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Post Info TOPIC: Dust
Blobrana


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Dust around Galaxies
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Title: Distribution of Dust around Galaxies: An Analytic Model
Authors: Shogo Masaki, Naoki Yoshida

We develop an analytic halo model for the distribution of dust around galaxies. The model results are compared with the observed surface dust density profile measured through reddening of background quasars in the Sloan Digital Sky Survey (SDSS) reported by Menard et al.(2010). We assume that the dust distribution around a galaxy is described by a simple power law, similarly to the mass distribution, but with a sharp cut-off at \alpha R_{vir} where R_{vir} is the galaxy's virial radius and \alpha is a model parameter. Our model reproduces the observed dust distribution profile very well over a wide range of radial distance of 10 - 10^{4} h^{-1}kpc. For the characteristic galaxy halo mass of 2 x 10^{12} h^{-1}stellar masses estimated for the SDSS galaxies, the best fit model is obtained if \alpha is greater than unity, which suggests that dust is distributed to over a few hundred kilo-parsecs from the galaxies. The observed large-scale dust distribution profile is reproduced if we assume the total amount of dust is equal to that estimated from the integrated stellar evolution over the cosmic time.

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Blobrana


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RE: Dust
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Astronomers detect vast amounts of gas and dust around black hole in early universe

Using the IRAM array of millimetre-wave telescopes in the French Alps, a team of European astronomers from Germany, the UK and France have discovered a large reservoir of gas and dust in a galaxy that surrounds the most distant supermassive black hole known. Light from the galaxy, called J1120+0641, has taken so long to reach us that the galaxy is seen as it was only 740 million years after the Big Bang, when the universe was only 1/18th of its current age. Team leader Dr. Bram Venemans of the Max-Planck Institute for Astronomy in Heidelberg, Germany will present the new discovery on Wednesday 28 March at the National Astronomy Meeting in Manchester.
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Blobrana


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Exploding stars can make good dust factories
 
ESA's Herschel space observatory has discovered that titanic stellar explosions can be excellent dust factories. In space, the dust mixes with gas to become the raw material for new stars, planets and, ultimately, life. This discovery may solve a mystery of the early Universe.
The discovery was made while Herschel was charting emission from cold dust in the Large Magellanic Cloud, a small galaxy near to the Milky Way. It is the perfect observatory for the job because cold dust radiates far-infrared light, the wavelengths Herschel is designed to detect.
Herschel saw a spot of light at the location of supernova 1987A, an exploding star first seen from Earth in February 1987, and the closest known supernova in the past 400 years.
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Blobrana


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Supernovae Seed Galaxies with Massive Amounts of Dust

Dust on earthly objects is often an indicator of antiquity. But that is not always the case for cosmic objects, some of which have quite a bit of dust despite their relative youth.
Galaxies out toward the edge of the visible universe, so distant that astronomers see them as they existed less than a billion years after the big bang, seem to already harbour large quantities of interstellar dust. But just how that dust appeared in such a short time remains unsettled.
Now a group of astronomers reports that exploding stars known as supernovae could be a major dust producer in those early galaxies.
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Blobrana


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Cosmic dust is fogging up attempts to study light left over from the Big Bang, and Canadian scientists aim to clear up the problem.
The microscopic dust permeates the universe, producing confusing signals in data collected by the Planck space telescope, which is designed to study distant light originating from the beginning of the universe 13 billion years ago.
The dust - mainly sand and soot particles, each about the size of a bacterium - makes up about one per cent of the mass in space, not very much compared with the mass of hydrogen and helium, said University of Toronto astronomer Peter Martin.
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Blobrana


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Spinning cosmic dust motes set speed record

Some dust grains out in deep space are spinning at mind-boggling rates. According to data from the European Space Agency's Planck space telescope, these interstellar particles are turning on their axis tens of billions of times every second.
The measurements, which set a record for spinning objects, could lead to a more accurate map of the cosmic microwave background, the afterglow of the big bang, by allowing scientists to better account for distortions caused by microwaves emitted by the grains.
The smallest grains, only 100 atoms or so wide, are so light that they can be set spinning by collisions with photons and fast-moving atoms
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Blobrana


