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  • richardmitnick 7:49 am on November 19, 2014 Permalink | Reply
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    From ESO: “Spooky Alignment of Quasars Across Billions of Light-years” 


    European Southern Observatory

    19 November 2014
    Contacts

    Damien Hutsemékers
    Institut d’Astrophysique et de Géophysique — Université de Liège
    Liège, Belgium
    Tel: +32 4 366 9760
    Email: hutsemekers@astro.ulg.ac.be

    Dominique Sluse
    Institut d’Astrophysique et de Géophysique — Université de Liège
    Liège, Belgium
    Tel: +32 4 366 9797
    Email: dsluse@ulg.ac.be

    Richard Hook
    ESO education and Public Outreach Department
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    VLT reveals alignments between supermassive black hole axes and large-scale structure

    New observations with ESO’s Very Large Telescope (VLT) in Chile have revealed alignments over the largest structures ever discovered in the Universe. A European research team has found that the rotation axes of the central supermassive black holes in a sample of quasars are parallel to each other over distances of billions of light-years. The team has also found that the rotation axes of these quasars tend to be aligned with the vast structures in the cosmic web in which they reside.

    ESO VLT

    web

    Quasars are galaxies with very active supermassive black holes at their centres. These black holes are surrounded by spinning discs of extremely hot material that is often spewed out in long jets along their axes of rotation. Quasars can shine more brightly than all the stars in the rest of their host galaxies put together.

    A team led by Damien Hutsemékers from the University of Liège in Belgium used the FORS instrument on the VLT to study 93 quasars that were known to form huge groupings spread over billions of light-years, seen at a time when the Universe was about one third of its current age.

    ESO FORS1
    ESO/FORS on the VLT

    “The first odd thing we noticed was that some of the quasars’ rotation axes were aligned with each other — despite the fact that these quasars are separated by billions of light-years,” said Hutsemékers.

    The team then went further and looked to see if the rotation axes were linked, not just to each other, but also to the structure of the Universe on large scales at that time.

    When astronomers look at the distribution of galaxies on scales of billions of light-years they find that they are not evenly distributed. They form a cosmic web of filaments and clumps around huge voids where galaxies are scarce. This intriguing and beautiful arrangement of material is known as large-scale structure.

    The new VLT results indicate that the rotation axes of the quasars tend to be parallel to the large-scale structures in which they find themselves. So, if the quasars are in a long filament then the spins of the central black holes will point along the filament. The researchers estimate that the probability that these alignments are simply the result of chance is less than 1%.

    “A correlation between the orientation of quasars and the structure they belong to is an important prediction of numerical models of evolution of our Universe. Our data provide the first observational confirmation of this effect, on scales much larger that what had been observed to date for normal galaxies,” adds Dominique Sluse of the Argelander-Institut für Astronomie in Bonn, Germany and University of Liège.

    The team could not see the rotation axes or the jets of the quasars directly. Instead they measured the polarisation of the light from each quasar and, for 19 of them, found a significantly polarised signal. The direction of this polarisation, combined with other information, could be used to deduce the angle of the accretion disc and hence the direction of the spin axis of the quasar.

    “The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos,” concludes Dominique Sluse.

    More information

    This research was presented in a paper entitled Alignment of quasar polarizations with large-scale structures, by D. Hutsemékers et al., to appear in the journal Astronomy & Astrophysics on 19 November 2014.

    The team is composed of D. Hutsemékers (Institut d’Astrophysique et de Géophysique, Université de Liège, Liège, Belgium), L. Braibant (Liège), V. Pelgrims (Liège) and D. Sluse (Argelander-Institut für Astronomie, Bonn, Germany; Liège).

    See the full article here.

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  • richardmitnick 7:51 pm on November 9, 2014 Permalink | Reply
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    From ESO: “MUSE Reveals True Story Behind Galactic Crash” Revised 


    European Southern Observatory

    10 November 2014

    The new MUSE instrument on ESO’s Very Large Telescope (VLT) has provided researchers with the best view yet of a spectacular cosmic crash. The new observations reveal for the first time the motion of gas as it is ripped out of the galaxy ESO 137-001 as it ploughs at high speed into a vast galaxy cluster. The results are the key to the solution of a long-standing mystery — why star formation switches off in galaxy clusters.

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    ESO MUSE
    ESO/MUSE

    ESO Muse2
    ESO/Muse simplified view

    ESO VLT
    ESO VLT Interior
    ESO/VLT

    A team of researchers led by Michele Fumagalli from the Extragalactic Astronomy Group and the Institute for Computational Cosmology at Durham University, were among the first to use ESO’s Multi Unit Spectroscopic Explorer (MUSE) instrument on the VLT. Observing ESO 137-001 — a spiral galaxy 200 million light-years away in the southern constellation of Triangulum Australe (The Southern Triangle) — they were able to get the best view so far of exactly what is happening to the galaxy as it hurtles into the Norma Cluster.

    MUSE gives astronomers not just a picture, but provides a spectrum — or a band of colours — for each pixel in the frame. With this instrument researchers collect about 90 000 spectra every time they look at an object, and thereby record a staggeringly detailed map of the motions and other properties of the observed objects [1].

