEIR LATEST FINDINGS FROM PLANCK]

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
    IOP Institute of Physics

     
  • richardmitnick 2:02 pm on September 22, 2014 Permalink | Reply
    Tags: , , , , , , ESA Planck,   

    From Symmetry: “Cosmic dust proves prevalent” 

    Symmetry

    September 22, 2014
    Kathryn Jepsen

    Space dust accounts for at least some of the possible signal of cosmic inflation the BICEP2 experiment announced in March. How much remains to be seen.

    Space is full of dust, according to a new analysis from the European Space Agency’s Planck experiment.

    planck

    That includes the area of space studied by the BICEP2 experiment, which in March announced seeing a faint pattern left over from the big bang that could tell us about the first moments after the birth of the universe.

    gwb
    Gravitational Wave Background from BICEP2

    The Planck analysis, which started before March, was not meant as a direct check of the BICEP2 result. It does, however, reveal that the level of dust in the area BICEP2 scientists studied is both significant and higher than they thought.

    “There is still a wide range of possibilities left open,” writes astronomer Jan Tauber, ESA project scientist for Planck, in an email. “It could be that all of the signal is due to dust; but part of the signal could certainly be due to primordial gravitational waves.”

    BICEP2 scientists study the cosmic microwave background, a uniform bath of radiation permeating the universe that formed when the universe first cooled enough after the big bang to be transparent to light. BICEP2 scientists found a pattern within the cosmic microwave background, one that would indicate that not long after the big bang, the universe went through a period of exponential expansion called cosmic inflation. The BICEP2 result was announced as the first direct evidence of this process.

    The problem is that the same pattern, called B-mode polarization, also appears in space dust. The BICEP2 team subtracted the then known influence of the dust from their result. But based on today’s Planck result, they didn’t manage to scrub all of it.

    How much the dust influenced the BICEP2 result remains to be seen.

    In November, Planck scientists will release their own analysis of B-mode polarization in the cosmic microwave background, in addition to a joint analysis with BICEP2 specifically intended to check the BICEP2 result. These results could answer the question of whether BICEP2 really saw evidence of cosmic inflation.

    “While we can say the dust level is significant,” writes BICEP2 co-leader Jamie Bock of Caltech and NASA’s Jet Propulsion Laboratory, “we really need to wait for the joint BICEP2-Planck paper that is coming out in the fall to get the full answer.”

    [Me? I am rooting for my homey, Alan Guth, from Highland Park, NJ, USA]

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.


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  • richardmitnick 4:46 am on May 6, 2014 Permalink | Reply
    Tags: , , , , ESA Planck   

    From Planck at ESA: “Planck takes magnetic fingerprint of our Galaxy” 

    ESASpaceForEuropeBanner
    European Space Agency

    ESA Planck
    Planck

    6 May 2014
    Markus Bauer
    ESA Science and Robotic Exploration Communication Officer
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: Markus.Bauer@esa.int

    Jan Tauber
    ESA Planck Project Scientist
    Tel: +31 71 565 5342
    Email: Jan.Tauber@esa.int

    Our Galaxy’s magnetic field is revealed in a new image from ESA’s Planck satellite. This image was compiled from the first all-sky observations of ‘polarised’ light emitted by interstellar dust in the Milky Way.

    Light is a very familiar form of energy and yet some of its properties are all but hidden to everyday human experience. One of these – polarisation – carries a wealth of information about what happened along a light ray’s path, and can be exploited by astronomers.

    Light can be described as a series of waves of electric and magnetic fields that vibrate in directions that are at right angles to each other and to their direction of travel.

    Usually, these fields can vibrate at all orientations. However, if they happen to vibrate preferentially in certain directions, we say the light is ‘polarised’. This can happen, for example, when light bounces off a reflective surface like a mirror or the sea. Special filters can be used to absorb this polarised light, which is how polarised sunglasses eliminate glare.

    In space, the light emitted by stars, gas and dust can also be polarised in various ways. By measuring the amount of polarisation in this light, astronomers can study the physical processes that caused the polarisation.

    In particular, polarisation may reveal the existence and properties of magnetic fields in the medium light has travelled through.

    The map presented here was obtained using detectors on Planck that acted as the astronomical equivalent of polarised sunglasses. Swirls, loops and arches in this new image trace the structure of the magnetic field in our home galaxy, the Milky Way.

    In addition to its hundreds of billions of stars, our Galaxy is filled with a mixture of gas and dust, the raw material from which stars are born. Even though the tiny dust grains are very cold, they do emit light but at very long wavelengths – from the infrared to the microwave domain. If the grains are not symmetrical, more of that light comes out vibrating parallel to the longest axis of the grain, making the light polarised.

    If the orientations of a whole cloud of dust grains were random, no net polarisation would be seen. However, cosmic dust grains are almost always spinning rapidly, tens of millions of times per second, due to collisions with photons and rapidly moving atoms.

    Then, because interstellar clouds in the Milky Way are threaded by magnetic fields, the spinning dust grains become aligned preferentially with their long axis perpendicular to the direction of the magnetic field. As a result, there is a net polarisation in the emitted light, which can then be measured.

    In this way, astronomers can use polarised light from dust grains to study the structure of the Galactic magnetic field and, in particular, the orientation of the field lines projected on the plane of the sky.

    In the new Planck image, darker regions correspond to stronger polarised emission, and the striations indicate the direction of the magnetic field projected on the plane of the sky. Since the magnetic field of the Milky Way has a 3D structure, the net orientation is difficult to interpret if the field lines are highly disorganised along the line of sight, like looking through a tangled ball of string and trying to perceive some net alignment.

    light
    Milky Way’s magnetic fingerprint

    However, the Planck image shows that there is large-scale organisation in some parts of the Galactic magnetic field.

    The dark band running horizontally across the centre corresponds to the Galactic Plane. Here, the polarisation reveals a regular pattern on large angular scales, which is due to the magnetic field lines being predominantly parallel to the plane of the Milky Way.

    The data also reveal variations of the polarisation direction within nearby clouds of gas and dust. This can be seen in the tangled features above and below the plane, where the local magnetic field is particularly disorganised.

    Planck’s Galactic polarisation data are analysed in a series of four papers just submitted to the journal Astronomy & Astrophysics, but studying the magnetic field of the Milky Way is not the only reason why Planck scientists are interested in these data. Hidden behind the foreground emission from our Galaxy is the primordial signal from the Cosmic Microwave Background (CMB), the most ancient light in the Universe.

    Cosmic Background Radiation Planck
    CMB by Planck

    The brightness of the CMB has already been mapped by Planck in unprecedented detail and scientists are now scrutinising the data to measure the polarisation of this light. This is one of the main goals of the Planck mission, because it could provide evidence for gravitational waves
    generated in the Universe immediately after its birth.

    In March 2014, scientists from the BICEP2 collaboration claimed the first detection of such a signal in data collected using a ground-based telescope observing a patch of the sky at a single microwave frequency. Critically, the claim relies on the assumption that foreground polarised emissions are almost negligible in this region.

    BICEP 2
    BICEP2 at South Pole Telescope

    Later this year, scientists from the Planck collaboration will release data based on Planck’s observations of polarised light covering the entire sky at seven different frequencies. The multiple frequency data should allow astronomers to separate with great confidence any possible foreground contamination from the tenuous primordial polarised signal.

    This will enable a much more detailed investigation of the early history of the cosmos, from the accelerated expansion when the Universe was much less than one second old to the period when the first stars were born, several hundred million years later.

    See the full article, with “more information”, here.

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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