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Spinning Dust Grains
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Title: Planck Early Results: New Light on Anomalous Microwave Emission from Spinning Dust Grains
Authors: Planck Collaboration: P. A. R. Ade, N. Aghanim, M. Arnaud, M. Ashdown, J. Aumont, C. Baccigalupi, A. Balbi, A. J. Banday, R. B. Barreiro, J. G. Bartlett, E. Battaner, K. Benabed, A. Benoît, J.-P. Bernard, M. Bersanelli, R. Bhatia, J. J. Bock, A. Bonaldi, J. R. Bond, J. Borrill, F. R. Bouchet, F. Boulanger, M. Bucher, C. Burigana, P. Cabella, B. Cappellini, J.-F. Cardoso, S. Casassus, A. Catalano, L. Cayón, A. Challinor, A. Chamballu, R.-R. Chary, X. Chen, L.-Y Chiang, C. Chiang, P. R. Christensen, D. L. Clements, S. Colombi, F. Couchot, A. Coulais, B. P. Crill, F. Cuttaia, L. Danese, R. D. Davies, R. J. Davis, P. de Bernardis, G. de Gasperis, A. de Rosa, G. de Zotti, J. Delabrouille, J.-M. Delouis, C. Dickinson, S. Donzelli, O. Doré, U. Dörl, M. Douspis, X. Dupac, G. Efstathiou,
T. A. En\sslin, H. K. Eriksen, F. Finelli, O. Forni, M. Frailis, E. Franceschi, S. Galeotta, K. Ganga, R. T. Génova-Santos, M. Giard, G. Giardino, Y. Giraud-Héraud, J. González-Nuevo, K. M. Górski, S. Gratton, A. Gregorio, A. Gruppuso, F. K. Hansen, D. Harrison, G. Helou, S. Henrot-Versillé, D. Herranz, S. R. Hildebrandt, E. Hivon, M. Hobson, W. A. Holmes, W. Hovest, R. J. Hoyland, K. M. Huffenberger, T. R. Jaffe, A. H. Jaffe, W. C. Jones, M. Juvela, E. Keihänen, R. Keskitalo, T. S. Kisner, R. Kneissl, L. Knox, H. Kurki-Suonio, G. Lagache, A. Lähteenmäki, J.-M. Lamarre, A. Lasenby, R. J. Laureijs, C. R. Lawrence, S. Leach, R. Leonardi, P. B. Lilje, M. Linden-V\ornle, M. López-Caniego, P. M. Lubin, J. F. Macías-Pérez, C. J. MacTavish, B. Maffei, D. Maino, N. Mandolesi, R. Mann, M. Maris, D. J. Marshall, E. Martínez-González, S. Masi, S. Matarrese, F. Matthai, P. Mazzotta, P. McGehee, P. R. Meinhold, A. Melchiorri, L. Mendes, A. Mennella, S. Mitra, M.-A. Miville-Deschênes, A. Moneti, L. Montier, G. Morgante, D. Mortlock, D. Munshi, A. Murphy, P. Naselsky, P. Natoli, C. B. Netterfield, H. U. N\orgaard-Nielsen, F. Noviello, D. Novikov, I. Novikov, I. J. O'Dwyer, S. Osborne, F. Pajot, R. Paladini, B. Partridge, F. Pasian, G. Patanchon, T. J. Pearson, M. Peel, O. Perdereau, L. Perotto, F. Perrotta, F. Piacentini, M. Piat, S. Plaszczynski, P. Platania, E. Pointecouteau, G. Polenta, N. Ponthieu, T. Poutanen, G. Prézeau, P. Procopio, S. Prunet, J.-L. Puget, W. T. Reach, R. Rebolo, W. Reich, M. Reinecke, C. Renault, S. Ricciardi, T. Riller, I. Ristorcelli, G. Rocha, C. Rosset, M. Rowan-Robinson, J. A. Rubi\no-Martín, B. Rusholme, M. Sandri, D. Santos, G. Savini, D. Scott, M. D. Seiffert, P. Shellard, G. F. Smoot, J.-L. Starck, F. Stivoli, V. Stolyarov, R. Stompor, R. Sudiwala, J.-F. Sygnet, J. A. Tauber, L. Terenzi, L. Toffolatti, M. Tomasi, J.-P. Torre, M. Tristram, J. Tuovinen, G. Umana, L. Valenziano, J. Varis, L. Verstraete, P. Vielva, F. Villa, N. Vittorio, L. A. Wade, B. D. Wandelt, R. Watson, A. Wilkinson, N. Ysard, D. Yvon, A. Zacchei, A. Zonca
et al. (156 additional authors not shown)

Anomalous microwave emission (AME) has been observed by numerous experiments in the frequency range ~10-60 GHz. Using Planck maps and multi-frequency ancillary data, we have constructed spectra for two known AME regions: the Perseus and Rho Ophiuchus molecular clouds. The spectra are well fitted by a combination of free-free radiation, cosmic microwave background, thermal dust, and electric dipole radiation from small spinning dust grains. The spinning dust spectra are the most precisely measured to date, and show the high frequency side clearly for the first time. The spectra have a peak in the range 20-40 GHz and are detected at high significances of 17.1sigma and 10.4sigma, respectively. In Perseus, spinning dust in the dense molecular gas can account for most of the AME; the low density neutral gas appears to play a minor role. In Rho Ophiuchus, the ~30 GHz peak is dominated by dense molecular gas, but there is an indication of an extended tail at frequencies 50-100 GHz, which can be accounted for by irradiated low density atomic gas. The dust parameters are consistent with those derived from other measurements. We have also searched the Planck map at 28.5 GHz for candidate AME regions, by subtracting a simple model of the synchrotron, free-free, and thermal dust. We present spectra for two of the candidates: bright HII regions that show evidence for AME, and are well fitted by spinning dust models.

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Blobrana


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Posts: 131433
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Galactic carbon-oxygen dust
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Using NASA's Spitzer Space Telescope, researchers have found evidence suggesting that stars rich in carbon complex molecules may form at the centre of our Milky Way galaxy.
This discovery is significant because it adds to our knowledge of how stars form heavy elements - like oxygen, carbon, and iron - and then blow them out across the universe, making it possible for life to develop.
Astronomers have long been baffled by a strange phenomenon: Why have their telescopes never detected carbon-rich stars at the centre of our galaxy even though they have found these stars in other places? Now, by using Spitzer's powerful infrared detectors, a research team has found the elusive carbon stars in the galactic centre.

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Blobrana


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RE: Dust
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The universe is a lot dustier than previously thought. But behind the dust lies a startling symmetry that has the worlds top scientists gaping into their telescopes.
Thats according to unique images about to be released in South Africa the result of an eight-year collaboration between a South African professor and one of the worlds top scientists.
The images reveal the first glimpses of some of Earths neighbouring galaxies, some more than 200 million light years away, which until now have been masked by large clouds of cosmic dust.

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Blobrana


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The clearest images ever of the building blocks of the universe have been captured.
Manchester scientists were among an international team that snapped the creation of cosmic dust around a dying star - which mimics conditions when our universe was formed.
Astronomers believe all planets and stars were created by swirling clouds of dust which solidified and paved the way for life.

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