    ESO 137-001 is being robbed of its raw materials by a process called ram-pressure stripping, which happens when an object moves at high speed through a liquid or gas. This is similar to how air blows a dog’s hair back when it sticks its head out of the window of a moving car. In this case the gas is part of the vast cloud of very thin hot gas that is enveloping the galaxy cluster into which ESO 137-001 is falling at several million kilometres per hour [2].

    The galaxy is being stripped of most of its gas — the fuel needed to make the next generations of young blue stars. ESO 137-001 is in the midst of this galactic makeover, and is being transformed from a blue gas-rich galaxy to a gas-poor red one. Scientists propose that the observed process will help to solve a long-standing scientific riddle.

    “It is one of the major tasks of modern astronomy to find out how and why galaxies in clusters evolve from blue to red over a very short period of time,” says Fumagalli. “Catching a galaxy right when it switches from one to the other allows us to investigate how this happens.”

    Observing this cosmic spectacle, however, is no mean feat. The Norma Cluster lies close to the plane of our own galaxy, the Milky Way, so it is hidden behind copious amounts of galactic dust and gas.

    With the help of MUSE, which is mounted on one of the VLT’s 8-metre Unit Telescopes at the Paranal Observatory in Chile, scientists could not only detect the gas in and around the galaxy, but were able to see how it moves. The new instrument is so efficient that a single hour of observing time was sufficient to obtain a high resolution image of the galaxy as well as the distribution and motion of its gas.

    The observations show that the outskirts of ESO 137-001 are already completely devoid of gas. This is a result of the cluster gas — heated to millions of degrees — pushing the cooler gas out of ESO 137-001 as this drives towards the centre of the cluster. This happens first in the spiral arms where the stars and matter are more thinly spread than at the centre, and gravity has only a relatively weak hold over the gas. In the centre of the galaxy, however, the gravitational pull is strong enough to hold out longer in this cosmic tug-of-war and gas is still observed.

    Eventually, all of the galactic gas will be swept away into bright streaks behind ESO 137-001 — telltale remnants of this dramatic robbery. The gas that is torn away from the galaxy is mixed with the hot cluster gas to form magnificent tails extending to a distance of over 200 000 light-years. The team had a closer look at these streams of gas to better understand the turbulence created by the interaction.

    Surprisingly the new MUSE observations of this gas plume show that the gas continues to rotate in same way the galaxy does, even after being swept out into space. Furthermore, researchers were able to determine that the rotation of stars in ESO 137-001 remains unchanged. This provides further evidence for the cluster gas, not gravity, being responsible for stripping the galaxy [3].

    Matteo Fossati (Universitäts-Sternwarte München and Max-Planck-Institut für extraterrestrische Physik, Garching, Germany) and a co-author of the paper concludes: “With the details revealed by MUSE we are getting closer to fully understanding the processes that go on in such collisions. We see the motions of the galaxy and the gas in detail — something that wouldn’t be possible without the new and unique MUSE instrument. These and future observations will help us develop a better idea of what is driving the evolution of galaxies.”
    Notes

    [1] MUSE is the first large integral field spectrograph ever installed at an 8-metre telescope. As a comparison, previous studies of ESO 137-001 collected no more than 50 spectra.

    [2] The NASA/ESA Hubble Space Telescope has provided a spectacular image of this object — but, unlike MUSE, cannot reveal the motions of the material.

    [3] If gravity were to play a role in the stripping process, the researchers would have expected to see disruptions within the galaxy.
    More information

    This research was presented in a paper entitled MUSE sneaks a peek at extreme ram-pressure stripping events. I. A kinematic study of the archetypal galaxy ESO137-001 to appear in Monthly Notices of the Royal Astronomical Society on 10 November 2014.

    The team is composed of Michele Fumagalli (Extragalactic Astronomy Group and Institute for Computational Cosmology, Durham University, United Kingdom), Matteo Fossati (Universitäts-Sternwarte München and Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), George K. T. Hau (ESO, Santiago, Chile), Giuseppe Gavazzi (Università di Milano-Bicocca, Italy), Richard Bower (Extragalactic Astronomy Group and Institute for Computational Cosmology, Durham University, United Kingdom), Alessandro Boselli (Laboratoire d’Astrophysique de Marseille, France) and Ming Sun (Department of Physics, University of Alabama, USA).

    See the full article here.

    From NASA

    nasa
    This image combines NASA/ESA Hubble Space Telescope observations with data from the Chandra X-ray Observatory. As well as the electric blue ram pressure stripping streaks seen emanating from ESO 137-001, a giant gas stream can be seen extending towards the bottom of the frame, only visible in the X-ray part of the spectrum.

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  • richardmitnick 3:36 pm on November 4, 2014 Permalink | Reply
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    From ESO: “Spiral Galaxies Stripped Bare” 2010 


    European Southern Observatory

    27 October 2010
    Richard Hook
    ESO, La Silla, Paranal, E-ELT and Survey telescopes Public Information Officer
    Garching, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Six spectacular spiral galaxies are seen in a clear new light in images from ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile. The pictures were taken in infrared light, using the impressive power of the HAWK-I camera, and will help astronomers understand how the remarkable spiral patterns in galaxies form and evolve.

    six

    ESO VLT
    ESO VLT Interior
    ESO/VLT

    ESO HAWK-I
    HAWK-I

    HAWK-I [1] is one of the newest and most powerful cameras on ESO’s Very Large Telescope (VLT). It is sensitive to infrared light, which means that much of the obscuring dust in the galaxies’ spiral arms becomes transparent to its detectors. Compared to the earlier, and still much-used, VLT infrared camera ISAAC, HAWK-I has sixteen times as many pixels to cover a much larger area of sky in one shot and, by using newer technology than ISAAC, it has a greater sensitivity to faint infrared radiation [2]. Because HAWK-I can study galaxies stripped bare of the confusing effects of dust and glowing gas it is ideal for studying the vast numbers of stars that make up spiral arms.

    ESO ISAAC
    ISAAC

    The six galaxies are part of a study of spiral structure led by Preben Grosbøl at ESO. These data were acquired to help understand the complex and subtle ways in which the stars in these systems form into such perfect spiral patterns.

    The first image shows NGC 5247, a spiral galaxy dominated by two huge arms, located 60–70 million light-years away. The galaxy lies face-on towards Earth, thus providing an excellent view of its pinwheel structure. It lies in the zodiacal constellation of Virgo (the Maiden).

    The galaxy in the second image is Messier 100, also known as NGC 4321, which was discovered in the 18th century. It is a fine example of a “grand design” spiral galaxy — a class of galaxies with very prominent and well-defined spiral arms. About 55 million light-years from Earth, Messier 100 is part of the Virgo Cluster of galaxies and lies in the constellation of Coma Berenices (Berenice’s Hair, named after the ancient Egyptian queen Berenice II).

    The third image is of NGC 1300, a spiral galaxy with arms extending from the ends of a spectacularly prominent central bar. It is considered a prototypical example of barred spiral galaxies and lies at a distance of about 65 million light-years, in the constellation of Eridanus (the River).

    The spiral galaxy in the fourth image, NGC 4030, lies about 75 million light-years from Earth, in the constellation of Virgo. In 2007 Takao Doi, a Japanese astronaut who doubles as an amateur astronomer, spotted a supernova — a stellar explosion that is briefly almost as bright as its host galaxy — going off in this galaxy.

    The fifth image, NGC 2997, is a spiral galaxy roughly 30 million light-years away in the constellation of Antlia (the Air Pump). NGC 2997 is the brightest member of a group of galaxies of the same name in the Local Supercluster of galaxies. Our own Local Group, of which the Milky Way is a member, is itself also part of the Local Supercluster.

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    Local Supercluster

    lg
    Local group

    Last but not least, NGC 1232 is a beautiful galaxy some 65 million light-years away in the constellation of Eridanus (the River). The galaxy is classified as an intermediate spiral galaxy — somewhere between a barred and an unbarred spiral galaxy. An image of this galaxy and its small companion galaxy NGC 1232A in visible light was one of the first produced by the VLT (eso9845). HAWK-I has now returned to NGC 1232 to show a different view of it at near-infrared wavelengths.

    As this galactic gallery makes clear, HAWK-I lets us see the spiral structures in these six bright galaxies in exquisite detail and with a clarity that is only made possible by observing in the infrared.
    Notes

    [1] HAWK-I stands for High-Acuity Wide-field K-band Imager. More technical details about the camera can be found in an earlier press release (eso0736).

    [2] More information about the VLT instruments can be found at: http://www.eso.org/public/teles-instr/vlt/vlt-instr.html.

    See the full article here.

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  • richardmitnick 6:48 pm on October 6, 2014 Permalink | Reply
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    From ESO: “Brilliant Star in a Colourful Neighbourhood” 2010 


    European Southern Observatory

    28 July 2010
    Contacts

    Douglas Pierce-Price
    ESO
    Garching, Germany
    Tel: +49 89 3200 6759
    Email: dpiercep@eso.org

    Richard Hook
    ESO, Survey Telescopes PIO
    Garching Tel: +49 89 3200 6655
    Email: rhook@eso.org

    A spectacular new image from ESO’s Wide Field Imager at the La Silla Observatory in Chile shows the brilliant and unusual star WR 22 and its colourful surroundings. WR 22 is a very hot and bright star that is shedding its atmosphere into space at a rate many millions of times faster than the Sun. It lies in the outer part of the dramatic Carina Nebula from which it formed.

    WR22

    ESO Wide Field Imager 2.2m LaSilla
    ESO WFI onMPG/ESO 2.2m telescope at LaSilla

    ESO 2.2 meter telescope
    ESO 2.2 meter telescope interior
    ESO MPG/ESO 2.2m telescope

    ESO LaSilla Long View
    LaSilla

    Very massive stars live fast and die young. Some of these stellar beacons have such intense radiation passing through their thick atmospheres late in their lives that they shed material into space many millions of times more quickly than relatively sedate stars such as the Sun. These rare, very hot and massive objects are known as Wolf–Rayet stars [1], after the two French astronomers who first identified them in the mid-nineteenth century, and one of the most massive ones yet measured is known as WR 22. It appears at the centre of this picture, which was created from images taken through red, green and blue filters with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. WR 22 is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun.

    WR 22 lies in the southern constellation of Carina, the keel of Jason’s ship Argo in Greek mythology. Although the star lies over 5000 light-years from the Earth it is so bright that it can just be faintly seen with the unaided eye under good conditions. WR 22 is one of many exceptionally brilliant stars associated with the beautiful Carina Nebula (also known as NGC 3372) and the outer part of this huge region of star formation in the southern Milky Way forms the colourful backdrop to this image.

    The subtle colours of the rich background tapestry are a result of the interactions between the intense ultraviolet radiation coming from hot massive stars, including WR 22, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image eso1031b. This area includes the remarkable star Eta Carinae and was featured in an earlier press release (eso0905).
    Notes

    [1] More information about Wolf–Rayet stars

    See the full article here.

    Another view, the Carina Nebula

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    This broad panorama of the Carina Nebula, a region of massive star formation in the southern skies, was taken in infrared light using the HAWK-I camera on ESO’s Very Large Telescope. Many previously hidden features, scattered across a spectacular celestial landscape of gas, dust and young stars, have emerged. Some of these features have been annotated in Commons. Trumpler 16 (annotated) is an open cluster that contains the luminous, massive blue variable Eta Carinae, one of the brightest stars in the galaxy, possibly as much as 120 times the mass of the Sun, and emitting the light of 4,000,000 Suns. Eta Carinae is nearing the end of its life, and is surrounded by a huge nebula, cast off by numerous eruptions of the star over the last several centuries; it is expected to explode into a supernova at any time. Trumpler 14 (annotated) contains the huge double star HD 93129 A/B. The young O3 class star HD 93129 A is one of the brightest stars in the galaxy that is still on the main sequence, and with a luminosity equivalent to 3,000,000 Suns, is very nearly as bright as Eta Carinae, but this is not obvious in the photo due to obscuring nebulosities.

    ESO HAWK-I
    ESO HAWK I

    ESOVLTI
    ESO VLT

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  • richardmitnick 6:01 am on September 10, 2014 Permalink | Reply
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    From ESO: “This Star Cluster Is Not What It Seems” 


    European Southern Observatory

    10 September 2014
    Contacts

    Alessio Mucciarelli
    University of Bologna
    Bologna, Italy
    Tel: +39 051 20 95705
    Email: alessio.mucciarelli2@unibo.it

    Lars Lindberg Christensen
    Head of ESO ePOD
    Garching bei München, Germany
    Tel: +49 89 3200 6761
    Cell: +49 173 3872 621
    Email: lars@eso.org

    VLT observations of Messier 54 show the lithium problem also applies outside our galaxy

    This new image from the VLT Survey Telescope at ESO’s Paranal Observatory in northern Chile shows a vast collection of stars, the globular cluster Messier 54. This cluster looks very similar to many others but it has a secret. Messier 54 doesn’t belong to the Milky Way, but is part of a small satellite galaxy, the Sagittarius Dwarf Galaxy. This unusual parentage has now allowed astronomers to use the Very Large Telescope (VLT) to test whether there are also unexpectedly low levels of the element lithium in stars outside the Milky Way.

    m54

    ESO Vista Telescope
    ESO Vista

    ESO VLT Interferometer
    ESO VLT at Paranal

    The Milky Way galaxy is orbited by more than 150 globular star clusters, which are balls of hundreds of thousands of old stars dating back to the formation of the galaxy. One of these, along with several others in the constellation of Sagittarius (The Archer), was found in the late eighteenth century by the French comet hunter Charles Messier and given the designation Messier 54.

    For more than two hundred years after its discovery Messier 54 was thought to be similar to the other Milky Way globulars. But in 1994 it was discovered that it was actually associated with a separate galaxy — the Sagittarius Dwarf Galaxy. It was found to be at a distance of around 90 000 light-years — more than three times as far from Earth as the galactic centre.

    Astronomers have now observed Messier 54 using the VLT as a test case to try to solve one of the mysteries of modern astronomy — the lithium problem.

    Most of the light chemical element lithium now present in the Universe was produced during the Big Bang, along with hydrogen and helium, but in much smaller quantities. Astronomers can calculate quite accurately how much lithium they expect to find in the early Universe, and from this work out how much they should see in old stars. But the numbers don’t match — there is about three times less lithium in stars than expected. This mystery remains, despite several decades of work [1].

    Up to now it has only been possible to measure lithium in stars in the Milky Way. But now a team of astronomers led by Alessio Mucciarelli (University of Bologna, Italy) has used the VLT to measure how much lithium there is in a selection of stars in Messier 54. They find that the levels are close to those in the Milky Way. So, whatever it is that got rid of the lithium seems not to be specific to the Milky Way.

    This new image of the cluster was created from data taken with the VLT Survey Telescope (VST) at the Paranal Observatory. As well as showing the cluster itself it reveals the extraordinarily dense forest of much closer Milky Way stars that lie in the foreground.
    Notes

    [1] There are several possible proposed solutions to the riddle. The first is that the calculations of the amounts of lithium produced in the Big Bang are wrong — but very recent tests suggest that this is not the case. The second is that the lithium was somehow destroyed in the earliest stars, before the formation of the Milky Way. The third is that some process in the stars has gradually destroyed lithium during their lives.
    More information

    This research was presented in a paper, The cosmological Lithium problem outside the Galaxy: the Sagittarius globular cluster M54, by A. Mucciarelli et al., to appear in Monthly Notices of the Royal Astronomical Society (Oxford University Press).

    The team is composed of: A. Mucciarelli (University of Bologna, Italy), M. Salaris (Liverpool John Moores University, Liverpool, UK), P. Bonifacio (Observatoire de Paris, France), L. Monaco (ESO, Santiago, Chile) and S. Villanova (Universidad de Concepcion, Concepcion, Chile).

    See the full article here.

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  • richardmitnick 7:17 pm on August 18, 2014 Permalink | Reply
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    From ESO: “Exoplanet Caught on the Move” 2010 


    European Southern Observatory

    10 June 2010
    Contacts
    Anne-Marie Lagrange
    LAOG
    Grenoble, France
    Tel: +33 4 7651 4203
    Cell: +33 6 89 17 40 98
    Email: anne-marie.lagrange@obs.ujf-grenoble.fr

    Henri Boffin
    ESO La Silla, Paranal and E-ELT press officer
    Garching, Germany
    Tel: +49 89 3200 6222
    Cell: +49 174 515 4324
    Email: hboffin@eso.org

    For the first time, astronomers have been able to directly follow the motion of an exoplanet as it moves from one side of its host star to the other. The planet has the smallest orbit so far of all directly imaged exoplanets, lying almost as close to its parent star as Saturn is to the Sun. Scientists believe that it may have formed in a similar way to the giant planets in the Solar System. Because the star is so young, this discovery proves that gas giant planets can form within discs in only a few million years, a short time in cosmic terms.

    exo

    Only 12 million years old, or less than three-thousandths of the age of the Sun, Beta Pictoris is 75% more massive than our parent star. It is located about 60 light-years away towards the constellation of Pictor (the Painter) and is one of the best-known examples of a star surrounded by a dusty debris disc. Earlier observations showed a warp of the disc, a secondary inclined disc and comets falling onto the star. “Those were indirect, but tell-tale signs that strongly suggested the presence of a massive planet, and our new observations now definitively prove this,” says team leader Anne-Marie Lagrange. “Because the star is so young, our results prove that giant planets can form in discs in time-spans as short as a few million years.”

    Recent observations have shown that discs around young stars disperse within a few million years, and that giant planet formation must occur faster than previously thought. Beta Pictoris is now clear proof that this is indeed possible.

    The team used the NAOS-CONICA instrument (or NACO), mounted on one of the 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT), to study the immediate surroundings of Beta Pictoris in 2003, 2008 and 2009. In 2003 a faint source inside the disc was seen, but it was not possible to exclude the remote possibility that it was a background star. In new images taken in 2008 and spring 2009 the source had disappeared! The most recent observations, taken during autumn 2009, revealed the object on the other side of the disc after a period of hiding either behind or in front of the star (in which case it is hidden in the glare of the star). This confirmed that the source indeed was an exoplanet and that it was orbiting its host star. It also provided insights into the size of its orbit around the star.

    ESO NACO
    NACO

    ESO VLT Interferometer
    ESO VLT Interior
    ESO VLT

    Images are available for approximately ten exoplanets, and the planet around Beta Pictoris (designated “Beta Pictoris b”) has the smallest orbit known so far. It is located at a distance between 8 and 15 times the Earth-Sun separation — or 8-15 Astronomical Units — which is about the distance of Saturn from the Sun. “The short period of the planet will allow us to record the full orbit within maybe 15-20 years, and further studies of Beta Pictoris b will provide invaluable insights into the physics and chemistry of a young giant planet’s atmosphere,” says student researcher Mickael Bonnefoy.

    The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. This discovery therefore bears some similarity to the prediction of the existence of Neptune by astronomers Adams and Le Verrier in the 19th century, based on observations of the orbit of Uranus.

    “Together with the planets found around the young, massive stars Fomalhaut and HR8799, the existence of Beta Pictoris b suggests that super-Jupiters could be frequent byproducts of planet formation around more massive stars,” explains Gael Chauvin, a member of the team.

    Such planets disturb the discs around their stars, creating structures that should be readily observable with the Atacama Large Millimeter/submillimeter Array (ALMA), the revolutionary telescope being built by ESO together with international partners.

    ALMA Array
    ALMA Array

    A few other planetary candidates have been imaged, but they are all located further from their host star than Beta Pictoris b. If located in the Solar System, they all would lie close to or beyond the orbit of the furthest planet, Neptune. The formation processes of these distant planets are likely to be quite different from those in our Solar System and in Beta Pictoris.

    “The recent direct images of exoplanets — many made by the VLT— illustrate the diversity of planetary systems,” says Lagrange. “Among those, Beta Pictoris b is the most promising case of a planet that could have formed in the same way as the giant planets in our Solar System.”

    The team is composed of A.-M. Lagrange, M. Bonnefoy, G. Chauvin, D. Ehrenreich, and D. Mouillet (Laboratoire d’Astrophysique de l’Observatoire de Grenoble, Université Joseph Fourier, CNRS, France), D. Apai (Space Telescope Science Institute, Baltimore, USA), A. Boccaletti, D. Gratadour, D. Rouan, and S. Lacour (LESIA, Observatoire de Paris-Meudon, France), and M. Kasper (ESO).

    See the full article, with notes, here.

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  • richardmitnick 2:26 pm on August 4, 2014 Permalink | Reply
    Tags: , , , , ESO VLT,   

    From SPACE.com: “Alien Planet-Hunting Telsecope Tool Snaps 1st Amazing Images (Video, Photos) 

    space-dot-com logo

    SPACE.com

    June 04, 2014
    Megan Gannon

    A new instrument designed to give scientists a direct look at nearby alien worlds has seen its “first light” in Chile, astronomers announced today (June 4).

    dust ring
    This infrared image shows the dust ring around the nearby star HR 4796A in the southern constellation of Centaurus.
    Credit: ESO/J.-L. Beuzit et al./SPHERE Consortium

    Called SPHERE (for Spectro-Polarimetric High-contrast Exoplanet REsearch), the new alien planet detection tool was mounted on the European Southern Observatory’s Very Large Telescope Unit Telescope 3 in the Atacama Desert last month.

    ESO SPHERE
    ESO/Sphere

    ESO VLT
    ESO/VLT

    In its first few days of operations, SPHERE already has produced images of Saturn’s moon Titan and dust discs around stars as it gears up to take pictures of exoplanets, ESO officials said.

    Using space- and ground-based telescopes, astronomers have detected more than 2,000 exoplanets since spotting the first ones back in the 1990s. But scientists have rarely been able to look at these worlds directly because the weak glow of a planet is often outshined by bright light from its parent star. Instead, astronomers often use indirect techniques like the transit method, in which they look for telltale dips in a star’s brightness caused when a planet crosses in front of the star.

    To be observed directly, planets usually need to be very large and very far away from their parent star. The first confirmed direct photo of an alien planet in 2010 showed a world eight times the mass of Jupiter that orbited its host star at from more than 300 times the distance between Earth and the sun.

    SPHERE is designed to get the highest contrast possible in a small patch of sky around a star to see exoplanets that might otherwise be hidden. To boost the contrast in its images, SPHERE uses adaptive optics to correct for the blurring effects of the Earth’s atmosphere as well as a coronagraph also blocks out starlight.

    titan
    This infrared image of Saturn’s largest moon, Titan, was one of the first produced by the SPHERE instrument soon after it was installed on ESO’s Very Large Telescope in Chile in May 2014.
    Credit: ESO/J.-L. Beuzit et al./SPHERE Consortium

    SPHERE’s first shot, taken in the infrared wavelength, shows the dust ring around the nearby star HR 4796A, which is in the southern constellation of Centaurus. Though it doesn’t show a planet, the clarity of this disc demonstrates SPHERE’s impressive ability to reduce the glare from a star, ESO officials said.

    Another instrument in Chile designed to directly image exoplanets snapped its first photos within the last year. The Gemini Observatory’s Planet Imager, installed at the 8-meter Gemini South telescope, had its first light on Nov. 11, 2013 and took photos of a planet orbiting the star Beta Pictoris.

    Gemini South telescope
    Gemini South

    Gemini Planet Imager
    Gemini Planet Imager

    See the full article here.

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  • richardmitnick 6:32 pm on July 9, 2014 Permalink | Reply
    Tags: , , , , ESO VLT   

    From ESO: “VLT Clears Up Dusty Mystery” 


    European Southern Observatory

    9 July 2014
    Contacts

    Christa Gall
    Aarhus University
    Denmark
    Cell: +45 53 66 20 18
    Email: cgall@phys.au.dk

    Jens Hjorth
    Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen
    Copenhagen, Denmark
    Email: jens@dark-cosmology.dk

    Richard Hook
    ESO education and Public Outreach Department
    Garching bei München, Germany

    Tel: +49 89 3200 6655
    Email: rhook@eso.org

    New observations reveal how stardust forms around a supernova

    A group of astronomers has been able to follow stardust being made in real time — during the aftermath of a supernova explosion. For the first time they show that these cosmic dust factories make their grains in a two-stage process, starting soon after the explosion, but continuing for years afterwards. The team used ESO’s Very Large Telescope (VLT) in northern Chile to analyse the light from the supernova SN2010jl as it slowly faded. The new results are published online in the journal Nature on 9 July 2014.

    ESO VLT
    ESO/VLT

    stardust

    The origin of cosmic dust in galaxies is still a mystery. Astronomers know that supernovae may be the primary source of dust, especially in the early Universe, but it is still unclear how and where dust grains condense and grow. It is also unclear how they avoid destruction in the harsh environment of a star-forming galaxy. But now, observations using ESO’s VLT at the Paranal Observatory in northern Chile are lifting the veil for the first time.

    An international team used the X-shooter spectrograph to observe a supernova — known as SN2010jl — nine times in the months following the explosion, and for a tenth time 2.5 years after the explosion, at both visible and near-infrared wavelengths. This unusually bright supernova, the result of the death of a massive star, exploded in the small galaxy UGC 5189A.

    “By combining the data from the nine early sets of observations we were able to make the first direct measurements of how the dust around a supernova absorbs the different colours of light,” said lead author Christa Gall from Aarhus University, Denmark. “This allowed us to find out more about the dust than had been possible before.”

    The team found that dust formation starts soon after the explosion and continues over a long time period. The new measurements also revealed how big the dust grains are and what they are made of. These discoveries are a step beyond recent results obtained using the Atacama Large Millimeter/submillimeter Array (ALMA), which first detected the remains of a recent supernova brimming with freshly formed dust from the famous supernova 1987A (SN 1987A; eso1401).

    ALMA Array
    ALMA

    The team found that dust grains larger than one thousandth of a millimetre in diameter formed rapidly in the dense material surrounding the star. Although still tiny by human standards, this is large for a grain of cosmic dust and the surprisingly large size makes them resistant to destructive processes. How dust grains could survive the violent and destructive environment found in the remnants of supernovae was one of the main open questions of the ALMA paper, which this result has now answered — the grains are larger than expected.

    “Our detection of large grains soon after the supernova explosion means that there must be a fast and efficient way to create them,” said co-author Jens Hjorth from the Niels Bohr Institute of the University of Copenhagen, Denmark, and continued: “We really don’t know exactly how this happens.”

    But the astronomers think they know where the new dust must have formed: in material that the star shed out into space even before it exploded. As the supernova’s shockwave expanded outwards, it created a cool, dense shell of gas — just the sort of environment where dust grains could seed and grow.

    Results from the observations indicate that in a second stage — after several hundred days — an accelerated dust formation process occurs involving ejected material from the supernova. If the dust production in SN2010jl continues to follow the observed trend, by 25 years after the supernova, the total mass of dust will be about half the mass of the Sun; similar to the dust mass observed in other supernovae such as SN 1987A.

    “Previously astronomers have seen plenty of dust in supernova remnants left over after the explosions. But they also only found evidence for small amounts of dust actually being created in the supernova explosions. These remarkable new observations explain how this apparent contradiction can be resolved,” concludes Christa Gall.

    The team is composed of Christa Gall (Department of Physics and Astronomy, Aarhus University, Denmark; Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark; Observational Cosmology Lab, NASA Goddard Space Flight Center, USA), Jens Hjorth (Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark), Darach Watson (Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark), Eli Dwek (Observational Cosmology Lab, NASA Goddard Space Flight Center, USA), Justyn R. Maund (Astrophysics Research Centre School of Mathematics and Physics Queen’s University Belfast, UK; Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark; Department of Physics and Astronomy, University of Sheffield, UK), Ori Fox (Department of Astronomy, University of California, Berkeley, USA), Giorgos Leloudas (The Oskar Klein Centre, Department of Physics, Stockholm University, Sweden; Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark), Daniele Malesani (Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark) and Avril C. Day-Jones (Departamento de Astronomia, Universidad de Chile, Chile).

    See the full article, with notes, here.

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  • richardmitnick 4:57 am on July 8, 2014 Permalink | Reply
    Tags: , , , , ESO VLT   

    From ESO: “Explained: Why many surveys of distant galaxies miss 90% of their targets” 2010 


    European Southern Observatory

    Astronomers have long known that in many surveys of the very distant Universe, a large fraction of the total intrinsic light was not being observed. Now, thanks to an extremely deep survey using two of the four giant 8.2-metre telescopes that make up ESO’s Very Large Telescope (VLT) and a unique custom-built filter, astronomers have determined that a large fraction of galaxies whose light took 10 billion years to reach us have gone undiscovered. The survey also helped uncover some of the faintest galaxies ever found at this early stage of the Universe.

    ESOVLTI
    ESO/VLT

    field

    Astronomers frequently use the strong, characteristic “fingerprint” of light emitted by hydrogen known as the Lyman-alpha line, to probe the amount of stars formed in the very distant Universe. Yet there have long been suspicions that many distant galaxies go unnoticed in these surveys. A new VLT survey demonstrates for the first time that this is exactly what is happening. Most of the Lyman-alpha light is trapped within the galaxy that emits it, and 90% of galaxies do not show up in Lyman-alphas.

    “Astronomers always knew they were missing some fraction of the galaxies in Lyman-alpha surveys,” explains Matthew Hayes, the lead author of the paper, published this week in Nature, “but for the first time we now have a measurement. The number of missed galaxies is substantial.”

    To figure out how much of the total luminosity was missed, Hayes and his team used the FORS camera at the VLT and a custom-built narrowband filter to measure this Lyman-alpha light, following the methodology of standard Lyman-alpha surveys. Then, using the new HAWK-I camera, attached to another VLT Unit Telescope, they surveyed the same area of space for light emitted at a different wavelength, also by glowing hydrogen, and known as the H-alpha line. They specifically looked at galaxies whose light has been travelling for 10 billion years (redshift 2.2 [3]), in a well-studied area of the sky, known as the GOODS-South field.

    ESO FORS1
    FORS1 on VLT

    ESO HAWK I
    ESO HAWK I

    “This is the first time we have observed a patch of the sky so deeply in light coming from hydrogen at these two very specific wavelengths, and this proved crucial,” says team member Göran Östlin. The survey was extremely deep, and uncovered some of the faintest galaxies known at this early epoch in the life of the Universe. The astronomers could thereby conclude that traditional surveys done using Lyman-alpha only see a tiny part of the total light that is produced, since most of the Lyman-alpha photons are destroyed by interaction with the interstellar clouds of gas and dust. This effect is dramatically more significant for Lyman-alpha than for H-alpha light. As a result, many galaxies, a proportion as high as 90%, go unseen by these surveys. “If there are ten galaxies seen, there could be a hundred there,” Hayes says.

    Different observational methods, targeting the light emitted at different wavelengths, will always lead to a view of the Universe that is only partially complete. The results of this survey issue a stark warning for cosmologists, as the strong Lyman-alpha signature becomes increasingly relied upon in examining the very first galaxies to form in the history of the Universe. “Now that we know how much light we’ve been missing, we can start to create far more accurate representations of the cosmos, understanding better how quickly stars have formed at different times in the life of the Universe,” says co-author Miguel Mas-Hesse.

    The breakthrough was made possible thanks to the unique camera used. HAWK-I, which saw first light in 2007, is a state-of-the-art instrument.

    “There are only a few other cameras with a wider field of view than HAWK-I, and they are on telescopes less than half the size of the VLT. So only VLT/HAWK-I, really, is capable of efficiently finding galaxies this faint at these distances,” says team member Daniel Schaerer.

    See the full article, with notes, here.

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  • richardmitnick 8:45 am on June 30, 2014 Permalink | Reply
    Tags: , , , , ESO VLT   

    From ESO: “VLT Finds Fastest Rotating Star” 2011 


    European Southern Observatory

    5 December 2011
    Philip Dufton
    Queen’s University of Belfast
    Belfast, UK
    Tel: +44 028 9097 3552
    Email: P.Dufton@qub.ac.uk

    Richard Hook
    ESO, La Silla, Paranal, E-ELT & Survey Telescopes Press Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    ESO’s Very Large Telescope has picked up the fastest rotating star found so far. This massive bright young star lies in our neighbouring galaxy, the Large Magellanic Cloud, about 160 000 light-years from Earth. Astronomers think that it may have had a violent past and has been ejected from a double star system by its exploding companion.

    stars

    ESOVLTI
    ESO’s VLT

    An international team of astronomers has been using ESO’s Very Large Telescope at the Paranal Observatory in Chile, to make a survey of the heaviest and brightest stars in the Tarantula Nebula (eso1117), in the Large Magellanic Cloud. Among the many brilliant stars in this stellar nursery the team has spotted one, called VFTS 102, that is rotating at more than two million kilometres per hour — more than three hundred times faster than the Sun and very close to the point at which it would be torn apart due to centrifugal forces. VFTS 102 is the fastest rotating star known to date.

    The astronomers also found that the star, which is around 25 times the mass of the Sun and about one hundred thousand times brighter, was moving through space at a significantly different speed from its neighbours.

    “The remarkable rotation speed and the unusual motion compared to the surrounding stars led us to wonder if this star had had an unusual early life. We were suspicious.” explains Philip Dufton (Queen’s University Belfast, Northern Ireland, UK), lead author of the paper presenting the results.

    This difference in speed could imply that VFTS 102 is a runaway star — a star that has been ejected from a double star system after its companion exploded as a supernova. This idea is supported by two further clues: a pulsar and an associated supernova remnant in its vicinity.

    The team has developed a possible back story for this very unusual star. It could have started life as one component of a binary star system. If the two stars were close, gas from the companion could have streamed over and in the process the star would have spun faster and faster. This would explain one unusual fact — why it is rotating so fast. After a short lifetime of about ten million years, the massive companion would have exploded as a supernova — which could explain the characteristic gas cloud known as a supernova remnant found nearby. The explosion would also have led to the ejection of the star and could explain the third anomaly — the difference between its speed and that of other stars in the region. As it collapsed, the massive companion would have turned into the pulsar that is observed today, and which completes the solution to the puzzle.

    Although the astronomers cannot yet be sure that this is exactly what happened, Dufton concludes “This is a compelling story because it explains each of the unusual features that we’ve seen. This star is certainly showing us unexpected sides of the short, but dramatic lives of the heaviest stars.”

    The team is composed of P.L. Dufton (Astrophysics Research Centre, Queen’s University Belfast (ARC/QUB), UK), P.R. Dunstall (ARC/QUB, UK), C.J. Evans (UK Astronomy Technology Centre, Royal Observatory Edinburgh (ROE), UK), I. Brott (University of Vienna, Department of Astronomy, Austria), M. Cantiello (Argelander Institut fur Astronomie der Universitat Bonn, Germany, Kavli Institute for Theoretical Physics, University of California, USA), A. de Koter (Astronomical Institute ‘Anton Pannekoek’, University of Amsterdam, The Netherlands), S.E. de Mink (Space Telescope Science Institute, USA), M. Fraser (ARC/QUB, UK), V. Henault-Brunet (Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, ROE, UK), I.D. Howarth (Department of Physics & Astronomy, University College London, UK), N. Langer (Argelander Institut fur Astronomie der Universitat Bonn, Germany), D.J. Lennon ( ESA,Space Telescope Science Institute, USA), N. Markova (Institute of Astronomy with NAO, Bulgaria), H. Sana (Astronomical Institute ‘Anton Pannekoek’, University of Amsterdam, The Netherlands), W.D. Taylor (SUPA, Institute for Astronomy, University of Edinburgh, ROE, UK).

    See the full article, with notes, here.

    Another view:

    tar
    This first light image of the TRAPPIST national telescope at La Silla shows the Tarantula Nebula, located in the Large Magellanic Cloud (LMC) — one of the galaxies closest to us. Also known as 30 Doradus or NGC 2070, the nebula owes its name to the arrangement of bright patches that somewhat resembles the legs of a tarantula. Taking the name of one of the biggest spiders on Earth is very fitting in view of the gigantic proportions of this celestial nebula — it measures nearly 1000 light-years across! Its proximity, the favourable inclination of the LMC, and the absence of intervening dust make this nebula one of the best laboratories to help understand the formation of massive stars better. The image was made from data obtained through three filters (B, V and R) and the field of view is about 20 arcminutes across.

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